Thus, our procedure offers the possibility of collecting viable testicular cells at different stages of spermatogenesis from immature animals for biochemical, physiological, and toxicological studies (e.g., for screening candidate drugs). In addition, it seems likely that this method could be further developed for clinical application to human testicular tissue.
In conclusion, we report here that as soon as the stages of spermatogenesis arise in the immature testis, apoptosis is stage-specific. Increased apoptosis of pachytene spermatocytes during stages VII and VIII represents the major difference between immature spermatogenesis and the corresponding adult process, and it is suggested to be an important regulatory aspect of the development of spermatogenesis in rats. Apoptosis during the first spermatogenic wave was mediated by activation of caspase 3 and was correlated to expression of members of the Bcl-2 family of proteins. Targeted apoptosis of midpachytene spermatocytes and stage-dependent, specific expression of the Bax protein in these same cells further indicate the important role played by this protein in maturation of the spermato-genic epithelium in the rat testis.