大黄酚对Huh-7细胞SREBP表达及脂质代谢的影响
Effects of chrysophanol on expression of SREBPs and lipid metabolism in Huh-7 cells
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摘要: 大黄具有泻下、降脂和减肥等作用, 但其降脂药效物质及作用机制尚不清楚。本文探讨大黄的主要活性成分大黄酚(chrysophanol)对人肝癌细胞株( human liver carcinoma Huh-7 cells, Huh-7)固醇调节元件结合蛋白(sterol regulatory element-binding proteins, SREBPs)表达及脂质代谢的影响。以双荧光素酶报告基因检测试剂盒检测大黄酚对SREBP的转录抑制作用; 总胆固醇(total cholesterol, TC)和甘油三酯(triglyceride, TG)测定试剂盒检测细胞内TC、TG水平; 荧光定量RT-PCR法检测SREBP及靶基因mRNA的表达; 采用CCK-8试剂盒检测细胞存活率。结果显示, 经大黄酚(40 µmol·L-1)干预16 h后, 使细胞内TC、TG水平显著减少; 大黄酚可以抑制SREBP转录, 并呈现出一定的浓度依赖性; 能显著下调SREBP及靶基因的表达; 大黄酚对细胞活力无明显影响。结果提示, 大黄酚可能通过下调肝细胞SREBP及靶基因的表达, 从而降低细胞内TC、TG的含量, 减轻肝细胞脂肪变性, 起到改善脂质代谢的作用。Abstract: Rhubarb is a traditional Chinese medicines which possess laxative, lipid-lowering, and weight-loss activities, but the active compounds of lipid-lowering and underlying molecular mechanisms are not yet clear. This study aims to explore the effects of chrysophanol on the mRNA expressions of sterol regulatory element-binding proteins (SREBPs) and lipid metabolism in human liver carcinoma Huh-7 cells, which is one of the active compounds obtained from Rhubarb. A reporter gene assay was used to test the transcription of SREBP. The intracellular triglyceride and total cholesterol contents were measured by using commercially available test kits. The SREBPs target genes expressions were measured by Quantitative Real-Time PCR. Cell viability was evaluated by Cell Counting Kit-8. As the results shown, chrysophanol (40 �mol·L-1, 16 h) could notably inhibited human SRE promoter activity in a dose-dependent manner and decrease intracellular cholesterol and triglyceride levels. Furthermore, the mRNA expressions of SREBPs target genes were significantly downregulated by chrysophanol treatment. However there are no significant differences on cell viability when compared with the control group. These results suggested that chrysophanol might improve lipid metabolism through suppressing the mRNA expressions of SREBPs target genes to attenuate intracellular lipid accumulation.
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