抄録
Comparison of immunohistochemical staining of proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine (BrdU) was studied in rat livers. Experiment 1: Rats were subjected to twothirds partial hepatectomy (PH). Three animals were killed at 1, 2, 3, 4, 7, and 14 days after PH. Experiment 2: Rats were given a single intraperitoneal injection of 500 mg/kg body weight of Dgalactosamine (D-gal). Three animals were sacrificed at 24 and 32 hours, 3, 7, and 14 days after administration. One hundred mg/kg body weight of bromodeoxyurine (BrdU) were administered in both experiments as a single intraperitoneal injection at I hour before sacrifice. Sequential changes in cellular proliferations were investigated by immunohistochemical staining of PCNA and BrdU using formlin-fixed and paraffin was embedded sections. In experiment 1, mitotic index of hepatocytes reached the highest values at 3 days after PH. Both the largest PCNA and BrdU labeling were found at 24 hours after PH. In addition, PCNA and BrdU labeling in bile ducts reached a peak 2 days after PH. In experiment 2, necrosis and vacuolar degeneration of hepatocytes were marked at 24-32 hours after D-gal administration, and proliferation of bile ducts and oval cells was noted at 3 days after administration. PCNA and BrdU labeling in the bile duct epithelial cells and hepatocytes had the highest values at 24 hours and 3 days after administration, respectively. A good correlation between PCNA and BrdU labeling was obtained not only in hepatocytes but in bile ducts in both experiments. These results strongly support that immunohistochemical staining of PCNA is a useful marker to examine cell proliferation even in tissues fixed by formalin and embedded in paraffin wax in the field of toxicologic pathology.
