Response of the spermatogenic system to chemical mutagen dipin in SAMP1 senescence-accelerated mice

Specific features of spermatogenesis were studied in senescence-accelerated mice of the strain SAMP1 after one-time injection of the chemical mutagen dipin. Quantitative and histomorphological changes in the spermatogenic epithelium proved to develop gradually. Cell loss and disorganization of spermatogenesis reached the peak as late as on days 28 and 35 after the injection. Differentiating spermatogonia manifested increased sensitivity to dipin. In prophase I of meiosis, developing spermatocytes proved to be less sensitive to the cytotoxic action of dipin at the pachytene than at the preleptotene-leptotene stages. Spermatogenesis in most seminiferous tubules was restored by day 56 after dipin treatment. At the end of the experiment (day 100), both quantitative parameters and morphological pattern of spermatogenesis did not differ significantly from those in the control. Thus, the cytotoxic action of dipin does not lead to irreversible structural disorganization of the spermatogenic epithelium in SAMP1 mice. Radioautography revealed a large proportion of highly differentiated Sertoli cells with H-3-thymidine-labeled nuclei in experimental animals. In some cases, structures resembling embryonic seminiferous tubules were revealed in the vicinity of rete testis in histological sections of testes of experimental mice. These structures contained the cells morphologically similar to gonocytes and immature Sertoli cells.