Roth Zvi
Department of Animal Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, POB 12 Rehovot, 76100, Israel.
Reprod Fertil Dev. 2021 Jan;33(2):66-75. doi: 10.1071/RD20213.
The ovarian pool of follicles, and their enclosed oocytes, is highly sensitive to hyperthermia. Heat-induced changes in small antral follicles can later manifest as impaired follicle development and compromised competence of the enclosed oocytes to undergo maturation, fertilisation and further development into an embryo. This review describes the main changes documented so far that underlie the oocyte damage. The review discusses some cellular and molecular mechanisms by which heat stress compromises oocyte developmental competence, such as impairment of nuclear and cytoplasmic maturation and mitochondrial function, changes in the expression of both nuclear and mitochondrial transcripts and the induction of apoptosis. The review emphasises that although the oocyte is exposed to heat stress, changes are also evident in the developed embryo. Moreover, the effect of heat stress is not limited to the summer; it carries over to the cold autumn, as manifest by impaired steroid production, low oocyte competence and reduced fertility. The spontaneous recovery of oocytes from the end of the summer through the autumn until the beginning of winter suggests that only subpopulations of follicles, rather than the entire ovarian reserve, are damaged upon heat exposure.
卵巢中的卵泡池及其包裹的卵母细胞对高温高度敏感。热诱导的小窦状卵泡变化随后可表现为卵泡发育受损以及包裹的卵母细胞进行成熟、受精并进一步发育成胚胎的能力受损。本综述描述了迄今为止记录的导致卵母细胞损伤的主要变化。该综述讨论了热应激损害卵母细胞发育能力的一些细胞和分子机制，如核成熟和细胞质成熟以及线粒体功能受损、核转录本和线粒体转录本表达的变化以及细胞凋亡的诱导。该综述强调，尽管卵母细胞受到热应激，但发育中的胚胎也会出现明显变化。此外，热应激的影响不仅限于夏季；它会延续到寒冷的秋季，表现为类固醇生成受损、卵母细胞能力低下和生育力降低。从夏末到秋季直至初冬卵母细胞的自发恢复表明，热暴露时只有部分卵泡亚群受到损伤，而不是整个卵巢储备。
