RESUMO
Objective To investigate the effect of YTH domain family protein 2(YTHDF2)on an-giotensin Ⅱ(Ang Ⅱ)-induced hypertrophy and apoptosis of primary neonatal rat cardiomyocytes.Methods The expression level of YTHDF2 was detected in the primary neonatal rat cardiomyo-cytes with or without Ang Ⅱ stimulation(AngⅡ group and normal group).The cells were divid-ed into blank group(transfected with siRNA+PBS),siYTHDF2 group(transfected with siYTHDF2+PBS),model group(siRNA+Ang Ⅱ)and experimental group(siYTHDF2+Ang Ⅱ)to investi-gate the effects of silencing YTHDF2 on the hypertrophy and apoptosis of cardiomyocytes.West-ern blotting and RT-qPCR were used to detect the expression of YTHDF2 at protein and mRNA levels,and RT-qPCR was employed to measure the mRNA levels of myocardial hypertrophic related genes atrial natriuretic peptide(ANP),brain natriuretic peptide(BNP)and beta-myosin heavy chain(β-MHC),and cardiomyocyte apoptosis related genes Bax and B lymphocytoma 2 gene(Bcl-2).The surface area of cardiomyocytes was observed by α-actin immunofluorescence staining.Cardiomyocyte apoptosis was observed by TUNEL staining,and the binding relationship between YTHDF2 and Bcl-2 was verified by immunoprecipitation.Results The expression of YTHDF2 at protein and mRNA levels were significantly higher in the AngⅡ group than the nor-mal group(1.49±0.03 vs 0.97±0.09,1.50±0.08 vs 1.00±0.07,P＜0.05).Compared with the blank group,the surface area of cardiomyocytes was notably enlarged,apoptotic rate was obvi-ously increased,the mRNA levels of ANP,BNP,β-MHC and Bax were significantly increased,and that of Bcl-2 was remarkably decreased in the model group(P＜0.05).The experimental group obtained decreased surface area and apoptotic rate of cardiomyocytes,lower mRNA levels of ANP,BNP,β-MHC and Bax,and increased mRNA expression of Bcl-2(P＜0.05).Conclusion Silencing YTHDF2 can alleviate Ang Ⅱ-induced hypertrophy and apoptosis in primary neonatal rat cardiomyocyte,and YTHDF2 inhibits the expression of Bcl-2 by binding to it.
RESUMO
Objective:To investigate the mechanisms underlying the effect of levocarnitine on myocardial cell fibrosis, proliferation, apoptosis and migration.Methods:Between June and December 2022, an overexpression vector for tissue inhibitor-1 of metalloproteinase(TIMP-1)and siRNA TIMP-1 were used to transfect rat H9c2 cardiomyocytes(from the cell bank of the Chinese Academy of Sciences), and transfection efficiency was measured using fluorescence reverse transcription quantitative PCR(RT-qPCR). After treating H9c2 cells with angiotensin Ⅱ(AngⅡ), the expression of the MMP3 and TIMP-1 genes in the cells was detected by RT-qPCR.A CCK8 kit was used to assess the effect of levocarnitine intervention on the proliferation of myofibroblasts after overexpression or knockdown of TIMP-1.The effects of levocarnitine on apoptosis and migration of myofibroblasts were detected by flow cytometry and Transwell assays.Results:The RT-qPCR results showed that the expression level of the MMP3 gene(1.38±0.05)in cardiomyocytes treated with AngⅡ for 24 hours exhibited an upward trend( P<0.01), while the expression level of the TIMP-1 gene(0.71±0.03)showed a downward trend( P<0.01). In addition, H9c2 cells with TIMP-1 overexpression(905.98±24.17)and knockdown(0.18±0.01)%, respectively, were successfully constructed.Based on CCK-8 detection results, knockdown of TIMP-1(86.56±7.98)% was able to promote the proliferation of H9c2 cells induced by levocarnitine( P<0.01). Apoptosis experiments showed that inhibition of TIMP-1 expression(23.22±2.69)significantly reduced the apoptosis level of H9c2 cells induced by levocarnitine( P<0.01). Migration experiments showed that inhibition of TIMP-1 expression(217.67±23.44)significantly promoted the migration ability of H9c2 cells induced by levocarnitine( P<0.01). Conclusions:After intervention to reduce TIMP-1 expression, levocarnitine can promote proliferation, inhibit apoptosis and promote migration of myofibroblasts and may therefore ameliorate myocardial fibrosis.
