Animal model: common bile duct ligation

Male Sprague–Dawley rats (260–280 g) were caged at 24°C with a 12-h light/dark circle and allowed free access to food and water. Secondary biliary cirrhosis was induced by common bile duct ligation (CBDL) [12]. In brief, under ketamine anesthesia (100 mg/kg, intramuscularly), the common bile duct was exposed through a midline abdominal incision and doubly ligated with 3-0 silk. The section between the ligatures was cut. The incision was then closed and the animal allowed to recover. A high yield of secondary biliary cirrhosis was noted 4 weeks later [13]. Weekly vitamin K injection (50 μg/kg, intramuscularly) was applied to avoid coagulation defect.

The Taipei Veterans General Hospital Animal Committee approved the study (grant number IACUC 2012-106). All animals received humane care according to the criteria outlined in the ‘Guide for the Care and Use of Laboratory Animals’ prepared by the National Academy of Sciences and published by the National Institutes of Health (NIH Publication 86-23, revised 1985).