Tohoku J. Exp. Med., 2008, 216(4)

Antiapoptotic Mechanisms of Chinese Medicine Formula, Guan-Xin-Er-Hao, in the Rat Ischemic Heart

HONG-WEI ZHAO,¹ FENG QIN,² YI-XIA LIU,¹ XI HUANG^1,2 AND PING REN²

¹Laboratory of Ethnopharmacology, West China Hospital, Sichuan University, Chengdu, PR China
²Laboratory of Ethnopharmacology and Institute of Integrated Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha, PR China

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 μmol 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.

keywords —— Traditional Chinese medicine; Guan-Xin-Er-Hao; Apoptosis; Mitochondrial pathway.

© 2008 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2008, 216, 309-316

Correspondence: Xi Huang, Laboratory of Ethnopharmacology and Institute of Integrated Chinese and Western Medicine, Xiangya Hospital, Central South University, Changsha 410008, PR China.

e-mail: tcmhuangx59@163.com