Nagano M, Avarbock M R, Leonida E B, Brinster C J, Brinster R L
School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6009, USA.
Tissue Cell. 1998 Aug;30(4):389-97. doi: 10.1016/s0040-8166(98)80053-0.
Spermatogenesis occurs within the seminiferous tubules of mammals by a complex process that is highly organized, extremely efficient and very productive. At the foundation of this process is the spermatogonial stem cell that is capable of both self-renewal and production of progeny cells, which undergo differentiation over a period of weeks to months in order to generate mature spermatozoa. It had been thought that germ cells survive only a brief period in culture, generally less than a few weeks. However, an accurate assessment of the presence of spermatogonial stem cells in any cell population has only recently become possible with development of the spermatogonial transplantation technique. Using this technique, we have demonstrated that mouse spermatogonial stem cells can be maintained in culture for approximately 4 months and will generate spermatogenesis following transplantation to the seminiferous tubules of an appropriate recipient. Extensive areas of cultured donor cell-derived spermatogenesis are generated in the host, and production of mature spermatozoa occurs. Cultivation of the testis cells on STO feeders is beneficial to stem cell survival. These results provide the first step in establishing a system that will permit spermatogonial stem cells to be cultivated and their number increased in vitro to allow for genetic modification before transplantation to a recipient testis.
精子发生过程在哺乳动物的生精小管内通过一个高度有序、极其高效且产量很高的复杂过程进行。这个过程的基础是精原干细胞，它既能自我更新，又能产生子代细胞，这些子代细胞会在数周乃至数月的时间里经历分化，以生成成熟的精子。过去人们认为生殖细胞在培养环境中只能存活很短一段时间，通常不到几周。然而，随着精原细胞移植技术的发展，最近才有可能准确评估任何细胞群体中精原干细胞的存在情况。利用这项技术，我们已经证明，小鼠精原干细胞可以在培养环境中维持约4个月，并且在移植到合适受体的生精小管后能够产生精子发生。宿主中会产生大量源自培养的供体细胞的精子发生区域，并且会产生成熟的精子。在STO饲养层上培养睾丸细胞有利于干细胞存活。这些结果为建立一个系统迈出了第一步，该系统将允许精原干细胞在体外进行培养并增加其数量，以便在移植到受体睾丸之前进行基因改造。
