Establishment of a mouse model for bile duct repair and tissue engineering.

Due to the lack of a suitable model, research on biliary biology is far behind that on other organs. A mouse model of common bile duct (CBD) dilation (BDD) was first established and compared with CBD ligation mice (BDL). Then, in a transplantation experiment, the dilated CBD of recipient BDD mice was injured by making an elliptical incision and repaired by transplanting a bile duct patch from donor BDD mice. Biochemical and histological changes were analyzed and cell proliferation of the bile duct grafts was determined. Slightly dilated and unblocked CBD with a diameter of 2.89±0.76 mm was obtained in BDD mice, while the CBD diameter was 0.51±0.08 mm in the Sham group and 4.71±0.64 mm in the BDL group on day 14 after surgery. The liver damage was very mild in BDD mice compared with BDL mice, proving that the BDD model could be further used for bile duct transplantation. By cross transplanting the bile duct patch from enhanced green fluorescence protein and wild-type BDD mice, it was found that the CBD injury was well repaired and the cells of the bile duct patch were completely replaced by recipient-derived cells at 12 week after the repair operation. α Smooth muscle actin, Ki67 and cytokeratin 19 immunofluorescence staining showed that the proliferation of bile duct epithelial cells and abundant active fibroblasts were found within the bile duct patch during the regeneration process. Therefore, a reliable new mouse model of bile duct injury and repair was successfully established and can be used in the study of biliary repair mechanisms and tissue engineering of biliary ducts.