Study question What are the underlying mechanisms of melatonin to treat endometriosis? Summary answer Melatonin inhibited estrogen receptors/HIF1α/VEGF signaling pathway and limited the endometriotic lesions growth and angiogenesis. What is known already Currently, alternative pharmaceutical for endometriosis is needed urgently due to lack of satisfactory treatment option. The role of melatonin in inhibiting progression of endometriosis has attracted widespread attention in recent years. Several experimental animal studies showed melatonin decreased endometriotic lesion volume, albeit the exact mechanism is still unknown. As an estrogen-dependent disease, estrogen can not only stimulate the proliferation and growth of endometriotic lesions, but also stabilize HIF-1α and thus promote HIF-1α–induced VEGF via binding to estrogen receptors. Herein, estrogen receptors might be a therapeutic target to block the lesion growth and angiogenesis, subsequently inhibit the progression of endometriosis. Study design, size, duration We investigated the role of melatonin in endometriosis in vitro and in vivo. Endometriotic epithelial (12Z) and stromal (Hs 832(C).T) cell lines were cultured and treated with melatonin for 24 hours. Subcutaneous endometriotic model was surgically established in C57BL/6 mice, and randomly assigned to receive vehicle or melatonin for 21days. All experiments were performed 3-8 times for comparisons. Participants/materials, setting, methods The effect of melatonin on endometriotic cells was determined by MTT cell viability assay. Endometriotic lesion size and body weight were measured every 2-3 days after transplantation. RNA and protein expressions of estrogen receptors, HIF1α and VEGF were detected by qPCR and Western blotting and/or immunostaining in in vitro and in vivo experiments. In vivo imaging by Cellvizio was used to examine microvascular network of the developing endometriotic lesions. Main results and the role of chance Melatonin exerted inhibitory effects on cell growth in a dose and time-dependent manner in 12Z and Hs 832(C).T cell lines, and reduced the volume and weight of the ectopic endometriotic lesions without major change in body weight and behaviour. In addition, melatonin significantly decreased the percentage of area (48.41 vs 33.13%), average length (546.7 vs 240.9um) and total number of junctions (53.30 vs 26.68) of microvessels in the lesions. Melatonin also specially and significantly downregulated estrogen receptor β (ERβ) and G protein-coupled estrogen receptor 30 (GPR30) at RNA and protein levels while estrogen receptor α (ERα) was not significantly changed in both 12Z and Hs 832(C).T cells and endometriotic lesions. Furthermore, the expressions of downstream HIF1α and VEGF were significantly decreased after melatonin treatment. Limitations, reasons for caution Melatonin has been reported to employ a wide range of biological effects. Therefore, its suppressive effects on estrogen receptors/HIF1α/VEGF signaling pathway might be part of the pharmacological mechanisms to treat endometriosis. Further studies are also needed to explore the therapeutic mechanisms of melatonin from other perspectives. Wider implications of the findings Our findings add mechanistic insight in support of the use of melatonin as an adjuvant therapy in the management of endometriosis. Melatonin shows the potential to act as a novel alternative therapeutic drug to treat endometriosis with fewer side effects. Trial registration number NA

中文翻译：

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P-337 褪黑激素通过抑制雌激素受体介导的血管生成途径对子宫内膜异位症发挥治疗作用

研究问题褪黑激素治疗子宫内膜异位症的潜在机制是什么？总结回答褪黑激素抑制雌激素受体/HIF1α/VEGF信号通路，限制子宫内膜异位病变的生长和血管生成。已知情况 目前，由于缺乏令人满意的治疗选择，迫切需要用于子宫内膜异位症的替代药物。褪黑激素在抑制子宫内膜异位症进展中的作用近年来引起了广泛关注。几项实验动物研究表明，褪黑激素可减少子宫内膜异位症病变的体积，尽管确切的机制仍不清楚。作为一种雌激素依赖性疾病，雌激素不仅可以刺激子宫内膜异位病变的增殖和生长，还可以稳定HIF-1α，从而通过与雌激素受体结合促进HIF-1α诱导的VEGF。在此处，雌激素受体可能是阻断病变生长和血管生成的治疗靶点，随后抑制子宫内膜异位症的进展。研究设计、规模、持续时间 我们在体外和体内研究了褪黑激素在子宫内膜异位症中的作用。培养子宫内膜异位上皮 (12Z) 和基质 (Hs 832(C).T) 细胞系并用褪黑激素处理 24 小时。在 C57BL/6 小鼠中通过手术建立皮下子宫内膜异位模型，并随机分配接受载体或褪黑激素治疗 21 天。所有实验进行3-8次进行比较。参与者/材料，设置，方法褪黑激素对子宫内膜异位细胞的影响通过MTT细胞活力测定法确定。移植后每2-3天测量一次子宫内膜异位病变大小和体重。雌激素受体的 RNA 和蛋白质表达，在体外和体内实验中，通过 qPCR 和蛋白质印迹和/或免疫染色检测 HIF1α 和 VEGF。Cellvizio 的体内成像用于检查发展中的子宫内膜异位病变的微血管网络。主要结果和偶然作用褪黑激素在 12Z 和 Hs 832(C).T 细胞系中以剂量和时间依赖性方式对细胞生长产生抑制作用，并减少异位子宫内膜异位病变的体积和重量，而在体重和行为。此外，褪黑激素显着​​降低了病灶中微血管的面积百分比（48.41 vs 33.13%）、平均长度（546.7 vs 240.9um）和连接总数（53.30 vs 26.68）。褪黑激素还特别显着下调 RNA 和蛋白质水平的雌激素受体 β (ERβ) 和 G 蛋白偶联雌激素受体 30 (GPR30)，而 12Z 和 Hs 832(C).T 中的雌激素受体 α (ERα) 没有显着变化。细胞和子宫内膜异位病变。此外，褪黑激素处理后下游HIF1α和VEGF的表达显着降低。限制，谨慎的原因 据报道，褪黑激素具有广泛的生物效应。因此，其对雌激素受体/HIF1α/VEGF信号通路的抑制作用可能是治疗子宫内膜异位症的药理机制的一部分。还需要进一步的研究从其他角度探索褪黑激素的治疗​​机制。研究结果的更广泛意义 我们的研究结果增加了支持使用褪黑激素作为子宫内膜异位症管理的辅助治疗的机制洞察力。褪黑激素显示出作为治疗子宫内膜异位症的新型替代治疗药物的潜力，副作用较少。试用注册号 NA