Faculty of Veterinary Science, The University of Sydney, Camperdown, New South Wales, Australia.
Theriogenology. 2013 Apr 15;79(7):1027-33. doi: 10.1016/j.theriogenology.2013.01.013. Epub 2013 Mar 1.
Cryopreserved, sex-sorted stallion sperm has been shown to have poor fertility. During this study, the effects of cryoprotectant (glycerol [GLY] and dimethyl formamide [DMF]), cryoprotectant equilibration time (0, 30, 60, 90, or 120 minutes), and cryoprotectant concentration (2%, 3%, or 4% vol/vol) on stored sex-sorted and stored nonsorted stallion sperm were evaluated. Total motility, viability, and DNA integrity (determined using sperm chromatin structure assay) of sperm were assessed after thawing. Equilibration for 90 minutes improved total motility (33.8%) compared with 0 (28.5%) or 120 minutes (29.8%; P < 0.05), though viability was higher after 120 minutes (33.1%) compared with 0 (30.5%) or 30 minutes (31.0%; P < 0.01). The viability of nonsorted sperm decreased as cryoprotectant concentration increased (P < 0.001), and total motility of nonsorted sperm was higher when DMF alone was used (15.8%, 16.6%, and 24.0% for GLY, GLY and DMF, and DMF respectively; P < 0.001). Sex sorting was detrimental to the postthaw quality of sperm; at 45 minutes after thawing, total motility of nonsorted sperm was higher than that of sex-sorted sperm (37.4% vs. 5.6%; P < 0.001), the viability of sex-sorted sperm was lower than that of nonsorted sperm (12.4% vs. 30.0%; P < 0.001, averaged over postthaw time), and sex-sorted sperm had higher detectable DNA fragmentation index (DFI) (63.6% vs. 11.3%, P < 0.001) and mean DFI (285.1 vs. 211.3, P < 0.001) than nonsorted sperm. The viability of sex-sorted sperm was improved by GLY and DMF or DMF compared with GLY (22.6%, 25.3%, and 19.3%, respectively; P < 0.05), and the DNA integrity of sex-sorted sperm was improved by the use of DMF compared with GLY (detectable DFI, 60.2 vs. 66.8, P < 0.05; and mean DFI, 280.9 vs. 289.2, P < 0.05, respectively). In conclusion, postthaw characteristics of stored sex-sorted and stored nonsorted stallion sperm were improved by the use of DMF as a cryoprotectant, though the parameters to benefit differed between sorted and nonsorted sperm.
冷冻保存的、经性别分选的种马精子已被证明具有较差的生育能力。在这项研究中，研究了冷冻保护剂（甘油[GLY]和二甲基甲酰胺[DMF]）、冷冻保护剂平衡时间（0、30、60、90 或 120 分钟）和冷冻保护剂浓度（2%、3%或 4%体积/体积）对冷冻保存的性别分选和非性别分选的种马精子的影响。解冻后评估精子的总活力、活力和 DNA 完整性（使用精子染色质结构分析测定）。与 0 分钟（28.5%）或 120 分钟（29.8%）相比，平衡 90 分钟可提高总活力（33.8%）（P<0.05），但活力在 120 分钟时更高（33.1%）与 0 分钟（30.5%）或 30 分钟（31.0%）相比（P<0.01）。随着冷冻保护剂浓度的增加，非性别分选精子的活力降低（P<0.001），单独使用 DMF 时，非性别分选精子的总活力更高（GLY、GLY 和 DMF 分别为 15.8%、16.6%和 24.0%；P<0.001）。性别分选对解冻后精子质量有害；在解冻后 45 分钟时，非性别分选精子的总活力高于性别分选精子（37.4%对 5.6%；P<0.001），性别分选精子的活力低于非性别分选精子（12.4%对 30.0%）；P<0.001，平均解冻时间），并且性别分选精子的可检测 DNA 片段化指数（DFI）更高（63.6%对 11.3%），平均 DFI（285.1 对 211.3，P<0.001）高于非性别分选精子。与 GLY 相比，GLY 和 DMF 或 DMF 提高了性别分选精子的活力（分别为 22.6%、25.3%和 19.3%），与 GLY 相比，DMF 提高了性别分选精子的 DNA 完整性（可检测到的 DFI，60.2 对 66.8，P<0.05；平均 DFI，280.9 对 289.2，P<0.05）。总之，尽管分选和非分选精子的受益参数不同，但使用 DMF 作为冷冻保护剂可改善储存的性别分选和储存的非性别分选种马精子的解冻后特性。
