Multinucleated cells are involved in normal development and apoptosis in mouse testes

Multinucleated cells are present in impaired spermatogenesis and in the senescent testis. Following accumulating evidence from our previous studies on the identification of multinucleated cells during normal testicle development, the current study further investigated the possible mechanism and role of these multinucleated cells. Healthy male Kunming mice were used in the present study. The association between multinucleated cells and cell apoptosis were analyzed using TUNEL analysis and immunohistochemistry. The results showed that multinucleated cells are widespread in the testicular tissue of seminiferous tubules on postnatal days 23, 27, 30, 33, 36, 40, 47, 50 and 54 suggesting that these cells are involved in the process of normal development of mouse testis. Histochemical analysis revealed a lack of proliferating cell nuclear antigen, cyclin D1 protein expression in multinucleated cells, suggesting that these cells are not involved in the G1 and S phases of the cell cycle and cell proliferation. Increased expression of Bax and caspase 3 was detected, revealing that multinucleated cells may be associated with cell apoptosis during testicular development. To the best of our knowledge, this study demonstrated for the first time that multinucleated cells are present during normal testicular development and may be associated with spermatogonial stem cell apoptosis. Therefore, multinucleated cells may be important in the spermatogenesis process.