Sperm pretreatment with glutathione improves IVF embryos development through increasing the viability and antioxidative capacity of sex-sorted and unsorted bull semen

The antioxidant of reduced glutathione (GSH) is the most abundant thiol in cells for the maintenance of the intracellular redox balance. The study aimed to assay the effect of sperm treatment with GSH before incubation with oocytes on the development potential of embryos obtained by in vitro fertilization (IVF). Also the mitochondrial membrane potential (Delta psi m), plasma membrane integrity (viability), DNA fragmentation, reactive oxygen species (ROS) content, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities, methane dicarboxylic aldehyde (MDA) level as indices of lipid peroxidation in sex-sorted and unsorted sperm from three bulls were investigated using flow cytometry and enzyme-labeled instrument individually. The results showed that 2 mmol L-1 GSH increased significantly the cleavage rate (86.68% vs. 82.78%), 4- to 8-cell rate (82.30% vs. 73.43%) and blastocyst rate (43.15% vs. 35.24%) of IVF embryos compared with untreated group. Furthermore, addition of GSH increased significantly the Delta psi m and viability, decreased the ratio of DNA fragmentation in sex-sorted or unsorted semen (P<0.05), except the sex-sorted semen from bull 019. Similarly, activities of SOD, CAT and GPx were increased significantly. However, the contents of MDA were decreased significantly both in sex-sorted and unsorted semen treated with GSH (P<0.05). These results suggest that sperm pretreatment with GSH during IVF can maintain better the viability and fertility of sperm through reducing apoptosis and increasing the antioxidant capacity, which improves the IVF embryos development.