The Effects Of Resveratrol On The Quality Of Frozen-thawed Bull Semen

With the rapid development of artificial insemination,semen cryopreservation technology has also been continuously improved.But in the freezing and thawing process,due to many factors,motility,plasma membrane integrity and acrosome integrity of thawed bovine spermstill will greatly reducecompared with fresh sperm,the fertilization ability of sperm will be greatly weakened.The causesleading to this problem not only relevant to temperature,osmotic pressure and oxidative stress,but also other factors,such asthe changesof the structure and function of sperm.Resveratrol is a natural non flavonoid polyphenol compounds,and it play an important role in anti-inflammatory,antiviral,antitumor and regulating the redox signals,and can interact with target molecules in various intracellular signaling pathways.At present,there has been no report to evaluate the effect of different concentrations of resveratrol on the cryopreservation of bovine semen.This study intended to add different concentration of resveratrol into the bovine semen dilution,and after comparing the motility,plasma membrane integrity,acrosome integrity of frozen bull semen and antioxidant indexes including total antioxidant capacity,malondialdehyde content and glutathione peroxidase activity,finally we selected for the optimal concentration of resveratrol for bull semen cryopreservation.The main results of this research were as following:1.In a certain concentration range(15?M to 150?M),on the one hand,with the increase of concentration of resveratrol,the motility,acrosome integrity and plasma membrane frozen-thawed sperm also increased;but on the other hand,when the resveratrol concentration exceeds a certain level,the quality of frozen sperm decreased significantly.The motility,acrosome integrity and plasma membrane integrity of frozen-thawed sperm were significantly higher than the control group and other experimental groups(P< 0.05)when the concentration of resveratrol was 150 ?M,and reached 55.7%,72.5% and 53.5%,respectively.When the concentration of resveratrol reached 200 ?M,the sperm motility,acrosome integrity and plasma membrane integrity decreased compared with the results of the 150 ?M treatment group.The sperm motility was significantly lower than that of the control group(P< 0.05),but there was no significant difference in plasma membrane integrity between the two groups(P> 0.05).The acrosome integrity rate of 200 ?Mtreatment group was not significantly different from that of the 100 ?M treatment group(P> 0.05).150 ?M resveratrol was the optimum concentration.2.In the process of cryopreservation of bull semen,with the increase of resveratrol concentration(15 ?M-150 ?M),the T-AOC and GSH-Px activity of bovine sperm gradually increased and MDA content decreased gradually,this indicated that there was a dose dependent manner between sperm antioxidant capacity and resveratrol concentration.The GSH-Px activity of frozen-thawed sperm reached the highest level,and the content of MDA was the lowest with the addition of 150 ?M resveratrol,which reached 113.3 mol/l and 96.14 nmol/ml,respectively,and both GSH-Px activity and MDA content were significantly lower than that of the control group(P< 0.05).The T-AOC of 100 ?M group was the highest,but there was no significant difference between the experimental group and the 150 ?M group(P> 0.05).The total antioxidant capacity(T-AOC)and MDA content of the treatment group added 200 ?M resveratrol were significantly lower than those in the control group(P< 0.05),and GSH-Px activity was lower than that of the control group,but the difference was not significant(P> 0.05).Therefore,the antioxidant capacity of frozen-thawed spermatozoa was the highest when adding 150 ?M resveratrol.3.The correlation analysis results showed that the correlations between sperm motility and T-AOC and between sperm motility and MDA content were significant(P< 0.05),and the correlation coefficients were 0.85 and-0.76,respectively.There was no significant correlation between acrosome integrity,MDA content,T-AOC and GSH-Px(P> 0.05).The correlations betweenGSH-Px activity and sperm motility and between GSH-Px activity andplasma membrane integrity reached to extremely significant level(P< 0.01),and the correlation coefficients were 0.99 and 0.98,respectively,which provided a new method for evaluating sperm plasma membrane damage,this method was more accurate.In conclusion,adding a certain concentration of resveratrol in the bovine semen dilution improved the quality and antioxidant capacity of frozen-thawed bovine spermatozoa,and 150 ?M resveratrol was the optimum concentration.