Clinic for Horses - Unit for Reproductive Medicine, University of Veterinary Medicine, Bünteweg 15, 30559, Hannover, Germany.
Anim Reprod Sci. 2011 May;125(1-4):112-8. doi: 10.1016/j.anireprosci.2011.03.001. Epub 2011 Mar 15.
Cryopreserved stallion sperm displays a high degree of male-to-male variability with respect to cell viability after thawing. Animals that have semen with low viability after cryopreservation are classified as 'poor' freezers, and when post-thaw viability is high they are designated as 'good' freezers. Cryoprotective agents that are used for cryopreserving stallion sperm include glycerol, ethylene glycol, methyl formamide, and dimethylformamide, and are typically used in concentrations ranging from 1% to 4%. The aim of this study was to evaluate the osmotic stresses that stallion sperm is exposed to during cryopreservation, and to determine if sperm from 'good' and 'poor' freezers show differences in osmotic tolerance limits and in the suitability of cryoprotective agents. Concentrations of 2-3% of the above mentioned cryoprotectants with freezing extender osmolalities ranging from 580 to 895 mOsm kg(-1) showed the highest motility rates after freeze-thaw, both for 'good' and 'poor' freezers, for all cryoprotectants tested with slightly higher values for glycerol. Freeze-thawed semen from 'poor' freezers was found to have a lower percentage of progressively motile sperm compared to that of 'good' freezers. Assessment of plasma and acrosomal membrane integrity after return to isosmotic conditions revealed that cryopreserved sperm from 'poor' freezers showed lower osmotic tolerance limits as compared to sperm from 'good' freezers. Semen from 'poor' freezers that was frozen using freezing extenders supplemented with more then 2% cryoprotectant showed decreased viability and increased acrosome reaction upon return to isoosmotic conditions, whereas 'good' freezers could withstand cryoprotectant concentrations up to 3% before a decline in viability was observed.
冷冻保存的种马精子在解冻后显示出高度的个体间变异性，与细胞活力有关。冷冻保存后活力低的动物被归类为“差”冷冻剂，而解冻后活力高的则被指定为“好”冷冻剂。用于冷冻保存种马精子的冷冻保护剂包括甘油、乙二醇、甲酰胺和二甲基甲酰胺，通常使用浓度范围为 1%至 4%。本研究旨在评估冷冻保存过程中种马精子所承受的渗透压力，并确定“好”和“差”冷冻剂的精子在渗透耐受性极限和冷冻保护剂适用性方面是否存在差异。在冷冻保护剂浓度为 2-3%、冷冻液渗透压为 580-895mOsmkg(-1)的条件下，冷冻解冻后的精子活力最高，对于所有测试的冷冻保护剂，“好”和“差”冷冻剂的活力都很高，其中甘油的活力略高。与“好”冷冻剂相比，“差”冷冻剂的冷冻解冻精液中具有较高比例的渐进运动精子。在恢复等渗条件后评估血浆和顶体膜完整性，发现与“好”冷冻剂相比，“差”冷冻剂的冷冻保存精子的渗透耐受性极限较低。使用补充有超过 2%冷冻保护剂的冷冻液冷冻的“差”冷冻剂精液的活力降低，顶体反应增加，而“好”冷冻剂在观察到活力下降之前可以耐受高达 3%的冷冻保护剂浓度。