RESUMO
Objective:To evaluate the role of reactive oxygen species (ROS) in attenuation of hypoxia-reoxygenation (H/R) injury in rat cardiomyocytes by pinacidil postconditioning and the relationship with nuclear factor erythrid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway.Methods:Adult rat cardiomyocytes were isolated and cultured and then divided into 4 groups ( n=20 each) by a random number table method: control group (group C), H/R group, pinacidil postconditioning group (group P) and reactive oxygen scavenger N-(2-mercaptopropionyl)-glycine(MPG)+ pinacidil postconditioning group (group MPG+ P). Group C was continuously exposed to 95%O 2+ 5%CO 2 in an incubator at 37 ℃ for 105 min. The cells were exposed to 5%CO 2+ 1%O 2+ 94%N 2 in an incubator at 37 ℃ for 45 min followed by reoxygenation for 60 min to prepare H/R injury model. The cells were exposed to hypoxia for 45 min and then treated with pinacidil 50 μmol/L for 5 min followed by reoxygenation for 60 min in group P. The cells were exposed to hypoxia for 45 min, treated with MPG 2 mmol/L for 10 min, and then treated with pinacidil for 5 min followed by reoxygenation for 60 min in group MPG+ P. The content of Ca 2+ and activity of Nrf2 in cardiomyocytes were measured at the end of reoxygenation. The ultrastructure of cardiomyocytes was observed, and mitochondrial ultrastructure was evaluated using mitochondrial Flameng score. The expression of Nrf2, superoxide dismutase (SOD1), quinone oxidoreductase 1 (NQO1), and heme oxygenase 1 (HO-1) protein and mRNA was detected using Western blot and real-time polymerase chain reaction. Results:Compared with group C, the Ca 2+ content, Nrf2 activity and mitochondrial Flameng score were significantly increased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was aggravated in group H/R. Compared with H/R group, the Ca 2+ content and mitochondrial Flameng score were significantly decreased, the Nrf2 activity was increased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was up-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was attenuated in P group. Compared with P group, the Ca 2+ content and mitochondrial Flameng score were significantly increased, the Nrf2 activity was decreased, the expression of Nrf2, SOD1, NQO1 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the damage to the ultrastructure of cardiomyocytes was aggravated in MPG+ P group. Conclusions:ROS is involved in attenuation of H/R injury by pinacidil postconditioning, which is associated with activation of the Nrf2-ARE signaling pathway in rat cardiomyocytes.
RESUMO
Objective:To investigate the efficacy of phenolamine in the treatment of sepsis-induced myocardial dysfunction and its effect on cardiac function, myocardial injury index, and hemodynamics in patients.Methods:The clinical data of 79 patients with sepsis-induced myocardial dysfunction who received treatment in Huangshi Central Hospital, Edong Healthcare Group from February 2017 to February 2020 were retrospectively analyzed. These patients were divided into a control group (without phenolamine treatment, n = 41) and an observation group (with phenolamine treatment, n = 38) according to whether they received phenolamine treatment or not. Clinical efficacy, cardiac function, myocardial injury index, and hemodynamic index pre- and post-treatment were compared between the two groups. Results:There was no significant difference in 28-day mortality rate between the two groups ( P > 0.05). Intensive care unit length of stay and mechanical ventilation duration in the observation group were (9.33 ± 3.52) days and 83.00 (28.50, 138.00) hours, which were significantly shorter than (12.17 ± 4.15) days and 111.00 (47.50, 169.00) hours in the control group ( t = 3.26, Z = -2.27, both P < 0.05). The response rate in the observation group was significantly higher than that in the control group [81.58% (31/38) vs. 60.98% (25/41), χ2 = 4.05, P < 0.05]. After 7 days of treatment, the left ventricular ejection fraction in each group was significantly increased, and the left ventricular end-diastolic diameter and left ventricular end-systolic diameter in each group were significantly decreased compared with before treatment (all P < 0.05). After 7 days of treatment, the left ventricular ejection fraction in the observation group was significantly higher than that in the control group ( t = 3.29, P < 0.05), and left ventricular end-diastolic diameter and left ventricular end-systolic diameter were significantly lower than those in the control group ( t = 5.94, 11.21, both P < 0.05). N-terminal pro-brain natriuretic peptide and cardiac troponin I levels in each group were significantly decreased with time (both P < 0.05). At 24 and 72 hours and 7 days after treatment, N-terminal pro-brain natriuretic peptide and cardiac troponin I levels in the observation group were significantly lower than those in the control group (both P < 0.05). After 7 days of treatment, heart rate in each group decreased significantly compared with that before treatment (both P < 0.05), mean arterial pressure, cardiac index, and stroke output index in each group increased significantly compared with those before treatment (all P < 0.05). After 7 days of treatment, heart rate in the observation group was significantly lower than that in the control group ( t = 4.90, P < 0.05), and mean arterial pressure, cardiac index, and stroke output index in the observation group were significantly higher than those in the control group ( t = 4.37, 3.23, 6.01, all P < 0.05). Conclusion:Phentolamine can improve hemodynamics, reduce myocardial injury and improve cardiac function in patients with sepsis-induced myocardial dysfunction.
RESUMO
Objective To investigate the role and underlying mechanism of cathepsin B in myocar-dial injury in mice with diabetic cardiomyopathy(DCM).Methods Twenty 8-week-old male SPF C57BL/6 mice were randomly divided into wild-type(WT)group and WT DCM group,with 10 mice in each group.Another 20 8-week-old male SPF-grade mice with cathepsin B knockout(KO)were randomly and equally assigned to KO group and KO DCM group.HE staining was used to observe morphological changes,Prussian blue staining was employed to detect iron deposition,while immunohistochemical staining with 4-hydroxynonenal(4-HNE)was used to assess lipid peroxidation level in the myocardial tissues.Western blotting was performed to detect the expression of heme oxygenase-1(HO-1),superoxide dismutase 2(SOD2),and nuclear factor E2-related factor 2(Nrf2),while RT-PCR was applied to evaluate the expressions of Nrf-2,HO-1,and phospholipid hydroperoxide glutathione peroxidase 4(GPX4).Results Compared to the WT DCM group,the KO DCM group presented improved cell arrangement in cardiac tissues and sig-nificant reduction in inflammatory cell infiltration.Furthermore,the KO DCM group displayed a significant decrease in iron deposition compared to the WT DCM group.Additionally,the KO DCM group exhibited a significant reduction in 4-HNE expression compared to the WT DCM group.The protein levels of Nrf2,SOD2,and HO-1 were significant increased in the KO DCM group than the WT DCM group(0.68±0.21 vs 0.39±0.13,0.59±0.10 vs 0.28±0.09,1.03±0.10 vs 0.48±0.04,P＜0.05).Moreover,elevated mRNA levels of GPX4,Nrf2 and HO-1 were also observed in the KO DCM group than the WT DCM group(0.65±0.09 vs 0.40±0.10,0.61±0.11 vs 0.34±0.11,0.62±0.12 vs 0.39±0.09,P＜0.05).Conclusion Cathepsin B exacerbates myocardial injury in DCM mice through ferroptosis.
