Beltrán-Frutos Ester, Seco-Rovira Vicente, Martínez-Hernández Jesús, Ferrer Concepción, Serrano-Sánchez María Isabel, Pastor Luis Miguel
Department of Cell Biology and Histology, Medical School, IMIB-Arrixaca, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30120 Murcia, Spain.
Animals (Basel). 2022 Jun 22;12(13):1605. doi: 10.3390/ani12131605.
Testicular regression occurs during the non-breeding season in many mammals. This affects spermatogenesis, resulting in decreased or arrested activity. Both lead to a decrease or cessation in sperm production. In recent years, the cellular mechanisms that lead to infertility in males in non-reproductive periods have been studied in very different species of mammals. At the start of the present century, the main mechanism involved was considered as an increase in the apoptotic activity of germ cells during the regression period. The loss of spermatogonia and spermatocytes causes not only a decrease in spermatogenesis, but an arrest of the seminiferous epithelium activity at the end of regression. Recently, in some mammal species, it was found that apoptosis is the usual mechanism involved in epithelium activity arrest, although it is firstly atrophied by massive desquamation of the germ cells that are released from their binding with the Sertoli cells, and which are shed into the lumen of the seminiferous tubule. In other species, it has been shown that not only germ cell apoptosis, but also Sertoli cell apoptosis, including decreased proliferative activity, spermatophagy or autophagy, are involved in testicular regression. Furthermore, the most recent studies indicate that there are multiple patterns of seminiferous epithelium regression in seasonally breeding animals, which may not only be used by different species, but also by the same ones to reproduce in the best conditions, ensuring their survival. In conclusion, at this time, it is not possible to consider the existence of a paradigmatic cellular mechanism in the involution of the seminiferous epithelium applicable to all male mammals with seasonal reproduction, rather the existence of several mechanisms which participate to a greater or lesser extent in each of the species that have been studied to date.
在许多哺乳动物的非繁殖季节会发生睾丸退化。这会影响精子发生，导致活性降低或停滞。两者都会导致精子产生减少或停止。近年来，已经在非常不同种类的哺乳动物中研究了导致雄性在非繁殖期不育的细胞机制。在本世纪初，主要涉及的机制被认为是在退化期生殖细胞凋亡活性增加。精原细胞和精母细胞的损失不仅会导致精子发生减少，还会在退化末期导致生精上皮活性停滞。最近，在一些哺乳动物物种中发现，凋亡是参与上皮活性停滞的常见机制，尽管它首先是由于与支持细胞结合的生殖细胞大量脱落而萎缩，这些生殖细胞被排入生精小管腔。在其他物种中，已经表明不仅生殖细胞凋亡，而且支持细胞凋亡，包括增殖活性降低、精子吞噬或自噬，都参与睾丸退化。此外，最新研究表明，季节性繁殖动物的生精上皮退化有多种模式，这不仅可能被不同物种使用，也可能被同一物种用于在最佳条件下繁殖，确保它们的生存。总之，目前，不可能认为存在一种适用于所有季节性繁殖雄性哺乳动物的生精上皮退化的典型细胞机制，而是存在几种在迄今研究的每个物种中或多或少都有参与的机制。
