The Role Of RIPK1 Kinase Activity In The Pathogenesis Of Perioperative Stroke

Background:Perioperative stroke is a perioperative complication with high disability and high mortality without specific treatment.Receptor interacting protein kinase 1?RIPK1?,an essential cytoskeletal protein and signal transduction molecule in cells,is involved in the regulation of necroptosis,apoptosis and inflammation.Nevertheless,the role of RIPK1kinase activity in the perioperative stroke is still not fully understood.Objective:This work was aimed to clarify the role of RIPK1 kinase activity in the pathogenesis of perioperative stroke and to explore its possible mechanism,which may provide experimental evidences for treatment of perioperative stroke and new targets for developing neuroprotective drugs.Methods:8-10 weeks old male C57BL/6 wild-type?WT?mice were divided into sham group and MCAO group randomly.The model of cerebral ischemia-reperfusion injury was established by suture method.The suture of the MCAO group was pulled out 1 h after ischemia,and the one of the sham group was pulled out immediately after insertion.Brain tissues were collected24 hours after reperfusion.The mRNA expression of RIPK1 was detected by qRT-PCR;The protein expression of RIPK1 was detected by immunoblotting.In addition,male C57BL/6 wild-type?WT?and RIPK1 kinase dead mutant mice(Ripk1^?/?,Ripk1^K45A/K45A)were treated by MCAO.The neurobehavioral scores of the mice in each group were tested 24h after reperfusion and the brain tissues of each group were collected subsequently.The infarction volume of the brain was measured by TTC staining.The morphology of neurons in the lesion area were observed by H&E staining.The cell death of the lesion area was compared by TUNEL staining.The expression levels of inflammatory factors were detected by qRT-PCR.Results:Compared with the sham group,the neurobehavioral scores and the infarction volume of the brain were significantly increased at 24h in the MCAO group.The mRNA level and protein level of RIPK1 was significantly increased in the lesion area.Compared with the WT group,Ripk1^?/?group and Ripk1^K45A/K45A group showed a significant decrease in neurobehavioral scores and cerebral infarction volume at 24h.Compared with the WT group,the cell death and the levels of pro-inflammatory cytokines were decreased in Ripk1^?/?group.Conclusion:Blocking the kinase activity of RIPK1 has a protective effect on perioperative stroke via decreasing cell death and neuroinflammation.