RESUMO
Objective To investigate the mechanism of maslinic acid on pyroptosis and inflammato-ry response in myocardial ischemia/reperfusion(IR)injury.Methods H9C2 cardiomyocytes were randomly divided into control group,control+maslinic acid group,hypoxia reoxygenation(HR)group,and HR+maslinic acid group.Cellular model of HR injury was constructed by hypoxia for 4 h and then reoxygenation for 12 h.Forty-eight male SD rats were randomly divided into Sham group,IR group,IR+maslinic acid group,IR+maslinic acid+Tri group(n=12).Rat model of myocardial IR injury was established by ligating the left anterior descending branch for 30 min followed by reperfusion for 2 h.The viability of cardiomyocytes was detected,the levels of LDH,CK-MB,IL-1β and IL-18 in the supernatant of cardiomyocytes and rat serum samples were detec-ted in each group.Drug-molecular docking was performed to predict the binding site and binding force of maslinic acid and NOD-like receptor thermal protein domain-associated protein 3(NLRP3).Western blotting was used to detect IκBα,NF-κB P65,NLRP3,apoptosis-associated speck-like protein(ASC),and gasdermid D-N terminal(GSDMD-N)in each group of cardiomyo-cytes and myocardial tissues.Results Compared with the Control group,significantly reduced cell viability,enhanced protein levels of p-IκBα,p-NF-κB P65 and higher releases of LDH,IL-1β and IL-18 were observed in the HR group(P＜0.05).Maslinic acid treatment reversed HR-induced changes in above indicators(P＜0.05).Compared with the Sham group,the protein levels of p-IκBα,p-NF-κB P65,NLRP3,ASC,GSDMD-N and the releases of serum CK-MB,LDH,IL-1βand IL-18 were significantly increased in the IR group(P＜0.05).Maslinic acid treatment also reversed above indicators induced by IR injury(P＜0.05).The protein levels of p-IκBα,p-NF-κB P65,NLRP3,ASC and GSDMD-N were significantly increased,and the releases of serum CK-MB,LDH,IL-1β and IL-18 were also elevated in the IR+maslinic acid+Tri group than the IR+maslinic acid group(1681.00±136.20 U/L vs 1251.00±213.60 U/L,1776.00±185.80 U/L vs 1330.00±172.50 U/L,4.32±0.45 vs 2.95±0.26,3.89±0.20 vs 2.47±0.29,P＜0.05).Conclusion Maslinic acid can show target intervention in NLRP3 activity,thereby inhibiting inflammatory re-sponse and cell pyroptosis,and ultimately attenuate myocardial IR injury effectively.
RESUMO
Objective To explore the role of NLRP3/Caspase-3 in myocardial apoptosis induced by ischemia/reperfusion(IR)injury and its effect on myocardiocyte autophagy in rats.Methods A total of 60 SPF-grade male rats were randomly divided into sham operation,model,and nimodip-ine treatment groups,with 20 rats in each group.Rat model of myocardial IR injury was estab-lished in the rats of the two latter groups.Cardiac function was assessed,and the levels of myocar-dial enzymes and cytokines were measured.Additionally,myocardial pathological changes were de-tected using HE staining.Furthermore,flow cytometry was utilized to determine the apoptotic rate of myocardiocytes,and the autophagosomes were counted under transmission electron micro-scope.Moreover,the expression of NLRP3 and Caspase-3 was measured using RT-PCR and West-ern blotting.Results Significant differences were observed in left ventricular end diastolic pres-sure,left ventricular systolic pressure,maximal rate of rise and fall in left ventricular pressure,ap-optotic rate of myocardial cells,and levels of TNF-α,IL-6,CK,AST and LDH in the three groups(P＜0.01).Notably,both the model group and nimodipine treatment group exhibited significantly higher autophagosome than the sham operation group(10.55±1.87 and 6.32±1.43 vs 3.45±0.67 units,P＜0.01),and the nimodipine group displayed a significantly lower autophagosome count than the model group(P＜0.01).The mRNA and protein levels of NLRP3 and Caspase-3 were notably higher in the model group and nimodipine group than the sham operation group(P＜0.01),and in the model group than the nimodipine group(P＜0.01).Conclusion Myocardial IR injury in rats can increase myocardiocyte apoptosis,reduce cardiac function,induce inflammatory response,and enhance autophagosome formation,which is related to the abnormal high expression of NLRP3/Caspase-3.
