大黄素诱导HK-2细胞凋亡的机制探讨

Apoptosis mechanisms induced by emodin in HK-2 cells

目的:探讨大黄中游离蒽醌大黄素诱导人近曲小管上皮细胞(HK-2)的细胞凋亡作用机制。方法:体外培养HK-2细胞,利用MTT法评价大黄素对HK-2细胞的增殖抑制作用,利用TUNEL染色检测大黄素对HK-2细胞凋亡的影响,流式细胞技术检测大黄素对HK-2细胞线粒体膜电位的影响,凋亡相关蛋白检测采用Western Blot分析;结果:大黄素作用HK-2细胞48 h后,明显抑制细胞的增殖,IC50值为130.65μmol.L-1。大黄素浓度为80μmo.lL-1时促使细胞凋亡,线粒体膜电位降低,Western Blot分析凋亡相关蛋白显示,大黄素作用HK-2细胞后,抑制细胞外信号调节激酶1/2(extracelluar signal regulated kinase 1/2,ERK1/2)的磷酸化,并且呈现明显的剂量和时间效应关系,细胞内Bcl-2表达降低,Bax没有明显的变化,致使促凋亡基因蛋白占优势,细胞向促调亡的方向发展,细胞色素c释放增加,从而使Caspase-8活化,激活下游Caspase-3,引起细胞的凋亡;大黄素对HK-2细胞的损伤效应可能是通过MAPK/ERK信号转导通路抑制ERK磷酸化,而导致了细胞凋亡。结论:大黄素能够引起HK-2细胞的凋亡,其机制可能涉及MAPK/ERK信号转导通路抑制途径。

Objective：To investigate the cytotoxic effect of emodinon on human proximaltubular epithelial cell line （HK-2）. Methods：MTT assay was used to evaluate the IC50 of anthraquinone in HK-2 cells. The apoptosis effect was detected with TUNEL assay. Mitochondrial membrane potential （MMP） was measured with flow cytometer. Apoptotic related proteins were analyzed with Western Blot analysis. Results：Emodin markedly inhibited the proliferation of HK-2 cells after 48 hours culture. The IC50 was 130.65 μmol·L^-1. Emodin caused cell apoptosis on HK-2 cells at 80 μmol·L^-1. During it induced apoptosis in HK-2 cells, the level of MMP decreased. Western blotting analysis of apoptotic related proteins revealed that the phosphorylation of extraeelluar signal regulated kinase 1/2 （ERK1/2） were inhibited after treatment with emodin, the expression level of Bcl-2 decreased significantly ,the release of cytochrme C increased,Caspase-8 and Caspase-3 were activated in HK-2 cells,but the level of Bax didn＇t changed. These results implied that emodin might lead to apoptosis though suppressing MAPK/ERK signal pathway. Conclusion：Emodin induces apoptosis involves suppressing MAPK/ERK signal pathway in HK-2 cells.