Non-human primates are our closest relatives and therefore offer valuable comparative models for human evolutionary studies and biomedical research. As such, Japanese macaques ( Macaca fuscata ) have contributed to the advancement of primatology in both field and laboratory settings. Specifically, Japanese macaques serve as an excellent model for investigating postnatal development and seasonal breeding in primates because of their relatively prolonged juvenile period and distinct seasonal breeding activity in adulthood. Pioneering histological studies have examined the developmental associations between their reproductive states and spermatogenesis by morphological observation. However, a molecular histological atlas of Japanese macaque spermatogenesis is only in its infancy, limiting our understanding of spermatogenesis ontogeny related to their reproductive changes. Here, we performed immunofluorescence analyses of spermatogenesis in Japanese macaque testes to determine the expression of a subset of marker proteins. The present molecular histological analyses readily specified major spermatogonial subtypes as SALL4 + A spermatogonia and Ki67 + /C-KIT + B spermatogonia. The expression of DAZL, SCP1, γH2AX, VASA, and calmegin further showed sequential changes regarding the protein expression profile and chromosomal structures during spermatogenesis in a differentiation stage-specific manner. Accordingly, comparative analyses between subadults and adults identified spermatogenic deficits in differentiation and synchronization in subadult testes. Our findings provide a new diagnostic platform for dissecting spermatogenic status and reproduction in the Japanese macaques.

中文翻译：

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日本猕猴（Macaca fuscata）精子发生的分子组织学

非人类灵长类动物是我们的近亲，因此为人类进化研究和生物医学研究提供了有价值的比较模型。因此，日本猕猴 (Macaca fuscata) 在野外和实验室环境中为灵长类动物学的进步做出了贡献。具体而言，日本猕猴是研究灵长类动物出生后发育和季节性繁殖的绝佳模型，因为它们的幼年期相对较长，成年期具有明显的季节性繁殖活动。开创性的组织学研究通过形态学观察检查了它们的生殖状态和精子发生之间的发育关联。然而，日本猕猴精子发生的分子组织学图谱还处于起步阶段，限制了我们对与其生殖变化相关的精子发生个体发育的理解。在这里，我们对日本猕猴睾丸中的精子发生进行了免疫荧光分析，以确定标记蛋白子集的表达。目前的分子组织学分析很容易将主要的精原细胞亚型指定为 SALL4 + A 精原细胞和 Ki67 + /C-KIT + B 精原细胞。DAZL、SCP1、γH2AX、VASA 和钙镁蛋白的表达进一步显示出精子发生过程中蛋白质表达谱和染色体结构以分化阶段特异性方式发生的连续变化。因此，亚成体和成体之间的比较分析确定了亚成体睾丸分化和同步方面的生精缺陷。