Effects of Alcohol on Mitochondrial Functions of Cumulus Cells in Mice

Alcohol is an important compound used in food, agriculture, and medicine. In this study, we investigated the effect of alcohol on oocyte quality in mice by exposing animals for different duration times during an estrous cycle. Cumulus-oocyte complexes were collected from mice after pregnant mare serum gonadotropin-and human chorionic gonadotropin-induced superovulation. Ovulation number, E-2 level in serum, and parthenogenetic embryo development in vitro were evaluated. Mitochondrial gene expression, mitochondrial membrane potential, and reactive oxygen species (ROS) levels in the cumulus were also assessed. The results showed that acute exposure to alcohol did not affect ovulation time (p > 0.05). Blasocyst formation rate in vitro was significantly improved after 1 and 2 days of alcohol exposure (p < 0.01). Mitochondrial membrane potential was significantly increased after 1-4 days of alcohol exposure (p < 0.05), but it decreased after 5 days (p < 0.05). ROS levels remained relatively low after 2, 3, and 4 days of exposure (p < 0.05), and they significantly increased after 6 days (p < 0.05). In addition, alcohol altered the expression of mitochondrial and nuclear genes in the cumulus. Taken together, our data suggest that acute exposure to alcohol affects oocyte quality by influencing the function and gene expression in the cumulus. These results underscore potential implications for the development of human reproductive therapeutics.