肝纤维化大鼠肝组织Smads基因表达状况及意义

Expression of Smads gene in CCl_4-induced liver ?brosis and its signi?cance in rats

目的:研究CCl4诱导的肝纤维化大鼠肝组织Smad基因表达的变化及其意义.方法:80只健康雄性SD大鼠分为2组:正常组(C组,n=40)和模型组(M组,n=40).以CCl4sc法诱导肝纤维化,HE和VG胶原染色观察肝脏胶原沉积情况,原位杂交法及免疫组化法检测肝组织Smads分子表达水平变化.结果:与C组比较,M组大鼠肝脏组织学积分显著增加(3.29±0.68vs0,P<0.05),平均胶原面积显著增加(290.86±89.37μm2vs56.12±21.45μm2,P<0.01),肝组织Smad4蛋白表达率较C组明显增加(4.27%±0.43%vs2.86%±0.86%,P<0.05),而Smad7蛋白表达虽然增加,但水平低下;Smad3mRNA表达A值明显增加(0.167±0.092vs0.010±0.002,P<0.05),Smad4mRNA表达A值也明显增加(0.241±0.098vs0.021±0.004,P<0.05),Smad6、Smad7mRNA虽然增加,但表达水平仍然低下.结论:实验性大鼠肝纤维化存在肝脏Smads分子表达水平的比例失调,TGF-Smad信号通路可能参与了肝纤维化的形成与发展.

AIM： To investigate the expression of Smads gene and its significance in rats with liver fibrosis induced by carbon tetrachloride （CCl4）. METHODS： Eighty healthy male SD rats were randomly divided into two groups： normal control group （n = 40） and hepatic fibrosis model group （n = 40）. Experimental liver fibrosis was induced by subcutaneous injection of CCl4. The deposition of collagen fiber in liver was detected with Masson and VG staining. The expression of Smad3, Smad4, Smad6, and Smad7 were assayed with in situ hybridization （ISH） and immunohistochemistry （IHC）. RESULTS： A significant increase of collagen deposition and rearrangement of the parenchyma were noted in fibrosis model rats. The semi- quantitative histological scores （3.29 ± 0.68 vs 0, P 〈 0.01） and average area of collagen deposition （290.86 ± 89.37 μm^2 vs 56.12 ± 21.45 μm^2, P 〈 0.05） in model group were significantly increased. The positive rate of Smad4 protein expression was higher in model group than that in control group （4.27% ± 0.43% vs 2.86% ± 0.86%, P 〈 0.05）, but the positive rate of Smad7 protein expression was not markedly different between the two groups. The A values of Smad3 mRNA （0.167 ± 0.092 vs 0.010 ± 0.002, P 〈 0.05） and Smad4 mRNA （0.241 ± 0.098 vs 0.021 ± 0.004, P 〈 0.05） were significantly higher in model group that those in control group. Meanwhile, although the expression levels of Smad6 and Smad7 mRNA were increased in model animals, there were no significant differences between the two groups. The protein expression of Smad4 and the mRNA expression of Smad6 and Smad7 were at very low levels both in normal and in model animals. CONCLUSION： Unbalanced expression of Smads exists in experimental hepatic fibrosis of rats. TGF-β-Smad signal pathway may take part in the occurrence and progression of liver fibrosis in rats.