RESUMO
Resumo Fundamento O período neonatal é marcado por muitas alterações importantes no sistema cardiovascular, principalmente na primeira semana de vida. Diferentemente da população adulta, estudos sobre dados de eletrocardiograma (ECG) no período neonatal são escassos. Este é o primeiro estudo a descrever alterações eletrocardiográficas em uma coorte de recém-nascidos com ecocardiogramas normais. Objetivos Analisar padrões eletrocardiográficos de uma população de recém-nascidos a termo, sem anomalias morfológicas ou funcionais cardíacas, e comparar os resultados com a literatura. Métodos Neste estudo observacional, ecocardiogramas e resultados de ECG de 94 neonatos divididos em três grupos etários (até 24 horas, entre 25 e 72 horas, e entre 73 e 168 horas de vida) foram avaliados e comparados com aqueles descritos por Davignon et al. Um valor de p < 0,05 foi considerado estatisticamente significativo. Resultados Diferenças significativas na direção da onda T foram detectadas nas derivações V1 (p= 0,04), V2 (p= 0,02), V3 (p= 0,008) e V4 (p= 0,005). Houve diferenças entre nossos resultados e a literatura atual na maioria dos parâmetros. Conclusão Recém-nascidos a termo com menos de 24 horas de vida apresentaram significativamente mais ondas T positivas que aqueles com mais horas de vida. Encontramos muitas diferenças nos parâmetros de ECG em comparação aos descritos por Davignon et al., particularmente nas amplitudes de P, Q, R, S, duração do QRS, R/S e R+S. Esses achados indicam a necessidade de mais estudos para uma interpretação definitiva do ECG em recém-nascidos.
Abstract Background The neonatal period is marked by major changes in the cardiovascular system, especially in the first week of life. Unlike the adult population, studies on electrocardiogram (ECG) data in the neonatal period are scarce. This is the first study to describe electrocardiographic changes in a cohort of newborns with normal echocardiograms. Objectives To analyze the electrocardiographic patterns of a population of full-term NB, without any cardiac morphological or functional anomalies, and compare the results with the literature. Methods In this observational study, echocardiograms and ECG results from 94 newborns divided in three age groups (up to 24 hours, between 25 and 72 hours, and between 73 and 168 hours of life) were evaluated and compared with those reported by Davignon et al. A p-value <0.05 was considered statistically significant. Results There were significant differences in T-wave direction in leads V1 (p= 0.04), V2 (p= 0.02), V3 (p= 0.008) and V4 (p= 0.005) between the three age groups. There were differences between our findings and the current literature in most of the parameters. Conclusion Term newborns within 24 hours of life showed significantly more positive T waves than older ones. Many differences from the Davignon's ECG parameters were found, particularly in the P, Q, R, S amplitudes, QRS duration, R/S and R+S. These findings indicate that more studies are needed for a definitive interpretation of the ECG in newborns.
RESUMO
Resumo Fundamento A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo interventricular. Objetivo Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT). Métodos Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05. Resultados O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT. Conclusão O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.
Abstract Background The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. Objective To investigate whether low- to moderate-intensity resistance exercise training (RT) is beneficial to LV and cardiomyocyte contractile functions in rats during the development of monocrotaline (MCT)-induced PAH. Methods Male Wistar rats (Body weight: ~ 200 g) were used. To assess the time to potential heart failure onset (i.e., end point), rats were divided into sedentary hypertension until failure (SHF, n=6) and exercise hypertension until failure (EHF, n=6) groups. To test RT effects, rats were divided into sedentary control (SC, n = 7), sedentary hypertension (SH, n=7), and exercise hypertension (EH, n=7) groups. PAH was induced by two MCT injections (20 mg/kg, with 7 days interval). Exercise groups were submitted to an RT protocol (Ladder climbing; 55-65% of carrying maximal load), 5 times/week. Statistical significance was assumed at P < 0.05. Results RT prolonged the end point (~25 %), enhanced the physical effort tolerance (~ 55%), and mitigated the LV and cardiomyocyte contractility dysfunctions promoted by MCT by preserving the ejection fraction and fractional shortening, the amplitude of shortening, and the velocities of contraction and relaxation in cardiomyocytes. RT also prevented increases in left ventricle fibrosis and type I collagen caused by MCT, and maintained the type III collagen and myocyte dimensions reduced by MCT. Conclusion Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.
RESUMO
Objective:To evaluate the role of reactive oxygen species (ROS) in hypoxia postconditioning-induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway in rat cardiomyocytes.Methods:Primary cardiomyocytes of adult rats were isolated and cultured and divided into 4 groups ( n=20 each) using a random number table method: normal group (group N), hypoxia-reoxygenation group (group HR), hypoxia postconditioning group (group HPO) and hypoxia postconditioning plus an ROS scavenger N-(2-Amidinopropionyl)-glycine (MPG) group (group HPO+ MPG). Cells were exposed to hypoxia for 45 min followed by 60 min reoxygenation to develop the cardiomyocyte hypoxia-reoxygenation injury model.In HPO group, cells were subjected to 3 cycles of 5-min hypoxia/5-min reoxygenation after 45 min hypoxia, followed by reoxygenation for 60 min.In HPO+ MPG group, MPG (final concentration 2 mmol/L) was added at 35 min of hypoxia, cells were subjected to hypoxia for 10 min, and the other treatments were similar to those previously described in group HPO.At the end of reoxygenation, the intracellular calcium level and Nrf2 activity were measured, the ultrastructure of cardiomyocytes was observed, and the Flameng score of mitochondria was assessed, and the expression of Nrf2, NAD(P)H quinine oxidoreductase 1 (NQO1), superoxide dismutase 1 (SOD1) and heme oxygenase-1 (HO-1) protein and mRNA was detected using real-time polymerase chain reaction and Western blot. Results:Compared with group N, the intracellular free Ca 2+ level, Nrf2 activity and Flameng score were significantly increased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was down-regulated in group HR ( P<0.05). Compared with group HR, the intracellular free Ca 2+ level and Flameng score were significantly decreased, the Nrf2 activity was increased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was up-regulated in group HPO ( P<0.05). Compared with group HPO, the intracellular free Ca 2+ level and Flameng score were significantly increased, the Nrf2 activity was decreased, and the expression of Nrf2, NQO1, SOD1 and HO-1 protein and mRNA was down-regulated in group HPO+ MPG ( P<0.05). Conclusions:The mechanism by which hypoxia postconditioning activates the Nrf2/ARE signaling pathway in rat cardiomyocytes may be related to ROS.
