Study On PGI₂/TxA₂ Receptor(IP/TP) And COX-2 In Ischemia-reperfusion Injury After Liver Transplantation In Rats

Objective:To study the expression of PGI₂/TxA₂ receptor(IP/TP)and cyclooxygenase-2(COX-2)in rat sufferring from ischemia-reperfusion injury after liver transplantation and its mechanism.Method:Rats were randomly divided into three groups:control group(E1),orthotropic liver transplantation group(E2)and Nimesulide associated with orthotropic liver transplantation group(E3).The samples were collected at 0,3,6,12 and 24h after operationv,of which the expression of COX-2 mRNA,IPmRNA and TPmRNA was detected by RT-PCR,expression and location of COX-2 detected with immunohistochemistry, extent of liver injury classified with Hematoxylin Eosin staining,and serum ALT,AST detected to tell change of liver enzyme.Result:Immunohistochemistry in E2 Group showed that COX-2 expression was significantly increased,mainly distributed in the district of liver sinusoidal endothelial cells,whereas in liver cells and macrophage cells, COX-2 expression in E3 group was significantly decreased.Expression of IPmRNA,TPmRNA,COX-2mRNA in the E2 group was significantly increased than that of E1 group(P＜0.05),and ratios of IP / TP increased(P＜0.05),TP and IP in E3 group were significantly lower(P＜0.05),and the ratios was reduced than E2 group(P＜0.05);From HE staining in E2 group liver injury can be seen Obviously,and liver damage in E3 group reduced than E2 significantly.Serum AST and ALT in the E2 group was higher than that of E3 group of which was decreased notely(P＜0.05).The above phenomena were up to the most in six hours of reperfusion.Conclusion:The balance of IP/TP play a great role in the ischemia reperfusion injury of liver transplantation and liver transplantation IRI.Transplantation IRI can be ameliorated whih changing imbalance of IP/TP in succession with inhibition of liver COX-2.