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ObjectiveTo investigate the mechanism of Baihuan Xiaoyao Decoction （Xiaoyaosan added with Lilii Bulbus and Albiziae Cortex） in alleviating depression-like behaviors of juvenile rats by regulating the polarization of microglia. MethodSixty juvenile SD rats were randomized into normal control， model， fluoxetine， and low-， medium-， and high-dose （5.36， 10.71， 21.42 g·kg-1， respectively） Baihuan Xiaoyao decoction groups. The rat model of juvenile depression was established by chronic unpredictable mild stress （CUMS）. The sucrose preference test （SPT） was carried out to examine the sucrose preference of rats. Forced swimming test （FST） was carried out to measure the immobility time of rats. The open field test （OFT） was conducted to measure the total distance， the central distance， the number of horizontal crossings， and the frequency of rearing. Morris water maze （MWM） was used to measure the escape latency and the number of crossing the platform. The immunofluorescence assay was employed to detect the expression of inducible nitric oxide synthase （iNOS， the polarization marker of M1 microglia） and CD206 （the polarization marker of M2 microglia）. Real-time polymerase chain reaction was employed to determine the mRNA levels of iNOS， CD206， pro-inflammatory cytokines ［tumor necrosis factor （TNF）-α， interleukin （IL）-1β， and IL-6］ and anti-inflammatory cytokines （IL-4 and IL-10） in the hippocampus. Western blotting was employed to determine the protein levels of iNOS and CD206 in the hippocampus. The levels of IL-4 and IL-6 in the hippocampus were detected by enzyme-linked immunosorbent assay. ResultCompared with the normal control group， the model rats showed a reduction in sucrose preference （P<0.05）， an increase in immobility time （P<0.05）， decreased motor and exploratory behaviors （P<0.05）， and weakened learning and spatial memory （P<0.05）. In addition， the model rats showed up-regulated mRNA and protein levels of iNOS and mRNA levels of IL-1β， IL-6， and TNF-α （P<0.05）. Compared with the model group， Baihuan Xiaoyao decoction increased the sucrose preference value （P<0.05）， shortened the immobility time （P<0.01）， increased the motor and exploratory behaviors （P<0.05）， and improved the learning and spatial memory （P<0.01）. Furthermore， the decoction down-regulated the positive expression and protein level of iNOS， lowered the levels of TNF-α， IL-1β， and IL-6 （P<0.01）， promoted the positive expression of CD206， and elevated the levels of IL-4 and IL-10 （P<0.01） in the hippocampus of the high dose group. Moreover， the high-dose Baihuan Xiaoyao decoction group had higher sucrose preference value （P<0.01）， shorter immobility time （P<0.01）， longer central distance （P<0.01）， stronger learning and spatial memory （P<0.01）， higher positive expression and protein level of iNOS （P<0.01）， lower levels of TNF-α， IL-1β， and IL-6 （P<0.05， P<0.01）， lower positive expression and mRNA level of iNOS （P<0.05）， and higher levels of IL-4 and IL-10 （P<0.05， P<0.01） than the fluoxetine group. ConclusionBaihuan Xiaoyao decoction can improve the depression-like behavior of juvenile rats by inhibiting the M1 polarization and promoting the M2 polarization of microglia in the hippocampus.
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ObjectiveTo explore the effects of Wenyang Jieyu prescription （WJP） on neuroinflammation and synaptic plasticity in the mouse model of depression induced by maternal separation combined with restraint stress. MethodThe mice on postnatal day 0 （PD0） were randomized into a control group and a modeling group. Maternal separation combined with restraint stress was employed to establish the mouse model of depression. After the removal of female mice， the modeled mice were randomized into model， Wenyang prescription （5.85 g·kg-1）， Jieyu prescription （12.03 g·kg-1）， WJP （16.71 g·kg-1）， and fluoxetine （2.6 mg·kg-1） groups on the weaning day （PD21）， with 15 mice in each group. The mice were administrated with corresponding drugs mixed with the diet from PD21 to PD111. The sucrose preference test， open field test， O-maze test， and novel object recognition test were then carried out to evaluate the depression state， memory， and learning ability of the mice. Immunohistochemistry （IHC） was employed to observe the ionized calcium-binding adapter molecule-1 （Iba-1） in hippocampal microglia. High performance liquid chromatography （HPLC） was employed to measure the content of noradrenaline （NE） and epinephrine （E） in the hippocampus. Enzyme-linked immunosorbent assay （ELISA） was employed to determine the content of interleukin （IL）-18 and IL-1β in the hippocampus. Western blot was employed to determine the protein levels of NOD-like receptor protein 3 （NLRP3）， apoptosis-associated speck-like protein containing a CARD （ASC）， cysteine aspartate-specific protease-1 （Caspase-1）， IL-1β， synaptophysin （Syn）， and postsynaptic density 95 （PSD95）. ResultCompared with control group， the model group showed decreased sucrose preference rate， time spent in central zone within 5 min， total movement distance， time spent in the open arm， and cognition index （P<0.05， P<0.01）. The microglia in the model group presented amoeba-like appearance， the Iba1 increased. Moreover， the model group showed decreased content of NE and E （P<0.01）， elevated levels of IL-1β and IL-18 （P<0.01）， down-regulated protein levels of PSD95 and Syn （P<0.05， P<0.01）， and up-regulated protein levels of NLRP3， ASC， Caspase-1， and IL-1β （P<0.05， P<0.01）. Compared with model group， WJP and fluoxetine increased the sucrose preference rate， time spent in central zone within 5 min， total movement distance， time spent in the open arm， and cognition index （P<0.05， P<0.01）. They recovered the microglia and the Iba1 decreased. Moreover， the drugs increased the content of NE and E （P<0.05， P<0.01）， lowered the levels of IL-1β and IL-18 （P<0.01）， up-regulated the protein levels of PSD95 and Syn （P<0.01）， down-regulated the protein levels of NLRP3， ASC， Caspase-1， and IL-1β （P<0.05， P<0.01）. ConclusionWJP can treat the depressive behavior induced by maternal separation combined with restraint stress in mice， with the performance outperforming Wenyang prescription and Jieyu prescription. It may alleviate the neuroinflammation induced by microglia and improve the synaptic plasticity by regulating the NLRP3 pathway and increasing neurotransmitters in the hippocampus.
