Role Of P38MAPK On Cerebral Edema And AQP-4Expression After Rat Cerebral Ischemia Reperfusion In Rats

Objective: To observed the expression of p38mitogen-activated proteinkinase and aquaporin-4(AQP-4) after cerebral ischemia and reperfusion in ratsand explore the p38MAPK on cerebral ischemia reperfusion ischemic braintissue surrounding area AQP-4expression and brain edema.Methods:Fifty-four SPF male Sprague-Dawley rats weighing240～260g were randomlydivided into3groups: sham operation (sham)group;ischemia reperfusion (I/R)group;p38inhibitor (SB)group.The focal ischemia reperfusion rat model wasestablished by the modified suture method.The rats of I/R group and SB groupwere exposed to DMSO(10%,400μg/kg)or p38inhibitor SB203580(400μg/kg)15min before suffered from cerebral ischemia. Neurologic function was scoredat24h reperfusion after2h ischemia.Then to10%chloral hydrate excessiveanesthesia,brains were removed,where around the optic chiasm was cut into2mm coronal brain slices,H-E was used to examine brain tissueinjury,Immunohistochemical staining and Western blot used to detect theischemic brain tissue surrounding area where p-p38and AQP-4expression,wet-dry ratio was measured to estimate cerebral edema.Results: 1.The neurologic function deficit was serious in group I/R and group SBcompared to group Sham (P<0.05);compared with the I/R group, rats alleviateneurological defects SB group (P<0.05).2.Sham group rat brain was normal,compared with the I/R group, the extent of neuronal necrosis lighter SB group.3.Compared with Sham group,p-p38levels in brain tissue surrounding theischemic area I/R group rats rose (P<0.05),AQP-4expressionincreased(P<0.05),ischemic hemisphere brain water content liters higher(P<0.05);compared with the I/R group,p-p38expression in brain tissue levelsof the surrounding area SB group ischemic rats decreased(P<0.05),AQP-4downregulated(P<0.05),ischemic hemisphere brain water content reduced(P<0.05).Conclusions: p38signaling pathway participates in rat cerebralischemia upregulation of AQP-4and brain edema formation after reperfusion;blocking this pathway can attenuate AQP-4up-regulation and mitigate thecerebral edema.SB203580can inhibit the activation of p38reduce ischemicbrain tissue surrounding area increase of AQP-4expression in cerebral edema.