Martins J L A, Villaverde A I S B, Lima A F M, Steagall P V M, Ferreira J C P, Taconeli C A, Lopes M D
Departamento de Reprodução Animal e Radiologia Veterinária, College of Veterinary Medicine and Animal Science, UNESP, Botucatu, Brazil.
Reprod Domest Anim. 2009 Jul;44 Suppl 2:366-8. doi: 10.1111/j.1439-0531.2009.01432.x.
The aim of this study was to investigate the impact of a 24-h cooling period prior to freezing on domestic cat epididymal sperm viability. Fifteen tomcats were submitted to routine orchiectomy and sperm samples were retrieved from both epididymides in a Tris-glucose-20% egg yolk extender. For each tomcat, the diluted sperm was split into two equal volumes and cooled to 5 degrees C at a rate of 0.5 degrees C/min; one sample for 60 min (control) and the other for 24 h (cooled). After the cooling period, samples from both groups were frozen using an identical freezing protocol. Sperm samples were evaluated in three different periods: immediately after harvesting, after cooling at 5 degrees C for 24 h (cooled group) and after freezing-thawing of control and cooled groups. Evaluations consisted of sperm motility and progressive status, sperm morphology and plasma membrane integrity (PMI) using two fluorescent probes. After cooling for 24 h, a decrease (p < 0.05) in sperm motility, progressive status and PMI was observed when compared to sperm samples immediately after collection. Comparing the results obtained after thawing, no difference (p < 0.05) was found regarding sperm motility, progressive status, PMI and sperm morphology between control and cooled groups. The results from the present study show that cooling cat epididymal spermatozoa at 5 degrees C for 24 h prior to freezing does not lead to major damage of spermatozoa impairing the freeze-thaw process.
本研究的目的是调查冷冻前24小时冷却期对家猫附睾精子活力的影响。15只雄猫接受常规睾丸切除术，并在含有Tris-葡萄糖-20%蛋黄的稀释液中从双侧附睾采集精子样本。对于每只雄猫，将稀释后的精子分成两等份，以0.5℃/分钟的速率冷却至5℃；一份样本冷却60分钟（对照组），另一份冷却24小时（冷却组）。冷却期结束后，两组样本均采用相同的冷冻方案进行冷冻。精子样本在三个不同阶段进行评估：采集后立即评估、在5℃下冷却24小时后（冷却组）以及对照组和冷却组冻融后评估。评估内容包括精子活力和前进状态、精子形态以及使用两种荧光探针检测的质膜完整性（PMI）。冷却24小时后，与采集后立即检测的精子样本相比，精子活力、前进状态和PMI均有所下降（p<0.05）。比较解冻后获得的结果，对照组和冷却组在精子活力、前进状态、PMI和精子形态方面未发现差异（p<0.05）。本研究结果表明，冷冻前将猫附睾精子在5℃下冷却24小时不会导致精子受到严重损伤从而影响冻融过程。