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ObjectiveTo investigate the antidepressant effect of Sinisan （SNS） by regulating glycogen aynthase kinase-3β （GSK-3β）/tumor necrosis factor alpha-induced protein 3（A20）/CCAAT enhancer binding protein β（C/EBPβ） to inhibit the activation of microglia. MethodA total of 72 male C57/6J mice were randomly divided into the normal group， model group， fluoxetine group （5.0 mg·kg-1）， low-dose Sinisan group （4.9 g·kg-1）， medium-dose Sinisan group （9.8 g·kg-1）， and high-dose Sinisan group （19.6 g·kg-1）， with 12 mice in each group. After one week of adaptive feeding， chronic unpredictable mild stress （CUMS） was performed to establish the depression model. In the fifth week， drug treatment was conducted for four weeks. In the ninth week， behavioral tests were performed， including sucrose preference test （SPT）， open field test （OPT）， elevated plus maze （EPM） test， and forced swimming test （FST）. Western blot was used to detect the expression levels of interleukin-1β （IL-1β）， interleukin-6 （IL-6）， nitric oxide synthase （iNOS）， GSK-3β， A20， and C/EBPβ in the cortex. The expression of M1-polarized ionized calcium-binding adapter molecule 1 （Iba1） and cluster of differentiation 68 （CD68） in microglia was detected by immunofluorescence. ResultAfter eight weeks of CUMS， compared with the normal group， the mice in the model group had a significantly reduced sucrose preference rate （P<0.01）， and the activity in the central area of the OPT was significantly reduced （P<0.01）. The activity in the open arm area of the EPM test was significantly reduced （P<0.05）， and the immobility time of FST was increased （P<0.01）. The expression levels of inflammatory proteins IL-1β， IL-6， and iNOS were increased （P<0.01）， and the fluorescence co-localization index of Iba1 and CD68 was increased （P<0.05）. The protein expression levels of GSK-3β and C/EBPβ were significantly increased （P<0.05， P<0.01）. After four weeks of SNS intervention， compared with the model group， the mice in the SNS group had significantly increased sucrose preference rate （P<0.01）， significantly increased activities in the central area and the open arm area in the OPT and the EPM test （P<0.05）， and significantly reduced immobility time in the FST （P< 0.01）. The protein expression levels of IL-1β， IL-6， and iNOS were significantly decreased （P<0.05）， and the fluorescence co-localization index of Iba1 and CD68 was decreased in the high-dose SNS group （P<0.05）. The protein expression levels of GSK-3β and C/EBPβ in the medium-dose and high-dose SNS groups were significantly decreased （P<0.01）， and that of A20 was significantly increased （P<0.01）. ConclusionThe antidepressant effect of SNS is related to the regulation of GSK-3β/A20/C/EBPβ protein expression and the inhibition of M1-type activation of microglia.
