Aging-related Changes in In Vitro-matured Bovine Oocytes: Oxidative Stress, Mitochondrial Activity and ATP Content After Nuclear Maturation

作者：Koyama Keisuke; Kang Sung Sik; Huang Weiping; Yanagawa Yojiro; Takahashi Yoshiyuki; Nagano Masashi^*

来源：Journal of Reproduction and Development, 2014, 60(2): 136-142.

DOI：10.1262/jrd.2013-115

• Aging
• ATP
• Bovine oocytes
• Mitochondria
• ROS

The objective of this research was to clarify the aging-related changes in in vitro-matured bovine oocytes. Firstly, we examined the fertilization and embryonic development of bovine oocytes after 22 and 30-34 h of in vitro maturation (IVM). The oocytes after 30-34 h of IVM (penetrated by sperm at around 40 h after starting IVM) showed a lower developmental rate to blastocysts (P%26lt;0.01), although normal fertilization rates were similar regardless of IVM duration. In the next experiment, reactive oxygen species (ROS), mitochondrial activity and ATP content in oocytes after 20, 30 and 40 h of IVM were examined. The lowest level of ROS was found in the group subjected to 30 h of IVM. The mitochondrial activity and ATP content in the group subjected to 40 h of IVM were higher than in the group subjected to 20 h of IVM (P%26lt;0.01), and those in the group subjected to 30 h of IVM showed intermediate values. Thereafter, the mitochondrial activities at 3 days after in vitro fertilization in embryos derived from the oocytes subjected to 22 and 34 h of IVM were evaluated. In the group subjected to 34 h of IVM, high-polarized mitochondria were frequently observed at the periphery of blastomeres. The present results suggest that high mitochondrial activity observed in oocytes after prolonged IVM culture and localization of high-polarized mitochondria at the periphery of blastomeres during early embryonic development may be associated with the low developmental competence in aged bovine oocytes.

• 出版日期2014-4