盆腔铁过载介导早期胚胎铁死亡参与子宫内膜异位症不孕的机制研究

The treatment of endometriosis-associated infertility has been a challenge in gynecology. Abnormal pelvic cavity environment is a major cause of infertility, and iron overload of pelvic cavity fluid is a prominent pathological feature of endometriosis, while its pathogenic mechanism remains unclear. Ferroptosis is a recently identified iron-dependent cell death manner while its correlation with endometriosis-associated infertility requires further study. Our previous studies demonstrated that iron content was increased in pelvic cavity fluid of endometriosis patients. Increased iron content lead to mouse embryo development inhibition, and mitochondrion damage, while ferroptosis inhibitor rescued embryonic development and mitochondrial function. We thus hypothesized that iron overload of pelvic cavity induced embryo ferroptosis through injured mitochondrial function and therefore lead to endometriosis-associated infertility. In the present study, we will explore the mechanism of iron overload induced infertility in molecular, cellular and individual levels. We will verify iron overload lead to embryo ferroptosis; identify the key role of mitochondrion in embryo ferroptosis; and illustrate the role of Keap1/Nrf2 signaling in ferroptosis by regulating mitochondrial function. This study will contribute to our understanding of the pathogenesis of endometriosis-associated infertility and provide a potential target for therapy.

子宫内膜异位(内异)症不孕的治疗一直是困扰妇科领域的难题。盆腔内环境异常是导致内异不孕的重要因素，盆腔液铁过载是内异症的重要病理表征，其致病机制尚不明确。铁死亡是近年来发现的一种铁依赖的新型细胞死亡方式，但与内异症不孕的关系仍有待研究。申请人前期实验发现，内异患者盆腔液铁含量增加并显著抑制早期胚胎发育、损伤线粒体功能；加入铁死亡抑制剂能显著改善胚胎发育及线粒体功能。据此基础提出假设：内异盆腔液铁过载损伤线粒体功能引起早期胚胎铁死亡从而导致内异症不孕的发生。本项目拟从分子、细胞、个体等多层面研究铁过载导致内异症不孕的具体机制。证实盆腔铁过载导致早期胚胎铁死亡的发生；明确线粒体在胚胎铁死亡中的关键作用；并阐明抗氧化应激通路Keap1/Nrf2通过调控线粒体在胚胎铁死亡中的作用。通过本项目的研究，将有助于我们深入理解内异症不孕的发生机制，并为临床治疗提供新的靶点。

目的：子宫内膜异位(内异)症不孕的治疗一直是困扰妇科领域的难题。盆腔内环境异常是导致内异不孕的重要因素，内异腹水铁过载会影响早期胚胎发育，其致病机制尚不明确。本研究通过模拟体内高铁环境培养胚胎，试图阐明铁过载介导早期胚胎损伤的机制。方法：利用内异腹水和高铁培养基培养小鼠胚胎，检测胚胎成囊率，胚胎铁死亡的发生及线粒体的结构与功能。结果：内异腹水存在铁过载现象并降低小鼠胚胎的成囊率，诱导胚胎发生铁死亡表现为GPX4表达下降，脂质过氧化产物增加。损伤线粒体功能：ATP产量下降，ROS生成增加及膜电位发生超极化。通过加入铁死亡抑制剂Fer-1培养可抑制高铁培养引起的胚胎铁死亡的发生并改善线粒体的功能。此外，Smart-seq 分析结果显示 HMOX1 在胚胎铁死亡中上调，并且通过抑制HMOX1的表达可抑制铁死亡的发生并维持线粒体功能。结论：内异腹水铁过载介导早期胚胎发生铁死亡，HMOX1的表达在胚胎铁死亡的发生中起重要作用。通过本项目的研究，将为我们深入了解内异症不孕的致病机理提供新的理论依据，也为内异症不孕的治疗提供新的靶点。