微囊藻毒素-LR诱导雌性小鼠卵巢颗粒细胞凋亡、卵泡闭锁加速的机制研究

Apoptosis of ovarian granulosa cells and accelerated follicular atresia induced by environmental contaminant was acknowledged as important cause of clinical premature ovarian failure (POF). Our preliminary studies showed that microcystin-LR (MC-LR) produced by freshwater cyanobacteria significantly stimulated follicular atresia and destroy fertility in female mice. Oxidative stress was induced by MC-LR treatment in granulosa cells. Meantime, down-regulated miR-200c-3p, up-regulated NT-3 and pERK were also observed. Based on previous results, the present project was aimed at exploring the underlining mechanism. Firstly, figure out molecular mechanisms of oxidative stress and miR-200c-3p in MC-LR induced ovarian granulosa cells apoptosis. Secondly, establish and improve the female follicle culture system in vitro and verify the influence of MC-LR on the survival and development of follicle. Finally, confirm the pivotal roles of oxidative stress and miR-200c-3p in MC-LR induced follicular atresia and subfertility in female mice. This study is of great significance for raising public awareness on female reproductive toxicity of MC-LR and ensuring female reproductive health.

环境污染物诱发的卵巢颗粒细胞凋亡、卵泡闭锁加速，是引起临床卵巢早衰的重要原因。本实验室率先发现，淡水蓝藻产生的微囊藻毒素-LR（MC-LR）显著促进雌性小鼠卵泡闭锁，损害雌性生殖能力。MC-LR在诱导颗粒细胞凋亡的过程中，颗粒细胞内发生氧化应激，miR-200c-3p显著下调，其靶基因NT-3表达上调，磷酸化ERK增多。为进一步探明MC-LR诱导卵巢颗粒细胞凋亡、加速卵泡闭锁的分子机制，本项目拟在前期基础上，开展以下研究：①在细胞水平探索氧化应激与miR-200c-3p下调在MC-LR诱导卵巢颗粒细胞凋亡中的分子机制；②建立和完善雌性小鼠卵泡体外培养体系，确认MC-LR对卵泡生长发育的影响；③动物模型验证氧化应激与miR-200c-3p下调在MC-LR促进卵泡闭锁、损害生殖能力中的关键作用。该研究对于提高人们对MC-LR雌性生殖毒性的认识，保障女性生殖健康具有重要意义。

环境污染物诱发的卵巢颗粒细胞凋亡、卵泡闭锁加速，是引起临床卵巢早衰的重要原因。近年来，随着水体富营养化进程加快、程度加剧，蓝藻水华频频发生，MC-LR源源不断释放入水，河流、湖泊、水库等许多饮用水源都面临MC-LR污染问题。本课题组研究发现MC-LR暴露引起卵巢颗粒细胞产生氧化应激，激活ERK/NF-κB通路；同时，miR-200c-3p下调通过其靶基因NT-3过表达而激活ERK/NF-κB通路，启动线粒体依赖的颗粒细胞凋亡，加速卵泡闭锁。MC-LR暴露卵巢颗粒细胞通过上调DRP1而引起线粒体分裂加强，打破了颗粒细胞线粒体动力学平衡状态，线粒体肿胀、破裂、碎片化，线粒体嵴溶解。我们也在动物、组织、细胞和分子水平发现MC-LR暴露后卵巢颗粒细胞miR-3473g表达下调，其靶基因StAR表达上调，从而引起孕酮水平的升高。研究获得了原创性结果，阐明了新机制，对于提高人们对MC-LR雌性生殖毒性的认识，保障女性生殖健康具有重要意义。