Domestic Animal Biotechnology Department, Miyazaki Livestock Research Institute, Nishi-Morokata-Gun, Miyazaki, Japan.
Mol Reprod Dev. 2012 Jan;79(1):31-40. doi: 10.1002/mrd.21401. Epub 2011 Nov 29.
This study was undertaken to investigate the effects on the nuclear maturation and subsequent embryonic development of bovine oocytes exposed to heat stress (HS) when treating bovine oocytes before in vitro maturation (IVM) with 1 µM cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition pore opening. Mitochondrial activity, reactive oxygen species (ROS), and apoptosis levels of the oocytes were also assessed. Nuclear maturation rates of both the HS-exposed oocytes treated with or without CsA groups (HS + CsA or HS group) were significantly lower (P<0.05) than that of the control group, while the rate of the HS + CsA group was significantly higher (P<0.05) than that of the HS group. Furthermore, although the cleavage and blastocyst formation rates of the HS group were significantly lower than those of the control groups (P<0.05), both rates of the HS + CsA group recovered to the same level as those of the control group. The HS group showed a significantly higher ROS level, lower mitochondrial activity in the oocytes, and TUNEL-positive cumulus cells, but not oocytes, compared with those of the control group (P<0.05), whereas the TUNEL-positive and mitochondrial activity levels of the HS + CsA group recovered to those of the control group. These results indicate that 1 µM CsA treatment before IVM may mitigate reduced mitochondrial activity, increase number of apoptotic cumulus cells under HS, and improve the nuclear maturation and developmental competence of bovine oocytes.
本研究旨在探讨在体外成熟（IVM）前用 1µM 环孢素 A（CsA）处理牛卵母细胞以抑制线粒体通透性转换孔（MPTP）开放时，热应激（HS）对牛卵母细胞核成熟和随后胚胎发育的影响。还评估了卵母细胞的线粒体活性、活性氧（ROS）和凋亡水平。HS 暴露组（HS+CsA 或 HS 组）与对照组相比，卵母细胞核成熟率显著降低（P<0.05），而 HS+CsA 组的卵母细胞核成熟率显著高于 HS 组（P<0.05）。此外，虽然 HS 组的卵裂和囊胚形成率明显低于对照组（P<0.05），但 HS+CsA 组的这两个率均恢复到与对照组相同的水平。与对照组相比，HS 组卵母细胞中的 ROS 水平显著升高，线粒体活性显著降低，且 TUNEL 阳性丘细胞而非卵母细胞数量增加（P<0.05），而 HS+CsA 组的 TUNEL 阳性和线粒体活性水平恢复到对照组水平。这些结果表明，IVM 前用 1µM CsA 处理可能减轻 HS 下卵母细胞中减少的线粒体活性、增加凋亡丘细胞的数量，并提高牛卵母细胞核成熟和发育能力。
