Department of Zoology, University of Allahabad, Prayagraj, Uttar Pradesh, India.
J Exp Zool A Ecol Integr Physiol. 2023 Nov;339(9):898-910. doi: 10.1002/jez.2740. Epub 2023 Aug 2.
While the seasonal testicular cycle has been well studied regarding internal components, no attention has been given to the testicular capsule (tunica albuginea and tunica serosa). This study elucidated the structure-function modulations of intra-testicular functions by its capsule in the finch red munia (Amandava amandava) during the annual testicular cycle. The birds were studied during breeding (preparatory and breeding) and nonbreeding (regressive and quiescent) reproductive phases using hematoxylin-eosin and acridine orange-ethidium bromide capsule staining, hormonal ELISA (LH and testosterone) and immunohistochemical expression of neuropeptides (GnRH, GnIH) and androgen receptor (AR). The thickness of the tunica albuginea was significantly increased with multiple myoid layers during the nonbreeding phases (p < 0.05). The thickness of the tunica serosa was not altered, although characteristics and distribution of squamous cells showed significant seasonal alterations. Immunoreactive (-ir) AR and GnIH cells were differentially localized on both layers of the capsule. Strong AR-ir cells on tunica serosa during breeding phases showed increased expression of the receptor; a significant increase in plasma LH and testosterone was also observed during the breeding cycle (p < 0.01). Contrarily, intense GnIH-ir cells on both the capsular layers peaked during testicular regression. Differential structural alterations of the testicular capsule provide mechanical support and help maintain internal homeostasis in tune with changing seasons. The seasonal expressions and alterations of reproduction-related receptors, hormones, and neuropeptides provide evidence for the potential regulatory roles of the capsule in the peripheral modulation of intratesticular functions.
虽然季节性睾丸周期的内部成分已经得到了很好的研究，但对于睾丸囊（白膜和浆膜）却没有引起关注。本研究阐明了在雀形目红梅花雀（Amandava amandava）的年度睾丸周期中，其囊对睾丸内功能的结构-功能调节作用。在繁殖（预备和繁殖）和非繁殖（退化和静止）生殖阶段，使用苏木精-伊红和吖啶橙-溴化乙锭囊染色、激素 ELISA（LH 和睾酮）以及神经肽（GnRH、GnIH）和雄激素受体（AR）的免疫组织化学表达来研究这些鸟类。在非繁殖阶段，白膜的厚度随着多层肌纤维的增加而显著增加（p<0.05）。浆膜的厚度没有改变，尽管鳞状细胞的特征和分布显示出明显的季节性变化。囊的两层均有不同定位的 GnRH 和 GnIH 免疫反应性（-ir）细胞。在繁殖阶段，浆膜上的 AR-ir 细胞强烈表达受体；在繁殖周期中也观察到血浆 LH 和睾酮的显著增加（p<0.01）。相反，在睾丸退化期间，两层囊上的 GnIH-ir 细胞强烈表达。睾丸囊的结构差异改变为提供机械支撑，并有助于维持与季节变化相适应的内部平衡。与生殖相关的受体、激素和神经肽的季节性表达和改变为囊在睾丸内功能的外周调节中的潜在调节作用提供了证据。
