Mechanism Of TLR4/Src Signaling Pathway In Pyroptosis Of Hippocampus Induced By Hepatic Ischemia-reperfusion In Rats

Background: liver transplantation is the most effective treatment for end-stage liver disease,and Hepatic ischemia reperfusion(HIR)is an inevitable process during liver transplantation that can cause the release of reactive oxygen species and inflammatory mediators,which have negative effects on the hippocampus.To some extent restrict the recovery of patients after operation.In addition,pyroptosis is proinflammatory programmed cell death and plays an important role in ischemia-reperfusion.pyroptosis relies on caspase 1,impels the formation of NLRP3 inflammasome and release of proinflammatory and cytokine,and eventually cell death.while Toll like receptor 4(TLR4)is a protein that plays an important role in ischemic brain diseases,mainly located in macrophages and dendritic cells,which are closely involved in the immune function of the body.It can activate pyroptosis through TLR4-NLRP3-GSDMD pathways.The activation of TLR4 is also associated with phosphorylation of Src.However,the influence of HIR on hippocampus pyroptosis in rats via the TLR4/Src signaling pathway remains unknown.Methods: HIR models was established in the 6-week-old SD rats with ischemia for 1.5 h,reperfusion for 6h,24 h,3d and 7d,respectively,and the samples were extracted.First,we detected oxidative stress levels,IL-18 and IL-1β levels with enzyme-linked immunosorbent assay(ELISA),pyroptosis of the hippocampus through pyroptosis-related proteins with western blot,histopathological changes with Hematoxylin – eosin staining(HE).To further clarify pyroptosis,HIR 6 hours of rats were selected for grouping: sham operation group(sham group),hepatic ischemia reperfusion(HIR)group,Caspase 1 inhibitor Ac-YVAD-CMK + HIR group(Ac group).Other rats were divided into sham operation group(sham group),hepatic ischemia reperfusion(HIR)group,TLR4 inhibitor TAK 242 + HIR group(TAK group),Src inhibitor PP2 + HIR group(PP2 group)for mechanism of HIR on hippocampal neurons pyroptosis in rats.the expression of TLR4,p-Src and their combination by western blot and immunoprecipitation after HIR.we detected the expression of pyroptosis related protein and TLR4、p-Src by western blot,the expression of hippocampus pyroptosis by immunohistochemistry,and the correlation of TLR4 and Src by immunoprecipitation.Results: The levels of oxidative stress,IL-18,IL-1β and pyroptosis related proteins increased after reperfusion.In addition,there were histological changes such as edema and disorder of cell arrangement in arrangement.Furthermore,the expression of TLR4 and p-Src had the same trend as the expression of IL-18 and IL-1β.The interaction between TLR4 and Src increased after HIR.After inhibition of TLR4 and SRC with TAK-242 and PP2,the expression levels of TLR4,p-Src and pyroptosis-related proteins were downregulated.Conclusion: HIR induced hippocampus injury in rats,and its mechanism may be related to pyroptosis of hippocampus mediated by the TLR4/Src signaling pathway.