Abstract: Objective To investigate the relationship of matrix metalloproteinase-7 (MMP-7) in liver tissue of biliary atresia (BA) with liver fibrosis and bile duct reaction, and explore the role of MMP-7 in the process of liver fibrosis and its clinical significance. Methods Data of 15 BA patients with liver biopsy in Kasai operation in our hospital from June 2017 to April 2018 were collected (G1 group)，and data of 41 patients with liver biopsy who underwent liver transplantation after Kasai operation from January 2015 to January 2016 were enrolled as transplantation group. The transplantation group was divided into two groups according to the interval time between Kasai operation and liver transplantation: G2 group (n=28, the interval time was less than 2 years) and G3 group (n=13, the interval time was more than 2 years). Hematoxylin-Eosin (HE) staining was used to observe the degree of liver fibrosis. Immunohistochemical staining was used to detect the expressions of MMP-7 and CK-19. Results (1) Immunohistochemical results showed that MMP-7 was mainly expressed in bile duct epithelial cells, hyperplastic bile ducts and hepatocytes around the portal area. With the progress of hepatic fibrosis, the expressions of MMP-7 were increased in biliary duct cells and hepatocytes, and which were strongly expressed in biliary duct cells than those of hepatocytes. Semi-quantitative analysis showed that the expression levels of MMP-7 were (0.068± 0.017) vs. (0.093±0.017) vs. (0.084±0.016) in the three groups (F=10.541，P＜0.001). CK-19 staining showed that bile duct reactions of three groups were (0.119±0.036) vs. (0.157±0.040) vs. (0.110±0.044) (F=7.296，P＜0.001). The expression levels of MMP-7 and CK-19 protein were significantly higher in G2 group than those of other two groups (P＜0.05). There was no significant difference between G1 and G3 groups (P＞0.05). (2) The liver fibrosis in the three groups were 2 (2, 3) vs. 4 (3, 4) vs. 4 (2, 4) (H=17.785, P＜0.001), and the fibrosis was significantly higher in the G2 group than that of other two groups (P＜ 0.017). (3) Correlation test showed that the expression of MMP-7 protein was positively correlated with the degree of liver fibrosis (rs=0.609, P＜0.001), but there was no correlation with bile duct reaction (r=0.007, P=0.962). Conclusion The expression of MMP-7 protein is highly expressed in liver tissue after Kasai operation, and it increases with the severity of liver fibrosis. MMP-7 may participate in the process of BA liver fibrosis and suggest that the survival of autologous liver is poor.

Key words: biliary atresia, liver cirrhosis, matrix metalloproteina-7, native liver survival