IL-33 induced cholangiocyte proliferation is restricted to the extrahepatic bile ducts.

Balb/c mice (n = 2/group) were injected i.p. with PBS or IL-33 and tissues were harvested 24 hours or 4 days later. Two hours prior to harvest, BrdU was administered i.p. to mark rapidly proliferating cells. (A) Representative sections of EHBD and liver after immunofluorescence staining with anti-cytokeratin (CK;green) and anti-BrdU (red) antibodies with DAPI (blue) nuclear stain. (B) The percentage of BrdU+ cells among all CK+ cells. Data are combined from two independent experiments, n = 4 mice per group total. Mean +/- s.d. ** = p<0.005 by two-tailed Student’s t-test. ns = not significant.