南方医科大学学报 ›› 2018, Vol. 38 ›› Issue (04): 375-.

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TNF-α、TGF-β1在胆汁淤积性肝硬化中平衡调控肝脏干细胞分化

杨博,罗庆,康权,肖程,王健,李志鹏,龚梦嘉,毕杨   

  • 出版日期:2018-04-20 发布日期:2018-04-20

Tumor necrosis factor-α and transforming growth factor-β1 balance liver stem cell differentiation in cholestatic cirrhosis

  • Online:2018-04-20 Published:2018-04-20

摘要: 目的探讨TNF-α、TGF-β1在胆汁淤积性肝硬化中的变化及其对肝脏干细胞分化平衡的影响。方法Balb/c小鼠行胆总管 结扎术,血生化指标和肝脏HE染色评价造模情况;免疫组织化学和蛋白印迹检测造模后TNF-α、TGF-β1的变化;以小鼠胚胎肝 脏干细胞HP14-19为研究对象,TNF-α、TGF-β1分不同浓度干预,蛋白印迹、Real-time PCR、PAS染色评价分化情况。结果胆总 管结扎组中血生化指标明显升高(P<0.05),HE染色见胶原纤维增多,TNF-α、TGF-β1表达高于假手术组(P<0.05);TNF-α、TGF-β1 诱导分化3 d后,其分化情况与对照组相比,无明显差别;诱导分化5 d后,TNF-α、TGF-β1各浓度组的PAS染色强于对照组,TNF-α 20、40、80 ng/mL浓度组的细胞角蛋白18(ck18)明显高于细胞角蛋白19(ck19)(P<0.05),而TGFβ1则相反,20、40、80 ng/mL浓度组 的ck19 高于ck18(P<0.05);诱导分化10 d 后,TNF-α、TGF-β1促分化的趋势与诱导5 d 时相同,且蛋白印迹、PAS染色更强,但 Real-time PCR表达更低。结论胆总管结扎术能成功模拟胆汁淤积性肝硬化,TNF-α、TGF-β1在该疾病中表达均增加,但它们对 于肝脏干细胞的分化平衡发挥着相互制约的作用:前者主要促进肝脏干细胞向肝细胞分化,而后者则主要促进其向胆管细胞分化。

Abstract: Objective To investigate the changes of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) in mice with cholestatic cirrhosis and their role in regulating the balance of liver stem cell differentiation. Methods Balb/c mice were subjected to bile duct ligation (BDL), and serum biochemical parameters were measured and hepatic histopathology was observed using HE staining to evaluate the modeling of cholestatic cirrhosis. Immunohistochemistry and Western blotting were used to detect the changes of TNF-α and TGF-β1 in the mice after modeling. Mouse embryonic hepatic stem cells (HP14-19) were treated with different concentrations of TNF-α and TGF-β1, and the cell differentiation was assessed using Western blotting, real-time PCR, and PAS staining. Results The mice receiving BDL showed significantly increased blood biochemical parameters (P<0.05), and HE staining revealed obviously increased collagen fibers in the liver with significantly increased expressions of TNF-α and TGF-β1 (P<0.05). In HP14-19 cells, induction with TNF-α and TGF-β1 for 3 days did not cause significant changes in cell differentiation, but induction for 5 days resulted in significantly increases intensity of PAS staining in the cells. The cells induced with 20, 40, and 80 ng/mL TNF-α for 5 days exhibited a significantly stronger expression of cytokeratin 18 than cytokeratin 19 (P<0.05), while induction with 20, 40, and 80 ng/mL TGF-β1 produced opposite changes in cytokeratin 18 and cytokeratin 19 expressions. Further induction of the cells with TNF-α and TGF-β1 for 10 days, did not alter the expression patterns of cytokeratin 18 and cytokeratin 19 observed on day 5, but their protein expression levels and PAS staining intensity of the cells were enhanced and their mRNA expressions became lowered. Conclusion Common bile duct ligation can induce conditions simulating cholestatic cirrhosis in mice. TNF-α and TGF-β1 are elevated in cholestatic cirrhosis and play opposite roles in regulating the differentiation balance of liver stem cells: the former promotes the differentiation of liver stem cells into hepatocytes, while the latter promotes the cell differentiation into colangiocytes.