Abstract：
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.
摘要：
OPN5是一种主要的脑深部光感受器（DBPs），将光周期信息转化为神经内分泌信号来调节鸟类的繁殖。本研究通过主动免疫OPN5研究了OPN5介导的光周期调节生殖的机制。在相同的光周期下，将96只雌性鹌鹑分为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免疫组接种OPN5蛋白，对照组接种空白疫苗。在d1、d30、d60和d126收集样品。结果表明，光周期切换到8L：16D降低了产蛋率，GSI%,YF和WF的数量，血清PRL水平，P4和E2、垂体PRL和TSHβ蛋白在两组中的表达(P<0.05)。OPN5免疫组产蛋率高于对照组(P<0.05)。对照组显示垂体中GnRHR和TSHβ基因表达减少，下丘脑中GnIH和DIO3转录物和/或蛋白质丰度增加。(P<0.05)。OPN5免疫组的mRNA和蛋白质水平的DIO3表达均较低。(P<0.05)。光周期从8L:16D切换到12L:12D增加了产蛋率，GSI%,YF和WF的数量，血清PRL水平，两组PRL蛋白表达(P<0.05),OPN5免疫组反应更为明显(P<0.05)。与对照组相比，用OPN5免疫的鹌鹑在下丘脑中的OPN5和DIO2转录和/或蛋白质水平较高，但沿过渡光周期的DIO3表达较低（P<0.05）。结果表明，OPN5响应光周期转变，其激活介导相关信号，上调TSH-DIO2/DIO3通路和VIP-PRL分泌，以促进鹌鹑生殖功能。
