Abstract: Abstract： Objective To investigate the expression and significance of integrin αvβ8, p38 and extracellular signalregulated protein kinase 1/2 (ERK1/2) proteins, which are TGF- β1 pathway related regulatory protein, in liver fibrosis of children with biliary atresia (BA). Methods Fifteen cases of BA (Kasai group) and 10 cases of congenital biliary dilatation (CBD group) were collected in Tianjin Children’ s Hospital. And liver biopsy specimens were collected in Tianjin first central hospital, including 10 cases of BA children who underwent liver transplantation due to liver failure after Kasai operation (liver transplantation group). The specimens of front part of the right lobe of the liver were taken for HE and immunohistochemistry (IHC) staining. The expressions of αvβ8, p38 and ERK1/2 in liver were observed by IHC staining in three groups of liver tissues. Results HE staining showed fibroblast hyperplasia occasionally in CBD group, portal area expansion, fibrous tissue proliferation and wide spread bridging fibrosis with few pseudo lobules in Kasai group. In transplantation group, portal area was widened, the degree of fibrosis was severe and bridging fibrosis generally formed resulted in pseudo lobules widely. Imunohistochemistry showed that the expressions of αvβ8 and ERK1/2 were weakly positive, and the expression of p38 was negative in CBD group. In Kasai group, the expressions of αvβ8, p38 and ERK1/2 proteins were all strongly positive in liver cytoplasm, biliary epithelial cells and vascular endothelial cell cytoplasm. In liver transplantation group the expressions of αvβ8, p38 and ERK1/2 proteins were all strongly positive. The semi-quantitative analysis showed that the expressions levels of αvβ8, p38 and ERK1/2 were significantly higher in Kasai and liver transplantation groups than those of CBD group (P < 0.05). There were no significant differences in expression levels of αvβ 8, p38 and ERK1/2 between Kasai group and transplantation group (P > 0.05). Conclusion The expressions of αvβ8, p38 and ERK1/2 are gradually increased in liver of BA with the process of fibrosis, which indicate that they may be involved in the process of BA liver fibrosis.

Key words: biliary atresia, liver cirrhosis, p38 mitogen-activated protein kinases, mitogen-activated protein kinase 1, liver fibrosis, αvβ8, p38, ERK1/2