Figure 4

Histological images from a control pig (Pig C4; a,c) and an irradiated pig with hepatic fibrosis (Pig R1; b,d). (a,b) Tissue samples sections stained with Masson’s trichrome stain for evaluation of hepatic fibrosis in a control pig (a) and an irradiated pig (b) with mild fibrosis. (c,d) Tissue sections immunohistochemically stained with an antibody against the nuclear antigen Ki-67, specific for hepatocytes in the proliferating phases of the cell cycle. When compared with the control pig, the number of proliferating hepatocytes in the irradiated pig (d) is markedly higher.