Long-term culture of male germline stem cells from hamster testes.

Spermatogonial stem cells provide the foundation for spermatogenesis in male animals. We recently succeeded in culturing and genetically engineering mouse spermatogonial stem cells, but little is known regarding the culture and growth requirements of spermatogonial stem cells in other animal species. In this study, we report the successful long-term culture of spermatogonial stem cells from hamster testes. Spermatogonial stem cells were purified using an anti-ITGA6 antibody and cultured in the presence of glial cell line-derived neurotrophic factor. The cells continued to proliferate for at least 1 year. During this period, they were genetically modified using a lentivirus and underwent spermatogenesis after transplantation into the testes of immunodeficient nude mice. However, germ cells generated in the surrogate xenogeneic recipients did not differentiate beyond the spermatid stage, and these round spermatids could not produce offspring through in vitro microinsemination. These results suggest that the germ cells may not have acquired characteristics necessary for fertility in the xenogeneic microenvironment. Nevertheless, the successful establishment of culture conditions conducive for hamster spermatogonial stem cell growth and maintenance indicates that this technique can be extended to other animal species in which current genetic modification techniques are impossible or inefficient.