Influence of the male reproductive tract on the reproductive potential of round spermatids abnormally released from the seminiferous epithelium.

Round spermatids can be collected from testicular biopsy material or occasionally from semen samples. We evaluated the influence of the passage of round spermatids through the male reproductive tract on their reproductive potential. A model of abnormal release of round spermatids from the seminiferous epithelium was created in mature male rats (group A). Additional sham-treated rats of the same age served as a control group (group B). Round spermatids were collected from the testicles of rats of both groups, the epididymides of rats of group A, and the vaginae of mature female rats mated with rats of group A. Isolated round spermatids were processed for ooplasmic injections. Injected oocytes were cultured. At 96 h post-injection, the blastocyst development rate was significantly higher in the groups of oocytes injected with testicular spermatids than the groups of oocytes injected with spermatids recovered from the vaginae, or the head, body, or tail of the epididymides. It appears that round spermatids recovered from testicular biopsy material have larger reproductive capacity than ejaculated round spermatids, due to mechanical or chemical detrimental influences of storage/passage through the male reproductive tract (outside the testicle) on the capacity of round spermatids to induce optimal early embryonic development.