Effect Of Dexamethasone Preconditioning On Hepatic Ischemia-reperfusion Injury In Rats In Different Period

Objective: To explore the potiental protective effect of dexamethasone（DEX）on hepatic ischemie-reperfusion injury in different period in rats,and the changes of pathological and inducible nitric oxide synthase (iNOS)activity before and after the intervention of dexamethasone.Methods: Forty-two SD rats were randomly divided into three groups,sham operation group(S), normal saline group(NS), and dexamethasoneprecon- dition group(DEX)．NS group and DEX group were both divided into3 subgroups according to different reperfusion time. In S groups, the abdomenof rats was only opened and closed. In NS and DEX group of animals,Pringle’S manoeuvre was applied for 30 minutes, then reperfusionrespectively 1 hour, 6 hours, 12 hours. Before reperfusion 5 mg/kg normalsaline and dexamethasone was injected via tail intravenous respectively in NSand DEX group. The protein of inducible nitric oxide synthase (iNOS) in livertissue was detected by western blotting methods. Hepatic function wasunderstan by detection serum biochemical enzyme. Hepatic pathologicalchanges were measured by HE staining.Results: Compared with other groups, the activity of iNOS in NS groupwas much higher (p<0.05), which decreased after the intervention ofdexamethasone (p<0.01), especially in DEX12h. Pathological slices of livertissue showed significant damage in IR group and which was and lessenedafter intervention (p<0.01).Conclusion: The expression of iNOS protein in normal liver is little, but increased obviously in ischemie-reperfusion induced hepatic injury. With theintervention of dexamethasone, the activity of iNOS was reduced inischemie-reperfusion induced hepatic tissue and played as a protective effectin ischemie-reperfusion induced hepatic injure.