RESUMO
Objective To investigate the role of nitric oxide synthase(NOS)in the regulation of myocardial ischemia-reperfusion(IR)injury in ovariectomized(OVX)rats.Methods A total of 132 female SD rats were subjected,and 48 of them were randomly divided into sham operation group,IR group,OVX group and combined group,with 12 in each group.In order to explore the role of endothelous NOS(eNOS)and inducible NOS(iNOS)in ovariectomization increasing myo-cardial IR injury,another 84 mice were divided into negative sham group,negative IR group,nega-tive combined group,eNOS+IR group,eNOS combined group,iNOS small interfering RNA(si-iNOS)+IR group and si-iNOS combined group,with 12 in each group.The mice of the corre-sponding groups were injected with adeno-associated virus(AAV)overexpressing eNOS or knoc-king down iNOS via tail vein before OVX modeling.Myocardial infarct size,serum levels of lac-tate dehydrogenase(LDH)and creatine phosphokinase isoenzyme(CK-MB),LVEF,LVFS,and expression levels of eNOS and iNOS in the myocardial tissues were measured.Results The com-bined group had significantly increased level of iNOS in myocardium,larger myocardial infarct size and elevated serum LDH and CK-MB levels,but decreased myocardial expression of eNOS and LVEF and LVFS values than the IR group(P＜0.05).When compared with the negative combined group,the myocardial infarct size and serum LDH and CK-MB levels were decreased[(23.51±3.22)％and(26.21±2.93)％vs(58.78±5.42)％,(176.31±15.48 and 169.52±17.12 vs 328.85±37.12 U/L,35.41±6.41 and 34.77±5.94 vs 88.73±9.14 U/L,P＜0.05],and the LVEF and LVFS values were increased[(41.31±3.12)％and(42.09±3.41)％vs(30.77± 2.15)％,(21.47±1.57)％and(21.32±1.42)％vs(15.92±1.33)％,P＜0.05]in the eNOS com-bined group and si-iNOS combined group.Conclusion The decrease of eNOS expression and in-crease of iNOS expression are related to the aggravation of myocardial IR injury in OVX rats.