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Objective To explore the impact of the sialic acid binding lectin-E(Siglec-E)on the inhibitory properties of parthenolide(PTL)against lipopolysaccharide(LPS)-induced M1 polarization of microglia(BV2).Methods ①Single cell sequencing data of Siglece related mouse brain tissue was obtained from Gene Expression Omnibus(GEO)database and divided into the WT group(n=3)and the Siglece-/-group(n=4).The microglia cells were screened,and the enrichment analysis was performed to analyze related differential genes and pathways.BV2 cells were constructed by the shRNA interference technique and were divided into NC-shRNA and Siglece-shRNA to detect the expression level of Siglec-E(Siglece).② NC-shRNA and Siglece-shRNA cells were respectively divided into the Control group,LPS group,PTL group and PTL+LPS group(n=3).The mRNA levels of markers of M1 polarization in microglia,iNOS,IL-1 β and IL-6,were detected by RT-qPCR.Siglecefl/fl and Cx3cr1cre mice were mated to obtain microglia-specific Siglece deletion(Siglecefl/fl×Cx3cr1cre)mice,and LPS-induced neuroinflammation model was established.③ Nine WT and Siglecefl/fl×Cx3cr1cre male mice were assigned to the Control group,LPS group and PTL+LPS group(n=3).RT-qPCR,immunofluorescence assay and Western blotting were used to verify the knock-out effect and polarization-related pathways,and to investigate the mechanism of Siglec-E affecting PTL inhibition of M1 polarization of microglia.Results Compared with the NC-shRNA group,the expression of Siglec-E in the Siglece-shRNA group was significantly decreased(P<0.01),indicating that the Siglec-E knock-down cell model was successfully established.With the stimulation of LPS,mRNA levels ofiNOS,IL-1 β and IL-6 were significantly up-regulated compared with the Control group both in shRNA cells and Siglece-shRNA cells(P<0.01).With the influence of PTL and LPS,the markers of M1 polarization in NC-shRNA cells mentioned before were significantly decreased(P<0.05),while for Siglice-shRNA cells,there were no significant changes in the markers of M1 polarization.PTL inhibited the phosphorylation of JNK and IκB protein(P<0.01)and the nuclear translocation of NF-κB in BV2 cells,down-regulated Siglec-E,and weakened the inhibitory effect.Compared with mice in the WT group,the expression of Siglec-E in microglia of Siglecefl/fl×Cx3cr1cre mice was decreased significantly(P<0.01),and the inhibitory effect of PTL on the phosphorylation of NF-κB in microglia of Siglecefl/fl×Cx3cr1cre mice was also decreased.Conclusion The absence of Siglec-E in microglia attenuates the inhibition of M1 polarization by the MAPK/NF-κB pathway targeted by PTL.
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Objective To explore the expression of triggering receptor expressed on myeloid cells 2(TREM2)in high-glucose microglia and to investigate the role of TREM2 in the proliferation,migration and phagocytosis of high-glucose microglia.Methods Microglia cells were divided into control group and high-glucose treatment group(67.5 mmol/L glucose,24 h).The microglia cells were counted and the expression of Iba1 and TREM2 was de-tected.TREM2 siRNA was transfected to detect the proliferation and migration of microglia.The amyloid β-peptide(Aβ)with a fluorescent tag was added to observe the phagocytosis of Aβ by microglia.Results Compared to normal microglia,the number of microglia significantly decreased after high-glucose treatment(P＜0.001),while the ex-pression of TREM2 and Iba1 markedly increased(P＜0.001).High glucose and TREM2 did not affect the prolifer-ation of microglia.Compared to the normal group,the migration of microglia significantly decreased after high-glu-cose treatment(P＜0.05)and TREM2 did not affect the migration ability of high-glucose microglia.Compared to the normal group,the phagocytosis of Aβ by microglia significantly decreased in the high-glucose treated group(P＜0.001).Furthermore,TREM2 knockdown further decreased the phagocytosis of Aβ by high-glucose microglia(P＜0.001).Conclusions The expression of TREM2 in microglia significantly increases after high-glucose treat-ment,which significantly affects phagocytosis of Aβ by microglia.
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Objective To explore the effect of scutellarin on lipopolysaccharide(LPS)induced neuroinflammation in BV-2 microglia cells.Methods BV-2 microglia were cultured and randomly divided into 6 groups:control group(Ctrl),cyclic GMP-AMP synthetase(cGAS)inhibitor RU320521 group(RU.521 group),LPS group,LPS+RU.521 group,LPS+scutellarin pretreatment group(LPS+S)and LPS+S+RU.521 group.The expressions of cGAS,stimulator of interferon gene(STING),nuclear factor kappa B(NF-κB),phosphorylated NF-κB(p-NF-κB),neuroinflammatory factors PYD domains-containing protein 3(NLRP3)and tumor necrosis factor α(TNF-α)in BV-2 microglia were detected by Western blotting and immunofluorescent double staining(n= 3).Results Western blotting and immunofluorescent double staining showed that compared with the control group,the expression of cGAS,STING,p-NF-κB,NLRP3 and TNF-α in BV-2 microglia increased significantly after LPS induction(P<0.05),while the expression of cGAS,STING,p-NF-κB,NLRP3 and TNF-α in LPS+S group were significantly lower than those in LPS group(P<0.05).Treatment with cGAS pathway inhibitor RU.521 showed similar effects as the pre-treatment group with scutellarin.In addition,the change of NF-κB in each group was not statistically significant(P>0.05).Conclusion Scutellarin inhibits the neuroinflammation mediated by BV-2 microglia cells,which may be related to cGAS-STING signaling pathway.
