Effect of Glutathione Supplementation on in vitro Maturation of Oocytes in Goats

Abstract

Oxidative stress is a significant impediment to in vitro embryo production. Glutathione (GSH) is among the strongest antioxidants. This study aimed to assess the effect of adding GSH to the in vitro maturation (IVM) medium on the maturation rate and oxidative status of goat oocytes during IVM. The goat oocytes (n=372) were divided into a control (T1; without GSH) group, and experimented groups (0.5,
1, and 2 mM/mL of GSH, T2, T3, and T4 respectively). The maturation rate, assessed by expansion of cumulus cells, and 1st polar body extrusion, was evaluated. Additionally, the oxidative status of oocytes post IVM was assessed through total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels. The current study's findings indicated that the cumulus cells expansion and first polar body extrusion rates were (74.26% and 24.75%), (80.90% and 34.52%), (91.4% and 43.01%) and (84.27% and 30.34%) for T1, T2, T3, and T4, respectively. Moreover, the results of the antioxidant enzymes activities showed that MDA level was reduced (P<0.05) in T3 compared to other groups. Also, the TAC was higher (P<0.05) in T3 in comparison with other groups. Moreover, the concentration of GPx, was higher in T3, and T4 compared to other groups. However, no difference was found in the SOD level between the experimental groups. In conclusion, these results indicate that supplementing the oocyte maturation medium with glutathione (GSH), especially at concentration of 1 mM/mL can improve IVM rate, and the antioxidant capacity of goat oocytes.