RESUMO
Aim To discuss whether specific mitochon-drial ATP-sensitive potassium channel opener diazoxide ( DZ ) postconditioning activates RISK signaling path-way to protect isolated rat hearts against ischemica reperfusion injury ( IRI ) . Methods Langendorff de-vice was used to establish rat in vitro model of myocar-dial ischemia reperfusion. SD rats were randomly di-vided into normal group ( NOR ) , control group ( CON ) , diazoxide after treatment group ( DZ ) , and LY294002 antagonistic nitrogen Triazine group ( DZ +LY) , with 8 cases in each. The following was com-pared:①whether heart function of each group changed at the end of equilibration and reperfusion; ② at the end of myocardial perfusion and separation, protein was extracted, and protein kinase B ( PKB / Akt ) , P70S6 kinase (P70S6K), endothelial nitric oxide syn-thase ( eNOS) phosphorylation level of expression were analysed by Western blot. Results ① Indicators of changes in heart function: for DZ group at the end of reperfusion , HR , CF , LVDP , LVEDP , +d p/d tmax and -dp/dtmax were significantly better than those in CON group and DZ + LY group ( P 0.05 ) . Conclusion Diazoxide postconditioning through the activation of RISK signa-ling pathway can protect isolated rat hearts against is-chemia reperfusion injury.
RESUMO
Objective To study the protective effect of glucocorticoid preconditioning on the myocardial ischemic and reperfused hearts.Methods Totally 18 rabbits were randomly divided into three groups: myocardial ischemia-reperfusion model(model),high-dose glucocorticoid given by one time group(high-dose group) and low-dose glucocorticoid given by several times group(low-dose group),with six rabbits in each group.Myocardial ischemia was induced by left anterior descending coronary artery ligation.ST segments were recorded by the BL-420 biological signal acquisition system.Plasma malondial dehyde(MDA) was examined before ischemia,at 15 min after ischemia and 30 min after reperfusion;ischemic heart muscles were prepared with cryotomy and stained histochemically.Succinic dehydrogenase activity was observed in the ischemic region.Results There was shorter time of ST-segment recovery in the high-dose group and the low-dose group than that in the model group.Serum level of MDA in the high-dose group was lower than in the low-dose group(P