Cryopreserved spermatozoon has some defects on membrane causing hyper activation, cryo-capacitation and timeless (early) acrosome reaction that lead to low fertility. While low fertility is generally accepted as a consequence of cryopreservation of sperm cells, a lot of studies are being carried out on cryopreservation techniques to improve spermatozoon membrane integrity and also viability. Some studies point out that using materials such as Cannabinoids can be effective in achieving this aim. The main effects of endocannabinoids on spermatozoa are the inhibition of motility, capacitation and acrosome reaction. The aim of this study was to determine the effect of soluted Met-anandamide in extender on post thawing sperm motility, capacitation and acrosome reaction in ram semen cryopreservation. For this aim, ten ejaculated collected from five mature Bakhtiari rams were diluted with extender containing Met-anandamide, equilibrated and then cryopreserved in liquid nitrogen vapour (approximately -125 to -130°C). Cryopreserved semen samples were preserved in liquid nitrogen until evaluation. Post thawing sperm analyses revealed that the Cannabinoids agonists affected the motility of ram sperm after thawing (P<0.05), resulting in an increase in the AEA (arachidonoylethanolamide) concentration (10, 100 and 1000 nM) which significantly reduced sperm motility. subsequent freezing and thawing. On the other hand, the degrading enzyme of endocannabinoid FAAH may have had a reduction effect on sperm motility and increased capacitation and early acrosome reaction (P<0.05). In conclusion, endocannabinoid system may be used to improve ram sperm freezing.

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