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目的:探讨外源性多巴胺诱导PC12细胞凋亡以及人参皂甙Rg1保护作用的分子机制。方法:流式细胞仪定量测定PC12细胞的凋亡和Bcl-2、Bax蛋白的表达;电子显微镜观察PC12细胞的形态;凝胶电泳评价DNA的断裂;荧光分光光度计法测定caspase-3的活力;半定量RT-PCR分析bcl-2和bax mRNA的表达。结果:多巴胺(浓度为0.15、0.30、0.45和0.60mmol/L)诱导PC12细胞凋亡,各剂量组细胞凋亡率分别从对照组1.1％±0.4％增加到41％±3％,46.4％±2.7％,53％±3％和64.5％±2.7％;人参皂甙Rg1 10μmol/L预处理24h后,较多巴胺0.45mmol/L单独处理时,PC12细胞的凋亡率和caspase-3的活力分别从53％±3％和683±8(平均荧光强度)下降到1.9％±0.6％和325±5,Bcl-2蛋白阳性率从14.3％±1.1％增加到25.9％±1.6％,Bax蛋白阳性率从48％±3％下降到35％±3％。结论:人参皂甙Rg1通过抑制cas-pase-3的激活并调节Bcl-2和Bax两者间蛋白的比值对抗多巴胺对PC12细胞凋亡的诱导作用。
Objective: To investigate the molecular mechanism of exogenous dopamine-induced apoptosis in PC12 cells and the protective effect of ginsenoside Rg1. Methods: Apoptosis and expression of Bcl-2 and Bax proteins were detected by flow cytometry. The morphology of PC12 cells was observed by electron microscope. DNA fragmentation was evaluated by gel electrophoresis. The activity of caspase-3 was measured by fluorescence spectrophotometry. Semiquantitative RT-PCR analysis of bcl-2 and bax mRNA expression. RESULTS: Dopamine (at concentrations of 0.15, 0.30, 0.45, and 0.60 mmol/L) induced apoptosis in PC12 cells. The apoptosis rate of each dose group increased from 1.1% ± 0.4% in the control group to 41% ± 3% in the control group, 46.4% ± 2.7%, 53%±3% and 64.5%±2.7%; after 24 hours of pretreatment with ginsenoside Rg1 10 μmol/L, more than 0.45 mmol/L of p-amine alone, the apoptosis rate and caspase-3 activity of PC12 cells were 53%±3% and 683±8 (mean fluorescence intensity) decreased to 1.9%±0.6% and 325±5, and the positive rate of Bcl-2 protein increased from 14.3%±1.1% to 25.9%±1.6%. Bax protein positive rate From 48% ± 3% to 35% ± 3%. CONCLUSION: Ginsenoside Rg1 can inhibit the induction of apoptosis of PC12 cells by inhibiting the activation of cas-pase-3 and regulating the ratio of protein between Bcl-2 and Bax.