Effect of different levels of glycerol and cholesterol-loaded cyclodextrin on cryosurvival of ram spermatozoa.
This study was conducted to determine the optimum level of glycerol and cholesterol-loaded cyclodextrin (CLC) in a Tris-based diluent for cryopreservation of ram spermatozoa. Ram semen was treated with 0, 1.5, 3 or 4.5 mg CLC/120 × 10(6)  cells in Tris-based diluents containing 3, 5 or 7% glycerol in a factorial arrangement 3 × 4 and frozen in liquid nitrogen vapour. Sperm motility, viability (eosin-nigrosin staining) and functional membrane integrity (hypo-osmotic swelling test) were assessed immediately after thawing (0 h) and subsequently after 3 and 6 h at 37°C. There was an interaction between CLC and glycerol on the functional membrane integrity (p < 0.05). In the presence of 3% glycerol, the highest functional membrane integrity (32.2%) was found in the spermatozoa treated with 1.5 mg CLC/120 × 10(6)  sperm. Post-thaw sperm motility was highest in 1.5 mg CLC immediately after thawing (40.5%) and after 3-h (30.6%) incubation at 37°C (p < 0.05). Viability of spermatozoa was higher in all CLC treatments than in the untreated samples, and it was highest (33.9%) in the spermatozoa treated with 1.5 mg CLC (p < 0.05). These data indicate that the addition of cholesterol to sperm membranes by 1.5 mg CLC/120 × 10(6)  cells may allow the use of a lower concentration of glycerol (3%), which is sufficient to mitigate the detrimental effects of freezing and thawing.
Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran.
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Motamedi-Mojdehi
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Roostaei-Ali Mehr
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Rajabi-Toustani
D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002470:Cell Survival; D002784:Cholesterol / Q000032:analysis*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary; D003451:Cryoprotective Agents / Q000737:chemistry*; D003505:Cyclodextrins / Q000032:analysis*; D005990:Glycerol / Q000032:analysis*; D008297:Male; D055101:Semen Analysis / Q000662:veterinary; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D012756:Sheep; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure
D003451:Cryoprotective Agents; D003505:Cyclodextrins; D002784:Cholesterol; D005990:Glycerol