Abstract: Objective To observe the expression and function of TGF-β1 and Smad2 in liver fibrosis of biliary atresia. Methods Liver biopsy specimens were collected from autopsy(normal group, n=5), congenital biliary dilatation (CBD group, n=10), biliary atresia patients who undergoing Kasai procedure (Early hepatic fibrosis group, n=19), liver transplantation(transplantation group, n=11) ,the first three groups were collected from January 2010 to July 2014 in Tianjin childrens’ hospital, the last group was collected from January 2013 to January 2014 in Tianjin first central hospital. The hematoxylin ＆ eosin staining were used to observe the degree of liver fibrosis of every single sample, immunohistochemistry were used to observe the expression of TGF-β1 and Smad2 in liver tissues of these samples. At the same time, Quantitative Real-time Polymerase Chain Reaction was used to test the mRNA quantitative of TGF-β1 and Smad2 between these samples. Results HE: That the autopsy group showed no fibrosis, the CBD group had mild fiber cells hyperplasia, the Kasai group had severe fibrosis and the transplantation group had significant pseudolobule in the hematoxylin ＆ eosin staining. IHC: TGF-β1 was expressed in the cytoplasm of hepatocytes、bile duct cells、lymphocytes and neutrophils. The value of TGF-β1 average optical density was highest in the Kasai group and it had significant difference between four groups (P < 0.05); Smad2 was expressed in the cytoplasm of hepatocytes、bile duct cells、lymphocytes, and there were no difference between these four groups（P＞0.05）. qRT-PCR: Both TGF-β1mRNA and Smad2mRNA was different between these samples(P<0.017). Conclusion In early stage of BA,TGF-β1 and Smad2 made a contribution to liver fibrosis until the formation of P-P,P-C desmosome structure. However, after that while BA fibrosis became more serious, the pro-fibrogenic function of TGF-β1 and Smad2 became less.

Key words: biliary atresia , liver cirrhosis , transforming growth factor beta1 , Smad 2 protein, liver fibrosis