Figure 2.

A) In Mdr2^−/− mice, the increase in IBDM (by immunohistochemistry for CK-19; CK-19–positive bile ducts indicated by red arrows) and biliary proliferation in isolated cholangiocytes was reduced by exposure to the dark or to melatonin. B) Dark exposure or melatonin did not alter the IBDM of normal WT (FVB/NJ) mice. PCR data are means ± sem of 4 evaluations in cholangiocytes collected from 3 cumulative preparations of cholangiocytes from 4 mice (n = 12 mice). Original magnification, ×25. *P < 0.05 vs. WT mice, ^#P < 0.05 vs. Mdr2^−/− mice.