Spermatogenesis is an intricate developmental process during which undifferentiated spermatogonia, containing spermatogonial stem cells (SSCs), undergo self-renewal and differentiation to generate eventually mature spermatozoa. Spermatogenesis occurs in seminiferous tubules within the testis, and the seminiferous tubules harbor Sertoli and germ cells. Sertoli cells are an essential somatic cell type within the microenvironment that support and steer male germ cell development, whereas spermatogonia are the primitive male germ cells at the onset of spermatogenesis. While the developmental progression of Sertoli cells and spermatogonia has been well established in mice, much less is known in other mammalian species including pigs. To acquire knowledge of Sertoli cell and spermatogonial development in pigs, here we collected as many as nine ages of Duroc porcine testes from the neonate to sexual maturity, i.e., testes from 7-, 30-, 50-, 70-, 90-, 110-, 130-, 150- and 210-day-old boars, and performed histological and immunohistochemical analyses on testis sections. We first examined the development of spermatogenic cells and seminiferous tubules in porcine testes. Then, by immunofluorescence staining for marker proteins (AMH, SOX9, DBA, UCHL1, VASA, KIT, Ki67 and/or PCNA), we delved into the proliferative activity and development of Sertoli cells and of spermatogonial subtypes (pro-, undifferentiated and differentiating spermatogonia). Besides, by immunostaining for β-catenin and ZO-1, we studied the establishment of the blood-testis barrier in porcine testes. In this longitudinal study, we have systematically investigated the elaborate Sertoli cell and spermatogonial developmental patterns in pigs from the neonate to sexual maturity that have so far remained largely unknown. The findings not only extend the knowledge about spermatogenesis and testicular development in pigs, but also lay the theoretical groundwork for porcine breeding and rearing.

中文翻译：

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猪的支持细胞和精原细胞发育

精子发生是一个复杂的发育过程，在此过程中，含有精原干细胞 (SSC) 的未分化精原细胞进行自我更新和分化，最终产生成熟的精子。精子发生发生在睾丸内的曲细精管中，曲细精小管含有支持细胞和生殖细胞。支持细胞是微环境中必不可少的体细胞类型，支持和引导雄性生殖细胞发育，而精原细胞是精子发生开始时的原始雄性生殖细胞。虽然支持细胞和精原细胞的发育进程已在小鼠中得到很好的证实，但在包括猪在内的其他哺乳动物物种中却知之甚少。获取猪支持细胞和精原细胞发育的知识，在这里我们收集了多达九个年龄的杜洛克猪从新生儿到性成熟的睾丸，即7天、30天、50天、70天、90天、110天、130天、150天和210天的睾丸-老公猪，并对睾丸切片进行组织学和免疫组织化学分析。我们首先检查了猪睾丸中生精细胞和曲细精管的发育。然后，通过对标记蛋白（AMH、SOX9、DBA、UCHL1、VASA、KIT、Ki67 和/或 PCNA）进行免疫荧光染色，我们深入研究了支持细胞和精原细胞亚型（亲、未分化和分化）的增殖活性和发育。精原细胞）。此外，通过对β-catenin和ZO-1的免疫染色，我们研究了猪睾丸中血睾丸屏障的建立。在这项纵向研究中，我们系统地研究了猪从新生儿到性成熟的复杂的支持细胞和精原细胞发育模式，到目前为止，这些模式在很大程度上仍是未知的。这些发现不仅扩展了关于猪精子发生和睾丸发育的知识，而且为猪的育种和饲养奠定了理论基础。