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Objective To investigate the effect of microglia activation regulated by C-X3-C motif chemokine ligand 1(CX3CL1)-C-X3-C motif chemokine receptor 1(CX3CR1)pathway on memory function in hemorrhagic shock/resuscitation rats.Methods The experiment was divided into two parts.In the first part,the rats were randomly divided into sham group,model-0.5 hour group,model-1.5 hour group,model-3 hour group,10 rats in each group.There were differences in the time of hemorrhagic shock among each group.In the second part,rats were randomly divided into control group and CX3CL1 group,10 rats in each group.The rats in CX3CL1 group were treated with CX3CL1 protein factor(intraventricular injection),and the rats in control group were treated with saline.All rats were trained in Morris water maze experiments before model construction,and tests of Morris water maze experiments were carried out after 4 days of model construction.After completion,the whole brains were taken for HE staining and immunohistochemical staining.Cerebrospinal fluid was taken for detection of inflammatory cytokines,and hippocampus tissues were taken for Real-time PCR detection and Western blotting detection.Results Compared with the sham group,the escape latency of rats in model group increased,the number of platform crossings and the resident time in the third quadrant decreased.The neuronal state was impaired in HE staining in model group.In addition,compared with the sham group,the expression of ionized calcium binding adaptor molecule-1(Iba1)in the brain of the rats in model group increased,the contents of tumor necrosis factor-α(TNF-α)and interleukin(IL)-6 in the cerebrospinal fluid increased,and the M1-type microglia markers CD16,TNF-α,IL-1β and inducible nitric oxide synthase(iNOS)mRNA content increased.At the same time,compared with the sham group,the expressions of CX3CL1 and CX3CR1 in the brain of model group decreased,and the expressions of phosphorylated nuclear factor-κB(p-NF-κB)and nucleotide binding oligomerization domain(NOD)-like receptor protein 3(NLRP3)increased.However,compared with the control group,rats in CX3CL1 group had reduced escape latency,increased platform crossing times and quadrantⅢresident time,and recovered neuronal states.In addition,the expression of Iba1 in the brain of CX3CL1 group decreased,the contents of TNF-α and IL-6 in the cerebrospinal fluid decreased,the mRNA contents of M1-type microglia markers like CD16,TNF-α,IL-1β and iNOS decreased,and the mRNA contents of markers of M2-type microglia glial like CD206,transforming growth factor-β(TGF-β),arginase-1(Arg1),Chitinase 3-like protein 1(Ym 1)increased.Conclusion CX3CL1 can help inhibit the excessive activation of microglia,induce the polarization of microglia to M2 type,inhibit the polarization of M1 type,reduce the release of inflammatory cytokines,and alleviate the memory function damage induced by hemorrhagic shock/resuscitation.
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Objective To discuss the relationship between activated glia cells in distal segment of the spinal cord and widespread pain.Methods Fifty female rats were randomly divided into sham group,the chronic constriction injury of the infraorbital nerve(CCI-ION)group,CCI-ION+minocycline(Mino)group,CCI-ION+L-2-aminoadipic acid(LAA)group,and CCI-ION+normal saline(NS)group,n=10 for each group.CCI-ION model was established and Mino,LAA,and normal saline were delivered intrathecally to CCI-ION rats.Immunofluorescence staining was used to detect activated astrocytes and microglia in the medulla oblongata,cervical,thoracic,and lumbar spinal cord segments.On the 7th,14th,21st,28th day,von Frey filaments were used to evaluate the mechanical withdrawal threshold of vibrissa pad,and electronic von Frey tactile pain meter was used to measure the mechanical withdrawal threshold of front paw,chest and hind paw.The radiant thermal stimulator was used to measure the thermal withdrawal threshold of hind paw.Results After intrathecal injection of Mino to inhibit microglia,the activated microglia in each spinal cord segment decreased.Moreover,inhibiting astrocytes by using LAA significantly reduced activated astrocytes in spinal dorsal horn from distal segments.Behavioral assay showed that after intrathecal injection of Mino and LAA,the mechanical allodynia of vibrissa pad in CCI-ION rats was relieved.However,there was no significant difference(P>0.05)in the thermal and mechanical withdrawal thresholds in the hind paw of CCI-ION rats after intrathecal injection of Mino,while intrathecal injection of LAA significantly increased the thermal and mechanical withdrawal thresholds in the hind paw,indicating the relief of widespread pain induced by CCI-ION.Conclusion The activated astrocytes in distal segments of the spinal cord mediated CCI-ION-induced widespread pain.
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Chronic pain has been a prominent public health issue in China for years,affecting over 30%of the population.The mechanism of chronic pain has always been a controversial and difficult topic of pain medicine research.The polarization of microglia inherent in the central nervous system when the external microenvironment changes and the subsequent neuroinflammatory response are critical in chronic pain.Microglia can polarize into pro-inflammatory M1 or anti-inflammatory M2 phenotypes during neuroin-flammatory reactions,exerting neurotoxic or neuroprotective effects in the nervous system,respectively.The aim of the article is proposed to provide an overview of the main mechanisms of microglial polarization and-how it might contribute to chronic pain.
