Chen Hong, Chen Kexing, Zhao Fange, Guo Yihan, Liang Yue, Wang Zhengrong, Liu Tengfei, Chen Shulin
College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, 712100, China.
College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, 712100, China.
Theriogenology. 2022 Mar 1;180:53-62. doi: 10.1016/j.theriogenology.2021.12.023. Epub 2021 Dec 20.
Testosterone is an important steroid hormone that is indispensable for male sexual development and the reproductive system. Leydig cells (LCs), where autophagy is extremely active, reside in the testicular interstitium and are the major sites of testosterone production. However, the ultrastructural characteristics and the functional role of autophagy in LCs of livestock remain unknown. In this study, the LCs of the dairy goats were investigated to identify the steroidogenic activity and autophagy levels at different ages of development by light microscopy, immunohistochemistry (IHC), immunofluorescence (IF), and transmission electron microscopy (TEM). Morphological results showed that the steroidogenic activity (3β-HSD staining) and ultrastructural characteristics of the LCs were changed with increasing age. TEM results demonstrated that the organelles involved in testosterone synthesis, e.g., smooth endoplasmic reticulum, mitochondria, and lipid droplets, were abundantly distributed within the cytoplasm of LCs in pubertal and adult testes. Moreover, autophagy activity was enhanced in the testes at pubertal and adult stages compared with that at the juvenile stage. Several different autophagic vacuoles, including pre-autophagosomes, autophagosomes, and autolysosomes, were observed within the cytoplasm of LCs from pubertal and adult testes. However, immunofluorescent staining and TEM results showed that no typical lipophagic or mitophagic vacuoles were observed in the cytoplasm of LCs. Furthermore, primary LCs from dairy goats were used to study the effect of autophagy on testosterone production. After treatment with 3-methyladenine (3-MA, an autophagy inhibitor), the primary LCs decreased testosterone production. In contrast, treatment with rapamycin (an autophagy activator), enhanced steroidogenesis in LCs. Collectively, these in vivo and in vitro results suggested that autophagy activity is related to steroidogenesis in LCs of dairy goats, which may ultimately influence the spermatogenesis and fertility of these animals.
睾酮是一种重要的类固醇激素，对男性性发育和生殖系统不可或缺。睾丸间质细胞（LCs）存在于睾丸间质中，自噬极其活跃，是睾酮产生的主要部位。然而，家畜睾丸间质细胞中自噬的超微结构特征和功能作用仍不清楚。在本研究中，通过光学显微镜、免疫组织化学（IHC）、免疫荧光（IF）和透射电子显微镜（TEM）对奶山羊的睾丸间质细胞进行了研究，以确定不同发育年龄阶段的类固醇生成活性和自噬水平。形态学结果表明，睾丸间质细胞的类固醇生成活性（3β-HSD染色）和超微结构特征随年龄增长而变化。透射电子显微镜结果表明，参与睾酮合成的细胞器，如滑面内质网、线粒体和脂滴，大量分布在青春期和成年睾丸的睾丸间质细胞胞质内。此外，与幼年阶段相比，青春期和成年阶段睾丸中的自噬活性增强。在青春期和成年睾丸的睾丸间质细胞胞质内观察到几种不同的自噬泡，包括自噬前体、自噬体和自溶酶体。然而，免疫荧光染色和透射电子显微镜结果表明，在睾丸间质细胞胞质内未观察到典型的脂噬或线粒体自噬泡。此外，利用奶山羊的原代睾丸间质细胞研究自噬对睾酮产生的影响。用3-甲基腺嘌呤（3-MA，一种自噬抑制剂）处理后，原代睾丸间质细胞的睾酮产生减少。相反，用雷帕霉素（一种自噬激活剂）处理可增强睾丸间质细胞的类固醇生成。总的来说，这些体内和体外结果表明，自噬活性与奶山羊睾丸间质细胞的类固醇生成有关，这可能最终影响这些动物的精子发生和生育能力。
