الملخص
SUMMARY: Hypoxic preconditioning is known to induce neuroprotection, but its effects and pathways in chronic brain pathology still unknown. The aim was to establish an involvement of a7 subunit of nicotinic acetylcholine receptors (a7nAchRs), and sirtuins of 1 (SIRT1) and 3 (SIRT3) types in the effects of hypoxic hypobaric preconditioning on brain damage in mice with chronic cerebral hypoperfusion caused by the left common carotid artery occlusion. The male C57/6j (C57, wild type) and a7nAchRs(-/-) mice were divided to six experimental groups (10 mice per group): sham-operated C57, C57 with chronic cerebral hypoperfusion, C57 with hypoxic hypobaric preconditioning and chronic cerebral hypoperfusion, sham-operated a7nAchRs(-/-) mice, a7nAchRs(-/-) with chronic cerebral hypoperfusion, a7nAchRs(-/-) with hypoxic hypobaric preconditioning and chronic cerebral hypoperfusion. For preconditioning, mice were exposed to hypoxia by "lifting" in barochamber to simulated altitude of 5600 m a.s.l. for 1 h/day on 3 consecutive days before surgical manipulation. Expressions of SIRT1, SIRT3 in brain tissue, and histopathological changes of the hippocampi were examined. It was shown that 8-week chronic hypoperfusion of the brain, caused by unilateral occlusion of the common carotid artery, was accompanied by injury to the neurons of the hippocampi of both hemispheres, which was more pronounced on the side of the occlusion. This damage, as well as the mechanisms of neuroprotection induced by hypoxic preconditioning, were maintained for at least 8 weeks by mechanisms mediated through a7nAChRs. Deficite of a7nAChRs was accompanied with reduction of neuronal damage caused CCH in 8 weeks, as well as preconditioning effects, and lead to compensatory activation of regulatory and protective mechanisms mediated by SIRT1, in normal conditions and in CCH. In wild-type (C57) mice, protective mechanisms in CCH were realized to a greater extent by increased expression of SIRT3 in both hemispheres of the brain.
Se sabe que el precondicionamiento hipóxico induce neuroprotección, pero aún se desconocen sus efectos y vías en la patología cerebral crónica. El objetivo fue establecer la participación de la subunidad a7 de los receptores nicotínicos de acetilcolina (a7nAchR) y las sirtuinas de tipo 1 (SIRT1) y 3 (SIRT3) en los efectos del precondicionamiento hipóxico hipobárico sobre el daño cerebral en ratones con hipoperfusión cerebral crónica causada por la oclusión de la arteria carótida común izquierda. Los ratones macho C57/6j (C57, tipo salvaje) y a7nAchRs(-/-) se dividieron en seis grupos experimentales (10 ratones por grupo): C57 con operación simulada, C57 con hipoperfusión cerebral crónica, C57 con precondicionamiento hipobárico hipóxico y crónica. hipoperfusión cerebral, ratones a7nAchRs(-/-) operados de forma simulada, a7nAchRs(-/-) con hipoperfusión cerebral crónica, a7nAchRs(-/-) con precondicionamiento hipobárico hipóxico e hipoperfusión cerebral crónica. Para el preacondicionamiento, los ratones fueron expuestos a hipoxia "levantándolos" en una cámara de barro a una altitud simulada de 5600 m s.n.m. durante 1 h/día durante 3 días consecutivos antes de la manipulación quirúrgica. Se examinaron las expresiones de SIRT1, SIRT3 en tejido cerebral y los cambios histopatológicos de los hipocampos. Se demostró que la hipoperfusión cerebral crónica de 8 semanas, causada por la oclusión unilateral de la arteria carótida común, se acompañaba de lesión de las neuronas del hipocampo de ambos hemisferios y que era más pronunciada en el lado de la oclusión. Este daño, así como los mecanismos de neuroprotección inducidos por el precondicionamiento hipóxico, se mantuvieron durante al menos 8 semanas mediante mecanismos mediados por a7nAChR. El déficit de a7nAChR se acompañó de una reducción del daño neuronal causado por CCH en 8 semanas, así como de efectos de precondicionamiento, y condujo a una activación compensatoria de mecanismos reguladores y protectores mediados por SIRT1, en condiciones normales y en CCH. En ratones de tipo salvaje (C57), los mecanismos de protección en CCH se realizaron en mayor medida mediante una mayor expresión de SIRT3 en ambos hemisfe- rios del cerebro.
الموضوعات
Animals , Mice , Brain Ischemia , Sirtuin 1/metabolism , Sirtuin 3/metabolism , alpha7 Nicotinic Acetylcholine Receptor/metabolism , Hypoxia , Cerebrovascular Circulation , Blotting, Western , Carotid Stenosisالملخص
Acute respiratory distress syndrome (ARDS) is a critical, life-threatening condition marked by severe inflammation and impaired lung function. Mesenchymal stromal/stem cells (MSCs) present a promising therapeutic avenue due to their immunomodulatory, anti-inflammatory, and regenerative capabilities. This review comprehensively evaluates MSC-based strategies for ARDS treatment, including direct administration, tissue engineering, extracellular vesicles (EVs), nanoparticles, natural products, artificial intelligence (AI), gene modification, and MSC preconditioning. Direct MSC administration has demonstrated therapeutic potential but necessitates optimization to overcome challenges related to effective cell delivery, homing, and integration into damaged lung tissue. Tissue engineering methods, such as 3D-printed scaffolds and MSC sheets, enhance MSC survival and functionality within lung tissue. EVs and MSC-derived nanoparticles offer scalable and safer alternatives to cell-based therapies. Likewise, natural products and bioactive compounds derived from plants can augment MSC function and resilience, offering complementary strategies to enhance therapeutic outcomes. In addition, AI technologies could aid in optimizing MSC delivery and dosing, and gene editing tools like CRISPR/Cas9 allow precise modification of MSCs to enhance their therapeutic properties and target specific ARDS mechanisms. Preconditioning MSCs with hypoxia, growth factors, or pharmacological agents further enhances their therapeutic potential. While MSC therapies hold significant promise for ARDS, extensive research and clinical trials are essential to determine optimal protocols and ensure long-term safety and effectiveness.
