Long-term (6-wk) hindlimb suspension inhibits spermatogenesis in adult male rats.
Long-term (6-wk) hindlimb suspension inhibits spermatogenesis in adult male rats.
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DOI：
10.1152/japplphysiol.00931.2001
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发表时间：
2002-03
影响因子：
3.3
通讯作者：
J. Tash;D. C. Johnson;G. Enders
中科院分区：
文献类型：
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作者：
J. Tash;D. C. Johnson;G. Enders
国际空间站将允许在太空中长期居住并长期暴露在微重力（microG）下。一个令人关切的问题是长期暴露于microG对物种繁殖能力的影响。通常用于模拟microG的模型是大鼠后肢悬吊（HLS），其中后肢被抬高到笼底以上，并带有尾带。这里描述的实验是第一次检查长期HLS对成年雄性大鼠睾丸功能的影响。对自由漫游（对照）、仅尾部套有挽具但后肢与笼底接触（TO）的动物和HLS动物进行6周试验。在TO和HLS动物中，通过用缝线部分收缩腹股沟管来预防隐睾。在6周实验结束时比较所有参数。HLS显著降低睾丸重量和精子发生，使得除了圆形精子细胞之外没有生精细胞存在，并且附睾缺乏成熟精子。在许多小管中，观察到除少数精原细胞外的所有生殖细胞丢失，导致与支持细胞相似的组织病理学。对照组和TO组动物的精子发生似乎未受影响。支持细胞和间质细胞外观，睾酮，黄体生成素，促卵泡激素水平，附睾和精囊重量没有变化的HLS。HLS并未升高皮质醇;因此压力可能不是一个因素。这些结果表明，长期HLS严重抑制精子发生，而睾丸雄激素的产生没有。这些结果对于长期暴露于microG对阴囊哺乳动物（包括人类）生殖能力的严重影响具有重要意义。
The International Space Station will allow extended habitation in space and long-term exposure to microgravity (microG). A concern is the impact of long-term microG exposure on the ability of species to reproduce. The model often used to simulate microG is rat hindlimb suspension (HLS), where the hindlimbs are elevated above the cage floor with a tail harness. Experiments described here are the first to examine the effect of long-term HLS on testicular function in adult male rats. Free-roaming (controls), animals with only the tail harnessed but hindlimbs in contact with the cage floor (TO), and HLS animals were tested for 6 wk. Cryptorchidism was prevented in TO and HLS animals by partial constriction of the inguinal canal with sutures. All parameters were compared at the end of the 6-wk experiment. Testicular weights and spermatogenesis were significantly reduced by HLS, such that no spermatogenic cells beyond round spermatids were present and epididymides were devoid of mature sperm. In many tubules, loss of all germ cells, except a few spermatogonia, resulting in histopathology similar to the Sertoli cell, was observed. Spermatogenesis appeared unaffected in control and TO animals. Sertoli and Leydig cell appearance, testosterone, luteinizing hormone, and follicle-stimulating hormone levels, and epididymal and seminal vesicle weight were unchanged by HLS. Cortisone was not elevated by HLS; thus stress may not be a factor. These results demonstrate that spermatogenesis is severely inhibited by long-term HLS, whereas testicular androgen production is not. These results have significant implications regarding serious effects of long-term exposure to microG on the reproductive capability of scrotal mammals, including humans.