Avian Reproductive and Endocrinology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, MP, 470003, India.
Govt. P.G. College, Bina, Sagar, MP, 470003, India.
Photochem Photobiol Sci. 2023 Sep;22(9):2205-2218. doi: 10.1007/s43630-023-00442-0. Epub 2023 Jun 2.
Light has a very important function in the regulation of the normal physiology including the neuroendocrine system, biological rhythms, cognitive behavior, etc. The variation in photoperiod acts as a stressor due to imbalance in endogenous hormones. Estrogen and its receptors ER alpha and beta play a vital role in the control of stress response in birds. The study investigates the estrogenic effects of a well-known medicinal plant Withania somnifera (WS), mediated by estrogen receptor alpha (ERα) in the hypothalamic pre-optic area (POA) and paraventricular nuclei (PVN). Further the study elucidates its anti-oxidants and anti-apoptotic activities in the brain of Japanese quail. To validate this hypothesis, mature male quails were exposed to long day length for 3 months and then transferred to intermediate day length to become photorefractory (PR) while controls were still continued under long daylength. Supplementation of WS root extract in PR quail increases plasma estrogen and lowers corticosterone. Further, in PR quail the variation in light downregulates immunoreactivity of ERα, oxidative stress and antioxidant enzyme activities i.e. superoxide dismutase and catalase in the brain. Neuronal apoptosis was observed in the POA and PVN of PR quail as indicated by the abundant expression of Caspase-3 and p53 which reduces after the administration of WS root extract. The neuronal population also found to decrease in PR although it increased in WS administered quails. Further, the study concluded that change in photoperiod from 3 months exposure of 16L: 8D to 13.5L: 10.5D directly activates neuronal apoptosis via expression of Caspase3 and p53 expression in the brain and increases neuronal and gonadal oxidative stress while WS root extract reverses them via enhanced estrogen and its receptor ERα expression in the hypothalamic pre-optic and PVN area of Japanese quail.
光是正常生理机能调节中非常重要的一个因素，包括神经内分泌系统、生物节律、认知行为等。由于内源性激素的失衡，光周期的变化会成为一种应激源。雌激素及其受体 ERα和 ERβ在鸟类应激反应的控制中起着至关重要的作用。本研究探讨了一种著名药用植物睡茄（WS）通过雌激素受体 alpha（ERα）在下丘脑视前区（POA）和室旁核（PVN）中的雌激素作用。进一步研究了其在鹌鹑大脑中的抗氧化和抗凋亡活性。为了验证这一假设，成熟雄性鹌鹑被暴露在长日照下 3 个月，然后转移到中间日照，成为光感受性（PR），而对照组仍继续处于长日照下。PR 鹌鹑补充 WS 根提取物可增加血浆雌激素并降低皮质酮。此外，在 PR 鹌鹑中，光照的变化会下调 ERα的免疫反应性，以及大脑中的氧化应激和抗氧化酶活性，即超氧化物歧化酶和过氧化氢酶。POA 和 PVN 中的神经元凋亡如 Caspase-3 和 p53 的大量表达所表明的那样，在给予 WS 根提取物后减少。尽管在 WS 处理的鹌鹑中增加了，但 PR 中的神经元数量也减少了。此外，该研究得出的结论是，从 3 个月的 16L:8D 暴露到 13.5L:10.5D 的光周期变化直接通过大脑中 Caspase3 和 p53 表达激活神经元凋亡，并增加神经元和性腺的氧化应激，而 WS 根提取物通过增强雌激素及其受体 ERα在日本鹌鹑下丘脑视前区和 PVN 区域的表达来逆转这些变化。
