Effects of anti-lipid peroxidases on frozen-thawed boar spermatozoa

Abstract

This study evaluated the effects of anti-lipid peroxidases when supplemented to the thawing and incubation media of frozen-thawed boar spermatozoa. Semen pellets were thawed and incubated in media with 1.0 mM α-tocopherol or diethylenetriamine. After 1 h, the acrosome reaction was induced using calcium ionophore A23187, and acrosomes were evaluated using Wells--Awa staining. The number of spermatozoa with fragmented DNA was evaluated using silver staining after single-cell gel electrophoresis. Membrane lipid peroxidation was measured by the end point generation of malondialdehyde. The diethylenetriamine-supplemented media had a higher (P < 0.05) percentage of acrosome-reacted spermatozoa (84.4 ± 4.1%) compared to the control (78.3 ± 4.2%) and α-tocopherol-supplemented (78.0 ± 3.9%). The control had a higher (P < 0.05) percentage of spermatozoa with fragmented DNA (59.3 ± 4.3%) compared to the DETA (28.7 ± 4.1%) and α-tocopherol supplementation (28.0 ± 3.8%). Spermatozoa supplemented with diethylenetriamine had higher amounts (P < 0.05) of malondialdehyde generated (3.60 ± 0.05 μM/10(7) cells) compared to the α-tocopherol supplementation (0.14 ± 0.05 μM/10(7) cells) and the control (0.12 ± 0.05 μM/10(7) cells). These results indicate that supplementing with either 1.0 mM diethylenetriamine or α-tocopherol during semen thawing and incubation protects against DNA fragmentation, and diethylenetriamine increases the percent of spermatozoa capable of completing the acrosome reaction that could induce membrane lipid peroxidation.