Effects of estradiol on type I, III collagens and TGF β1 in hepatic fibrosis in rats

Effects of Ginkgo biloba extract on liver fibrosis induced by carbon tetrachloride in rats

AIM: To study the effects of Ginko biloba extract (EGb) on hepato-fibrosis induced by carbon tetrachloride (Cl₄) in rat model.

METHODS: Rat liver fibrosis model was induced by Cl₄ administration. Wistar rats were randomly divided into 5 groups: normal control group, a model group, a interven-tional group, a therapeutic group, and a EGb group. The EGb interventional group, apart from administration of Cl₄, was treated concurrently with EGb 0.3 g/kg, ig once a day; the EGb therapeutic group was treated with EGb 0.3 g/kg, ig once a day after cirrhosis was induced successfully, and the EGb group was treated only with EGb 0.3 g/kg, ig once a day. At the end of wk 8 and 16, all the rats were sacrificed. The pathological changes of liver were observed by H-E and Von-Gieson staining.The expression of mRNA and proteins of collagen I/TGF₁ in liver were determined by RT-PCR and immunohistochemistry.

RESULTS: The degree of liver fibrosis and level of mRNA and proteins of collagen I/TGF₁ in liver were significantly reduced in the EGb interventional and therapeutic groups compared with those in the model group (type I collagen mRNA: 0.0 778±0.054 vs 0.2 361±0.113, 0.1 075±0.007 vs 0.2 361±0.113, P < 0.01; type I collagen proteins: 0.2 563±0.0 009 vs 0.2 885±0.0 025, 0.2 541±0.0 076 vs 0.2 885±0.0 025 , P < 0.01; TGF₁ mRNA: 0.523±0.015 vs 0.956±0.049 , 0.524±0.009 vs 0.956±0.049, P < 0.01; TGF₁ proteins: 0.2 785±0.0 012 vs 0.3 015±0.0 012, 0.2 791±0.0 016 vs 0.3 015±0.0 012, P < 0.01).The EGb group had the same results as the normal control group.

CONCLUSION: EGb has prophylactic and therapeutic effects on CCl₄-induced rat liver fibrosis, probably through its anti-lipoperoxidation, suppressing the activation of hepatic stellate cells and transition and reducing the synthesis of hepatic type I collagen and TGF₁.

Expression of TGFβ1 and its receptors, Smad3 andSmad7 in rats with experimental liver fibrosis

AIM: To investigate the expression of TGFβ1, TGFRⅠ,TGFR Ⅱ, Smad3, Smad7 in fibrotic liver induced by the exposure of carbon tetrachloride (CCl₄) in rats.

METHODS: A total of 24 Wistar rats were randomly allocated into two study groups: normal group and model group-CCl₄ rats. The latter group was administered with CCl₄ solution to induce liver fibrosis. All the rats were killed after 8 wks. The level of TGFβ1, TGFR Ⅰand TGFRⅡmRNA were examined by RT-PCR. The expression of TGF-1, Smad3 and Smad7 were detected by immunohistochemical staining in liver tissue. The serum hyalauronic acid (HA) and the liver histopathology were also examined by RIA and HE staining respectively.

RESULTS: In comparison with the normal group, TGFβ1, TGFR Ⅰ and TGFRⅡmRNA were significantly increased in model rats, the expression of TGF-1 and Smad3 was increased and the expression of Smad7 was decreased in livers of the model group (TGF-1, Smad3 and Smad7 in normal and model group were 0.61±0.33 vs 1.57±0.53, 0.248±0.042 vs 0.785±0.904, 4.674±1.143 vs 0.470±0.097 respectively, P < 0.05). The content of serum HA was increased in model rats (HA in normal and model group was(78.4±19.2 g/L) vs (263.2±107.0) g/L, P < 0.01). The histological changes of fibrosis were also remarkable.

CONCLUSION: TGFβ1/TGF receptors /Smad signaling involve the formation and development of liver fibrosis. The TGFβ1 /Smad signal pathway plays key roles in liver fibrogensis. It may be a new pathway for the treatment of liver fibrosis.