硫氧还蛋白的调节变化对大鼠心肌细胞凋亡的影响

Effects of altered thioredoxin expression on cardiomyocyte apoptosis in rats with acute myocardial infarction

目的:探讨血管紧张素Ⅱ受体1(AT_1)和一氧化氮合酶(NOS)对硫氧还蛋白(Trx)表达及细胞凋亡的影响。方法:SD大鼠30只,完全随机分组:假手术组(sham)、急性心肌梗死组(AMI)、氯沙坦组(LOS)、氯沙坦+硝基左旋精氨酸组(LOS+L-NNA)、硝基左旋精氨酸组(L-NNA)。用结扎冠状动脉左前降支法制备AMI模型。L-NNA抑制一氧化氮合酶,LOS阻断AT_1受体。RT-PCR半定量检测心肌Trx、Bcl-2、Bax mRNA表达,Western blotting检测Trx蛋白表达。结果:AMI组与假手术组相比较,Trx mRNA及蛋白表达增加,Bax mRNA表达增强,Bcl-2 mRNA表达降低(P<0.05)。LOS组与AMI组相比较Bcl-2mRNA,Trx蛋白表达增加(P<0.05)。L-NNA组与AMI组相比较,Trx mRNA及蛋白表达降低,Bcl-2 mR-NA表达增加(P<0.05)。LOS+L-NNA组与LOS组相比较Bax mRNA、Bcl-2 mRNA、Trx mRNA及蛋白表达均降低(P<0.05)。L-NNA组与LOS+L-NNA组相比较,Bax mRNA、Bcl-2 mRNA、Trx mRNA及蛋白表达差异无统计学意义。结论:Trx在心肌梗死大鼠中通过拮抗心肌细胞凋亡而对心肌起保护作用。大鼠急性心肌梗死过程中NOS和AngⅡ受体信号转导通路对Trx表达及细胞凋亡有重要的调节作用。

Objective：To investigate the regulatory effects of nitric oxide synthase （NOS） and angiotensin Ⅱ （ AngⅡ ） on expression of thioredoxin （Trx） and cardiomyocyte apotosis in rats with actute myocardial infarction（AMI）. Methods： Thirty SD rats were randomly divided into 5 groups （n = 6 each）： the sham operation group （ sham）, the AMI group, the losartan group （ LOS）, the losartan ＋ N-nitro-L-arginine group （ LOS ＋ L-NNA）, the N-nitro-L-arginine group （L-NNA）. The left anterior descending branch of coronary artery was ligated to develop AMI model. L-NNA was used to inhibit the NOS, as was LOS to block the ATt receptor. RT- PCR was employed to detect the Trx mRNA, Bax mRNA, Bcl-2 mRNA in myoeardium. Thioredoxin was measured by Western blotting analysis. Results： The levels of Bax mRNA, Trx mRNA and Trx protein expression were elevated,while the level of Bcl-2 mRNA was lower in AMI group than in sham group（ all P 〈 0.05 ）. Compared with AMI group, the levels of Bcl-2 mRNA and Trx protein expression were higher in LOS group. The levels of Trx mRNA and protein expression were lower,while Bcl-2 mRNA expression was higher in L-NNA group than in AMI group（ all P 〈 0.05 ）. The levels of Bax mRNA, Bcl-2 mRNA,Trx mRNA and protein expression were lower in LOS ＋ L-NNA group than in LOS group （ all P 〈 0. 05 ）. Conclusion ： Thioredoxin plays important role against cardiomyocyte apotosis in AMI rats. During acute myocardial infarction, nitric oxide synthase and angiotensin Ⅱ type 1 receptor signaling pathway may have a critical role in regulating Trx expression and myocyte apotosis.