基于下丘脑胰岛素抵抗的高雄激素诱导多囊卵巢综合征病理机制研究

Hyperandrogenism interacted closely with insulin resistance (IR) is important pathophysiological mechanisms associated with PCOS anovulation and abnormal metabolism, and hypothalamic IR play particularly important role in this process . Previously in our study shown that hypothalamic IR and abnormal GnRH secretion were presence in DHT-induced PCOS model; If inhibition of hypothalamic insulin signaling pathways in normal rats, then the rat was accompanied by glucose intolerance; hypothalamic IR induced by hyperandrogenism involved in endoplasmic reticulum stress / IKK / NF-kB and Kisspeptin signaling pathways. Based on result on our research, this subject will apply the PCOS rat model and hypothalamic GT1-7 cell combined with electrophysiological and molecular biology experimental techniques to 1) clarify androgen-induced hypothalamic IR is important central mechanisms in PCOS; 2) explore the role of hypothalamic endoplasmic reticulum / IKK / NF-kB and KISS signaling pathway in Hypothalamic IR which induced by androgen; 3)analyze hypothalamic IR role in metabolic disorders in androgen-induced PCOS by studying the relationship of hypothalamic IR and food intake behavior; 4) Study hypothalamic IR involved in KISS signaling pathway which might be to interference with secretion of GnRH neurons and ovulation disorders. The purpose of this study demonstrate the hypothalamic IR in the pathogenesis of androgen-induced PCOS, and might be provide new potential targets for prevention and treatment of PCOS.

多囊卵巢综合征（PCOS）的高雄激素与胰岛素抵抗（IR）存在相互作用、与排卵障碍密切关联，是PCOS重要的病理生理机制，而生殖内分泌中枢下丘脑IR尤为重要。申请人在双氢睾酮诱导PCOS模型发现，下丘脑存在IR及GnRH分泌异常；抑制正常大鼠中枢胰岛素信号通路，出现糖耐量异常；高雄激素诱导下丘脑局部IR，涉及内质网应激/IKK/NF-kB及Kisspeptin等信号通路。本课题应用PCOS大鼠模型结合体内外电生理及分子生物学等实验技术：阐明高雄激素诱导下丘脑IR是PCOS重要中枢机制；探索内质网/IKK/NF-kB及KISS信号通路在高雄激素诱导下丘脑IR中的调控作用；研究下丘脑IR对摄食中枢功能的影响，分析其在PCOS代谢紊乱中的作用；研究下丘脑IR通过KISS信号通路干扰GnRH神经元分泌诱导排卵障碍，最终论证下丘脑IR在高雄激素诱导的PCOS中的病理机制，为PCOS防治提供新的潜在靶点

下丘脑是调控机体能量代谢的中枢，本研究通过1）构建高雄激素诱导的PCOS大鼠模型，研究高雄激素是否通过影响下丘脑胰岛素信号通路，从而影响NPY/Agrp和POMC的表达，导致摄食过多性肥胖和代谢异常；2）通过优化体外诱导人胚胎干细胞向类下丘脑弓状核神经细胞分化方案，定向诱导分化具备生殖和代谢调控功能的下丘脑神经前体细胞和弓状核神经细胞；并在此模型上，采用不同浓度雄激素干预，探讨下丘脑神经早期变化。 .我们的研究结果表明：.1.PCOS患者外周血NPY水平显著高于正常女性，表明摄食增多可能是PCOS人群出现代谢异常的一条途径；.2.对青春期前雌性大鼠皮下埋置DHT缓释棒，证实高雄激素可以引起摄食增多、肥胖、糖脂代谢障碍和排卵障碍。摄食增多出现在肥胖之前，且DHT诱导的大鼠肥胖是摄食依赖性的。.3.本研究发现高雄激素通过引起下丘脑胰岛素抵抗，促进下丘脑弓状核摄食基因NPY/Agrp的表达，导致摄食依赖性肥胖。高雄激素对下丘脑摄食中枢的调控，是独立于肥胖而存在的。不同于高脂饮食通过激活下丘脑炎症微环境导致摄食增多机制，高雄激素抑制下丘脑局部炎症因子TNFα表达和NF-KB信号通路，是其对下丘脑摄食中枢调节的独特机制。.4.对DHT诱导后PCOS大鼠模型的下丘脑转录组测序及生物信息学分析，发现高雄激素可引起下丘脑中枢基因改变主要参与营养物质及生物分子代谢、细胞代谢、生长发育、激素调控及免疫应答、酶活性调节三大方面的生物学过程。.5.成功构建了由人胚胎干细胞定向分化的具备生殖和代谢调控功能的下丘脑神经前体细胞和弓状核神经细胞平台，并进行不同浓度的雄激素干预。