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BACKGROUND:Exercise is an effective strategy to prevent and treat various cardiovascular diseases and protect the heart from ischemia-reperfusion injury.Its mechanism of action needs to be studied in depth. OBJECTIVE:To observe the effect of aerobic exercise preconditioning on myocardial ischemia-reperfusion injury and to explore the effect of endothelial nitric oxide synthase(eNOS)activation(including coupling and phosphorylation). METHODS:Eighty adult Wistar rats were randomly divided into sedentary(n=40)and exercise(n=40)groups.The rats in the exercise group were subjected to aerobic exercise for 8 weeks while those in the sedentary group were quietly fed and caged.After 8 weeks of intervention,three experiments were performed.(1)Experiment 1:After the last training,cardiac function,cardiac nitric oxide metabolite content and cardiac eNOS,phosphorylated eNOS-S1177,eNOS dimer and eNOS monomer protein expression levels were detected.(2)Experiment 2:Rats were divided into sedentary control group,exercise control group,sedentary+eNOS inhibitor group,exercise+eNOS inhibitor group,all of which were subjected to an in vitro myocardial ischemia-reperfusion injury experiment.eNOS inhibitor was continuously infused into the sedentary+eNOS inhibitor group and exercise+eNOS inhibitor group 10 minutes before reperfusion,and cardiac function and myocardial infarction area were detected 3 hours after reperfusion.(3)Experiment 3:Rats were divided into sedentary control group,exercise control group,sedentary+eNOS coupler group and exercise+eNOS coupler group,all of which were subjected to an in vitro myocardial ischemia-reperfusion injury experiment.The rats in the sedentary+eNOS coupler group and exercise+eNOS coupler group were treated with eNOS coupler.Myocardial infarct area,cardiac nitric oxide metabolite content,cardiac protein expression of eNOS,phosphorylated eNOS-S1177,eNOS dimer,eNOS monomer and 3-nitrotyrosine were detected 3 hours after reperfusion.The phosphorylated eNOS-S1177/eNOS ratio reflected the phosphorylated/dephosphorylated level of eNOS and eNOS dimer/monomer ratio reflected eNOS coupling/uncoupling level. RESULTS AND CONCLUSION:Experiment 1:Compared with the sedentary group,the exercise group had increased cardiac output and left ventricular ejection fraction(P<0.05),increased nitrite and S-nitrosothiol contents(P<0.05),upregulated phosphorylated eNOS-S1177,eNOS protein expression and phosphorylated eNOS-S1177/eNOS ratio(P<0.05),eNOS dimer protein expression and eNOS dimer/monomer ratios were elevated(P<0.05).Experiment 2:Compared with the sedentary control group,left ventricular development pressure increased(P<0.05)and myocardial infarct area decreased(P<0.05)in the exercise control group.Compared with the exercise control group,left ventricular development pressure decreased(P<0.05)and myocardial infarct area increased(P<0.05)in the exercise+eNOS inhibitor group.Experiment 3:Compared with the sedentary control group,the exercise control group had increased left ventricular developmental pressure(P<0.05),decreased myocardial infarct area(P<0.05),decreased phosphorylated eNOS-S1177/eNOS ratio(P<0.05),decreased eNOS dimer/monomer ratio(P<0.05),increased S-nitrosothiol content(P<0.05),and decreased 3-nitrotyrosine protein expression(P<0.05).Compared with the exercise control group,the exercise+eNOS coupler group had decreased left ventricular developmental pressure(P<0.05),increased myocardial infarct area(P<0.05),increased phosphorylated eNOS-S1177/eNOS ratio(P<0.05),increased eNOS dimer/monomer ratio(P<0.05),and elevated 3-nitro tyrosine protein expression(P<0.05).To conclude,aerobic exercise preconditioning could induce cardioprotection,which is related to uncoupling and dephosphorylation of eNOS during cardiac ischemia-reperfusion,thereby inhibiting the excessive production of nitric oxide and reducing nitro-oxidative stress.
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BACKGROUND:Existing studies have confirmed that exosomes can effectively promote pulp regeneration.However,the biological functions and properties of exosomes from preconditioned sources can be significantly changed,which have different effects on cell proliferation,migration and odontogenic differentiation. OBJECTIVE:To discuss the application status of exosomes and their preconditioning methods in the field of pulp regeneration,and summarize the preconditioning methods that affect the function of exosomes,and explore the effect of exosomes and their preconditioning on pulp regeneration. METHODS:The relevant articles were searched in WanFang,CNKI,PubMed,and Web of Science databases from 2006 to 2022.The Chinese and English search terms were"exosomes,pulp regeneration;preconditioning method".A total of 78 articles were included for analysis. RESULTS AND CONCLUSION:(1)Exosomes have the advantages of good biocompatibility,low immunogenicity and no cytotoxicity,and can induce the regeneration of pulp tissue by promoting stem cell tooth formation,neurogenesis and vascularization.(2)Exosomes derived from preconditioning can enhance the ability of tissue repair and regeneration and have a significant impact on the quality of regenerated dental pulp.(3)Currently,the preconditioning methods used in the field of dental pulp regeneration include inflammatory stimulation,hypoxia induction,conditioned medium and three-dimensional culture,and secreted exosomes can effectively improve the quality of regenerated dental pulp.Nevertheless,the specific effect and mechanism of different preconditioning methods on pulp regeneration need to be explored.
