Proliferating cell nuclear antigen (PCNA) expression in tooth primordia in the field vole (Microtus agrestis, Rodentia).

Cell proliferation in developing tooth germs has been studied particularly using bromodeoxyuridine (BrdU) incorporation into growing tooth primordia and by counting and three-dimensional (3D) reconstruction of mitoses in serial sections of developing teeth. PCNA has been proposed as an alternative marker of proliferation activity. The aim of our study was to detect immunohistochemically locations of PCNA-positive cells in developing tooth germs of Microtus agrestis (Rodentia). PCNA expression could be distinguished in oral epithelium and mesenchyme before first signs of dental lamina elevation. During bud, cap, and bell stages, positive immunostaining could be observed at defined sites in enamel organ, tooth papilla, and dental follicle. Rudimental tooth germs of the upper diastema, enamel knots, and inner enamel epithelium at day of ontogeny 18 and 19 showed negative reaction. PCNA marks cycling and early G0 cells and can be used successfully as a proliferation marker even in collection material.