日本研究人员报告说，他们成功地在体外将实验鼠的精原干细胞培育成了精子，这一成果将有助于男性不育症的研究。
日本横滨市立大学教授小川毅彦与理化学研究所合作，从出生8天的雄性实验鼠体内提取出精原干细胞，并从出生5天至8天的实验鼠体内摘取精巢，然后将精原干细胞注入精巢的生精小管内，经过43天的培养，精原干细胞发育成了精子细胞。
研究人员利用这些精子细胞，通过体外受精培育出52个受精卵，然后植入雌性实验鼠体内，最终产下5只小鼠。这5只小鼠都健康成长，其中3只雌鼠后来通过自然交配，又产下了21只小鼠。研究小组由此认为利用这种方法培育的精子具有正常功能。
研究人员还利用精原干细胞正常、但精巢内其他细胞异常以致无法产生精子的不育实验鼠进行了相同实验，将它们的精原干细胞注入正常实验鼠的精巢生精小管培养，也生成了正常精子。研究小组据此推测，一些男性不育症患者的精原干细胞也有可能是正常的。
这一成果发表在新一期英国《自然·通信》网络杂志上。小川毅彦说，虽然这项技术目前还无法直接用于人类，但通过观察试管中精子在精巢内形成的过程，可以弄清精子形成的必要条件，从而有助于对男性不育症的研究。(生物谷Bioon.com)
doi:10.1038/ncomms1478
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In vitro production of fertile sperm from murine spermatogonial stem cell lines
Takuya Sato,Kumiko Katagiri,Tetsuhiro Yokonishi,Yoshinobu Kubota,Kimiko Inoue,Narumi Ogonuki,Shogo Matoba,Atsuo Ogura & Takehiko Ogawa
Spermatogonial stem cells (SSCs) are the only stem cells in the body that transmit genetic information to the next generation. The long-term propagation of rodent SSCs is now possible in vitro, and their genetic modification is feasible. However, their differentiation into sperm is possible only under in vivo conditions. Here we show a new in vitro system that can induce full spermatogenesis from SSC lines or any isolated SSCs. The method depends on an organ culture system onto which SSCs are transplanted. The settled SSCs form colonies and differentiate up into sperm. The resultant haploid cells are fertile, and give rise to healthy offspring through micro-insemination. In addition, the system can induce spermatogenesis from SSCs that show spermatogenic failure due to a micro-environmental defect in their original testes. Thus, an in vitro system is established that can be used to correct or manipulate the micro-environmental conditions required for proper spermatogenesis from murine SSC lines.
