Immunocytochemical and quantitative study of actin, desmin and vimentin in the peritubular cells of the testes from elderly men.

A quantitative immunohistochemical study using light and electron microscopy was carried out to evaluate the morphological and quantitative distribution of the peritubular cells that immunoreact with actin, vimentin and desmin, alone or in combinations, in normal adult testes and the changes in these cells in elderly men. Seminiferous tubules in ageing testes were classified in three groups according to the degree of lamina propria thickening due to tubular sclerosis: group I, < 8 microns; group II, 8.1-12 microns; and group III, > 12.1 microns. The number of peritubular cells per cross-sectioned tubule increased from group I to group III tubules. However, no significant differences between ageing men and controls were found in the total number of peritubular cells per testis. Most peritubular cells of control testes and of group I and group II tubules displayed immunoreactivity to actin. The peritubular cells in the outermost layers of group III tubules showed no or scanty reaction. The number of actin-immunostained cells per cross-sectioned tubule decreased (P < 0.05) with tubular sclerosis. The total number of these cells per testis was significantly lower (P < 0.05) in elderly men. A narrow band around the seminiferous epithelium immunostained for desmin in control testes and group I tubules. These cells also immunoreacted to actin and vimentin. In group II and, principally, in group III tubules, only isolated peritubular cells were immunostained for desmin. The number of desmin-immunostained cells per cross-sectioned tubule decreased with tubular sclerosis and the total number per testis was also lower in elderly men. Vimentin immunostaining was observed in most peritubular cells in all tubule groups; these cells also immunoreacted to actin. Vimentin and desmin co-localized only in the inner peritubular cell layers. The number of vimentin-immunostained cells per cross-sectioned tubule increased with the degree of tubular sclerosis but the total number of these cells per testis did not differ significantly between control and ageing testes.