Immunohistochemical Expression of Bcl-2 and Bax after Bile Duct Ligation in the Rat

Yun, Ki Jung; Chae, Kwon Mook

Abstract

BACKGROUND/AIMS: The cell homeostasis is regulated by a balance between apoptosis, proliferation and growth arrest. Bcl-2 and Bax belong to a family of cytoplasmic proteins that regulate apoptosis. The aim of this study was to verify blood biochemistry, histologic findings and expression pattern of Bcl-2 and Bax during the bile duct proliferation.
METHODS
We induced bile duct proliferation by the bile duct ligation in Sprague-Dawley rats. The expression of Bcl-2 and Bax was visualized by immunohistochemical staining. The rats were sacrified 2, 4, 6, 8 weeks after bile duct ligation.
RESULTS
Bcl-2 was expressed in the bile duct of control rats (n=10) and bile duct- ligated rats (n=40). Bcl-2 expression in hepatocytes was noted in the bile duct-ligated rats but not in control rats. Bax was expressed in the bile duct and hepatocytes of the control and bile duct-ligated rats. Histologically, bile duct proliferation became infiltrative and accompanied periductal inflammatory cells in the bile duct-ligated rats. However, serum levels of AST, ALT, and bilirubin were not increased according to duration of bile duct ligation.
CONCLUSIONS
From these results, we suggest that hepatocellular expression of Bcl-2 after ligation is an adaptive phenomenon to resist apoptosis and expression of Bax in bile duct is due to inflammatory process.