Healing process of the guinea pig common bile duct after end-to-end anastomosis: pathological evaluation after 6 months.

BACKGROUND

The healing process of an injured bile duct is always associated with stricture formation, the specific mechanism of which remains unclear. Our objective in this study was to establish a guinea pig common bile duct end-to-end anastomosis (EEA) model after total transection of the common bile duct and to assess the postoperative healing process after 6 months.

MATERIALS AND METHODS

Thirty-two male guinea pigs were randomly divided into 4 groups with or without operation (a control group without operation and 3 groups examined 2, 3 and 6 months after biliary EEA reconstruction, respectively). Histological, immunohistochemical (proliferating cell nuclear antigen, α-smooth muscle actin, h-caldesmon, and Bcl-2 expression) and ultrastructural characteristics were examined and evaluated.

RESULTS

Myofibroblasts (MFBs) were differentiated from smooth muscle cells by α-SMA and h-caldesmon staining. Gross inspection of operated bile ducts revealed coarctation formation at the anastomotic stoma. Histological and immunohistochemical examinations showed significant inflammatory reaction, the presence of MFBs, epithelial proliferation and glandular element hyperplasia. Bcl-2 expression decreased in groups 2 and 3, indicating an epithelial self-protecting mechanism.

CONCLUSIONS

A guinea pig common bile duct EEA model was successfully established. Glandular elements, bile duct epithelial cells and MFBs all played crucial roles in the bile duct healing process. It seems important to elucidate the pathomechanisms of these components for restoring bile duct physiological function.