RESUMO
Objective:To evaluate the effect of rat cardiac fibroblasts (RCF) on the expression of connexin43 (Cx43) in H9c2 cells during hypothermic hypoxia/reoxygenation.Methods:H9c2 cells cultured in vitro were divided into 4 groups ( n=12 each) using the random number table method: control group (group C), hypothermic hypoxia/reoxygenation group (group HHR), RCF co-culture group (group Co) and RCF co-culture plus hypothermic hypoxia/reoxygenation group (group Co+ HHR). Group C was incubated at 37℃ in 5% CO 2 + 95% air for 5 h. Group HHR was incubated at 4 ℃ in 5% CO 2 + 95% N 2 for 1 h and then at 37 ℃ in 5% CO 2 + 95% air for 4 h. In group Co and group Co+ HHR, H9c2 cells 0.3×10 5 cells/well were inoculated in the lower chamber and RCF 0.6×10 5 cells/well in the the upper chamber of a transwell ? culture dish.Group Co was incubated at 37 ℃ in 5% CO 2 + 95% air for 5 h. Group Co+ HHR was incubated at 4℃ in 95% N 2 + 5% CO 2 for 1 h, and then incubated at 37 ℃ in 5% CO 2 + 95% air for 4 h. The mortality rate of H9c2 cells was measured by trypan blue staining, the expression of Cx43 and extracellular signal-regulated protein kinases 1/2 (ERK1/2) by immunofluorescence, and the expression of Cx43, phosphorylated Cx43, ERK1/2 and phosphorylated ERK1/2 by Western blot. Results:Compared with group C, the mortality rate of H9c2 cells was significantly increased, the expression and phosphorylation of Cx43 were decreased, and the expression and phosphorylation of ERK1/2 were increased in group HHR ( P<0.05), and no significant change was found in the mortality rate of H9c2 cells or expression and phosphorylation of Cx43 and ERK1/2 in group Co ( P>0.05). Compared with group Co, the mortality rate of H9c2 cells was significantly increased, and the expression and phosphorylation of Cx43 and ERK1/2 were decreased in group Co+ HHR ( P<0.05). Compared with group HHR, the mortality rate of H9c2 cells was significantly increased, and the expression and phosphorylation of Cx43 and ERK1/2 were decreased in group Co+ HHR ( P<0.05). Conclusions:RCFs can decrease the expression and activity of Cx43 in H9c2 cells during hypothermic hypoxia/reoxygenation, and the mechanism may be related to the down-regulation of ERK1/2 expression and inhibition of ERK1/2 activity.
RESUMO
Objective:To evaluate the role of ferroptosis in hypoxia-reoxygenation (H/R) injury in cardiomyocytes cultured in high-fat high-glucose (HFHG) medium.Methods:Cardiomyocytes H9c2 cells were commonly cultured and divided into 3 groups ( n=20 each) using a random number table method: control group (C group), HFHG-H/R group and Ferrostatin-1 (Fer-1) plus HFHG-H/R group (Fer-1+ HFHG+ H/R group). H9c2 cells were cultured in a HFHG medium for 12 h and then exposed to 1%O 2-5%CO 2-94%N 2 for 4 h, followed by 2 h reoxygenation in a cell incubator.Fer-1 at a final concentration of 10 μmol/L was added while the cells were cultured in the HFHG medium in group Fer-1+ HFHG+ H/R.At 2 h of reoxygenation, the cell viability was measured using CCK-8 assay, the activity of lactate dehydrogenase (LDH) in the supernatant was measured using 2, 4-dinitrophenylhydrazine color method, the activity of reactive oxygen species (ROS) was measured by fluorescent probe DCFH-DA flow cytometry, and the expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), nuclear receptor coactivator 4 (NCOA4), and glutathione peroxidase 4 (GPX4) was detected by Western blot. Results:Compared with group C, the cell viability was significantly decreased, the activities of LDH release and ROS were increased, and the expression of ACSL4 and NCOA4 was up-regulated ( P<0.05), and no significant change was found in the expression of GPX4 in group HFHG+ H/R ( P>0.05). Compared with group HFHG+ H/R, the cell activity was significantly increased, the activities of LDH and ROS were decreased, and the expression of ACSL4 and NCOA4 was down-regulated ( P<0.05), and no significant change was found in the expression of GPX4 in Fer-1+ HFHG+ H/R group ( P>0.05). Conclusions:Ferroptosis is involved in the process of H/R injury in cardiomyocytes cultured in HFHG medium.
