肿瘤坏死因子-α对肝星状细胞增殖与凋亡的影响

Effects of tumor necrosis factor alpha on proliferation and apoptosis of HSCs

目的 :探讨肿瘤坏死因子 -α(TNF -α)在肝纤维化发病中的作用。方法 :采用TNF -α对体外培养的HSC进行干预 ,通过流式细胞术、电镜及TUNEL等方法 ,对HSC的增殖与凋亡进行研究。结果 :①流式细胞术显示 :TNF -α各组的G0 /G1期细胞比率明显高于对照组 ,而S期细胞比率明显低于对照组 ,各组的细胞增殖指数均明显低于对照组 ;在凋亡方面 ,TNF -α各组的HSC凋亡率明显高于对照组 ,TNF -α各组HSC中抗凋亡基因bcl - 2的表达明显低于对照组 ,而促凋亡基因bax的表达明显高于对照组。②TUNEL分析显示 :TNF -α(2 .0 μg/L)组的HSC凋亡率为 18.7%± 2 .5 % ,而对照组为 5 .3%± 1.2 % ,两者之间有显著差异。结论 :TNF -α能够阻止HSC从G0 /G1期进入S期 ,从而具有抑制HSC增殖的作用 ;TNF -α能够降低HSC中bcl- 2的表达、提高bax的表达 。

AIM:To explore the role of tumor n ecrosis factor alpha(TN F-α) in the pathogenesis of liver fibrosis. METHODS:The proliferation and apoptosis of hepatic stellate cells (HSCs) in vitro were detected with flow cytometry, electron microscopy and TUNEL. RESULTS:The flow cytometry analysis showed that the cell pr oliferation index (PI) in the TNF-α(0.5 μg/L, 2.0 μg/L, 8.0 μg/L) groups was evidently l ower than that in the control group ( P< 0 05). In the cell cycle distributi o n,the portion of G 0/G 1 phase in the TNF-α groups was significantly higher t han that in the control group( P< 0 05),but the portion of S phase in the TNF-α groups was eviden tly lower than that in the control group( P< 0 05). These indicated that TNF -α in terfered with HSCs entrance into S phase from G 0/G 1 phase whereupon the prol ifer ation of HSCs was inhibited. The apoptotic rate in the TNF-α groups was evident ly higher than that in the control group( P< 0 05). The gene expression of bcl-2 and bax was also detected with flow cytometry. The expression of b cl-2 in the T NF -α groups was evidently lower than that in the control group( P< 0 05),but the exp ression of bax in the TNF-α groups was significantly higher than that in the contro l group( P< 0 05). TUNEL analysis showed the apoptotic rate of HSCs in the T N F-α(2.0 μg/L) group was 18.7%±2.5% compared with 5 3%±1 2% in the control group( P< 0 05). CONCLUSIONS: TNF-α interfered with HSCs ent rance into S phase from G 0/G 1 phase whereupon the proliferation of HSCs was inhibited. TNF-α down -regulated bcl-2 gene expression and up-regulated bax gene expression wh ereupon the apoptosis of HSCs was induced.