Mitoquinone mesylate promotes oocyte maturation and subsequent embryonic development by regulating oxidative stress in Tibetan sheep.

In vitro maturation (IVM) is a very important technology for the modernization of animal husbandry. Previous studies have demonstrated that the mitochondria-targeting antioxidant mitoquinone mesylate (MitoQ) was known for its protective role in a variety of tissues and cells; however, its function in Tibetan sheep oocytes is not fully understood. This study used a Tibetan sheep model to evaluate the effects of oocytes exposed to MitoQ on maturation and subsequent embryonic development. During IVM, cumulus-oocyte-complexes were exposed to 0-400 nM MitoQ to evaluate the viability of cumulus cells expansion and oocyte maturation, and determine the optimal concentration of 100 nM. Here, we discovered that 100 nM MitoQ addition to the medium improved the Tibetan sheep oocyte maturation rate (P < 0.05) and cumulus cells expansion rate (P > 0.05). In addition, immunostaining showed that decreased ROS levels (P < 0.01), increased GSH levels (P < 0.01). MitoQ-treated oocytes showed enhanced mitochondrial activity (P < 0.01) and mitochondrial membrane potential (P < 0.05). MitoQ increased Ca levels (P < 0.01) and attenuated early apoptosis (P < 0.01). No differences were observed for cleavage rate (P > 0.05), and improved number of blastocyst cells and the blastocyst rate (P < 0.05) after in vitro fertilization. Moreover, various genes associated with oocyte oxidative stress (GCLC, SOD1) in mature oocytes were beneficially regulated in the MitoQ-treated oocytes. In conclusion, MitoQ can enhance the oocyte maturation rate, improve subsequent embryonic development in Tibetan sheep.