Supplementation of cryoprotective extender with resveratrol decreases apoptosis index and reactive oxygen species levels in post-thaw dog sperm

The use of artificial insemination (AI) has expanded widely in livestock and canine reproduction. This technique reduces the use of breeding dogs, which requires transportation of animals, is relatively costly, is time-consuming, and poses risks of disease transmission [1-3]. AI also facilitates breeding of the required, usually genetically superior dogs, both within and among countries [4,5]. Cryopreservation of genetic materials in livestock has various limitations that negatively affect fertility quality [6-9]. Cryo-induced damage causes alteration of sperm cell homoeostasis and leads to failure of the antioxidant system, which plays a major role in controlling the level of oxidative stress (OS) and is responsible for controlling excessive free radicals [10]. Various reports have shown that supplementation of antioxidants in cryopreserResveratrol (RSV, 3,5,4′-trihydroxytrans-stilbene) protects sperm from cryo-induced damage in various animal and human species. In this study, we aimed to assess the effect of dog sperm cryoprotective extender containing RSV on the quality of postthaw dog sperm. Sperm were collected from 4 Beagles and supplemented with different concentrations of RSV (0, 100, 200, and 400 μM). After thawing, apoptosis index, and reactive oxygen species (ROS) levels were assessed to determine post-thaw sperm quality. Dog sperm cryopreserved with 400 μM RSV showed significant improvement in post-thaw sperm quality with lower apoptosis index and ROS levels (p < 0.05). Our results showed that the supplementation of dog sperm cryoprotective extender with RSV at a concentration of 400 μM improved the post-thaw dog sperm quality in the term of sperm ROS production and apoptosis. In addition, we emphasize the necessity of testing the ROS levels and apoptosis index using flow cytometry to determine the quality of post-thaw semen.