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The incidence of dementia increased significantly in the context of an aging population,imposing a significant burden on the economy and society.Therefore,finding the specific mechanism underlying cognitive decline in aging is of paramount significance.Recently,the role of microglia in the initiation and progression of cognitive decline in aging has become a research hotspot.Microglia,the resident immune cells of CNS,play important roles in immunosurveillance,synaptic pruning,damage repair and maintaining immune homeostasis.However,microglia undergo a variety of changes in cell morphology,gene expression and functional status with aging.This article review the impact of normal aging on microglia and the role of microglia in the pathogenesis of cognitive decline in aging,to provide a novel strategy for slowing or preventing the onset of dementia.
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Objective:To determine the effect of gastrodin(GAS)on toll-like receptor 4(TLR4)expression in mi-croglia after hypoxic-ischemic brain damage.Methods:Hypoxia-ischemic brain damage(HIBD)model was established in neonatal rat in vivo.Thirty 3 d SD rats of were randomly divided into there groups:Sham group,HIBD model group,HIBD model+gastrodin intervention group(HIBD+G).Oxygen glucose deprivation(OGD)model was established in BV2 cells in vitro,Control group(Control),oxygen glucose deprivation group(OGD),OGD+gastrodin intervention group(OGD+G)were randomly set in vitro.Both Western Blot and immunofluorescence staining techniques were used to detect the expression of TLR4 in cells of each group in vitro and in the left corpus callosum region in vivo.Results:The expression of TLR4 was significantly increased in OGD-induced microglia.After gastrodin intervention,TLR4 expression was decreased significantly(P＜0.05).Conclusion:GAS can inhibit the expression of TLR4 in activated microglia and thus play a neuroprotective role in HIBD.
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Objective:To explore the mechanism of Mito-TEMPO inhibiting the activation of BV2 microglia induced by lead(Pb)exposure.Methods:Mouse microglia BV2 were cultured in vitro.The effects of different concentrations of lead exposure on the viability of BV2 cells were determined by MTT colorimetric method,and a model of lead expo-sure was developed and intervened with Mito-TEMPO antioxidant.Immunofluorescence staining was used to detect the expression of M1 activation marker CD86 protein.Enzyme-linked immunosorbent assay was used to detect the expression of pro-inflammatory factors interleukin-1 β(IL-1β),tumor necrosis factor α(TNF-α),interleukin-6(IL-6).Mito-chondrial superoxide indicator(MitoSOX)staining was used to detect the level of mitochondrial oxidative stress.JC-1 staining was used to detect mitochondrial membrane potential.The respiratory ability of mitochondria was detected by cell energy metabolism analysis system(O2k).Results:Compared with the control group,the expression of CD86 protein,the levels of pro-inflammatory cytokines IL-1β,TNF-α and IL-6 in BV2 cells increased significantly,the level of oxidative stress in mitochondria increased significantly,and the mitochondrial membrane potential and respiratory ability decreased significantly in lead exposed group.Mito-TEMPO treatment significantly reduced the oxidative stress and functional damage of mitochondria in BV2 cells,and significantly inhibited the M1 activation level of BV2 cells.Conclusion:The results show that Mito-TEMPO treatment can reverse the M1 activation of BV2 cells induced by lead exposure,and the specific mechanism may be related to the reduction of mitochondrial oxidative stress and dysfunction by Mito-TEMPO.
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Objective:To investigate the effect of minocycline on neuroinflammation of rats with post-traumatic stress disorder(PTSD).Methods:The rat model of PTSD was prepared by a single prolonged stress(SPS)method,and the rats were treated with minocycline(PTSD+Mino group)or normal saline(PTSD group)by gavage.The behavioral changes of rats were detected by light-dark box test.The expression of ionized calcium-binding adapter molecule 1(Iba-1)in hippocampus was detected by immunohistochemical staining.The contents of IL-1β and TNF-α in hippocampus were detected by ELISA,and the expression levels of IL-1β and TNF-α mRNA in hippocampus were detected by real-time RT-PCR(qRT-PCR).Results:After 3 days of SPS stimulation,the anxiety-like behavior of rats was obvious,the expression of Iba-1 in hippocampus was increased,and the contents of IL-1β and TNF-α in hippocampus were in-creased.Minocycline treatment significantly reduced anxiety-like behavior and decreased the expression of Iba-1 in the hippocampus of PTSD rats.Meanwhile,minocycline treatment also decreased the levels of IL-1β and TNF-α mRNA and protein in the hippocampus.Conclusion:Minocycline can improve the anxiety-like behavior of PTSD rats by inhibiting the activation of microglia.
