Nishio Katsutoshi, Yamazaki Mado, Taniguchi Masayasu, Besshi Kazuhiko, Morita Fumio, Kunihara Toshiki, Tanihara Fuminori, Takemoto Tatsuya, Otoi Takeshige
Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry (Ishii campus), Tokushima University , Ishii, Myozai-gun, Tokushima 779-3233 , Japan.
Joint Faculty of Veterinary Science, Yamaguchi University , Yamaguchi , Japan.
Acta Vet Hung. 2017 Mar;65(1):115-123. doi: 10.1556/004.2017.012.
The present study was conducted to clarify whether the meiotic stage of porcine oocytes has the highest sensitivity to hyperthermia during in vitro maturation by evaluating meiotic competence and DNA damage. Oocytes were exposed to 41 °C for 12 h at various intervals during 48 h of maturation culture. When the oocytes were exposed to 41 °C from 12 to 24 h of the maturation culture, the proportion of oocytes reaching metaphase II (MII) decreased as compared to the control oocytes cultured at 38.5 °C (P < 0.05). Moreover, the proportions of DNA fragmentation in all oocytes exposed to 41 °C in each culture period after 12 h from the start of maturation culture were significantly higher (P < 0.05) than for the control oocytes. When the meiotic stage of oocytes cultured at 38.5 °C between 12 and 24 h was examined, the majority of oocytes remained at the germinal vesicle (GV) stage at 12 h and approximately half of the oocytes reached metaphase I (MI) at 24 h. These results indicate that the meiotic stage of porcine oocytes having the highest sensitivity to hyperthermia during in vitro maturation is a transition period from the GV stage to the MI stage.
本研究旨在通过评估减数分裂能力和DNA损伤，阐明猪卵母细胞在体外成熟过程中减数分裂阶段是否对高温最敏感。在48小时的成熟培养过程中，卵母细胞在不同时间间隔暴露于41°C环境12小时。当卵母细胞在成熟培养的12至24小时暴露于41°C时，与在38.5°C培养的对照卵母细胞相比，达到中期II（MII）的卵母细胞比例降低（P < 0.05）。此外，从成熟培养开始12小时后，在每个培养阶段暴露于41°C的所有卵母细胞中的DNA片段化比例均显著高于对照卵母细胞（P < 0.05）。当检查在38.5°C培养12至24小时的卵母细胞的减数分裂阶段时，大多数卵母细胞在12小时时仍处于生发泡（GV）阶段，约一半的卵母细胞在24小时时达到中期I（MI）。这些结果表明，猪卵母细胞在体外成熟过程中对高温最敏感的减数分裂阶段是从GV阶段到MI阶段的过渡时期。
