Addition of resveratrol in boar insemination doses: impact on sperm membrane integrity and lipid peroxidation

Imbalances of reactive oxygen species in mammal cells generate oxidative stress, which is deleterious to membranes architecture and sperm physiology. In this way, oxidative stress of boar spermatozoa could reduce the life spam of inseminations doses. Aiming to improve quality of cooled boar semen, antioxidants were usually added to semen extenders. Thus, this experiment was performed aiming to study the effect of addition of resveratrol (RVT) on plasma membrane integrity, acrossomal status and sperm susceptibility to lipid peroxidation on stored semen (17˚C for 72 h). Thus, six ejaculates from six boars (n=36) were collected. After raw semen analysis, samples were extended in BTS medium supplemented with RVT, resulting in following treatments: T0 (BTS + RVT 0 mM), T1 (BTS + RVT 0.01 mM), T2 (BTS + RVT 0.1 mM) and T3 (BTS + RVT 1 mM). Treatments were cooled at 17 ˚C and evaluation was performed after 0, 24, 48 and 72 h for integrity of plasma membrane and acrosomal status. Sperm susceptibility to lipid peroxidation was performed by the technique of spontaneous thiobartituric acid reactive substances at 0 and 72 h. There was no interaction between time and treatment for TBARS assay (p>0.05); and there was no interference of the addition of RVT on spermatozoa susceptibility to lipid peroxidation (64.91 ± 4.52; 70.87 ± 6.30; 64.87 ± 4.68; 68.68 ± 3.74 ng of TBARs/sperm.106 to T0, T1, T2 and T3, respectively). There was an interaction between time and treatment for both plasma membrane and acrosomal integrity (p<0.05). The highest concentration of RVT (1mM) was deleterious for plasma membrane integrity in all of times assessed (0 hours: 91.89 ± 0.70a ; 92.22 ± 0.54a ; 92.26 ± 0.78a ; 84.54 ± 1.43b / 24 hours: 88.84 ± 1.55a ; 90.09 ± 1.34a ; 90.06 ± 1.39a ; 71.81 ± 2.57b / 48 hours: 89.03 ± 1.64a ; 89.77 ± 1.30a ; 88.97 ± 1.61a ; 59.70 ± 2.69b / 72 hours: 88.26 ± 1.55a ; 88.56 ± 1.63a ; 87.26 ± 1.96a ; 62.52 ± 3.44b ; for T0, T1, T2, and T3, respectively for all times assessed). Similarly, the highest concentration of RVT increases acrosomal lesions when compared with T1, T2 and T3 at all times (0 hours: 89.04 ± 1.70a ; 91.46 ± 1.45a ; 92.04 ± 1.43a ; 84.80 ± 1.74b / 24 hours: 91.50 ± 0.87a ; 92.75 ± 0.97a ; 93.15 ± 0.88a ; 80.14 ± 1.82b / 48 hours: 90.25 ± 1.52a ; 91.50 ± 1.25a ; 91.55 ± 1.46a ; 68.21 ± 2.38b / 72 hours: 88.49 ± 1.73a ; 89.86 ± 1.59a ; 90.30 ± 1.42a ; 69.21 ± 2.92b ; for T0, T1, T2 and T3, respectively for all times assessed). In conclusion, despite have not affected spermatozoa susceptibility to plasma peroxidation, addition higher than 1mM of RVT on boar semen decreased plasma and acrosomal integrity. However, additional studies need to be performed to elucidate resveratrol effect on spermatozoa physiology.