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BACKGROUND:Stem cell therapy is an alternative treatment strategy for restoring damaged myocardial tissue after acute myocardial infarction.Exercise preconditioning can induce endogenous cardioprotective effects in the body.However,the efficacy and mechanism of the combined application are still unclear. OBJECTIVE:To explore the effect and possible mechanism of exercise preconditioning combined with bone marrow mesenchymal stem cells on the therapeutic effect in rats with acute myocardial infarction. METHODS:Seventy male SD rats were randomly divided into sham operation group,model group,stem cell therapy group,exercise preconditioning group,and combined intervention group.Rats in the exercise preconditioning group and combined intervention group underwent 8-week aerobic exercise on the treadmill before modeling.The animal model of acute myocardial infarction was made by ligating the anterior descending coronary artery.The stem cell therapy group and the combined intervention group were injected with bone marrow mesenchymal stem cells(1×109 L-1,1 mL)through the tail vein the next day after modeling.After 4 weeks of treatment,the exercise performance was evaluated by a graded treadmill exercise test.The cardiac structure and function were detected by echocardiography.The left ventricle was isolated.2,3,5-Triphenyltetrazolium chloride staining was used to evaluate myocardial infarct size.Masson staining was used to obtain collagen volume fraction.CD31 immunohistochemical staining was used to detect myocardial capillary density.TUNEL staining was used to detect myocardial cell apoptosis.Immunoblotting was used to detect protein expression levels of stromal cell-derived factor 1,CXC chemokine receptor protein 4,tumor necrosis factor-α,interleukin-10,and vascular endothelial growth factor. RESULTS AND CONCLUSION:(1)Intervention efficacy:Compared with the sham operation group,exercise performance,left ventricular ejection fraction,left ventricular fractional shortening,and CD31 positive cell rate decreased(P<0.05);myocardial infarct size,collagen volume fraction,and myocardial apoptotic rate increased(P<0.05)in the model group.Compared with the model group,exercise performance was not statistically significant(P>0.05)in the stem cell therapy group,and the exercise performance improved(P<0.05)in the exercise preconditioning and combined intervention groups;left ventricular ejection fraction,left ventricular fractional shortening,and CD31 positive cell rate increased(P<0.05),and the myocardial infarct size,collagen volume fraction,and cardiomyocyte apoptosis rate decreased(P<0.05)in the stem cell therapy,exercise preconditioning,and combined intervention groups.Compared with the stem cell therapy group,exercise performance,left ventricular ejection fraction,left ventricular shortening fraction,and CD31 positive cell rate increased(P<0.05),myocardial infarct size,collagen volume fraction,and myocardial cell apoptosis rate decreased(P<0.05)in the combined intervention group.(2)Protein expression:Compared with the sham operation group,the expression of tumor necrosis factor-α increased(P<0.05),while interleukin-10 and vascular endothelial growth factor expression decreased(P<0.05)in the model group.Compared with the model group,the expression of CXC chemokine receptor protein 4 increased(P<0.05)in the stem cell therapy group and combined intervention group,and the expression of tumor necrosis factor-α decreased(P<0.05)while interleukin-10 and vascular endothelial growth factor increased(P<0.05)in the stem cell therapy group,exercise preconditioning group,and combined intervention group.Compared with the stem cell therapy group,the expression of tumor necrosis factor-α decreased(P<0.05),while CXC chemokine receptor protein 4,interleukin-10,and vascular endothelial growth factor increased(P<0.05)in the combined intervention group.To conclude,exercise preconditioning can enhance the therapeutic effect of bone marrow mesenchymal stem cells in rats with acute myocardial infarction,which can inhibit cardiac remodeling,improve cardiac function,and delay the progress of heart failure.Its mechanism is related to the promotion of stem cell homing,inhibition of inflammatory response,and promotion of angiogenesis.
الملخص
BACKGROUND:Exercise training is an important non-drug rehabilitation method for many heart diseases,and it can also enhance the heart's tolerance to adverse stressors(such as myocardial ischemia),that is,exercise preconditioning.Granulocyte colony-stimulating factor can effectively mobilize stem cell homing and differentiation and promote the repair of damaged myocardium.However,the effect of the combination of the two treatments is not yet clear. OBJECTIVE:To explore the effect of granulocyte colony-stimulating factor supplementation combined with high-intensity intermittent exercise preconditioning on cardiac remodeling in rats with acute myocardial infarction and investigate its possible mechanism. METHODS:Totally 58 male Wistar rats were divided into sham group(n=10),model group(n=12),model drug group(n=12),model exercise group(n=12)and model combined treatment group(n=12).The myocardial infarction rat model was made by coronary artery ligation.The model exercise group and the model combined treatment group were pretreated with 8 weeks of high-intensity intermittent exercise on an electric treadmill before modeling.The model drug group and the model combined treatment group were subcutaneously injected with human recombinant granulocyte colony-stimulating factor 3 hours after modeling for 5 days(10 μg/kg per day).At 8 weeks after administration,echocardiography was used to detect heart structure and function;heart was stained with 2,3,5-triphenyltetrazolium chloride and Masson staining to obtain myocardial infarct area and collagen volume fraction,respectively.Vessel density and cell apoptosis rate were detected by immunofluorescence.Real-time fluorescent quantitative PCR was utilized to detect the mRNA expression of embryonic genes(brain natriuretic peptide,β-myosin heavy chain)and myocardial contraction regulatory factors(α-myosin heavy chain,sarcoplasmic reticulum Ca2+-ATPase).Western blot assay was used to detect the protein expression of cardiac stromal cell-derived factor 1,CXC chemokine receptor protein 4,Janus kinase 2(JAK2),signal transducer and activator of transcription 3(STAT3),Bcl2,Bax,and cleaved caspase-3. RESULTS AND CONCLUSION:(1)Compared with sham group,myocardial infarct size,collagen volume fraction,and apoptosis rate increased(P<0.05);vessel density,left ventricular fractional shortening,and left ventricular ejection fraction decreased(P<0.05);brain natriuretic peptide and β-myosin heavy chain mRNA increased(P<0.05),α-myosin heavy chain and sarcoplasmic reticulum Ca2+-ATPase mRNA and α-myosin heavy chain/β-myosin heavy chain ratio decreased(P<0.05);stromal cell-derived factor 1,CXC chemokine receptor protein 4,Bax,cleaved caspase-3 protein expression increased(P<0.05);p-JAK2,p-STAT3,and Bcl-2 protein expression decreased(P<0.05)in the model group.(2)Compared with the model group,the above indexes in the model drug and model exercise groups were significantly improved(P<0.05).Compared with the model drug and model exercise groups,the above parameters were further ameliorated(P<0.05)in the model combined treatment group.(3)The results showed that supplementation of granulocyte colony-stimulating factor or high-intensity intermittent exercise preconditioning alone can improve cardiac remodeling in rats with acute myocardial infarction,and the combined therapy has a better effect,which may be related to the induction of stem cell homing and the activation of JAK2/STAT3 signaling pathway to inhibit cardiomyocyte apoptosis.