RESUMO
Objective:To evaluate the effects of different densities of rat cardiac fibroblasts (RCF) subjected to hypothermic hypoxia-reoxygenation on cardiomyocyte injury and intercellular coupling.Methods:RCF was cultured in vitro and divided into 3 groups ( n=12 each) using a random number table method: RCF density 0.5×10 5 cells/ml group (T 0.5 group), RCF density 1.0×10 5 cells/ml group (T 1.0 group), and RCF density 2.0×10 5 cells/ml group (T 2.0 group). The three groups were placed in an anoxic device, into which 95% N 2 + 5% CO 2 was continuously blown at the speed of 5 L/min for 15 min, and then placed in a 4 ℃ refrigerator for 1 h for low temperature treatment.After completion of culture, cells were placed in a incubator containing 95% air + 5% CO 2 at 37 ℃ for 4 h of reoxygenation.After the end of culture, RCF in three groups were indirectly co-cultured with cardiomyocytes of the same density (1.0×10 5 cells/ml) in a Transwell chamber for 16 h, cardiomyocytes were seeded in the lower chamber of Transwell, and RCF were seeded in the upper chamber of Transwell.After the end of co-culture, cardiomyocytes were collected for determination of the cell viability (by CCK8 method), apoptosis rate (by flow cytometry), expression of connexin 43 (Cx43) mRNA (by real-time fluorescence quantitative polymerase chain reaction), and expression of Cx43 and phosphorylated Cx43 (p-Cx43) (by Western blot). Results:Compared with T 0.5 group, the cell viability, apoptosis rate and expression of Cx43, p-Cx43 and Cx43 mRNA were significantly decreased in T 1.0 and T 2.0 groups ( P<0.01). Compared with T 1.0 group, the cell viability, apoptosis rate and expression of Cx43 and p-Cx43 were significantly decreased ( P<0.01), and no significant change was found in expression of Cx43 mRNA in cardiomyocytes in T 2.0 group ( P>0.05). Conclusions:RCF subjected to hypothermic hypoxia-reoxygenation induces cardiomyocyte injury in a density-dependent manner in a certain range, and the mechanism may be related to down-regulation of the expression of Cx43 and reduction of the activity of Cx43.
RESUMO
ABSTRACT Objective Analyze the effects of aerobic and anaerobic training on different ergometers on muscle and cardiac hypertrophy in rats. Methods The animals were separated into the following groups: Control (C), Aerobic Training in Water (ATW), Resistance Training in Water (RTW), Aerobic Training on Treadmill (ATT), and Resistance Training in Climbing (RTC). All training protocols were carried out for 4 weeks, 3 times/week. The cross-sectional area (CSA) of the gastrocnemius muscle cells and the areas of the cardiomyocytes were measured. Results In the fast-twitch fibers, there was an increase in CSA in the RTW and RTC groups compared to the ATW (p<0.01 and p<0.01) and ATT groups (p<0.01 and p<0.01). In the slow-twitch fibers, the ATW and ATT groups demonstrated a lower CSA compared to the RTW (p=0.03 and p<0.00) and RTC groups (p<0.01 and p<0.01). In the cardiomyocytes, there was an increase in the area of the RTW and RTC groups compared to groups C (p<0.01; p<0.01), ATW (p=0.02; p<0.01), and ATT (p<0.01; p<0.01). Conclusion The anaerobic training effectively promotes hypertrophy in the fast-twitch fibers and the cardiomyocytes. Level of Evidence V; Animal experimental study.
RESUMO Objetivo Analisar os efeitos dos treinamentos aeróbios e anaeróbios em diferentes ergômetros na hipertrofia muscular e cardíaca de ratos. Métodos Os animais foram separados nos grupos controle (C), treinamento aeróbio em natação (ATW), treinamento resistido em meio aquático (RTW), treinamento aeróbio em esteira rolante (ATT) e treinamento resistido em escalada (RTC). Os protocolos de treinamento foram realizados por 4 semanas, 3 x/semana. Foram mensurados a área de secção transversa (CSA) das células do músculo gastrocnêmio e as áreas dos cardiomiócitos. Resultados Nas fibras de contração rápida houve aumento da CSA dos grupos RTW e RTC em relação aos grupos ATW (p<0,01 e p<0,01) e ATT (p<0,01 e p<0,01). Nas fibras de contração lenta os grupos ATW e ATT demonstraram menor CSA comparado aos grupos RTW (p=0,03 e p<0,00) e RTC (p<0,01 e p<0,01). Nos cardiomiócitos houve aumento da área dos grupos RTW e RTC em comparação com os grupos C (p<0,01 e p<0,01), ATW (p=0,02 e p<0,01) e ATT (p<0,01 e p<0,01). Conclusão Os treinamentos anaeróbios promoveram hipertrofia nas fibras de contração rápida e nos cardiomiócitos. Nível de Evidência V; Estudo experimental em animais.
