The Study On The Protective Effects Of Ischemic Postconditioning On Liver Ischemia Reperfusion Injury In Rats

【Objective】To investigate the protective effects of ischemic postconditioning on liver ischemic reperfusion injury and the effects of ischemic postconditioning on expression of liver nitric oxide synthase in rats, and to provide a theoretical basis for the clinical application of this technology.【Methods】The model of 70% hepatic ischemic reperfusion was constructed in SD male rat. Sixty SD rats were randomly divided into five groups: sham group (SO group),ischemia reperfusion group (IR group) and ischemic postconditioning group (IPO group),IPO+endothelial nitric oxide synthase inhibitor(ADMA group),ischemic postconditioning group+ inducible nitric oxide synthase inhibitor(AG group). In group IPO, rats were treated as IR group, but at the onset of reperfusion, reflow was initiated with 10s of full blood flow, followed by 10s of re-occlusion, repeated six times. On the basis of IPO group just 5 minutes before the onset of reperfusion, rats in group ADMA and AG were given ADMA(3mg/kg) or AG(100mg/kg) as intravenous boluses. by dorsal penile vein. After ishcemic for 60minutes and reperfusion for 3 hours, changes of ALT,AST and NO in serum and changs of SOD,MDA and MPO in liver tissues were compared. Western Blot was used to check the expression of eNOS and iNOS protein in the reperfusion liver tissues. Histopathological changes were observed by light microscope.【Results】1,Compared with the SO group, ALT,AST and NO in serum were significantly higher than in the IR group, and the MDA and MPO content significantly higher whereas SOD activity was significantly lower in the IR group (p<0.01). And the protein expression of NOS also obviously increased, In group IR, it shows typical pathological changes of ischemic-reperfusion injury.2,Compared with the IR group, ALT,AST and NO in serum were significantly lower than in the IPO group, and the MDA and MPO content was significantly lower whereas SOD activity was significantly higher in the IPO group (p<0.01). And the protein expression of NOS also obviously increased. The pathological changes of ischemic reperfusion injury were extenuated in group IPO.3,Compared with the IPO group, ALT,AST in serum were significantly higher and NO in serum were significantly lower than in the ADMA group. And the MDA and MPO content was significantly higher whereas SOD activity was significantly lower in the ADMA group (p<0.01). The protein expression of eNOS obviously decreased. The pathological changes of ischemic-reperfusion injury were aggravated in group ADMA.4,Compared with the IPO group, NO in serum were significantly lower than in the AG group(p<0.01). And the protein expression of iNOS obviously decreased. But There were no significant differences in ALT,AST,MDA,MPO and SOD between the two groups(p<0.05). The pathological changes of ischemic-reperfusion injury also had no differences.【Conclusions】Ischemic postconditioning can protect liver from ischemic reperfusion injury in rats. Its mechanism might be related with the enhancement of antioxidantion and the inhibition of the netrophilic leukocyte recruitment and the induction of eNOS and NO.