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Objective To evaluate the impact and clinical significance of NOD-like receptor pyrin domain-containing protein 3(NLRP3)in the activation of lipopolysaccharide(LPS)-induced BV2 microglia cells.Methods shRNA plasmids were devised for BV2 microglia transfection,and the most effective transfection segment was identified via RT-PCR and Western blot assays.NLRP3 expression in the cell line was detected by Western blotting,while light microscopy was used to observe morpho-logical alterations in BV2 cells transfected with NLRP3-shRNA.Furthermore,enzyme-linked immunosorbent assay(ELISA)was used to quantify levels of inflammatory cytokines IL-18,IL-1β,TNF-α and NO in cell supernatants.Immunofluorescence staining was used to observe the expression and localization of microglial activation markers iNOS,Arg-1,Iba1,and NLRP3.Results NLRP3 was highly expressed in LPS-induced BV2 cells.The Western blot result showed that the mRNA expression level was the lowest and transfection was the least effective in NLRP3-mus-727 group.Microscopic examination revealed a round or short spindle-shaped morphology in BV2 cells transfected with shNLRP3,which was akin to resting state cells in the blank control group.ELISA showed that pro-inflammatory mediators IL-18,IL-1β,TNF-α and NO levels were decreased in BV2 cells trans-fected with shNLRP3(all P＜0.05).Immunofluorescence staining indicated a relative decrease in iNOS and Iba1 expression,with an upregulation of Arg-1 in BV2 cells transfected with shNLRP3.Conclusion NLRP3 is highly expressed in LPS-induced BV2 cells.Inhibition of NLRP3 expression can suppress the inflammatory response of BV2 cells induced by LPS,promoting their polarization towards the M2 phenotype.
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Objective This study was designed to investigate the effects of corilagin on morphine-tolerant rats and discuss the reaction mechanism.Methods A rat model of chronic morphine analgesia tolerance was established.The tail-flick latency of rats was detected by using the water bath tail-flick method.The positive cell rate of ionized calcium binding adapter molecule-1(Iba-1)was detected by using immunofluorescence assay.The protein expressions of Iba-1 and mitogen-activated protein kinase(MAPK)pathway-related proteins were detected by Western blotting.The release of interleukin-6(IL-6),tumor necrosis factor alpha(TNF-α)and interleukin-1 beta(IL-1β)was detected by using enzyme-linked immunosorbent assay(ELISA).The mRNA levels of IL-6,TNF-α and IL-1β were detected by using quantitative reverse transcriptase polymerase chain reaction(qRT-PCR).Results Compared with the morphine(Mor)group,the analgesic effect of morphine in morphine+corilagin(Mor+Cor)group was strengthened with the increase of corilagin concentration.Compared with the Control group,the positive cell rate of Iba-1,Iba-1 protein expression level,levels of inflammatory factors IL-6,TNF-α,IL-1β,and the phosphorylated expression levels of MAPK signaling pathway-related proteins extracellular regulated protein kinases(ERK),c-Jun N-terminal kinase(JNK)and p38 were significantly increased in the Mor group,which were then decreased in Mor+Cor group with the increase of corilagin con-centration.Morphine and corilagin treatment(alone or in combination)had no significant effects on the expression levels of ERK,JNK and p38.Conclusion Corilagin reduces morphine tolerance in rats by inhibiting MAPK pathway.
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Post-stroke cognitive impairment(PSCI)is mainly manifested as learning and memory disorders.Highly enriched RNA m6A methylation modification in mammalian brain is involved in glial cell-mediated neuroinflammation.Given that neuroinflammation is the main mechanism for neural damage and spatial and memory impairment of PSCI,it is speculated that RNA m6A methylation modification can regulate the inflammatory response of glial cells after stroke to improve PSCI.This review summarizes and analyzes the role of RNA m6A methylation modification in the development of PSCI and analyzes its detailed mechanism of regulating glial cell-mediated inflammation,which will provide reference for researchers in this field.
