Department of Animal Medicine, Production and Health (MAPS), Università di Padova, Legnaro (PD), Italy.
Equine Reproduction Laboratory, Colorado State University, Fort Collins, CO, USA.
J Equine Vet Sci. 2020 Apr;87:102902. doi: 10.1016/j.jevs.2019.102902. Epub 2019 Dec 26.
Different additives have been tested in cooled stallion sperm, in order to maintain sperm quality and to ameliorate the decrease in sperm fertility potential. In several species, caffeine and pentoxifylline promote sperm motility by increasing energy production. We evaluate the effects of caffeine and pentoxifylline when added to stallion sperm before or after cooling. Three ejaculates from five stallions each were processed and resuspended in skim milk extender. Caffeine (5 mM), pentoxifylline (3.5 mM), or both additives combined were included to sperm before or after cooling (4°C for 24 hours). Cooled sperm were incubated at 37°C and evaluated at 0, 30, 60, and 120 minutes for motility, morphology, viability (flow cytometry), and membrane functionality (hypo-osmotic swelling test). Results were analyzed by two-factor mixed model for repeated measures and Tukey comparisons. As main effects, the caffeine and pentoxifylline affected significantly motility and kinematic parameters, without interaction between treatment and incubation after cooling. No differences were observed whether the additives were added prior or after cooling. Pentoxifylline added after cooling reduced significantly motility during incubation, but with higher values at 30 minutes. We detected a decrease in morphologically normal sperm (P < .0001), caused by an increase of tail defects (P < .003) in the presence of both additives. Viability and membrane functionality were also significantly impaired by additives. Pentoxifylline when added after cooling improved sperm motility and kinematic parameters for a short period of time. However, sperm characteristic related to fertility potential was compromised after a prolonged exposure to caffeine or pentoxifylline.
为了维持精子质量并改善精子生育力下降，已经在冷却的种马精子中测试了不同的添加剂。在许多物种中，咖啡因和己酮可可碱通过增加能量产生来促进精子运动。我们评估了咖啡因和己酮可可碱在冷却前或冷却后添加到种马精子中的效果。从每头种马的三个精液中进行处理并重新悬浮在脱脂牛奶扩展剂中。在冷却（4°C 24 小时）之前或之后将咖啡因（5 mM）、己酮可可碱（3.5 mM）或这两种添加剂组合添加到精子中。冷却的精子在 37°C 下孵育，并在 0、30、60 和 120 分钟时评估运动性、形态、活力（流式细胞术）和膜功能（低渗肿胀试验）。结果通过重复测量的两因素混合模型进行分析，并进行 Tukey 比较。作为主要影响因素，咖啡因和己酮可可碱显著影响运动性和运动学参数，冷却后处理与孵育之间没有相互作用。无论添加剂是在冷却前还是冷却后添加，都没有观察到差异。己酮可可碱在冷却后添加会显著降低孵育期间的运动性，但在 30 分钟时会出现更高的值。我们在存在两种添加剂的情况下检测到形态正常精子的数量减少（P <.0001），这是由于尾巴缺陷增加（P <.003）所致。添加剂还显著损害了精子的活力和膜功能。己酮可可碱在冷却后添加可在短时间内改善精子运动性和运动学参数。然而，在长时间暴露于咖啡因或己酮可可碱后，与生育力潜力相关的精子特征受到损害。
