Novel partial common bile duct ligation procedure in rats with reduced mortality and delayed onset of cirrhosis.

Common bile duct ligation (BDL) in rats is a widely used animal model for the study of cholestatic liver injury; however, it has a high mortality rate and leads to rapid disease progression. To address these limitations, the present study developed a simplified partial BDL (p-BDL) procedure by inserting a 26G disposable venous indwelling needle during ligation of the common bile duct, and subsequently removing the needle to create a narrow passage through the ligature points. The rats were euthanized 1 or 2 months after the procedure for histological, immunohistochemical and gelatin zymography analyses of the liver. Notably, no animals died during the experimental period, demonstrating the low mortality rate of the model. When assessed 1 month post-p-BDL, the rats exhibited mild liver fibrosis, while at 2 months, severe liver fibrosis was observed. Corresponding changes in liver function indices were also noted. Specifically, markers of liver fibrosis, including collagen I, collagen III and α-smooth muscle actin, as well as matrix metalloproteinase (MMP)-2 and MMP-9, which contribute to extracellular matrix degradation, were significantly upregulated following p-BDL. These findings are similar to those observed following BDL, and indicate that the p-BDL model was successfully established. This model mitigates the drawbacks of traditional BDL and mimics chronic cholestatic cirrhosis, as observed clinically.