الملخص
Objective:To observe any effect of exercise preconditioning on the levels of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in the brain tissue of rats after induced cerebral ischemia and reperfusion, and how it might promote angiogenesis.Methods:Thirty-six male Sprague-Dawley rats were randomly divided into a sham-operation group, a model group and an exercise preconditioning group, each of 12. After adaptive running training for 3 days, the exercise preconditioning group ran daily for 30 minutes at 15m/min for 14 days, while the other two groups did not exercise. Middle cerebral artery occlusion and reperfusion were then induced in the model and exercise preconditioning groups using the modified Zea-Longa suture method. Rats in the sham-operation group were only cut open to expose the right carotid artery. Right after the modeling, and again 24 hours later neurological deficit was evaluated using the Zea-Longa score and modified neurological severity scoring (mNSS). Infarct sizes were measured using 2, 3, 5-triphenyl tetrazolium chloride staining. Any morphological changes were noted using hematoxylin and eosin (HE) staining, and the expression of CD31 protein, hypoxia-inducible factor-1α and vascular endothelial growth factor in the ischemic cerebral cortex were quantified immunohistochemically.Results:Right after the modelling, compared with the sham-operation group, the average Zea-Longa scores of the model and exercise groups had increased significantly, but were not significantly different from each other. Twenty-four hours later the average Zea-Longa score, mNSS score and relative cerebral infarction area of the model group had increased significantly compared with the sham-operation group, while the exercise preconditioning group′s averages had decreased significantly. The HE staining showed that compared with the sham-operation group, pathological changes such as loose tissue, reduced number of nerve cells, nucleolysis, and vacuolization of the cerebral cortex on the ischemic side were found in the model group. Compared with the model group, the pathological changes in the exercise preconditioning group were less serious. The levels of CD31 protein, HIF-1α and VEGF in the ischemic cerebral cortexes of the model group had by then increased significantly. But compared with the model group, those levels had increased more in the exercise preconditioning group.Conclusion:Exercise preconditioning can effectively promote angiogenesis after cerebral ischemia and reduce chronic injury. That may be related to the activation of the HIF-1α and/or VEGF signaling pathways.
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Hydration status refers to the balance between the intake and discharge of water in the body. When the ingested and discharged water are roughly equal and the body is in water balance, it is the normal hydration status, and when the water intake is too little or too much, it is the "dehydration" or "overhydration status". The hydration status of the body not only affects metabolism, but also affects the functions of the urinary system, cardiovascular system, nervous system, etc. In order to further clarify the relationship between body hydration status and decompression sickness (DCS), this paper reviewed relevant studies and analyzed the interaction between hydration and decompression safety during diving. The primary causes of dehydration in diving are "hyperbaric diuresis", "immersion diuresis", breathing dry gas, heat, and cold. Dehydration not only promotes the occurrence of DCS but also reduces the aerobic work efficiency and athletic performance of divers, as well as affects cognition and mood. A study found that appropriate rehydration before and during diving can reduce the risk of DCS, which possibly associates with the increase of blood volume, plasma surface tension, and vasoconstriction. Fluid therapy is also important for those who already have DCS. This paper analyzed the amount, nature, timing, and effect of rehydration involved in the above links, comprehensively sorted out the relationship between hydration and diving safety, summarized the existing problems, and provided reference for practical application and future research.
الملخص
Objective:To explore the effects of different duration of exercise preconditioning on changes in cerebral blood flow and microglia activation related proteins in rats with vascular dementia. Method:Sixty SPF SD male rats were used to prepare vascular dementia rat models by permanent ligation of bilateral common carotid arteries.They were randomly divided into the model group,sham-operated group,ex-ercise preconditioning 4-week model group,exercise preconditioning 4-week sham-operated group,exercise pre-conditioning 2-week model group and exercise preconditioning 2-week sham-operated group,with 10 rats in each group.The exercise preconditioning 4-week rats received 30 minutes of moderate intensity non-weight-bear-ing swimming training 5 times a week for 4 weeks before modeling,while the exercise preconditioning 2-week rats received the same training for 2 weeks.Morris water maze was used to detect the spatial learning and memory ability of rats,laser speckle imaging technique was used to observe the changes of cerebral blood flow and the opening of collateral circulation of rats at different time point before and after the model-ing,and Western Blotting was used to detect the expression of TLR4 and Iba 1 protein in hippocampus. Result:Compared with the sham-operated group and the exercise preconditioning 2-week sham-operated group,the average escape latency time of rats in the exercise preconditioning 4-week sham-operated group,the model group,the exercise preconditioning 4-week model group and the exercise preconditioning 2-week model group was significantly prolonged(P＜0.05).Compared with the exercise preconditioning 4-week sham-operated group,the average escape latency time of rats in the model group and the exercise preconditioning 4-week model group was significantly prolonged(P＜0.05).Compared with the model group and exercise preconditioning 4-week model group,the average escape latency time of rats in exercise preconditioning 2-week model group was significantly decreased(P＜0.05).The simple effect of repetitive measurement deviation analysis suggested that the average cerebral blood flow before modeling,2h after modeling,3d after modeling and 7d after model-ing was statistically significant between the groups(P＜0.05).The simple effect of time factor on average cere-bral blood flow of the model group,the exercise preconditioning 4-week model group and the exercise precon-ditioning 2-week model group was statistically significant(P＜0.01).The opening of collateral circulation of rats in each group was observed.Compared with the model group,less reduction in microvessel diameter was ob-served in the exercise preconditioning 2-week model group(P＜0.05).Compared with the sham-operated group,the exercise preconditioning 4-week sham-operated group and the exercise preconditioning 2-week sham-operat-ed group,Ibal and TLR4 protein expressions in the model group were significantly increased(P＜0.01).Com-pared with the model group,Ibal and TLR4 protein expressions in the exercise preconditioning 2-week model group were decreased(P＜0.05). Conclusion:Moderate intensity exercise preconditioning for 2 weeks can improve the learning and memory abili-ty of vascular dementia rats,but exercise preconditioning for 4 weeks has no obvious effect on the improve-ment of learning and memory ability.The mechanism may be related to the improvement of cerebral blood flow status and the inhibition of microglia activation.
