College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.
Theriogenology. 2024 Oct 15;228:81-92. doi: 10.1016/j.theriogenology.2024.08.005. Epub 2024 Aug 5.
OPN5 is one of the main deep brain photoreceptors (DBPs), converting photoperiodic information into neuroendocrine signals to regulate reproduction in birds. This study investigated the mechanism of OPN5-mediated photoperiodic regulation of reproduction by active immunization against OPN5. 96 female quail were divided into OPN5-immunized and control group under the same photoperiod: 16 L:8 D (d 1 to d 35), 8 L:16 D (d 36 to d 70) and 12 L:12 D (d 71 to d 126). OPN5-immunized group was conducted with OPN5 protein vaccination and control group was given a blank vaccine. Samples were collected on d 1, d 30, d 60, and d 126. Results showed switching photoperiod to 8 L:16 D decreased the laying rate, GSI%, numbers of YFs and WFs, serum levels of PRL, P4 and E2, and pituitary PRL and TSHβ protein expressions in both groups (P < 0.05). Whereas the OPN5-immunized group exhibited higher laying rates than the control group (P < 0.05). The control group showed reduced GnRHR and TSHβ gene expressions in the pituitary and increased GnIH and DIO3 transcript and/or protein abundance in the hypothalamus. (P < 0.05). The OPN5-immunized group had lower DIO3 expression at both mRNA and protein levels. (P < 0.05). Switching photoperiod from 8 L:16 D to 12 L:12 D increased the laying rates, GSI%, numbers of YFs and WFs, serum levels of PRL, and PRL protein expression in both groups (P < 0.05), and the responses were more pronounced in OPN5-immunized group (P < 0.05). In contrast to the control group, quail with OPN5-immunization had higher OPN5 and DIO2 transcript and/or protein levels but lower DIO3 expressions in the hypothalamus along the transition photoperiods (P < 0.05). The results revealed that OPN5 responds to photoperiod transition, and its activation mediates related signaling to up-regulate TSH-DIO2/DIO3 pathway and VIP-PRL secretion to prime quail reproductive functions.
OPN5 是主要的深部脑光感受器 (DBP) 之一，将光周期信息转化为神经内分泌信号，以调节鸟类的繁殖。本研究通过主动免疫 OPN5 来研究 OPN5 介导的光周期调节繁殖的机制。96 只雌性鹌鹑在相同的光周期下分为 OPN5 免疫组和对照组：16L:8D(d1 至 d35)、8L:16D(d36 至 d70)和 12L:12D(d71 至 d126)。OPN5 免疫组进行 OPN5 蛋白疫苗接种，对照组给予空白疫苗。分别于 d1、d30、d60 和 d126 收集样本。结果表明，将光照周期切换到 8L:16D 会降低两组的产蛋率、GSI%、YFs 和 WFs 数量、血清催乳素 (PRL)、P4 和 E2 水平以及垂体 PRL 和 TSHβ 蛋白表达水平(P<0.05)。然而，OPN5 免疫组的产蛋率高于对照组(P<0.05)。对照组显示垂体中 GnRHR 和 TSHβ 基因表达减少，下丘脑 GnIH 和 DIO3 转录物和/或蛋白丰度增加(P<0.05)。OPN5 免疫组的 DIO3 表达在 mRNA 和蛋白水平均较低(P<0.05)。将光照周期从 8L:16D 切换到 12L:12D 会增加两组的产蛋率、GSI%、YFs 和 WFs 数量、血清催乳素水平和 PRL 蛋白表达水平(P<0.05)，并且 OPN5 免疫组的反应更为明显(P<0.05)。与对照组相比，在过渡光照周期中，免疫 OPN5 的鹌鹑下丘脑 OPN5 和 DIO2 转录物和/或蛋白水平升高，但 DIO3 表达降低(P<0.05)。结果表明，OPN5 对光周期转换有反应，其激活介导相关信号转导，上调 TSH-DIO2/DIO3 途径和 VIP-PRL 分泌，为鹌鹑的繁殖功能做好准备。
