Editors' ChoiceINFERTILITY

Sperm Find Culture

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Science Translational Medicine  27 Apr 2011:
Vol. 3, Issue 80, pp. 80ec60
DOI: 10.1126/scitranslmed.3002540

Spermatogenesis in mammals is a lengthy and complicated process involving meiotic divisions of spermatogonial stem cells to form first spermatids and then mature sperm. Given this, it is not surprising that it has been very difficult to achieve successful spermatogenesis in a culture dish. Sato et al. now report the successful production of spermatids and mature sperm in organ cultures of neonatal mouse testes for up to 2 months. They cultured fragments of neonatal testis tissue on agarose gel in a well-established gas-liquid culture system. The sperm produced in culture were fully functional because microinseminating them into mouse oocytes resulted in production of normal offspring that were reproductively competent. Interestingly, when testicular tissue fragments were frozen in liquid nitrogen for up to 25 days and then thawed, these cryopreserved fragments were able to resume spermatogenesis when placed into culture. How did Sato et al. achieve this feat where others have repeatedly failed? These researchers discovered that a common additive in cell culture medium, fetal bovine serum, appeared to inhibit spermatogenesis. So, instead of using fetal bovine serum, they used a serum substitute called KnockOut Serum Replacement. Their modified organ culture system for mammalian testes will be invaluable for those studying spermatogenesis and male infertility. However, much further study will be needed before these exciting findings can be translated into treatments for human male infertility. The Sato et al. study may be of particular importance for male pediatric cancer patients undergoing radiation or chemotherapy. These preliminary results suggest that a biopsy of prepubertal testicular tissue could be cryopreserved and then thawed and cultured at some future date to produce mature sperm. In this way, even very young cancer patients would have the option to some day share in the joys, trials, and tribulations of parenthood.

T. Sato et al., In vitro production of functional sperm in cultured neonatal mouse testes. Nature 24, 504–507 (2011). [Abstract]

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