Embryo culture conditions are crucial as they can affect embryo quality and even offspring. Oviductal extracellular vesicles (EVs) long been considered a major factor influencing interactions between the oviduct and embryos, and thus its absence is associated with inferior embryonic development in in vitro culture. Herein, we demonstrated that melatonin is present in oviduct fluids and oviduct fluid-derived EVs. Addition of either EVs (1.87 × 1011 particles/mL) or melatonin (340 ng/mL) led to a significant downregulation of reactive oxygen species (ROS) and 5-methylcytosine (5-mC), as well as an increase in the blastocyst rate of embryos, which was inhibited by the addition of luzindole-a melatonin receptor agonist. A combination of EVs (1.87 × 1010 particles/mL) and melatonin (at 34.3 pg/mL) led to the same results as well as a significant decrease in the apoptosis index and increase in the inner cell mass (ICM)/trophectoderm (TE) index. These results suggest that an EV-melatonin treatment benefits embryonic development. Our findings provide insights into the role of EVs and melatonin during cell communication and provide new evidence of the communication between embryos and maternal oviduct.

中文翻译：

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细胞外的囊泡和褪黑激素通过调节活性氧和5-甲基胞嘧啶而有益于胚胎发育。

胚胎培养条件至关重要，因为它们会影响胚胎质量甚至后代。输卵管外囊泡（EVs）长期以来一直被认为是影响输卵管与胚胎之间相互作用的主要因素，因此其缺失与体外培养中胚胎发育不佳有关。在本文中，我们证明了褪黑素存在于输卵管液和输卵管液中。EV（1.87×1011颗粒/ mL）或褪黑激素（340 ng / mL）的添加导致活性氧（ROS）和5-甲基胞嘧啶（5-mC）的显着下调，以及胚泡的增加卢辛多尔-褪黑激素受体激动剂的加入会抑制胚胎的生长速度。电动汽车（1.87×1010颗粒/毫升）和褪黑激素的组合（34。3 pg / mL）导致相同的结果，并且凋亡指数显着降低，内细胞团块（ICM）/滋养外胚层（TE）指数增加。这些结果表明，EV-褪黑激素治疗有益于胚胎发育。我们的发现为了解电动汽车和褪黑激素在细胞通讯中的作用提供了见识，并为胚胎与母体输卵管之间的通讯提供了新的证据。