Mitochondria-targeted antioxidant MitoQ improves the quality of low temperature-preserved yak semen via alleviating oxidative stress.

Abstract

Low-temperature preservation of yak semen during transportation and conservation is crucial to accelerate yak breeding. The effects of low-temperature cooling on yak semen quality, however, are poorly understood. This study aimed to determine the dose-dependent effect of mitochondria-targeted antioxidant "MitoQ" on the motility, oxidative status, and mitochondrial function of yak semen during low-temperature preservation. Semen samples were collected from six adult healthy Maiwa yaks and preserved at 4 ℃ in semen extender containing 0, 50, 100, 200, and 400 nM MitoQ, respectively. Firstly, the motility, membrane integrity, acrosome integrity, and abnormity index of yak spermatozoa were evaluated to determine the optimal MitoQ concentration. Next, the effect of MitoQ at the optimal concentration on spermatozoa antioxidant capacity, including reactive oxygen species (ROS) and malondialdehyde (MDA) contents, total antioxidant capacity (T-AOC), and superoxide dismutase content (SOD) levels, as well as mitochondrial membrane potential were analyzed. Up to 96 h of low-temperature storage, 200 nM MitoQ showed the most optimal effect on motility, membrane integrity, and acrosome integrity (P < 0.05) but not on sperm morphology (P > 0.05). Also, 200 nM MitoQ markedly reduced yak spermatozoa ROS and MDA contents for up to 48 h of low-temperature storage (P < 0.05). Finally, 200 nM MitoQ significantly improved T-AOC, SOD, and mitochondrial membrane potential for up to 24, 48, and 72 h of low-temperature storage, respectively (P < 0.05). In summary, semen extender supplementation with 200 nM MitoQ is beneficial for low-temperature yak semen preservation via improving the oxidative status.