الملخص
Objective:To investigate the effect of exercise preconditioning on angiogenesis in ischemic brain tissue in rats with cerebral ischemia-reperfusion injury in the view of VEGF/VEGFR2/dock6 signaling pathway. Method:SD male rats were divided into sham group,model group and exercise preconditioning group by ran-dom number table method,with 18 rats in each group.The sham operation group and the model group were not given any treatment,while the exercise preconditioning group was given adaptive running training for 3 days at a speed of 10 m/min,once a day for 20 minutes each time.After the adaptive training,the exercise preconditioning group was given formal running training for 3 weeks,continuous training for 6 days a week,rest for 1 day,electric treadmill slope of 0°,speed of 15m/min,30min/d.Model group and exercise precondi-tioning group were modified to prepare the middle cerebal artery occlusion(MACO)models by Koizumi thread method,while sham operation group only given skin cutting without thread insertion.Zea longa score and modi-fied neurological severity score(mNSS)were used to score neurological deficit in rats,the relative infarct size of the brain was detected by TTC staining,the morphological changes of the ischemic cerebral cortex was ob-served by HE staining,the expression of CD31 in ischemic cerebral cortex was detected by immunohistochemis-try and the expressions of VEGFA,VEGFR2,Dock6 in ischemic cerebral cortex were detected by western blot. Result:①Zea-Longa scoring:after awaking from anesthetizati,compared with the sham group,the Zea-Longa scores of the other two groups were increased(P＜0.01),and there was no statistical significance in the Zea-Lon-ga scores between the two groups.At 72 hours after reperfusion,compared with the sham group,the Zea-Longa score of the rats in the model group was significantly increased(P＜0.01);compared with the model group,the Zea-Longa score of the rats in the exercise preconditioning group was significantly decreased(P＜0.05).②mNSS scoring:At 72 hours after reperfusion,compared with the sham group,the mNSS score of the rats in the mod-el group was significantly increased(P＜0.01);compared with the model group,the mNSS score of the rats in the exercise preconditioning group was significantly decreased(P＜0.05).③TTC staining:Compared with the sham group,the cerebral infarction volume in the model group was increased(P＜0.01),and compared with the mod-el group,the cerebral infarction volume in the exercise preconditioning group was decreased(P＜0.05).④ HE staining:Compared with the sham group,the model group rats appeared significant pathological changes in the cerebral cortex on the ischemic side.Compared with the model group,the pathological changes of the cerebral cortex on the ischemic side of the rats in the exercise preconditioning group were alleviated.⑤ Immunohisto-chemistry of CD31:Compared with the sham group,the expression of CD31 in the ischemic cerebral cortex of the model group was significantly increased(P＜0.05).The expression of CD31 in the ischemic cerebral cortex of the exercise preconditioning group was further increased(P＜0.05).⑥Western blot of VEGF,VEGFR2 and Dock6:Compared with the sham group,the expressions of VEGF(P＜0.05),VEGFR2(P＜0.05)and Dock6(P＜0.01)in the ischemic cerebral cortex of the model group were significantly increased;compared with the model group,the expressions of VEGF(P＜0.05),VEGFR2(P＜0.05)and Dock6(P＜0.01)in the ischemic cerebral cor-tex of the exercise preconditioning group were further increased. Conclusion:Exercise preconditioning can effectively promote angiogenesis after cerebral ischemia and reduce cerebral ischemia-reperfusion injury,which may be related to the activation of VEGF/VEGFR2/Dock6 signaling pathway.
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Objective:To investigate the role of HMGB1-TLR4-NF-κB signaling pathway in cerebral ischemia-reperfusion in-jury and the effect of adenosine preconditioning on the signaling pathway.Methods:Total 80 adult male Sprague-Dawley rats weighing 220～270 g were selected from the Animal Center of Xinxiang Medical University.The rats were randomly divided into F group(sham operation group),I/R group(ischemia reperfusion group)and AP group(adenosine preconditioning group).The MCAO model of rats was established by wire embolization.Quantitative analysis of neural function in successfully modeled rats using animal behavior scor-ing method,the morphological changes of brain cells were observed by HE staining,TTC staining was used to observe cerebral infarc-tion and cerebral infarction volume was calculated;Immunohistochemical staining was used to detect HMGB1,TLR4 and NF-κB pro-tein expression levels in brain tissues of each group.The data were statistically analyzed by one-way ANOVA in SPSS26.0 software.Results:After ischemia reperfusion,the neurological function of I/R group and AP group showed different degrees of impairment,and the neurological function scores of the two groups were significantly higher than that of F group,the difference was statistically signifi-cant(P<0.05),and the neurological function of the AP group was significantly less than that of I/R group,the difference was also sta-tistically significant(P<0.05).TTC staining showed that AP group,I/R group rat cerebral infarction volume was significantly more than F group[(93.670±4.509)mm3,(123.670±7.234)mm3 vs(0.000±0.000)mm3],and AP group rats infarction volume was signifi-cantly reduced than that in I/R group,the difference had statistical significance(P<0.05).Immunohistochemistry showed that HMGB1,TLR4,NF-κB protein in F group with a small amount of expressions in rats,while significantly expressed in AP group and I/R group relatively,and the AP group of each subgroup rat HMGB1,TLR4,NF-κB protein expressions significantly lower than the amount of I/R group,the difference had statistical significance(P<0.05).Conclusion:Adenosine preconditioning can reduce the expressions of HMGB1,TLR4 and NF-κB protein,and then protect the rats with cerebral ischemia-reperfusion injury.
الملخص
El precondicionamiento isquémico remoto es una manera eficaz de disminuir el daño por isquemia y reperfusión en el corazón y otros órganos como cerebro o riñón, en modelos experimentales. Este consiste en realizar entre 3 y 5 ciclos de 5 minutos de isquemia seguidos del mismo tiempo de reperfusión, en un tejido alejado del que se quiere proteger, normalmente una extremidad. Estudios preclínicos en animales indican que la isquemia precondicionante inicia señales nerviosas y humorales en el tejido isquémico remoto, que en el corazón activan mecanismos de protección. La señal nerviosa se origina en fibras sensoriales que a nivel cerebral producen una activación del sistema parasimpático. El nervio vago activa ganglios cardíacos intrínsecos del corazón lo que induce protección. Además, desde el tejido isquémico se liberan a la circulación diferentes mediadores que viajan en forma libre o en vesículas lipídicas (exosomas) que inician vías de señalización protectoras en el corazón. A pesar del éxito del precondicionamiento isquémico remoto en animales de experimentación, su aplicación en seres humanos no ha tenido resultados claros. Esta discrepancia puede deberse a una diversidad de factores tales como la edad, la existencia de otras patologías, uso de fármacos u otros tratamientos que afectan la respuesta de los pacientes. Se requiere un mayor conocimiento de las bases moleculares de este mecanismo de protección para que su aplicación en clínica sea exitosa.
