Expansion of oval cells and sinusoidal cells under CDE conditions is proliferative. Double-immunohistochemistry of BrdU with cytokeratin (A), BrdU with GFAP (B), BrdU with vimentin (C) and BrdU with F4/80 (D). In A, B and C, BrdU-positive nuclei are labelled in brown and the corresponding biomarkers in purple. In (D) BrdU-positive nuclei are labelled in purple and the corresponding Kupffer cell marker (F4/80) in brown. Nuclei were counterstained with hematoxylin (blue). Bars = 50 μm.