Rathi R, Honaramooz A, Zeng W, Turner R, Dobrinski I
Center for Animal Transgenesis and Germ Cell Research, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, 19348, USA.
Reproduction. 2006 Jun;131(6):1091-8. doi: 10.1530/rep.1.01101.
Grafting of testis tissue from immature animals to immunodeficient mice results in complete spermatogenesis, albeit with varying efficiency in different species. The objectives of this study were to investigate if grafting of horse testis tissue would result in spermatogenesis, and to assess the effect of exogenous gonadotropins on xenograft development. Small fragments of testis tissue from 7 colts (2 week to 4 years of age) were grafted under the back skin of castrated male immunodeficient mice. For 2 donor animals, half of the mice were treated with gonadotropins. Xenografts were analyzed at 4 and 8 months post-transplantation. Spermatogenic differentiation following grafting ranged from no differentiation to progression through meiosis with appearance of haploid cells. Administration of exogenous gonadotropins appeared to support post-meiotic differentiation. For more mature donor testis samples where spermatogenesis had progressed into or through meiosis, after grafting an initial loss of differentiated germ cells was observed followed by a resurgence of spermatogenesis. However, if haploid cells had been present prior to grafting, spermatogenesis did not progress beyond meiotic division. In all host mice with spermatogenic differentiation in grafts, increased weight of the seminal vesicles compared to castrated mice showed that xenografts were releasing testosterone. These results indicate that horse spermatogenesis occurs in a mouse host albeit with low efficiency. In most cases, spermatogenesis arrested at meiosis. The underlying mechanisms of this spermatogenic arrest require further investigation.
将未成熟动物的睾丸组织移植到免疫缺陷小鼠体内可实现完全精子发生，尽管在不同物种中的效率有所不同。本研究的目的是调查马睾丸组织移植是否会导致精子发生，并评估外源性促性腺激素对异种移植发育的影响。从7匹小马驹（2周龄至4岁）获取小块睾丸组织，移植到去势雄性免疫缺陷小鼠的背部皮肤下。对于2只供体动物，半数小鼠接受促性腺激素治疗。在移植后4个月和8个月对异种移植组织进行分析。移植后的精子发生分化程度不一，从无分化到通过减数分裂进展并出现单倍体细胞。外源性促性腺激素的施用似乎支持减数分裂后的分化。对于精子发生已进入或通过减数分裂的更成熟供体睾丸样本，移植后观察到分化生殖细胞最初有所减少，随后精子发生重新出现。然而，如果移植前存在单倍体细胞，精子发生不会超过减数分裂阶段。在所有移植组织中发生精子发生分化的宿主小鼠中，与去势小鼠相比，精囊重量增加表明异种移植组织在释放睾酮。这些结果表明，马的精子发生在小鼠宿主中发生，尽管效率较低。在大多数情况下，精子发生停滞在减数分裂阶段。这种精子发生停滞的潜在机制需要进一步研究。
