牛磺酸熊脱氧胆酸对细胞色素C介导HepG2细胞凋亡的作用  

Effect of Tauroursodeoxycbolic acid on cytochrome C -mediated apoptosis in HepG2 cells

作　　者：谢青[1] 李光明[1] 周霞秋[1] 廖丹[1] 俞红[1] 郭清[1] 

机构地区：[1]第二医科大学附属瑞金医院感染科,上海200025

出　　处：《中华肝脏病杂志》2003年第5期298-301,共4页Chinese Journal of Hepatology

摘　　要：目的 探讨牛磺酸熊脱氧胆酸(TUDCA)对牛磺酸脱氧胆酸(TDCA)诱导HepG2细胞凋亡阻抑作用及分子机制。 方法 应用Hoechst 3325 8染色、电镜和DNA电泳对细胞凋亡进行定性;应用流式细胞仪对凋亡细胞进行定量;检测TDCA单独孵育及与TUDCA共孵育时,胞浆中细胞色素C含量及Caspase-3、8、9蛋白酶活性的变化。 结果 TDCA 400μmol/L孵育12 h可诱导显著HepG2细胞凋亡,凋亡率为(50.35±2.20)％,细胞经TUDCA与TDCA共孵育后,细胞凋亡率明显下降,为(13.78±0.84)％;TUDCA能显著抑制TDCA引起的细胞色素C释放及Caspase-9、3蛋白酶活性升高,孵育12 h时,Caspase-3活性分别下降54.9％(t=16.88,P<0.01)和52.5％(t≥13.00,P<0.01),轻度降低Caspase-8活性升高,活性下降24.5％(t=1.94,P>0.05)。结论 稳定线粒体膜、阻止细胞色素C释放及随后Caspase-9、Caspase-3活化,是TUDCA抗凋亡的主要机制。抗凋亡作用可能是TUDCA治疗胆汁淤积性肝病取得显著疗效的重要机制之一。Objectives To investigate the effect of Tauroursodeoxycholic acid (TUDCA) on Taurodeoxycholic acid (TDCA)-induced HepG2 cell apoptosis and to clarify the molecular mechanism of its anti-apoptosis effect of TUDCA. Methods Morphologic evaluation of apoptotic cells was performed by Hoechst 33258 staining and electron microscope. DNA fragment was detected by electrophoresis on 1.5% agarose gels. Apoptosis rate was measured by flow cytometry using PI dye. Following incubation of HepG2 cells either with TDCA alone, or coincubation with TUDCA and TDCA, the releasing level of cytochrome c from mitochondria into cytosol was determined by western blot, also the activity of caspase-3, 8, 9. Results Incubating the cells with 400 μmol/L TDCA for 12 h induced the cells apoptosis significantly. The apoptotic rate decreased from 50.35% ± 2.20% to 13.78% ± 0.84% after coincubation with TUDCA, and this anti-apoptotic effect of TUDCA was confirmed by morphological and DNA ladder detection. TUDCA significantly inhibited the release of cytochrome C from mitochondria into cytosol, and the activity of caspase-9, 3 (t ≥ 13.00, P < 0,01), especially at 12 h, caspase-3 activity decreased by 54.9% (t = 16.88, P < 0.01) and 52.5%, however it had no obvious effect on the activity of caspase-8 (t = 1.94, P > 0.05). Conclusions TUDCA prevents HepG2 cells apoptosis induced by TDCA through modulating mitochondrial membrane stability, inhibiting the release of cytochrome c and the activation of procaspase-9 and 3. Anti-apoptotic mechanism of TUDCA may be considered to be one of the most important reasons that TUDCA exerts significant efficacy in the treatment of cholestatic liver diseases.

关 键 词：牛磺酸熊脱氧胆酸 细胞色素C 介导 HEPG2 细胞凋亡 作用 

分 类 号：R363[医药卫生—病理学]