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Protective effects of propofol pretreatment against ischemia-reperfusion injury in isolated rat heart

Objective To determine if nitric oxide(NO)is involved in the protective effect of propefolpretreatment(PP)against ischemia-reperfusion injury(I/R).Methods Eighteen male SD rats weighing 250-350 gwere randomly divided into 3 groups(n=6 each):A normal control;B I/R and C PP+I/R.The animals werekilled by a knock on the head.Hearts were immediately removed and passively perfused in a Langendorff apparatusat 37℃ with oxygenated(95% O_2,5% CO_2)Krebs-Hensleit(KH)solution at 90 cm H_20.In group B and C thehearts were subjected to 35 min global ischemia by suspension of perfusion followed by 120 min reperfusion.Ingroup C the hearts were perfused with KH solution containing 50 μmol·L~(-1) propofol for 10 min followed by 10 minpropefol wash-out before I/R.At the end of reperfusion myocardial specimen was obtained from left ventricle andhomogenized for determination of the activities of total NOS(iNOS+cNOS)aand SOD and expression of iNOS andheme-oxygenase-1(HO-1)and content of NO,The relationship between the NO content and activity and/orexpression of these protein and enzyme were analyzed by correlation analysis.Myocardium was examined with lightand electron microscope.Results The myocardial NO content,tNOS activity and tSOD activity were significantlylower in group B than in group A and C and there was no significant difference in NO content,and activity of tNOSand tSOD between group A and C.The NO content was positively correlated with tNOS and negatively correlatedwith Mn-SOD aetivety and HO-1 expression.Microscopic examination showed severe cell injury or necrosis in groupB but little injury in group C.Conclusion Ischemia and reperfusion decrease activity of tNOS and SOD butincrease HO-1 expression resulting in decrease in NO content.Propofol pretreatment protects the heart from I/Rinjury through increase in NOS and antioxidases(Mn-SOD,HO-1).