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BACKGROUND:As the incidence of spinal cord injury increases with the years and axon regeneration after spinal cord injury was very difficult.How to promote the recovery from spinal cord injury and improve the transplantation efficiency of stem cells and other therapeutic cells after spinal cord injury has been the focus of clinical and scientific research. OBJECTIVE:To establish the efficient transplantation and replacement of mouse spinal cord microglia in the spinal cord injury model. METHODS:CX3CR1 creER-/+::LSL-BDNF-/+-tdTomato mice,CX3CR1+/GFP mice,β-actin GFP mice and C57 BL/6J wild-type mice at 8-10 weeks of age were selected.According to the requirements of the experiment,they were randomly divided into six groups.(1)Sham operation group:eight C57 BL/6J wild-type mice were used when only the lamina was removed without injury.(2)Spinal cord contusion injury group:eight C57 BL/6J wild-type mice were used.(3)Spinal cord crush injury group:eight C57 BL/6J wild-type mice were used.(4)Conjoined symbiotic spinal cord strike injury group:β-actin GFP mice with green fluorescent blood were surgically stitched together with C57 BL/6J wild-type mice,using eight β-actin GFP mice and eight C57 BL/6J wild-type mice.(5)Mr BMT-X Ray group(using PLX5622 to eliminate the spinal microglia and bone marrow transplantation with X-ray radiation):Bone marrow cells from four CX3CR1 creER-/+::LSL-BDNF-/+-tdTomato mice were extracted and transplanted into eight C57 BL/6J wild-type mice for spinal cord injury modeling.(6)Mr BMT-Busulfan group(using PLX5622 to eliminate the spinal microglia and bone marrow transplantation with Busulfan):Bone marrow cells from four CX3CR1+/GFP mice were transplanted into eight C57 BL/6J wild-type mice.The percentage of cell transplantation replacement in this group was observed,and the spinal cord injury model was not established in this group.The sham operation group,spinal cord contusion injury group and spinal cord crush injury group were sampled by perfusion on day 14 after spinal cord injury.The conjoined symbiotic spinal cord strike injury group was sampled by perfusion on day 7 after spinal cord injury.Mr BMT-X Ray group was sampled by perfusion on day 28 after spinal cord injury.Mr BMT-Busulfan group was sampled by perfusion on day 28 after transplantation.The sampling site was a 1.2 cm long spinal cord with the T10 segment as the center.In the Mr BMT-X Ray group and Mr BMT-Busulfan group,additional mouse brain tissue was retained to see if it would lead to brain transplantation and replacement.The number and proportion of transplanted and replaced cells in the damaged area were measured using transgenic mice,symbiosis and immunofluorescence. RESULTS AND CONCLUSION:Compared with the traditional peripheral blood transplantation(9.8%)of mice in the conjoined symbiotic spinal cord strike injury group,the new transplantation methods,Mr BMT-X Ray and Mr BMT-Busulfan,could greatly improve the proportion of spinal microglia transplantation and replacement,which could reach 84.8%and 95.6%,respectively.The difference was significant(P<0.05).The results showed that Mr BMT-X Ray and Mr BMT-Busulfan could achieve efficient replacement of spinal microglia cells,and could improve the problems of low cell transplantation efficiency,few survival numbers and unclear differentiation of the traditional cell transplantation methods.In addition,Mr BMT-X Ray can only replace the microglia in the spinal cord,while Mr BMT-Busulfan could avoid brain inflammation and injury caused by X-ray radiation transplantation.
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BACKGROUND:Previous animal studies have shown that riluzole can inhibit neuroinflammatory response after spinal cord injury and promote functional recovery in injured rats,but the study on whether it can regulate the expression of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome in the acute stage is lacking. OBJECTIVE:To observe whether riluzole can reduce microglial pyroptosis and promote functional recovery after spinal cord injury by modulating NLRP3 inflammasome through animal experiments,histological experiments and molecular biology experiments. METHODS:Female SD rats were divided into sham operation,model and riluzole groups,with 12 rats in each group.In addition to the sham operation group,T10 spinal cord injury was conducted in rats.The model group was treated with intraperitoneal administration of riluzole with solvent cyclodextrin.The riluzole group was treated with a 4 mg/kg dose of riluzole injection.The effect of riluzole on motor function recovery was assessed using the BBB score and inclined plane test.The recovery of sensory-evoked potential and motor-evoked potential was measured by electrophysiology.Hematoxylin-eosin staining was used to evaluate spinal cord tissue repair.The regulatory effects of riluzole on NLRP3,Caspase-1 and gasdermin D protein expression in spinal cord tissues were detected by western blot assay.ELISA was utilized to detect the expression levels of inflammatory factors interleukin-1β and interleukin-18.The effects of riluzole on the expression of NLRP3,Caspase-1,gasdermin D and interleukin-1β in microglial cells of the injured spinal cord were determined by immunofluorescence staining. RESULTS AND CONCLUSION:(1)At 35 days after spinal cord injury,BBB score and inclined plane test score in the riluzole group were higher than those in the model group(P<0.05).(2)At 3 days after spinal cord injury,the protein expressions of NLRP3,cleaved Caspase-1,gasdermin D-N(N-terminal domain),interleukin-1β,and interleukin-18 in the spinal cord homogenate of the riluzole group were significantly lower than those of the model group(P<0.05).(3)At 3 days after spinal cord injury,the fluorescence intensity of NLRP3,Caspase-1,gasdermin D and interleukin-1β in the riluzole group was significantly lower than that in the model group(P<0.05).(4)At day 35 after spinal cord injury,hematoxylin-eosin staining showed that the area of spinal cord injury in the riluzole group was smaller than that in the model group.Electrophysiological tests showed that the latency periods of sensory-evoked potential and motor-evoked potential in the riluzole group were shorter than those in the model group,and the latency period of wave amplitude in the riluzole group was higher than that in the model group.(5)These results suggest that riluzole can promote the repair of injured spinal cord tissue,promote the repair of nerve conduction function,and further promote the recovery of motor function in rats with spinal cord injury,which may be achieved through the regulation of NLRP3 inflammasome and the reduction of microglial pyroptosis.
