Effects of glutathione on oocyte and embryo development in in vitro fertilization

Objective: To evaluate the effect of glutathione (GSH) supplementation in maturation and adaptation media on oocyte development, embryo quality, and oocyte viability after vitrification. Methods: The GSH concentrations were classified into four groups (0, 0.5, 1.0, and 1.5 mM) which were added to the maturation medium. The maturation process was conducted in vitro for 24 h. Following maturation, oocytes were fertilized with Bali bull semen for 5-6 h and then cultured for 48 h. The morphological quality of ocytes matured with GSH addition and the vitrification method used was evaluated. Parameters assessed included maturation rate, fertilization rate, embryo development, post-vitrification oocyte morphology, and quality of post-vitrification oocytes with GSH added to the adaptation medium. Results: The addition of GSH to the maturation medium significantly improved oocyte quality and embryo development ( P <0.05). Specifically, adding 1.5 mM GSH increased the percentage of oocytes reaching metaphase II from 57.6% without GSH oocytes to 79.0% with 1.5 mM GSH, two-pronuclei fertilization from 47.0% to 72.7%, embryo development from 37.1% to 57.2%, morula formation from 14.6% to 33.7%, and blastocyst formation from 8.1% to 23.8%. Additionally, the survival rate of oocytes post-vitrification increased to 75% with GSH supplementation. Conclusions: The addition of 0.5-1.5 mM of GSH to the maturation and adaptation media significantly enhanced the metaphase II stage, fertilization rates, cleavage rates, and the survival of oocytes after vitrification. Among the concentrations of 1.5 mM was the most effective in increasing oocyte development and maintaining oocytes viability post-vitrification.