Expression of TGF-beta1/Smad protein in rat liver fibrosis model and the role of IFN-gamma

Abstract

To study the impact of IFN-gamma on liver fibrosis and its possible mechanism. Thirty healthy male SD rats were randomly divided into two groups: fibrosis model group, IFN-gamma treatment group. Experimental liver fibrosis was induced by subcutaneous injection of CCl4. After 12-week-treatment, serum hyalurnic acid and TGF-beta1 was examined, histopathological changes and degrees of fibrosis were observed by optical microscopy. Meanwhile, the expression of TGF-beta1, TbetaR- I and Smad2/3 proteins was detected by immunohistochemistry and quantified by using computerized image analysis. (1) Pathological observation of hepatic specimens: histological examination showed that there were significant difference between normal group and fibrosis model group by comparing with the degrees of inflammation and fibrosis (P < 0.05). And the difference between fibrosis model group and IFN-gamma treatment group was significant (P < 0.05). (2) Changes of the hepatic fibrosis index (serum HA and TGF-beta1): the levels of serum HA, TGF-beta1 in fibrosis model group were higher than IFN-gamma treatment groups (P < 0.05). (3) Changes of gene protein levels about TGF-beta1/Smad: the expressions of TGF-beta1, TbetaR- I and Smad2/3 in rat hepatic tissue were detected with immunohistochemistry techniques. The expressions of the three items in model group were higher than normal group (P < 0.01). The difference between model group and IFN-gamma treatment group was significant (P < 0.05); IFN-gamma treatment group had significant results on treating experimental hepatic fibrosis. By the way of inhibiting expressions of TGF-beta1, TbetaR- I, Smad2/3, IFN-gamma treatment group exerted its anti-fibrosis effect.