Shen J G, Quo X S, Jiang B, Li M, Xin W, Zhao B L
Institute of Chinese Medicine, First Military Medical University, Guangzhou, China.
Biochim Biophys Acta. 2000 Feb 21;1500(2):217-26. doi: 10.1016/s0925-4439(99)00109-x.
The inhibitory effects of Chinonin, a natural antioxidant extracted from a Chinese medicine, on apoptotic and necrotic cell death of cardiomyocytes in hypoxia-reoxygenation process were observed in this study. The possible mechanisms of Chinonin on scavenging reactive oxygen species and regulating apoptotic related genes bcl-2 and p53 were also investigated. Neonatal rat cardiomyocytes were subjected to 24-h hypoxia and 4-h reoxygenation. Cell death was evaluated by DNA electrophoresis on agarose gel, cell death ELISA and annexin-V-FLUOS/propidium iodide (PI) double staining cytometry. Hypoxia caused the increase of apoptotic rates and the release of lactate dehydrogenase (LDH), while reoxygenation not only further increased the apoptotic rates and leakage of LDH, but also induced necrosis of cardiomyocytes. In addition, hypoxia increased the levels of NO(2)(-)/NO(3)(-) and thiobarbituric acid reacted substances (TBARS), while reoxygenation decreased NO(2)(-)/NO(3)(-), but further increased TBARS in the cultured media. Moreover, hypoxia up-regulated the expression levels of bcl-2 and p53 proteins, while reoxygenation down-regulated bcl-2 and further up-regulated p53. Chinonin significantly decreased the rates of apoptotic and necrotic cardiomyocytes, and inhibited the leakage of LDH. It also diminished NO(2)(-)/NO(3)(-) and TBARS, down-regulated the expression level of p53 protein, and up-regulated bcl-2 protein, respectively. The results suggest that Chinonin has preventive effects against apoptotic and necrotic cell death and its protective mechanisms are related to the antioxidant properties of scavenging nitric oxide and oxygen free radicals, and the modulating effects on the expression levels of bcl-2 and p53 proteins.
本研究观察了从一种中药中提取的天然抗氧化剂秦皮素对心肌细胞在缺氧复氧过程中凋亡和坏死性细胞死亡的抑制作用。还研究了秦皮素清除活性氧以及调节凋亡相关基因bcl-2和p53的可能机制。将新生大鼠心肌细胞进行24小时缺氧和4小时复氧处理。通过琼脂糖凝胶DNA电泳、细胞死亡ELISA以及膜联蛋白V-荧光素/碘化丙啶（PI）双染细胞术评估细胞死亡情况。缺氧导致凋亡率增加以及乳酸脱氢酶（LDH）释放，而复氧不仅进一步增加凋亡率和LDH泄漏，还诱导心肌细胞坏死。此外，缺氧增加了培养基中NO(2)(-)/NO(3)(-)和硫代巴比妥酸反应物（TBARS）的水平，而复氧降低了NO(2)(-)/NO(3)(-)，但进一步增加了TBARS。而且，缺氧上调了bcl-2和p53蛋白的表达水平，而复氧下调了bcl-2并进一步上调了p53。秦皮素显著降低了凋亡和坏死心肌细胞的比率，并抑制了LDH泄漏。它还分别降低了NO(2)(-)/NO(3)(-)和TBARS，下调了p53蛋白的表达水平，并上调了bcl-2蛋白。结果表明，秦皮素对凋亡和坏死性细胞死亡具有预防作用，其保护机制与清除一氧化氮和氧自由基的抗氧化特性以及对bcl-2和p53蛋白表达水平的调节作用有关。
