S-甲基异硫脲抑制梗塞兔心肌诱导型一氧化氮合酶的表达

目的　研究S 甲基异硫脲 (SMT)对梗塞兔心肌组织内诱导型一氧化氮合酶 (iNOS)活性的抑制作用。方法　对左房心耳和心尖中间弯曲的冠状动脉前外侧枝进行结扎 ,建立心肌梗塞模型。应用L 精氨酸转换为L 胍氨酸法测定家兔心肌梗塞区和非梗塞区诱导型一氧化氮合酶的活性 ,同时观察S 甲基异硫脲和NW 硝基 L 精氨酸 (L NNA)对诱导型一氧化氮合酶活性的抑制作用。结果　冠状动脉结扎后 48h、72h和 96h ,心肌梗塞区诱导型一氧化氮合酶活性比非手术组显著增加 (P <0 0 1) ,并在 72h达到峰值 ;梗塞后 72h左室壁cGMP含量也明显增加 (P <0 0 1) ;同时SMT能明显降低梗塞区心肌诱导型一氧化氮合酶的活性 (P<0 0 1)。结论　SMT能明显抑制梗塞兔心肌iNOS的活性 ,提示SMT对改善心脏功能和治疗急性心肌梗塞具有一定的临床效果。

S-methylisoureainhibits the expression of an inducible nitric oxide synthase in infarcted rabbit myocardium

AIM To investigate the inhibitory effect of S methylisourea and N W nitro L arginine ( L NNA) on the induction of inducible nitric oxide synthase (iNOS) in infarcted rabbit myocardium METHODS To produce myocardial infarction, the anterolater branch of the circumflex coronary artery was occluded midway between the left atrial appendage and apex The activity of iNOS in infarcted and non infarcted areas of rabbit myocardium was measured by the conversion of L [ 14 C] arginine to L [ 14 C] citrulline RESULTS The activity of iNOS in infarcted myocardium given 48 hour, 72 hour, and 96 hour after coronary occlusion was significantly increased as compared with that of non operation group (Sham) ( P <0 01), with peak activity occurring 72 hours after coronary occlusion 72 hours after coronary occlusion, cyclic GMP(cGMP) levels in left ventricle wall was significantly increased ( P< 0 01), and the activity of iNOS and cNOS in infarcted regions significantly inhibited by SMT and L NAA ( P< 0 01), respectively CONCLUSION SMT can significantly inhibit the activity of iNOS in infarcted rabbit myocardium These findings suggest that SMT may be beneficial in improving cardiac performance and in the treatment of acute myocardial infarction