RESUMO
Resumo Fundamento: É sabido que a resistência à insulina e a hiperglicemia são causas patológicas importantes no desenvolvimento de cardiomiopatia diabética (CMD). Entretanto, seus mecanismos moleculares precisos na patogênese da CMD ainda não estão claros. Objetivos: Estudos recentes revelam que os microRNAs (miRNAs) desempenham papéis essenciais na patogênese da CMD. Este projeto tem o objetivo de determinar os papéis de miR-34a e miR-125b na morte celular de cardiomiócitos causada por hiperglicemia. Métodos: Cardiomiócitos primários de ratos foram isolados e expostos a concentrações de glicose normais e altas. A viabilidade das células foi medida utilizando-se o ensaio MTT. As expressões de miR-34a e miR-125b foram detectadas por qRT-PCR. Alvos potenciais de miR-34a e miR-125b foram previstos pelo www.Targetscan.org, e validados a partir de tecidos cardíacos humanos. Um p<0,05 foi considerado significância estatística. Resultados: Demonstra-se neste estudo que o miR-34a e o miR-125b têm resposta celular reduzida no coração humano diabético. Além disso, os dados in vitro de cardiomiócitos primários de ratos demonstraram que o tratamento com glicose alta em curto prazo estimula a expressão de miR-34a e miR-125b. Demonstrou-se que, em condições de glicose alta, os cardiomiócitos de ratos apresentaram metabolismo de glicose intracelular, e a captação de glicose e a produção de lactato aumentaram significativamente. Foi identificado que as principais enzimas metabólicas da glicose, hexoquinase 2 (HK2) e lactato desidrogenase-A (LDHA) eram alvos diretos de miR-125b e miR-34a, respectivamente. A superexpressão de miR-125b e miR-34a poderia evitar a morte de celular de cardiomiócitos causada por hiperglicemia. Por fim, a recuperação de HK2 e LDHA em cardiomiócitos com superexpressão de miR-125b e miR-34a restaurou a sensibilidade de cardiomiócitos à hiperglicemia. Conclusões: Nossos resultados propõem um mecanismo molecular para proteção cardiovascular diabética mediada por microRNA e contribuirão para o desenvolvimento de estratégias de tratamento de disfunção cardiovascular associada a diabetes.
Abstract Background: It is well-known that insulin resistance and hyperglycemia are important pathological causes for the development of diabetic cardiomyopathy (DCM). However, its precise molecular mechanisms in the pathogenesis of DCM remain unclear. Objectives: Recent studies reveal that microRNAs (miRNA) play essential roles in the pathogenesis of DCM. This project aimed to determine the roles of miR-34a and miR-125b in hyperglycemia-induced cardiomyocyte cell death. Methods: Rat primary cardiomyocytes were isolated and exposed to normal and high concentrations of glucose. Cell viability was measured using MTT assay. Expressions of miR-34a and miR-125b were detected by qRT-PCR. Potential targets of miR-34a and miR-125b were predicted from www.Targetscan.org and validated from human heart tissues. A statistical significance of p<0.05 was considered. Results: The present study shows that miR-34a and miR-125b are downregulated in a human diabetic heart. Moreover, in vitro data from rat primary cardiomyocytes showed that short-term high glucose treatment stimulates miR-34a and miR-125b expressions. Under high glucose, it was found that rat cardiomyocytes displayed increased intracellular glucose metabolism, and glucose uptake and lactate production were significantly increased. It was also found that the key glucose metabolic enzymes, Hexokinase 2 (HK2) and Lactate dehydrogenase-A (LDHA), were direct targets of miR-125b and miR-34a, respectively. Overexpression of miR-125b and miR-34a could prevent hyperglycemia-induced cardiomyocyte cell death. Finally, the restoration of HK2 and LDHA in miR-125b and miR-34a overexpressed cardiomyocytes recovered the cardiomyocytes' sensitivity to hyperglycemia. Conclusion: Our results proposed a molecular mechanism for the microRNA-mediated diabetic cardiovascular protection and will contribute to developing treatment strategies for diabetes-associated cardiovascular dysfunction.
Assuntos
Animais , Ratos , MicroRNAs/genética , Hiperglicemia , Morte Celular , Miócitos Cardíacos , GlucoseAssuntos
Humanos , Doxorrubicina , Miócitos Cardíacos/metabolismo , Estresse Oxidativo , Heme/metabolismoRESUMO
Objective:To evaluate the effects of different density rat fibroblasts on the expression of conjunctin 43 (Cx43) in cardiomyocytes and cell viability.Methods:Cardiomyocytes and fibroblasts were co-cultured using Transwell, cardiomyocytes were inoculated into the lower chamber of Transwell and fibroblasts into the upper chamber of Transwell.The cells were divided into 3 groups ( n=12 each) by a random number table method: fibroblast density 0.5×10 5 cells/ml group (group C 0.5), fibroblast density 1×10 5 cells/ml group (group C 1), and fibroblast density 2×10 5 cells/ml group (group C 2), with the density of cardiomyocytes 1×10 5 cells/ml in three groups.Cardiomyocytes and fibroblasts were co-cultured for 20 h in three groups.Cardiomyocytes were collected after co-culture for determination of cell viability (by CCK8 method), apoptosis rate (by flow cytometry), and expression of Cx43 mRNA (by quantitative real-time polymerase chain reaction) and expression of Cx43 and phosphorylated Cx43 (p-Cx43) (by Western blot). Results:There was no significant difference in the apoptosis rate of cardiomyocytes among the three groups ( P>0.05). Compared with group C 0.5, the expression of Cx43 protein and mRNA and p-Cx43 was significantly up-regulated in group C 1, the cardiomyocyte viability was significantly increased, and the expression of Cx43 protein and mRNA and p-Cx43 was up-regulated in group C 2 ( P<0.05). Compared with group C 1, the cardiomyocyte viability was significantly increased, and the expression of Cx43 protein and mRNA and p-Cx43 was up-regulated in group C 2 ( P<0.05). Conclusion:Rat fibroblasts up-regulate the expression of Cx43 and enhance the activity of Cx43 in cardiomyocytes and enhance cell viability in a density-dependent manner in a certain range.