الملخص
BACKGROUND:Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system mediated by T cells.The Toll-like receptors(TLRs)/myeloid differentiation factor 88(MyD88)/nuclear factor kappa-B(NF-κB)signaling pathway plays an important role in the development of the disease.Exploring the specific mechanism of the signaling pathway is essential for further treatment of the disease and improving the prognosis of patients. OBJECTIVE:To review the TLRs/MyD88/NF-κB signaling pathway and its role in multiple sclerosis/experimental autoimmune encephalomyelitis models,which provides new ideas and strategies for the treatment of multiple sclerosis by inhibiting the TLRs/MyD88/NF-κB signaling pathway. METHODS:The literature related to the topic from January 2002 to December 2022 was searched in CNKI,WanFang and PubMed databases.A total of 61 articles were finally included for analysis. RESULTS AND CONCLUSION:The TLRs/MyD88/NF-κB signaling pathway is an important pathway that triggers a pro-inflammatory immune response.The TLRs/MyD88/NF-κB signaling pathway plays an important role in the development of multiple sclerosis by regulating the antigen presentation of dendritic cells,destroying the integrity of the blood-brain barrier,and promoting the activation of T cells,B cells and microglia.By targeting TLRs,MyD88 and NF-κB molecules,inhibiting the activation or signal transduction of TLRs,MyD88 and NF-κB,and reducing the secretion of pro-inflammatory factors,multiple sclerosis can be treated.Animal studies have shown that active ingredients of traditional Chinese medicines,such as flavonoids and glycosides,and traditional Chinese medicine compound formulas,such as Buyang Huanwu Tang,can also treat experimental autoimmune encephalomyelitis by regulating the TLRs/MyD88/NF-κB signaling pathway,which points to the direction of searching for medicines targeting the TLRs/MyD88/NF-κB signaling pathway for the treatment of multiple sclerosis.
الملخص
BACKGROUND:Microglia cells play a major role in maintaining the balance as well as the development and function reconstruction of the central nervous system.As a histone deacetylase inhibitor,Scriptaid can inhibit neuroinflammation and enhance neuroprotection. OBJECTIVE:To investigate the effect of silk fibroin methacryloyl hydrogel loaded with Scriptaid on the behaviors of microglia cells. METHODS:Microglia(BV2 cells)were cultured in medium containing different concentrations of Scriptaid(0,0.1,0.5,1,2,5,10 μmol/L).The optimal concentration of Scriptaid was screened by the CCK-8 assay and live/dead cell staining.Silk fibroin methacryloyl hydrogels loaded with or without Scriptaid were prepared using photocuring.The micromorphology,swelling properties,mechanical properties,slow release properties,and hydrophilicity of the hydrogels were characterized.Microglia(BV2 cells)were inoculated in the subventricular region of 24-well Transwell and cultured in five groups.In the control group,the cell culture medium was added to the lower chamber.In the lipopolysaccharide group,Scriptaid group,hydrogel group,and drug-loaded hydrogel group,cell culture media containing lipopolysaccharide were added into the lower chamber.After 24 hours of lipopolysaccharide intervention,in the Scriptaid group,hydrogel group and drug-loaded hydrogel group,Scriptaid,silk fibroin methacryloyl hydrogel,and silk fibroin methacryloyl hydrogel loaded with Scriptaid were added to the upper chamber,respectively.The culture medium was replaced with ordinary culture medium and continued to culture for 24 hours.The cell viability was detected by CCK-8 assay,and the cell phenotype was detected by immunofluorescence staining of induced nitric oxide synthase and arginase 1. RESULTS AND CONCLUSION:(1)Compared with the group without Scriptaid,the viability and number of BV2 cells were decreased after Scriptaid added.When Scriptaid 2 μmol/L or above was added,the cell viability was lower than the standardized cell viability(70%),and the number of BV2 cells was significantly reduced.Therefore,1 μmol/L Scriptaid was selected to be loaded into the hydrogel.(2)Characterization experiments showed that the addition of Scriptaid did not affect the microscopic morphology,swelling rate of water absorption,compression modulus and hydrophilicity of silk fibroin methacryloyl hydrogel,and silk fibroin methacryloyl hydrogel had slow release performance.(3)The result of CCK-8 assay showed that compared with the control group,silk fibroin methacryloyl hydrogel significantly increased the viability of BV2 cells(P<0.001).(4)Immunofluorescence staining showed that compared with the control group,the expression of inducible nitric oxide synthase was increased in the lipopolysaccharide group(P<0.01);the expression of inducible nitric oxide synthase was decreased(P<0.01)and the expression of arginase 1 was increased(P<0.001)in the drug-loaded hydrogel group;the expression of arginase 1 was increased in the Scriptaid group(P<0.01).(5)The results indicate that Scriptaid-loaded silk fibroin methacryloyl hydrogel is able to promote polarization of microglia to the M2 type after lipopolysaccharide induction.