Abstract: Objective To explore the effect of macrophages on bile acid metabolism. Methods The cholestasis model was established by ligating the common bile duct of 7 -week-old male CD 11 b-DTR mice. After 2 weeks, the bile acid profile and intestinal flora composition in the liver and colon were measured. Twenty-eight mice were divided into four groups: sham group, sham intervention (DT) group, bile duct ligation (BDL) group and bile duct ligation intervention (BDL+DT) group. Results Compared with the sham group, the contents of primary bile acid and total bile acid in the liver of the BDL group were significantly increased, while the contents of unbound primary bile acid and total bile acid in the liver of the BDL+DT group were significantly decreased compared with the BDL group, and the differences were statistically significant (all P< 0 . 05 ). In colonic contents, BDL+DT group had lower level of binding primary bile acid than that of the BDL group, and the difference was statistically significant (P< 0 . 05 ). The expression level of cyp 7 a 1 , a key enzyme for bile acid synthesis, in the BDL+DT group was lower than that in the BDL group, and the difference was statistically significant (P< 0 . 05 ). Conclusion Conditional macrophage knockout can interfere with cholestasis by changing the structure of intestinal microbiota.

Key words: macrophages; bile acid; intestinal microbiota; biliary atresia; mouse