Quantitative analysis of the cellular composition in seminiferous tubules in normal and genetically modified infertile mice.

The aim of this study was to establish a quantitative standard for the cellular composition in seminiferous tubules at each stage of spermatogenesis in the mouse testis, and thereby evaluate abnormalities in the infertile mouse testis. We applied a combination of lectin histochemistry for acrosomes and immunohistochemistry for various specific cell markers, both of which were visualized with fluorescence, on paraffin sections of the testis. We first examined seminiferous tubules from normal mice and counted the number of each cell type at each stage of spermatogenesis. We then examined seminiferous tubules from genetically modified mice deficient (-/-) for one of the cell adhesion molecules, nectin-2 or nectin-3, and compared the number of each cell type at each stage of spermatogenesis with the corresponding value in normal mice. In both nectin-2-/- and nectin-3-/- mice, which are infertile despite the apparently normal morphology of the seminiferous epithelia, we measured a progressive loss in the later-step spermatids, with significantly lower numbers of step 11-16 spermatids in nectin-3-/- mice and step 15-16 spermatids in nectin-2-/- mice as compared with that in normal control mice. The present study demonstrated that a quantitative analysis of cellular compositions at different stages in seminiferous tubules was useful for evaluating abnormalities in spermatogenesis.