Cryoprotective Effect of Four Penetrating Cryopro tectants on Rhesus Monkey (Macaca mulatta) Spermatozoa Cryopreservation

The present study aimed to examine four cryoprotectants:glycerol,dimethyl sulfoxide,ethylene glycol and propylene glycol on rhesus monkey sperm cryopreservation.Frozen-thawed sperm cryo-survival and function was evaluated by sperm motility,plasma membrane integrity and acrosome integrity,and sperm plasma membrane and acrosome status was determined by nuclei stain Hoechst 33258 and Fluorescein isothiocyanate-conjugated peanut agglutinin (FITC-PNA).The result showed that:for the ability of protection on post-thaw sperm motility,glycerol (47.3±5.7%) and ethylene glycol (44.8±6.7%)> dimethyl sulfoxide (22.9±0.9%)> ethylene glycol (0±0%);for the ability of protection on sperm plasma membrane integrity,glycerol (54.8±3.2%) and ethylene glycol (54.0±6.7%)> dimethyl sulfoxide (37.5±7.0%)> ethylene glycol (28.3±6.5%);for the ability of protection on sperm acrosome integrity,glycerol (82.2±2.4%) and ethylene glycol (82.4±2.4%)> dimethyl sulfoxide (68.7±5.7%) and ethylene glycol (72.3±3.5%) (P<0.05).The results indicate that cryoprotective effects of various penetrating cryoprotectants are different.Dimethyl sulfoxide and propylene glycol are not suitable for rhesus monkey sperm freezing,especially propylene glycol.Ethylene glycol with similar cryoprotective properties to glycerol could be successfully used in the cryopreservation of rhesus monkey spermatozoa.