Intracellular glutathione content, developmental competence and expression of apoptosis-related genes associated with G6PDH-activity in goat oocyte

To associate glucose-6-phosphate dehydrogenase (G6PDH) activity in goat oocytes with intracellular glutathione (GSH) content, meiotic competence, developmental potential, and relative abundance of Bax and Bcl-2 genes transcripts. Goat oocytes were exposed to brilliant cresyl blue (BCB) staining test and categorized into BCB+ (blue-cytoplasm), and BCB- (colorless-cytoplasm) groups. A group of oocytes were not exposed to BCB test and was considered as a control group. After maturation in vitro, a group of oocytes were used for determination of nuclear status and intracellular GSH content while another group was subjected to parthenogenetic activation followed by in vitro embryo culture. We found that BCB+ oocytes not only yielded higher rate of maturation, but also showed an increased level of intracellular GSH content than BCB- and control oocytes. Furthermore, BCB+ oocytes produced more blastocysts than BCB- and control oocytes. Our data revealed that the expression of anti-apoptotic (Bcl-2) and pro-apoptotic (Bax) genes were interacted with G6PDH-activity in mature oocyte, their surrounding cumulus cells, and blastocyst-stage embryos. The results of this study demonstrate that selection of goat oocytes based on G6PDH-activity through the BCB test improves their developmental competence, increases intracellular GSH content, and affects the expression of the apoptosis-related genes.