Histological species differences among chickens, rats, and mice in experimental cholestasis by bile duct ligation

Cholestasis is a hepatic disease reported in humans, dogs, and chickens and is characterized by various signs. Bile duct ligation (BDL) is a standard model for research in cholestasis in male rats and mice. However, the timing and degree of structural changes in BDL-subjected liver differ in the two animal species. This study focused on chickens as a choice model for cholestasis. Specifically, we aimed to evaluate the features of BDL in hens and compare them with those in rats and mice. Eighteen hens, 19 female ICR mice, and 18 female SD rats were randomly divided into the sham-operated and BDL groups. At 2, 4, and 6 weeks after BDL, and 4 weeks after the sham operation, liver and blood samples were collected and analyzed histologically and biochemically. Histologically, bile duct proliferation in BDL-subjected livers was first observed in the chickens and then the rats and mice, whereas CD44-positive small hepatocytes were observed only in chickens in the BDL group. Biochemically, the mRNA expression of the hepatocyte growth factor was higher in BDL-subjected chickens, while Interleukin 6 expression was higher in the BDL-subjected rats and mice than in animals in the sham group. In addition, farnesoid X receptor mRNA expression was lower in the BDL-subjected chickens than in the sham chickens. The BDL group had significantly higher total bile acid blood concentration than the sham group. In conclusion, the signs of hepatopathy caused by BDL differ among animal species. Furthermore, we propose that compared to BDL-subjected mice and rats, BDL-subjected chickens are a novel cholestasis animal model that demonstrates severe hepatopathy and liver restructuring.