大鼠肝硬化形成过程中肝组织TGF-β1，Smad3，Smad7水平动态的变化

Expression of transforming growth factor-β1,Smad3 and Smad7 in experimental liver cirrhosis in rats

目的:观察实验性大鼠肝硬化形成过程中,肝组织TGF-β1,Smad3,Smad7水平的动态变化,研究三者在肝硬化发生过程中的作用及机制.方法:以SD大鼠为实验对象,于实验开始时处死6只大鼠作为wk 0正常对照组,剩余大鼠,600 mL/L四氯化碳3 mL/kg,sc,2次/ wk,复制肝硬化动物模型.于wk 3,6,9,12各处死一批大鼠,用RT-PCR检测动物肝组织中TGF-β1,TGF-βRⅡ的mRNA表达水平,Western blot检测肝组织中Smad3,Smad7蛋白水平,免疫组织化学方法检测动物肝组织中TGF-β1的表达和定位.结果:正常肝组织中有少量TGF-β1,TGF-βRⅡ的mRNA表达.随着肝纤维化及肝硬化的形成,模型组wk 0,3,6,9,12,TGF-β1,TGF-βRⅡ和Smad3表达量分别逐渐递增(TGF-β1:0.19±0.12,0.29±1.02,0.89±0.23,0.98±0.77,1.7±1.00;TGF-βRⅡ:0.30±0.22,0.49±0.16,1.02±0.33,1.51±0.72,2.14±1.02;Smad3:0.44±0.24,0.84±0.69,1.10±0.16,1.40±0.12,1.75±1.05),Smad7表达量呈逐渐减少(1.35±0.12,1.09±0.78,1.14±0.31,1.11±0.91,0.74±1.21).正常肝组织TGF-β1可见少量表达,主要在中央静脉周围肝细胞中.随着肝纤维化及肝硬化的形成,TGF-β1表达增强(P<0.01).结论:随着肝硬化的形成,肝脏中TGF-β1,TGF-βRⅡ和Smad3表达增加,Smad7表达下降.

AIM： To observe changes in transforming growth factor （TGF）-β1, Smad3 and Smad7 during liver fibrosis, and to study their role hepatic tissue during the formation of experimental liver cirrhosis in rats. METHODS： Male rats were divided into control group and model group. Control： Six male rats were killed at the beginning of the experiment as the week 0 group. Model： The surplus rats was injected subcutaneously 600 mL/L CC14 in oil two times per week at the dosage of 3 mL/kg body weight. The rats were sacrificed after 3, 6, 9 and 12 wk. Expression of mRNA for TGF-β1 and TGF-β receptor Ⅱ （TGF-β R Ⅱ ） in rat liver was detected by reverse transcription-polymerase chain reaction （RT-PCR）, and Smad3 and Smad7 were determined by Western blotting. Meanwhile, the level of TGF-β1was measuredby immunocytochemistry RESULTS： TGF-β1 mRNA, TGF-β RⅡ mRNA and Smad3 at 3, 6, 9 and 12 wk were expressed in low amounts in the normal liver tissue, and were increased after CC14 treatment, while Smad7 at the same point was decreased （TGF-β1, 0.19 ± 0.12, 0.29 ± 1.02, 0.89 ± 0.23, 0.98 ± 0.77, 1.7 ± 1.00; TGF-β R Ⅱ, 0.30 ± 0.22, 0.49 ± 0.16, 1.02 ± 0.33,1.51 ± 0.72, 2.14± 1.02; Smad3, 0.44 ± 0.24, 0.84 ±0.69, 1.10 ± 0.16, 1.40 ± 0.12, 1.75 ± 1.05; Smad7, 1.35± 0.12,1.09 ± 0.78, 1.14 ± 0.31, 1.11 ± 0.91, 0.74± 1.21）. TGF-β1was expressed at a low level in the portal vein of the normal liver. It was up-regulated in rats after CC14 treatment （P 〈 0.01）. CONCLUSION： During hepatic fibrosis induced by CC14 in rats, expression of TGF-β1, TGF-β R Ⅱ and Smad3 was increased, while Smad7 was decreased. The mechanism may be that TGF-β1 causes liver fibrosis by increasing Smad3 and decreasing Smad7.