Mechanisms Of Preconditioning Against Ischemia Reperfusion Injury In Rats Liver

Objective: To study late preconditioning(PC) against ischemia/reperfusion(I/R) injury in rats liver. Methods 168 SD rats were divided into four groups: (1) S group: n=42,sham-operated control; (2)I/R group:n=42,Subjected to ischemic for 70-minute ischemia; (3) PC group: n=42,Two cycles of 5 min of ischemia followed by 5 min of reperfusion was performed before I/R;(4)PC+L group: n=42, L-NNA was administered before preconditioning then 70min ischemia. Followed by continuous reperfusion, serum ALT MDA NO NOS GSH GST and GSH-PX were examined in all groups during 0-48h; HSP 70 in the liver tissue were quantitatively analyzed and located by immunocytochemical technique. HSP 70 mRNAwere analyzed by PAGE Results Serum ALT and MDA in either I/R and PC+L group were markedly increased than in PC group (P<0.01) at any point after reperfusion.There is not significant difference between I/R group and P+L group during 0-3h(p>0.05) but during 6-48h(p<0.01). ALT and MDA were increased in PC+L vs PC group(p<0.05) and markedly decreased than I/R group during 6-48h(p<0.01). Expresstion of HSP 70 in PC and P+L group is gradually increased higher than in I/R group during 6-48h (P<0.01) ,so as HSP70 mRNA during l-12h.(p<0.01).Conc!usions: NO and HSP 70 might be participate in the protection against liver ischemia/reperfusion injury and NO might be protect liver in early preconditioning and HSP 70 might be associate with late preconditioning.