The influence of ascorbic acid on in vitro maturation of canine oocytes

Abstract It is known that L-ascorbic acid (vitamin C) can modulate many biochemical processes intracellularly or extracellularly as antioxidant. The aim of the present study was to examine the effects of media supplementation with ascorbic acid on canine oocyte meiotic maturation, viability and the cumulus cell expansion. Various concentrations of ascorbic acid supplemented in in vitro maturation (IVM) media were tested. Canine oocyte was exposed to different levels of ascorbic acid (0, 50, 150, 250, 500, 750µM). Cumulus expansion, meiotic maturation and degeneration of oocytes were assessed 72 h after in vitro culture. As results, on the group treated with 250µM ascorbic acid was a significant difference compared to the control group on nuclear maturation in stages metaphase I (MI) and metaphase II (MII) (26.98% vs. 6.00%). The groups treated with 50, 150, 250, 500µM had an increase in stage (GVBD), and a significant decrease of degenerate-undefined oocytes compared with the control (23.31%, 18.85%, 13.41% vs 40.80). Concentration 750µM had similar effect to that in the control group. The groups treated with 50, 150, 250, 500µM had an increase in meiosis resumption(GVBD), metaphase I (MI) and metaphase II (MII) with the best result in the group treated with 250 µM ascorbic acid.