Lara Nathália de Lima E Martins, Costa Guilherme Mattos Jardim, Avelar Gleide Fernandes, Guimarães Diva Anelie, França Luiz Renato
Laboratory of Cellular Biology, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Laboratory of Animal Reproduction, Biological Sciences Institute, Federal University of Pará, Belém, PA, Brazil.
Gen Comp Endocrinol. 2019 Mar 1;273:98-107. doi: 10.1016/j.ygcen.2018.05.013. Epub 2018 May 12.
Collared peccaries (Tayassu tajacu) present a unique testis cytoarchitecture, where Leydig cells (LC) are mainly located in cords around the seminiferous tubules (ST) lobes. This peculiar arrangement is very useful to better investigate and understand the role of LC in spermatogonial stem cells (SSCs) biology and niche. Recent studies from our laboratory using adult peccaries have shown that the undifferentiated type A spermatogonia (A or SSCs) are preferentially located in ST regions adjacent to the intertubular compartment without LC. Following these studies, our aims were to investigate the collared peccary postnatal testis development, from birth to adulthood, with emphasis on the establishment of LC cytoarchitecture and the SSCs niche. Our findings demonstrated that the unique LC cytoarchitecture is already present in the neonate peccary's testis, indicating that this arrangement is established during fetal development. Based on the most advanced germ cell type present at each time period evaluated, puberty (the first sperm release in the ST lumen) in this species was reached at around one year of age, being preceded by high levels of estradiol and testosterone and the end of Sertoli cell proliferation. Almost all gonocytes and SSCs expressed Nanos1, Nanos2 and GFRA1. The analysis of SSCs preferential location indicated that the establishment of SSCs niche is coincident with the occurrence of puberty. Taken together, our findings reinforced and extended the importance of the collared peccary as an animal model to investigate testis function in mammals, particularly the aspects related to testis organogenesis and the SSCs biology and niche.
领西猯（Tayassu tajacu）呈现出独特的睾丸细胞结构，其中睾丸间质细胞（LC）主要位于生精小管（ST）叶周围的索状结构中。这种特殊的排列对于更好地研究和理解LC在精原干细胞（SSCs）生物学及微环境中的作用非常有用。我们实验室最近对成年西猯的研究表明，未分化的A型精原细胞（A或SSCs）优先位于与无LC的小管间隔相邻的ST区域。基于这些研究，我们的目的是研究领西猯从出生到成年的出生后睾丸发育，重点是LC细胞结构的建立和SSCs微环境。我们的研究结果表明，独特的LC细胞结构在新生西猯的睾丸中就已存在，这表明这种排列在胎儿发育期间就已建立。根据每个评估时间段出现的最先进生殖细胞类型，该物种在大约一岁时达到青春期（ST管腔中首次释放精子），在此之前雌二醇和睾酮水平较高，支持细胞增殖结束。几乎所有的生殖母细胞和SSCs都表达Nanos1、Nanos2和GFRA1。对SSCs优先位置的分析表明，SSCs微环境的建立与青春期的出现同时发生。综上所述，我们的研究结果加强并扩展了领西猯作为研究哺乳动物睾丸功能的动物模型的重要性，特别是与睾丸器官发生以及SSCs生物学和微环境相关的方面。
