Effect of dimethyl alpha-ketoglutarate supplementation on the in vitro developmental competences of ovine oocytes

The supplementation of dimethyl alpha-ketoglutarate (DMKG) during the in vitro maturation (IVM) process has been shown to improve the in vitro developmental competences of porcine oocytes. Here, the effects of DMKG supplementation in IVM medium on the development competencies of ovine oocytes were investigated by analyzing the nuclear maturation rate to metaphase II (MII) stage, ATP synthesis, cortical granules (CGs) dynamic, F-actin polymerization, mitochondrial activity, mitochondrial damage, reactive oxygen species (ROS) production, intracellular glutathione (GSH) production, DNA damage, cellular apoptosis, fertilization capacity and blastocyst development potential of ovine oocytes. In addition, the oxidative stress damage model induced by H2O2 treatment was applied to confirm the antioxidative effect of DMKG supplementation on the development of ovine oocytes. The results showed that compared with MII oocytes without DMKG supplementation (Control group), 3 mM DMKG supplementation during IVM significantly (P < 0.05) increased nuclear maturation rate, ATP synthesis, CGs dynamic, F-actin polymerization, mitochondrial activity, GSH production and embryonic developmental competence and decreased ROS production, mitochondrial damage, DNA damage and cellular apoptosis level of ovine MII oocytes. Moreover, the reductions in the developmental competences of ovine MII oocytes caused by H2O2 induced oxidative stress damages were effectively ameliorated by the co-supplementation in IVM of 3 mM DMKG (P < 0.05). Our results demonstrate the promising effect of DMKG supplementation on the in vitro developmental competence of ovine oocytes via the reduction of oxidative stress damages and indicates further research into the clinical applications of DMKG and the development of ovine breeding technologies is warranted.