Liang Tie-jun, Yuan Jun-hua, Tan Yan-rong, Ren Wan-hua, Han Guo-qing, Zhang Jie, Wang Lai-cheng, Qin Cheng-yong
Department of Digestive Diseases, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.
Chin Med J (Engl). 2009 May 20;122(10):1209-13.
Hepatic fibrosis is the key stage of the pathological progress from hepatic injury to cirrhosis. Ursodeoxycholic acid (UDCA) has been known as having significant clinical therapeutic effects on chronic liver diseases. Our research aimed to study the effect of UDCA on the signaling pathway of transforming growth factor beta1 (TGFbeta1)/Smad and discuss its possible molecular mechanisms of inhibiting hepatic fibrosis.
Rat hepatic stellate cells were cultured in vitro and randomly assigned to 4 groups. Group A was control group, with only DMEM culture medium applied, and groups B, C, D were experimental groups, with different doses of UDCA (1.0 mmol/L, 0.5 mmol/L and 0.25 mmol/L respectively) added into their DMEM culture medium for further culture of 24 hours and 48 hours. The protein expressions of TGFbeta1, TGF type I receptor, Smad3, Smad4 and Smad7 were measured by Western blotting, as well as the expressions of TGFbeta1, Smad3, Smad7 and cAMP response element (CREB) binding protein (CBP) mRNA by real-time PCR. SPSS 11.5 statistical package was adopted for data analyses.
Compared with control group, the mRNA expressions of TGFbeta1 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly decreased (P < 0.05), the protein expressions of TGFbeta1 in the two above groups for 48 hours and in the high dose group for 24 hours significantly decreased (P < 0.05). The protein and mRNA expressions of Smad3 in each UDCA dose group for 24 hours and 48 hours significantly decreased, with significant difference among different UDCA dose groups and between that of 24 hours and 48 hours observed (P < 0.05). The protein and mRNA expressions of Smad7 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly increased. The CBP mRNA expression in each UDCA dose group for 24 hours and 48 hours significantly decreased (P < 0.05), with significant difference among different UDCA dose groups observed (P < 0.05).
UDCA could curb the development of hepatic fibrosis through affecting the signaling pathway of TGFbeta1/Smad by inhibiting the expressions of TGFbeta1, Smad3 and CBP and increasing the expression of Smad7.
肝纤维化是肝脏损伤向肝硬化病理进展的关键阶段。熊去氧胆酸（UDCA）已被证实对慢性肝病具有显著的临床治疗作用。本研究旨在探讨UDCA对转化生长因子β1（TGFβ1）/Smad信号通路的影响，并探讨其抑制肝纤维化的可能分子机制。
体外培养大鼠肝星状细胞，随机分为4组。A组为对照组，仅使用DMEM培养基；B、C、D组为实验组，分别在其DMEM培养基中加入不同剂量的UDCA（分别为1.0 mmol/L、0.5 mmol/L和0.25 mmol/L），继续培养24小时和48小时。采用蛋白质印迹法检测TGFβ1、TGFⅠ型受体、Smad3、Smad4和Smad7的蛋白表达，采用实时荧光定量PCR检测TGFβ1、Smad3、Smad7和环磷酸腺苷反应元件（CREB）结合蛋白（CBP）mRNA的表达。采用SPSS 11.5统计软件进行数据分析。
与对照组相比，高、中剂量UDCA组24小时和48小时的TGFβ1 mRNA表达显著降低（P<0.05），上述两组48小时及高剂量组24小时的TGFβ1蛋白表达显著降低（P<0.05）。各UDCA剂量组24小时和48小时的Smad3蛋白和mRNA表达均显著降低，不同UDCA剂量组之间以及24小时和48小时之间存在显著差异（P<0.05）。高、中剂量UDCA组24小时和48小时的Smad7蛋白和mRNA表达显著增加。各UDCA剂量组24小时和48小时的CBP mRNA表达均显著降低（P<0.05），不同UDCA剂量组之间存在显著差异（P<0.05）。
UDCA可通过抑制TGFβ1、Smad3和CBP的表达，增加Smad7的表达，影响TGFβ1/Smad信号通路，从而抑制肝纤维化的发展。
