[Expression of transforming growth factor-beta1 and connective tissue growing factor in schistosomal hepatic fibrosis of mice].

OBJECTIVE: To establish the model of hepatic fibrosis in mice infected with Schistosoma japonicum and observe the expression of transforming growth factor-beta1 (TGF-beta1) and connective tissue growing factor (CTGF) in mice model. METHODS: Thirty BALB/c mice were randomly assigned to control group and model group. Each mouse of model group was infected with (30 +/- 1) S. japonicum cercariae through the abdominal skin. Serum samples were collected at 4, 6, 8, 10, and 12 weeks after infection, and were analyzed for the levels of ALT and AST. Pathological changes and proliferation of hepatic collagen fibers in liver tissue were observed after HE staining and Masson staining. Immunohistochemistry and real-time PCR were used to detect the protein and mRNA expression of CTGF and TGF-pl. RESULTS: 6-12 weeks after infection, there was significant difference in ALT and AST between model group and control group (P43.05). At 12th week, ALT [(173.53 +/- 31.12) U/I] and AST [(301.00 +/- 34.87) U/LI in model group were higher than those in control group [(42.00 +/- 3.53) and 96.58 +/- 11.26) U/L] . In model group, egg granulomas formed in the liver, and the formation of hepatic fibrosis was significant in portal areas, and there was tree-like hepatic fibrosis around the portal vein branch. 8 weeks after infection, hepatic fibrosis area in mice of model group increased considerably, and there was significant difference in percentage of positive area of collagen between 12th week [(23.83 +/- 1.68) %] and control group [(1.23 +/- 0.14) %] (P < 0.05). 10 and 12 weeks after infection, the percentage of positive area of TGF-beta1 [(22.34 +/- 2.58)% and (25.82 +/- 3.01) %] and CTGF [(1 l.32 +/- 2.44)% and (14.51 +/- 2.05) %] was higher respectively than that of the control [(2.56 +/- 0.87)%, and (1.09 +/- 0.73)% (P < 0.05). 6, 8, 10, and 12 weeks after infection, both TGF-beta1 and CTGF mRNA increased gradually, higher than that in control group (P < 0.05). 10 weeks after infection, TGF-beta1 mRNA relative transcription level was the highest (0.0721 +/- 0.0187) and it was 0.0089 +/- 0.0037 in control group. CTGF mRNA relative transcription level reached the highest value (0.1136 +/- 0.0365) in 12 weeks after infection, while it was 0.0293 +/- 0.0184 in control group. CTGF mRNA expression was positively correlated with the duration of infection (r = 0.927, NO.05). CONCLUSION: The area and cell types of TGFb1 positive expression is the same as that of CTGF in liver tissue of schistosome infected mice (BALB/c). CTGF mRNA expression is significantly related to the duration of infection, but it is not the case for TGFbl.