The effect of antioxidants on motility, viability, acrosome integrity and DNA integrity of frozen-thawed epididymal cat spermatozoa

Antioxidants partially ameliorated the negative effects of reactive oxygen species (ROS) produced during cryopreservation. The objective of the present study was to investigate the effect of cysteine and a water-soluble vitamin E analogue on the quality of frozen-thawed epididymal cat spermatozoa. Epididymal spermatozoa were collected from eight male cats and divided into three aliquots; these were resuspended with a tris egg yolk extender I (EE-I), or the same extender supplemented with 5 mM dl-cysteine (EE-C) or with 5 mM of a water-soluble vitamin E analogue (EE-Ve). Prior to the freezing step, sperm suspensions were added to the extender with Equex STM paste (EE-II). Sperm motility, progressive motility, membrane integrity, and acrosome status were evaluated at collection, after cooling, and at 0, 2, 4, and 6 h post-thaw. Sperm DNA integrity was evaluated at 0 and 6 h post-thaw. Relative to the control group, supplementation with vitamin E improved (P < 0.05) post-thaw motility (69.4 ± 5.6%), progressive motility (3.9 ± 0.3), and membrane integrity (65.1 ± 8.1%) immediately after thawing, whereas cysteine supplementation improved (P < 0.05) post-thaw motility after 2 h of incubation (53.8 ± 12.2%) and DNA integrity after 6 h (84.1 ± 4.4%). However, neither antioxidant significantly increased the acrosome integrity of frozen-thawed spermatozoa. In conclusion, cysteine or vitamin E supplementation of tris egg yolk extender improved motility, progressive motility and integrity of the sperm membrane and DNA of frozen-thawed epididymal cat spermatozoa.