Parks J E, Lee D R, Huang S, Kaproth M T
Gamete Physiology, Department of Animal Science, Cornell University, 201 Morrison Hall, Ithaca, NY 14853, USA.
Theriogenology. 2003 Jan 1;59(1):73-86. doi: 10.1016/s0093-691x(02)01275-x.
In recent years, extraordinary progress has been made in a broad range of reproductive technologies, including spermatogonial transplantation in the male. However, effective procedures for the complete recapitulation of spermatogenesis in vitro, including meiosis, have remained elusive. Such procedures have the potential to facilitate (1) mechanistic studies of spermatogenesis, (2) directed genetic modification of the male germ line, and (3) treatment of male factor infertility. Early studies demonstrated the importance of germ cell-Sertoli association for germ cell survival in vitro. Recently, evidence for male germ cell survival and progression through meiosis has been reported for the rat, mouse, and man. We demonstrated the expression of spermatid-specific genes (protamine and transition protein 1) by alginate-encapsulate neonatal bull testis cells after 10 weeks in culture, suggesting that meiosis had occurred. Although identifiable germ cells in these cultures were very sparse, some indication of acrosome development was observed. Following round spermatid injection (ROSI) with presumptive spermatids produced in vitro, 50% of blastocysts produced were diploid and 37% were Y-chromosome positive. Improved culture conditions, which promote germ cell survival, differentiation, and proliferation, are essential for in vitro spermatogenesis (IVS) to become a useful technology. Other approaches to male germ cell manipulation and spermatid production are discussed.
近年来，包括雄性精原细胞移植在内的广泛生殖技术取得了非凡进展。然而，体外完全重现精子发生过程（包括减数分裂）的有效方法仍然难以捉摸。此类方法有可能促进：（1）精子发生的机制研究；（2）雄性生殖系的定向基因改造；（3）男性因素不孕症的治疗。早期研究表明，生殖细胞与支持细胞的结合对于体外生殖细胞存活至关重要。最近，已有关于大鼠、小鼠和人类雄性生殖细胞存活及减数分裂进展的报道。我们发现，培养10周后，藻酸盐包封的新生公牛睾丸细胞表达了精子特异性基因（鱼精蛋白和过渡蛋白1），这表明发生了减数分裂。尽管这些培养物中可识别的生殖细胞非常稀少，但观察到了一些顶体发育的迹象。用体外产生的推测精子进行圆形精子细胞注射（ROSI）后，产生的囊胚中有50%为二倍体，37%为Y染色体阳性。改善促进生殖细胞存活、分化和增殖的培养条件，对于体外精子发生（IVS）成为一项有用技术至关重要。本文还讨论了雄性生殖细胞操作和精子细胞产生的其他方法。
