Timing of operation for injurious biliary stricture and changes of collagen content in bile duct in pigs

Objective To establish an animal model of injurious biliary stricture (IBS) to investigate the relationship between timing of operation and collagen content in the bile duct to provide theoretical and experimental bases for selection of timing of operation for IBS in clinical practice. Methods Twenty-four Rongchang pigs were randomized into 4 groups. Group A was the normal control. The pigs in groups B, C and D were inflicted with obstructive jaundice for half a month, 1 month and 3 months, respectively. Partial ligation of the bile duct was conducted in the latter groups. The repairing method of the bile duct was end-to-end anastomosis after resection of the strictural segment. Changes in collagen content in the bile duct were observed. Results After bile duct obstruction, the bile duct wall presented with epithelial necrosis, fibrous tissue proliferation and thickening. The extent of fibrous tissue proliferation after prosthesis and collagen content at the anastomosis site were positively correlated to biliary obstruction duration. Longer interval between the prosthesis and bile duct injury and higher collagen content resulted in more chances and greater severity of recurrent biliary stricture. Conclusions The changes in collagen contents after bile duct injury are very important for pathogenesis of recurrent biliary stricture.