褪黑激素-Kisspeptin通路在单色光影响鸡下丘脑GnRH表达中的作用

Our previous study found that blue and green monochromatic lights could affect the secretion of melatonin, promote the expression of GnRH in chick hypothalamus, and therefore improve the productive performance. However, the mechanism of whether and how melatonin mediated the effect of monochromatic light on expression of GnRH in chick hypothalamus is not fully clear. The latest study found that KiSS-1/Kisspeptin is a key gene in regulating GnRH secretion. Therefore，the project will further investigate the effect of monochromatic light on the expression of Kisspeptin and GnRH in chick hypothalamus after blocking the secretion of melatonin, the function of GnIH in monochromatic light affect the expression of Kisspeptin and GnRH in chick hypothalamus via melatonin-mediated, and the receptor pathway and mechanism of intracellular signal transduction of melatonin regulate KiSS-1 gene promoter activity by using the in vivo and in vitro assay, such as molecular biology, cell biology and environmental physiology. The project will elucidate the mechanism of melatonin-Kisspeptin pathway in monochromatic light affect the expression of GnRH in chick hypothalamus. The research has a great significance in theory and practical application, such as to reveal the internal regular pattern between environmental changes and the functional expression of gene, to be effective use of color light information to change the traditional feeding mode and provide a new theoretical guidance in improving the productive performance in poultry.

本课题组前期研究发现蓝绿单色光能影响鸡褪黑激素分泌和促进鸡下丘脑GnRH表达，提高生产性能，但褪黑激素是否参与和如何介导单色光影响下丘脑GnRH表达的作用机制尚不完全清楚。新近发现KiSS-1/Kisspeptin是调控GnRH分泌的关键基因。据此，本项目拟通过分子生物学、细胞生物学和环境生理学等体内与体外结合的方法，研究阻断褪黑激素分泌后对单色光调节鸡下丘脑表达Kisspeptin和GnRH的影响、GnIH在褪黑激素介导单色光影响鸡下丘脑Kisspeptin和GnRH表达中的作用、褪黑激素调控KiSS-1启动子活性的受体途径及其胞内信号转导机制，以阐明褪黑激素-Kisspeptin通路在单色光影响鸡下丘脑GnRH表达的作用机制。研究成果对于揭示环境变化与基因功能表达的内在联系规律具有重要的理论意义；为改变养禽业传统饲养模式，合理利用光色信息提高家禽生产性能提供新的理论指导。

本课题组前期研究结果发现，单色光可影响鸡褪黑激素分泌和下丘脑GnRH的表达，但褪黑激素是否参与和如何介导单色光影响下丘脑GnRH 表达的作用机制尚不完全清楚。为此，本项目利用形态学、分子生物学、组织培养和环境生理学研究了褪黑激素在单色光影响鸡下丘脑GnRH表达中的作用和受体途径，并增加了褪黑激素介导光周期调控母兔发情机制的研究。研究发现，单色光可影响肉鸡血浆褪黑激素水平，褪黑激素通过间接途径（褪黑激素→下丘脑GnIH→下丘脑GnRH）介导单色光影响鸡下丘脑GnRH表达是通过膜受体Mel1c实现的；同时，光周期影响母兔血浆褪黑激素分泌，褪黑激素通过其膜受体MT1作用于下丘脑Kisspeptin神经元，影响GnIH表达，从而调控血浆FSH、LH和E2分泌，进而影响母兔发情。这些研究成果有助于揭示环境光照（光色和光照制度）影响家禽和哺乳动物生殖功能的神经内分泌调控机制，有望为改变传统的商业饲养模式和合理利用光照信息提高畜禽生产性能提供理论指导。