Morphological features and regulation of seasonal spermatogenesis in plateau zokor (Eospalax baileyi)
Morphological features and regulation of seasonal spermatogenesis in plateau zokor (Eospalax baileyi)
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DOI：
10.16829/j.slxb.150420
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发表时间：
2020-09-30
影响因子：
--
通讯作者：
Yang Qien
中科院分区：
文献类型：
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作者：
An Xiaoyu;Wang Yujun;Yang Qien
季节性繁殖是一种生活史适应，有助于动物在环境变化下生存。季节性繁殖受到下丘脑-垂体-性腺（HPG）轴的严格调节。高原鼢鼠（Eospalax baileyi）是一种原产于青藏高原的地下啮齿动物，只在4月至7月繁殖。地下哺乳动物的配子发生和生殖活动是如何调节的仍不清楚。在本研究中，我们发现成年雄性高原鼢鼠的精子发生受到季节性调节。高原鼢鼠的生精小管含有发育良好的生殖细胞，在繁殖季节（4月至6月）包括细长的精子。根据细胞关联和形态特征，生精上皮可分为10个阶段。在非繁殖季节，生精小管仅含有精原细胞和支持细胞，表明精子发生已被抑制。繁殖季节促性腺激素释放激素、黄体生成素和睾酮水平显着升高，褪黑激素显着降低（P < 0.05），而卵泡刺激素水平没有出现显着变化。进一步的分析表明，负责精原细胞分化的视黄酸的生物发生发生了巨大的变化。正如预期的那样，补充视黄酸诱导生殖休眠动物恢复精子发生。这些数据共同证明了高原鼢鼠季节性精子发生的形态特征和关键调控因素。该研究可为了解其他地下啮齿动物中存在的类似机制提供参考。
Seasonal reproduction is a life history adaptation that helps animals survive under the changes of their environments. Seasonal reproduction is tightly regulated by the hypothalamus-pituitary-gonad (HPG) axis. Plateau zokor (Eospalax baileyi) is an underground rodent native to the Qinghai-Tibet plateau and they breed only in April to July. How gametogenesis and reproductive activities are regulated in underground mammals remains largely unclear. In the present study, we showed that spermatogenesis in adult male plateau zokor was seasonally regulated. Seminiferous tubules of plateau zokor contained well-developed germ cells including elongated sperm during breeding season (April to June). Based on the cell association and morphological features, the seminiferous epithelium can be divided into 10 stages. During non-breeding season, seminiferous tubules only contained spermatogonia and Sertoli cells, indicating spermatogenesis had been arrested. Levels of gonadotropin-releasing hormone, luteinizing hormone and testosterone were significantly increased in breeding season with notable reduction of melatonin (P < 0.05), while follicle-stimulating hormone level did not show a significant change. Further analysis revealed that biogenesis of retinoic acid, responsible for spermatogonial differentiation, was changed dramatically. As expected, supplementation of retinoic acid induced resumption of spermatogenesis in reproductively dormant animals. Together, these data demonstrated morphological features and key regulatory factors of seasonal spermatogenesis in plateau zokor. This study can provide a reference for understanding similar mechanism existed in other underground rodents.