Fig. 2.

A and B: in BDL rats there was increased percentage of PCNA-positive cholangiocytes and intrahepatic bile duct mass (IBDM) compared with normal rats. Chronic exposure of BDL rats to complete dark decreases the percentage of PCNA-positive cholangiocytes and IBDM compared with BDL controls. Prolonged dark exposure had no effect on the proliferation of normal rats. Original magnification, ×40 (PCNA), ×10 (CK-19). Data are expressed as means ± SE. *P < 0.05 vs. normal rats. #P < 0.05 BDL + dark compared with BDL rats exposed to light-dark cycles. C: the architecture of normal rats exposed to 12:12-h light-dark cycles or prolonged dark was normal. BDL rats showed prominent biliary proliferation. BDL rats exposed to complete dark for 1 wk show lower cholangiocyte proliferation compared with BDL rats. Original magnification, ×10.