In experimental models, remote ischemic preconditioning effectively decreases ischemia reperfusion injury to the heart and other organs such as the brain or kidney. It consists of 3 to 5 cycles of 5 minutes of ischemia followed by 5 minutes of reperfusion, in a remote tissue, usually a limb. Preclinical studies in animals indicate that preconditioning ischemia initiates neural and humoral signals in the remote ischemic tissue, which activate protective mechanisms in the heart. The nervous signal originates in sensory fibers that activate the parasympathetic system in the brain. The vagus nerve activates the intrinsic cardiac ganglia of the heart, leading to protection from ischemic injury. Furthermore, mediators are released from the ischemic tissue into the circulation that travels freely or in lipid vesicles (exosomes) to the heart where they initiate protective signaling pathways. Despite the success of remote ischemic preconditioning in experimental animals, its application in humans has not produced clear results. This discrepancy may be due to a variety of factors such as age, the existence of other pathologic processes, or the use of drugs or other treatments that affect the patient´s response. An increased knowledge of the molecular bases of this protective mechanism is required for its clinical application to be successful.
الموضوعات
Humans , Reperfusion Injury/therapy , Ischemic Preconditioning/methods , Ischemic Preconditioning, Myocardial/methodsالملخص
Abstract Astrocytes are the most abundant cell subtypes in the central nervous system. Previous studies believed that astrocytes are supporting cells in the brain, which only provide nutrients for neurons. However, recent studies have found that astrocytes have more crucial and complex functions in the brain, such as neurogenesis, phagocytosis, and ischemic tolerance. After an ischemic stroke, the activated astrocytes can exert neuroprotective or neurotoxic effects through a variety of pathways. In this review, we will discuss the neuroprotective mechanisms of astrocytes in cerebral ischemia, and mainly focus on reactive astrocytosis or glial scar, neurogenesis, phagocytosis, and cerebral ischemic tolerance, for providing new strategies for the clinical treatment of stroke.
Resumo Os astrócitos são os subtipos de células mais abundantes no sistema nervoso central. Estudos anteriores acreditavam que os astrócitos são células de suporte no cérebro, que apenas fornecem nutrientes para os neurônios. No entanto, estudos recentes descobriram que os astrócitos têm funções mais cruciais e complexas no cérebro, como neurogênese, fagocitose e tolerância isquêmica. Após um acidente vascular cerebral isquêmico, os astrócitos ativados podem exercer efeitos neuroprotetores ou neurotóxicos através de uma variedade de vias. Nesta revisão, discutiremos os mecanismos neuroprotetores dos astrócitos na isquemia cerebral, e focaremos principalmente na astrocitose reativa ou cicatriz glial, neurogênese, fagocitose e tolerância isquêmica cerebral, para fornecer novas estratégias para o tratamento clínico do acidente vascular cerebral.
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Ischemic preconditioning (IPC) is a potential intervention known to protect the heart against ischemia/reperfusion injury, but its role in the no-reflow phenomenon that follows reperfusion is unclear. Dihydrotanshinone I (DT) is a natural compound and this study illustrates its role in cardiac ischemic injury from the aspect of IPC. Pretreatment with DT induced modest ROS production and protected cardiomyocytes against oxygen and glucose deprivation (OGD), but the protection was prevented by a ROS scavenger. In addition, DT administration protected the heart against isoprenaline challenge. Mechanistically, PKM2 reacted to transient ROS via oxidization at Cys423/Cys424, leading to glutathionylation and nuclear translocation in dimer form. In the nucleus, PKM2 served as a co-factor to promote HIF-1α-dependent gene induction, contributing to adaptive responses. In mice subjected to permanent coronary ligation, cardiac-specific knockdown of Pkm2 blocked DT-mediated preconditioning protection, which was rescued by overexpression of wild-type Pkm2, rather than Cys423/424-mutated Pkm2. In conclusion, PKM2 is sensitive to oxidation, and subsequent glutathionylation promotes its nuclear translocation. Although IPC has been viewed as a protective means against reperfusion injury, our study reveals its potential role in protection of the heart from no-reflow ischemia.
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Objective To investigate the application effect of remote ischemic preconditioning (RIPC) combined with controlled low central venous pressure (CLCVP) in hepatectomy. Methods A total of 80 patients who underwent elective partial hepatectomy in Yougchuan Hospital Affiliated to Chongqing Medical University from May 2021 to April 2022 were enrolled and divided into control group (group C), CLCVP group (group L), RIPC group (group R), and RIPC+CLCVP group (group RL) using a random number table, with 20 patients in each group. The patients in group L received CLCVP, those in group R received RIPC, and those in group RL received both CLCVP and RIPC. The patients were compared in terms of perioperative general status and the levels of tumor necrosis factor-α (TNFα), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin on preoperative day 1(D0), postoperative day 1(D1), postoperative day 3(D3), postoperative day 5(D5), and postoperative day 7(D7). A one-way analysis of variance or a repeated measures analysis of variance was used for comparison of normally distributed continuous data between groups, and the Kruskal-Wallis H test was used for comparison of continuous data with skewed distribution between groups; the chi-square test was used for comparison of categorical data. Results Compared with group R, group RL had a significantly shorter time of operation ( H =14.278, P =0.015), a significantly lower total infusion volume ( H =24.175, P =0.001), and a significantly lower estimated blood loss ( H =45.625, P < 0.001). Group and time factors had significant interaction effects on TNFα, ALT, and AST in the four groups ( P < 0.001; P =0.010; P =0.012). Group RL had a significantly lower level of TNFα than group L on D1( P < 0.001) and D3( P < 0.001). Group RL had a significantly lower level of ALT than group L on D1( P =0.008) and D7( P < 0.001). Conclusion For patients undergoing hepatectomy, RIPC combined with CLCVP can effectively reduce intraoperative blood loss, provide a clear surgical field, and shorten the time of operation; meanwhile, it can also inhibit inflammatory response by reducing TNFα, but it cannot effectively alleviate hepatic ischemia-reperfusion injury after hepatectomy under the context of CLCVP.
