RESUMO
BACKGROUND: Oxidative stress induced by reactive oxygen species (ROS) is associated with an impaired fertilization ability of spermatozoa. We investigated the effects of adding antioxidants to a sperm preparation medium on the functional parameters of the spermatozoa. METHODS: Spermatozoa were washed with Ham's F-10 media containing the antioxidants, ethylenediaminetetraacetic acid (EDTA) and catalase, at various concentrations, and then the ROS levels in sperm suspensions, and the forward motility, acrosome reaction, DNA integrity and lipid peroxidation of the spermatozoa were assessed. RESULTS: The ROS levels were significantly lower in sperm suspensions washed with the antioxidants (196 approximately 312 rlu; relative light units) than in control sperm (604 rlu, P < 0.05). The addition of 10 microM EDTA to the sperm preparation medium significantly improved the motility of the spermatozoa compared with the control group, the groups containing EDTA at other concentrations and the groups containing catalase. Catalase significantly increased the acrosome reaction rate of the spermatozoa. Both EDTA and catalase significantly decreased the DNA fragmentation rate of the spermatozoa. However, the antioxidants did not reduce lipid peroxidation. CONCLUSIONS: Supplementing sperm preparation medium with EDTA or catalase significantly improved the overall functional parameters of the spermatozoa by reducing the ROS levels.