Zhao Hong-Wei, Qin Feng, Liu Yi-Xia, Huang Xi, Ren Ping
Laboratory of Ethnopharmacology, West China Hospital, Sichuan University, Chengdu, PR China.
Tohoku J Exp Med. 2008 Dec;216(4):309-16. doi: 10.1620/tjem.216.309.
Considerable evidence indicates that apoptosis plays a critical role in acute myocardial infarction. We have previously shown that Guan-Xin-Er-Hao (GXEH), a Chinese medicine formula, attenuates postischemia myocardial apoptosis. The present study was designed to determine the mechanisms by which GXEH exerts its antiapoptotic effect. Adult male Sprague-Dawley rats were randomized to receive vehicle or GXEH (5 or 15 g/kg) orally 30 min before ischemia and subjected to myocardial ischemia of 3 h (apoptosis peak) or 24 h (necrosis peak) for determination of infarct size. Compared with rats receiving vehicle, those rats treated with GXEH (15 g/kg) showed significantly reduced infarct size, the reduced myocardial apoptosis, as judged by the decreases in TUNEL-positive staining (22.40 +/- 5.68% vs. 40.31 +/- 10.58%, p < 0.01), and the decrease in the degree of caspase-3 activation (82.97 +/- 10.54 vs. 159.95 +/- 9.16 mumol cleaved acetyl-Asp-Glu-Val-Asp-p-nitroanilide/mg protein, p < 0.01). Treatment with GXEH (15 g/kg) significantly reduced the release of mitochondrial cytochrome c, a primary mediator of apoptosis, the degree of caspase-9 activation, and the Bax/Bcl-2 ratio. Caspase-9 cleaves and activates caspase-3. Bax promotes apoptosis, while Bcl-2 inhibits apoptosis. Thus, the antiapoptotic mechanisms of GXEH may involve the mitochondrial cytochrome c-mediated caspase-3 activation in cardiomyocytes after acute myocardial infarction. Taken together, GXEH tilted the balance between Bax and Bcl-2 toward an antiapoptotic state, decreased mitochondrial cytochrome c release, reduced caspase-9 activation, and attenuated subsequent caspase-3 activation and postischemic myocardial apoptosis in rats. GXEH may be used as a promising agent for future treatment of cardiovascular diseases.
大量证据表明，细胞凋亡在急性心肌梗死中起关键作用。我们之前已经表明，中药方剂冠心二号（GXEH）可减轻缺血后心肌细胞凋亡。本研究旨在确定GXEH发挥抗凋亡作用的机制。成年雄性Sprague-Dawley大鼠在缺血前30分钟随机口服给予溶媒或GXEH（5或15克/千克），并进行3小时（凋亡高峰）或24小时（坏死高峰）的心肌缺血以测定梗死面积。与接受溶媒的大鼠相比，接受GXEH（15克/千克）治疗的大鼠梗死面积显著减小，心肌细胞凋亡减少，这通过TUNEL阳性染色的减少来判断（22.40±5.68%对40.31±10.58%，p<0.01），以及caspase-3激活程度的降低（82.97±10.54对159.95±9.16微摩尔裂解的乙酰天冬氨酸-谷氨酸-缬氨酸-天冬氨酸-对硝基苯胺/毫克蛋白，p<0.01）。GXEH（15克/千克）治疗显著降低了线粒体细胞色素c的释放，细胞色素c是细胞凋亡的主要介质，降低了caspase-9的激活程度以及Bax/Bcl-2比值。Caspase-9裂解并激活caspase-3。Bax促进细胞凋亡，而Bcl-2抑制细胞凋亡。因此，GXEH的抗凋亡机制可能涉及急性心肌梗死后心肌细胞中线粒体细胞色素c介导的caspase-3激活。综上所述，GXEH使Bax和Bcl-2之间的平衡向抗凋亡状态倾斜，减少线粒体细胞色素c释放，降低caspase-9激活，并减轻大鼠随后的caspase-3激活和缺血后心肌细胞凋亡。GXEH可能成为未来治疗心血管疾病的一种有前景的药物。