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@#Objective To investigate the effect of simvastatin and mechanical pretreatment on intimal hyperplasia of venous graft and its mechanism. Methods Twelve New Zealand rabbits were selected and randomly divided into 4 groups: a blank control group, a simvastatin topical treatment group, a mechanical precondition group and a combined group (n=3 in each group). Ultrasound was used to evaluate the changes of graft wall and blood flow velocity in the graft, and pathological section was used to evaluate the intimal hyperplasia. Human umbilical cord endodermal cells were cultured in vitro. A simvastatin group and a solvent control group were set to detect YAP phosphorylation, downstream target gene expression and cell proliferation. Results Vascular ultrasound showed that except the simvastatin topical treatment group, the flow velocity in vein grafts in the other three groups significantly increased 21 days after surgery compared with 7 days after surgery (P<0.01). Pathological sections showed that the thickness of new intima in the simvastatin topical treatment group, mechanical precondition group, combined group and blank control group were 45.56±4.11 μm, 201.28±16.71 μm, 143.57±7.82 μm, 249.45±13.33 μm, respectively, and there were statistical differences compared with the blank control group (P<0.05). In vitro results showed that compared with the solvent control group, cell death was observed in high concentration simvastatin (5 mmol/L) group, cell proliferation was inhibited in low concentration simvastatin (2.5 mmol/L) group (P<0.05), the expression of YAP protein in the simvastatin group was unchanged, but the expression of phosphorylated YAP protein significantly increased (P<0.05), and the expression of downstream target gene ccn1 was down-regulated (P<0.001). Conclusion Intravascular local application of simvastatin and mechanical preconditioning alone or in combination can inhibit intimal hyperplasia of venous graft. High concentration of simvastatin has cytotoxicity, while low concentration of simvastatin has inhibitory effect on cell proliferation. Simvastatin can inhibit the formation of new intima by inhibiting the entry of YAP into the nucleus and reducing the transcription of cell proliferation-related target gene ccn1.
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Objective:To evaluate the role of autophagy in morphine preconditioning-induced reduction of oxygen-glucose deprivation and restoration (OGD/R) injury in primary cortical neurons of mice and the relationship with c-Jun N-terminal kinase (JNK).Methods:Primary cortical neurons extracted from C57BL/6 neonatal mice within 24 h after birth were divided into 9 groups ( n=24 each) using a random number table method: control group (C group), OGD/R group, morphine preconditioning group (M group), autophagy inhibitor 3-methyladenine (3-MA) group (3-MA group), 3-MA+ morphine preconditioning group (3-MA+ M group), autophagy inhibitor chloroquine group (Ch group), chloroquine + morphine preconditioning group (Ch+ M group), JNK inhibitor SP600125 group (SP group) and SP600125 + morphine preconditioning group (SP+ M group). Morphine preconditioning: morphine was added at a final concentration of 3 μmol/L before OGD/R, and the cells were incubated for 2 h in OGD/R group. In 3-MA, Ch and SP groups, 3-MA 5 mmol/L, chloroquine 50 μmol/L and SP600125 25 μmol/L were added, respectively, and the cells were incubated for 150 min. In 3-MA+ M, Ch+ M and SP+ M groups, 3-MA 5 mmol/L, chloroquine 50 μmol/L and SP600125 25 μmol/L were added, respectively, at 30 min before morphine preconditioning. Then the cells were subjected to oxygen-glucose deprivation for 1 h followed by restoration of oxygen-glucose supply for 24 h. CCK-8 assay was used to detect the neuronal viability. The expression of JNK, phosphorylated JNK (p-JNK), microtubule-associated protein 1 light chain 3 (LC3), p62, Beclin1, caspase-3, and cleaved-caspase-3 was determined by Western blot. The autophagosomes and autolysosomes were counted using LC3-double fluorescent adenovirus transfection, and the neuronal apoptosis rate was determined by TUNEL staining. Results:Compared with C group, the neuronal viability was significantly decreased, the expression of Beclin1 was up-regulated, the expression of p62 was down-regulated, and the LC3Ⅱ/LC3Ⅰ ratio, p-JNK/JNK ratio, the number of autophagosomes and autolysosomes, cleaved-caspase-3/caspase-3 ratio and neuronal apoptosis rate were increased in OGD/R group ( P<0.001). Compared with OGD/R group, the neuronal viability, p-JNK/JNK ratio, LC3Ⅱ/LC3Ⅰ ratio and the number of autophagosomes and autolysosomes were significantly increased, the expression of Beclin1 was up-regulated, and the expression of p62 was down-regulated in M group, the LC3Ⅱ/LC3Ⅰ ratio was significantly decreased, and the expression of p62 was down-regulated in 3-MA group, the LC3Ⅱ/LC3Ⅰ ratio was significantly increased, and the expression of p62 was up-regulated in Ch group ( P<0.001), and no significant change was found in the parameters mentioned above in SP600125 group ( P>0.05). Compared with M group, the neuronal viability was significantly decreased, the LC3Ⅱ/LC3Ⅰ ratio was decreased, and the expression of p62 was up-regulated in M+ 3-MA group, the neuronal viability was significantly decreased, the LC3Ⅱ/LC3Ⅰ ratio was increased, and the expression of p62 was up-regulated in M+ Ch group, and the neuronal viability, LC3Ⅱ/LC3Ⅰ ratio and p-JNK/JNK ratio were significantly decreased, the expression of p62 was up-regulated, the number of autophagosomes and autolysosomes was decreased, the expression of Beclin1 was down-regulated, and the cleaved-caspase-3/caspase-3 ratio and neuronal apoptosis rate were increased in M+ SP group ( P<0.001). Conclusions:Morphine preconditioning can attenuate OGD/R injury by activating JNK, enhancing autophagy and inhibiting apoptosis in primary cortical neurons of mice.
