Effect of Glutathione (GSH) on Microscopic Parameters and DNA Integrity in Egyptian Buffalo Semen During Liquid and Frozen Storage

The current study was performed to test the of quality as well as the DNA integrity of preserved liquid and frozen buffalo spermatozoa due to addition of different concentrations of glutathione (0.50, 1.00, 2.00 and 3.00 mM). Liquid semen was preserved for 120 hour with or without addition of glutathione and examined for progressive motility, viability, plasma and acrosomal membranes integrity at 24, 48, 72, 96 and 120 hr of storage. Frozen-thawed semen was examined for the same criteria after thawing and during incubation for 9 hours. DNA integrity was assessed in fresh, cooled and frozen-thawed semen with or without addition of glutathione. Individual motility, viability, intact acrosomal and plasma membranes of stored spermatozoa were significantly (P<0.01) improved by inclusion of glutathione in the semen extender. The post-thaw sperm motility, viability, plasma and acrosomal membranes integrity were significantly higher (P<0.01) in samples treated with 0.50 mM and 1.00 mM glutathione than those of untreated spermatozoa. Addition of exogenous glutathione to the semen extender significantly (P<0.01) decreases the damaged DNA in frozen-thawed semen especially at concentration of 0.50 or 1.00 mM compared to control and 2.00 or 3.00 mM glutathione. The higher pregnancy rates ((60% and 55%) were obtained for semen samples treated with 0.50 and 1.00 mM, respectively. These results indicate that, addition of 0.50 or 1.00 mM GSH to semen diluent improve the keeping quality of liquid semen up to 120 hr, significantly improve sperm characteristics, reduce DNA damage following freezing and thawing and improve the fertility of frozen-thawed buffalo semen.