RESUMO
[Objective] To investigate the change of liver histology, proliferation of BDEC, and expression of TGF-β in different stages of liver chelestusis. [Methods] ①Rat cholestatic livers were induced by common bile duct ligation (BDL) and separated into 3 groups, namely control group (DO), 7 days after BDL group (DT), and 18 days after BDL group (D18). ② Histological changes of livers in different groups were evaluated based on Knodell HAI score. ③ Real-time PCR was used to detect the expression of TGF-β in liver tissue and isolated BDEC in different groups. ④ Statistically analyzing the correlation between Knedell HAl score and the levels of TGF-β_1 mRNA. ⑤ In vitro study was performed to investigate the effect of TGF-β_1 on an immortalized mouse intrahepatic bililary epithelial cell line (mIBEC). [Results] (I) Knedell HAI score and the proliferation of intrahepatic bile ducts increased as the liver cholestasis aggravated. ② The levels of TGF-β_1, TGF-β_2, and TGF-β_3 mRNA were significantly up-regulated in liver tissues and BDEC as the liver cholestasis aggravated. ③ Positive correlation was found between Knedell fibrotic score and the levels of TGF-β_1 mRNA in liver tissues and BDEC(r=0.9376, P<0.05 and r=0.9682, P < 0.01). ④ In vitro study showed that TGF-β_1 inhibited the proliferation of mIBEC. [Conclusion] ① Liver injury, biliary proliferation, and the levels of TGF-β mRNA expression increased as liver cholestasis aggravated. ② The interaction of TGF-β_1 and BDEC plays an important role in the pathogenesis of BDL induced cholestatic liver disease. ④ Up-regulated expression of TGF-β_1 mRNA in the proliferated BDEC participates in the formation of BDL induced cholestatic liver fibrosis.