TLR2介导小胶质细胞激活和神经炎症促进血管性痴呆进展的分子机制研究OACSTPCD

Objective To investigate the effect of TLR2 in mediating the pathological activa-tion of microglia and neuronal injury in vascular dementia(VaD)rat model and its molecular mechanisms.Methods In vitro experiments were carried out by using LPS-induced activation of hu-man microglia cell line HMC3 cells.The proliferation ability of HMC3 cells was determined by CCK-8 assay.Systemic TLR2 knockdown was performed by using Adv-TLR2 shRNA or Adv-shRNA NT.The VaD rat model was established by permanent bilateral common carotid artery occlusion(2VO).The expression levels of TLR2,NF-κB,Iba-1,Claudin-5 and ZO-1 in HMC3 cells and rats'white matter tissues were determined by Western blotting.The levels of inflammatory cytokines IL-6,IL-1β and TNF-α,and the ferroptosis-related indicators of Fe2+,malondialdehyde(MDA)and glutathione(GSH)in rats'white matter tissues were determined by ELISA.Morris water maze(MWM)test was used to determine rats'brain neuronal injury.Results The expression levels of TLR2,NF-κB and Iba-1 in the LPS group were enhanced when compared with those in the Control group(P<0.05).The expression levels of the above proteins in the Adv-TLR2 shRNA group were decreases when compared with those in the LPS groups(P<0.05).The expression levels of TLR2/NF-κB and Iba-1 were up-regulated,and those of Claudin-5 and ZO-1 were down-regulated in the white matter tissues of Model group rats,when compared with those of the Sham group,(P<0.05).In addition,the levels of inflammatory cytokines IL-6,IL-1β and TNF-α were up-regulated(P<0.05),the Fe2+and MDA levels were increased,and the GSH levels were decreased(P<0.05).TLR2 knockdown had reversed the values of above indicators in the Model+Adv-TLR2 shR-NA group when compared with those in the Model group(P<0.05).Morris water maze test showed that rats in the Model group and Model+Adv-TLR2 shRNA group took longer time to find the target quadrant(upper left quadrant)(P<0.05),stayed shorter time in the target quadrant(P<0.05)when compared with those in the Sham group,the swimming routes of rats in the four quad-rants of MWM were evenly distributed.Compared with Model group,the Model+Adv-TLR2 shRNA group showed a reversion in the values of above indicators and had a denser distribution of swim routes in the target quadrant.Conclusion Knock-down of TLR2 could inhibit the activation of mi-croglia and its mediated tight junction protein degradation and cerebrovascular barrier network leak-age,and reduce nerve damage in the vascular dementia rat model.