SummaryEnvironmental hypoxia exposure causes fertility problems in human and animals. Compelling evidence suggests that chronic hypoxia impairs spermatogenesis and reduces sperm motility. However, it is unclear whether paternal hypoxic exposure affects fertilization and early embryo development. In the present study, we exposed male mice to high altitude (3200 m above sea level) for 7 or 60 days to evaluate the effects of hypoxia on sperm quality, zygotic DNA methylation and blastocyst formation. Compared with age-matched controls, hypoxia-treated males exhibited reduced fertility after mating with normoxic females as a result of defects in sperm motility and function. Results of in vitro fertilization (IVF) experiments revealed that 60 days’ exposure significantly reduced cleavage and blastocyst rates by 30% and 70%, respectively. Immunohistochemical staining of pronuclear formation indicated that the pronuclear formation process was disturbed and expression of imprinted genes was reduced in early embryos after paternal hypoxia. Overall, the findings of this study suggested that exposing male mice to hypoxia impaired sperm function and affected key events during early embryo development in mammals.

中文翻译：

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父亲缺氧会损害受精过程和植入前胚胎发育

摘要环境缺氧暴露会导致人类和动物的生育问题。令人信服的证据表明，慢性缺氧会损害精子发生并降低精子活力。然而，尚不清楚父亲的缺氧暴露是否会影响受精和早期胚胎发育。在本研究中，我们将雄性小鼠暴露在高海拔地区（海拔 3200 米）7 或 60 天，以评估缺氧对精子质量、合子 DNA 甲基化和囊胚形成的影响。与年龄匹配的对照组相比，由于精子活力和功能缺陷，缺氧处理的雄性在与常氧雌性交配后表现出生育能力下降。结果体外受精 (IVF) 实验表明，暴露 60 天后，卵裂率和囊胚率分别显着降低了 30% 和 70%。原核形成的免疫组织化学染色表明，父系缺氧后早期胚胎的原核形成过程受到干扰，印记基因的表达降低。总体而言，这项研究的结果表明，将雄性小鼠暴露在缺氧环境中会损害精子功能并影响哺乳动物早期胚胎发育过程中的关键事件。