Proliferation Markers, Proliferating Cell Nuclear Antigen, Ki67, 5-Bromo-2′-Deoxyuridine, and Cyclin D1 in Mouse Olfactory Epithelium

Abstract

We immunohistochemically identified proliferating cells in the olfactory epithelium of mice, using an anti–proliferating cell nuclear antigen (PCNA) antibody, an anti-Ki67 antibody, an anti–5-bromo-2′-deoxyuridine (BrdU) antibody, and an anti–cyclin D1 antibody. Positive cells stained by the 4 antibodies were identified mainly in the basal layer. The mean numbers of positive cells stained by the 4 antibodies in 500 olfactory epithelium cells from each animal were as follows: PCNA-positive cells 42, Ki67-positive cells 23, BrdU-positive cells 13.7, and cyclin D1–positive cells 9.2. PCNA may be detected in both proliferating and resting cells. Ki67 is an intranuclear antigen expressed in proliferating, but not resting, cells. Anti-BrdU antibodies might stain proliferating cells only following the S-phase, but not the G1-phase. Cyclin D1 is a protein that works during the G1-phase of the cell cycle. When we stain proliferating cells using proliferating cell markers, it is important to consider the cell cycle phases during which each marker stains.