Safety assessment of poly(N-vinylcaprolactam) as a potential drug carrier in extenders for boar sperm cryopreservation

Effects of astaxanthin on plasma membrane function and fertility of boar sperm during cryopreservation

Mammalian sperm is highly susceptible to reactive oxygen species (ROS) during the cryopreservation process. Astaxanthin (AST), a red pigment of the carotenoid family, is recognized as having a variety of beneficial biological activities and effects, including antioxidant, anticancer, anti-diabetic, and anti-inflammatory. The present study aimed to investigate whether the presence of AST protected boar sperm from ROS stress during cryopreservation. Boar sperm was diluted with a freezing medium supplemented with different concentrations of AST (0, 0.5, 1, 2, or 5 μM). The addition of AST, especially at a concentration of 2 μM, exerted positive effects on post-thaw sperm motility parameters. Meanwhile, sperm plasma membrane integrity and acrosome integrity of post-thaw sperm were significantly increased, while lipid peroxidation was inhibited in response to 2 μM AST treatment. Interestingly, compared to the control, supplementation with 2 μM AST increased unsaturated fatty acids (UFAs) levels and decreased saturated fatty acids (SFAs) content in post-thaw sperm, leading to a decreased ratio of SFAs/UFAs in the AST group. In conclusion, the addition of AST to freezing extenders inhibited lipid peroxidation and regulated fatty acid composition of the sperm membrane, improved post-thaw sperm quality, and had no adverse effect on boar sperm in vitro fertilization (IVF) capacity and potential for embryonic development. Our data provide a novel insight into understanding the mechanisms of AST concerning protecting boar sperm quality against ROS damage during cryopreservation.