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AIM: To explore whether free radicals participate in cerebral ischemic tolerance and the up-regula-tion of p38 MAPK and ERK signaling pathways in rats induced by limb ischemic preconditioning (LIP). METHODS: A total of 128 Wistar rats with permanent occlusion of bilateral vertebral arteries were randomly divided into sham group (n=16), cerebral ischemia (CI) group (n=16), LIP+CI group (n=16), DMTU (a free radical scavenger)+LIP+CI group (n=64) and DMTU+sham group (n=16). Six rats in each group were used to observe the delayed neuronal death (DND) in hippocampal CA1 region by thionin staining at 7 d after the end of operation. Other 10 rats in each group were used to de-tect the expression of p38 MAPK and ERK in hippocampal CA1 region by immunohistochemistry and Western blot. RE-SULTS: Lethal CI resulted in obvious DND in hippocampal CA1 region. However, LIP reversed the above injurious changes, represented by the decrease in histological grade and the increase in neuronal density compared with CI group (P<0. 01). Moreover, LIP significantly up-regulated the expression of p38 MAPK and ERK in hippocampal CA1 region com-pared with CI group (P<0. 01). Administration of free radical scavenger DMTU via femoral vein before LIP partially re-versed the neuroprotective effect of LIP, and blocked the up-regulation of p38 MAPK and ERK expression in hippocampal CA1 region in rats compared with LIP+CI group (P<0. 01). CONCLUSION: Free radicals are involved in the neuropro-tection and up-regulation of p38 MAPK and ERK expression induced by LIP in rats.
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Objective:To explore the possible mechanisms of remote ischemic preconditioning (RIPC) combined with melatonin (MT) against cerebral ischemia-reperfusion injury and to evaluate the value of multimodal MRI.Methods:From December 2021 to December 2022, fifty SPF-grade male SD rats were selected and divided into sham surgery group ( n=10), middle cerebral artery occlusion model group ( n=10), melatonin (MT) group ( n=10), remote ischemic preconditioning (RIPC) group ( n=10) and MT+RIPC group ( n=10). Neurological function scoring and multimodal MRI examinations, including T 2 fluid-attenuated inversion recovery (FLAIR) imaging, diffusion-weighted imaging (DWI), and arterial spin labeling (ASL) imaging, were performed on rats after surgery. After the scans, the rats were euthanized. The brain tissues of 3 rats in each group were randomly selected for HE staining and immunohistochemical staining to observe the pathological morphology of brain tissues and to validate the expression of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). The remaining 6 rats were used for enzyme-linked immunosorbent assay to detect levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in brain infarction tissues. ANOVA test or Kruskal-Wallis H test was performed to compare the differences between groups. Results:There were statistically significant differences in neurological function scores and brain infarct volumes among the five groups ( P<0.001). Compared with the sham surgery group, the rats′ neurological function scores and brain infarct volumes were increased in the model group, RIPC group, MT group, and MT+RIPC group ( P<0.05); While compared with the model group, the rats′ neurological function scores and brain infarct volumes were decreased in the RIPC group, MT group, and MT+RIPC group ( P<0.05). MRI showed that abnormal signals were observed on the lesion hemisphere on the right side in rats of the four groups except for the sham surgery group. The lesions showed high signal on T 2 FLAIR and DWI, low signal on apparent diffusion coefficient map, and low perfusion on cerebral blood flow map. Pathological examination showed neuronal nuclear shrinkage in the necrotic area of the brain tissue in the model group, with surrounding neurons exhibiting edema and degeneration. In the RIPC and MT groups, edema and degeneration of neural cells around the infarction area were reduced, while the MT+RIPC group showed primarily neuronal edema with overall structural preservation. The range of Nrf2 and HO-1 protein positivity was significantly increased in the MT+RIPC group compared with the model group. The overall differences in IL-1β, TNF-α and IL-6 levels of 5 groups were statistically significant ( P<0.05), in which IL-1β, TNF-α and IL-6 levels in the model group, RIPC group, MT group, and MT+RIPC group increased compared with the sham-operated group ( P<0.05), and IL-1β, TNF-α, and IL-6 levels decreased in the RIPC group, MT group, and MT+RIPC group compared with the model group ( P<0.05). Conclusion:RIPC+MT exerts antioxidant effects through Nrf2/HO-1 pathway and also exhibits anti-inflammatory properties by reducing levels of IL-1β, IL-6, and TNF-α, thereby alleviating brain edema and neuronal damage, reducing infarct volume and improving neurological deficits in rats with cerebral artery occlusion. The multimodal MRI evaluation demonstrates the value of RIPC+MT in protecting against cerebral ischemia-reperfusion injury.
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Aim To investigate the role of transient receptor potential ankyrin 1 receptor in remote preconditioning of trauma-induced cardioprotection against myocardial ischemia-reperfusion injury and related mechanism. Methods SD rats were randomly divided into five groups: Sham operation group(Sham), model group(IR), remote preconditioning of trauma group(RPCT), TRPA1 inhibitor+remote preconditioning of trauma group(TCS+RPCT)and TRPA1 inhibitor group(TCS). The model of myocardial ischemia/reperfusion in rats was established, and the hemodynamics was monitored throughout the process. After reperfusion, the rat heart was taken to measure the myocardial infarction area and myocardial apoptosis rate, the activity and protein expression of mitochondrial aldehyde dehydrogenase 2(ALDH2)and the expression of 4-hydroxynonenal(4-HNE)were detected. Results Compared with sham group, myocardial infarction area and myocardial apoptosis cell increased. Meanwhile, the activity and expression of ALDH2 decreased and the production of 4-HNE increased in IR group. However, compared with IR group, RPCT group had decreased myocardial infarction area and the rate of cardiomyocyte apoptosis, the activity and expression of ALDH2 increased, the production of 4-HNE decreased. And then, compared with RPCT group, TCS+RPCT group reduced the myocardial protective effect of remote preconditioning of trauma. Conclusions TRPA1 receptor mediates the effect of remote preconditioning of trauma alleviating myocardial ischemia/reperfusion injury in rats. Its mechanism may be related to regulating ALDH2 activity and protein expression, and affecting the content of 4-HNE.