RESUMO
Objective:To evaluate the relationship between phosphorylation of glycogen synthase kinase-3β (GSK-3β) and high glucose-caused abolition of cardioprotection induced by sevoflurane postconditioning.Methods:H9c2 cells were incubated in normal glucose (5.56 mmol/L) DMEM culture medium or high glucose (33 mmol/L) DMEM culture medium.The cells were divided into 8 groups ( n=24 each) using a random number table method: normal control group (group NC), normal glucose-cultured hypoxia/reoxygenation (H/R) group (group NH/R), normal glucose-cultured sevoflurane postconditioning group (group NS), normal glucose-cultured GSK-3β inhibitor SB216763 group (group NSB), high glucose-cultured group (group HC), high glucose-cultured H/R group (group HH/R), high glucose-cultured sevoflurane postconditioning group (group HS) and high glucose-cultured GSK-3β inhibitor SB216763 group (group HSB). The model of cardiomyocyte H/R was established by subjecting cardiomyocytes to 3 h of hypoxia followed by reoxygenation.Immediately after onset of reoxygenation, cardiomyocytes were exposed to 2.4% sevoflurane for 30 min in Ns and HS groups.Before the beginning of reoxygenation, GSK-3β inhibitor SB216763 was added to the culture medium with the final concentration of 10 μmol/L in NSB and HSB groups.At 3 h of reoxygenation, the apoptosis rate was determined by Anexin V-PI flow cytometry, the expression of GSK-3β and phosphorylated GSK-3β (p-GSK-3β) was detected by Western blot, superoxide dismutase (SOD) activity was measured using xanthineoxidase method, and lactic dehydrogenase (LDH) activity and malondialdehyde (MDA) content were determined by colorimetric assay. Results:Compared with group NC, apoptosis rate, LDH activity and MDA content were significantly increased, and SOD activity was decreased in group NH/R and group HC, expression of GSK-3β was up-regulated, and expression of p-GSK-3β was down-regulated in group NH/R, expression of p-GSK-3β was up-regulated in group NS, and expression of p-GSK-3β was down-regulated in group HC ( P<0.05). Compared with group NH/R, apoptosis rate, LDH activity and MDA content were significantly decreased, and SOD activity was increased in group NS and NSB groups, and expression of GSK-3β was down-regulated, and expression of p-GSK-3β was up-regulated in group NS ( P<0.05). Compared with group HC, apoptosis rate, LDH activity and MDA content were significantly increased, SOD activity was decreased, expression of GSK-3β was up-regulated, and expression of p-GSK-3β was down-regulated in group HH/R ( P<0.05). Compared with group HH/R, apoptosis rate, LDH activity and MDA content were significantly decreased, and SOD activity was increased in group HSB ( P<0.05). Conclusion:The mechanism by which high glucose abolishes cardioprotection induced by sevoflurane postconditioning is related to inhibiting phosphorylation of GSK-3β.
RESUMO
Objective:To evaluate the effect of TBK1 overexpression on hypoxia-reoxygenation (H/R) injury in isolated mouse cardiomyocytes subjected to high glucose and the relationship with mitochondrial autophagy.Methods:Normally cultured log-phase HL-1 mouse cardiomyocytes were inoculated in a 6-well plate at a density of 1×10 6 cells/ml and were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), high glucose group (group HG), high glucose and H/R group (group HG+ H/R), and TBK1 overexpression group (group TBK1). The cells were incubated in culture medium with 1% fetal bovine serum and 1% double antibody for 24 h when the cell density reached 50%.When the cell density reached 80%, pcDNA3.1 (+ ) was used as a vector to achieve TBK1 overexpression.The cells were cultured with high glucose medium (33 mmol/L) for 24 h, exposed to 94% N 2+ 5% CO 2+ 1% O 2 for 24 h in an incubator at 37℃ followed by 12 h reoxygenation in an incubator containing 5% CO 2 at 37°C to establish the model of H/R injury to cardiomyocytes subjected to high glucose.After reoxygenation, CCK-8 assay was used to detect cell viability, the activity of lactic dehydrogenase (LDH) in supernatant was detected using LDH kit, mitochondrial contents were determined using Mito-Tracter green fluorescent probe, and the expression of TBK1 and mitophagy-related proteins PINK1, Parkin, LC3B and P62 was detected by Western blot. Results:Compared with group C, the cell viability was significantly decreased, the activity of LDH in supernatant was increased, mitochondrial contents were decreased, the expression of TBK1, PINK1, Parkin and LC3B was down-regulated, and the expression of P62 was up-regulated in HG group and HG+ H/R group ( P<0.05). Compared with group HG, the cell viability was significantly decreased, the activity of LDH in supernatant was increased, mitochondrial contents were decreased, the expression of TBK1, PINK1, Parkin and LC3B was down-regulated, and the expression of P62 was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG+ H/R, the the cell viability was significantly increased, the activity of LDH in supernatant was decreased, mitochondrial contents were increased, the expression of TBK1, PINK1, Parkin and LC3B was up-regulated, and the expression of P62 was down-regulated in group TBK1 ( P<0.05). Conclusion:The mechanism by which TBK1 overexpression reduces the H/R injury is related to restoring mitophagy in isolated mouse cardiomyocytes subjected to high glucose.