Abstract：
Boar sperm is highly susceptible to cold damage. When temperature drops to 5°C, the plasmatic membrane is destabilized. The freezing process causes a reduction of the fertility window because frozen/thawed boar sperm has less survivability. The aim of this work was to analyze the effect on sperm characteristics and response to capacitation stimuli of cooling to 5°C using a controlled protocol. Also, we evaluated if the addition of Glycerol 2% or 3% at 5°C was able to modify these parameters. For this purpose, we assessed motility, plasmatic membrane integrity and acrosomal membrane status. Capacitation was induced using Tyrode´s capacitating medium (TCM) and assessed by chlortetracycline stain and induction of acrosomal reaction with Progesterone. Motility patterns were analyzed using a CASA system. These tests were performed at three different points of the freezing curve: 37°C; 17°C and 5°C. Response to TCM vs TBM was only significant at 37°C. While at 37°C and 17°C capacitated sperm was below 20%, at 5°C reached 50% both in the TBM and TCM. CASA analysis showed that spermatozoa exposed to TCM had higher LIN and WOB than those in TBM. All parameters were similar in the Glycerol concentrations studied. These results suggest that the chilling process may be causing an effect similar to cryocapacitation along the cooling curve, starting subtle at 17°C and reaching 50% of the sperm population at 5°C, being independent of Glycerol concentration.
摘要：
猪精子极易受到冷损伤。当温度下降到5°C时，质膜不稳定。冷冻过程会导致生育力窗口的减少，因为冷冻/解冻的公猪精子的生存能力较低。这项工作的目的是使用受控方案分析对精子特征的影响以及对冷却至5°C的获能刺激的反应。此外，我们评估了在5°C下添加2%或3%的甘油是否能够改变这些参数。为此,我们评估了运动性，质膜完整性和顶体膜状态。使用Tyrode的获能培养基（TCM）诱导获能，并通过金霉素染色和与孕酮的顶体反应诱导进行评估。使用CASA系统分析了运动模式。这些测试在冷冻曲线的三个不同点进行:37°C;17°C和5°C。对TCM和TBM的反应仅在37°C时才显着。而在37°C和17°C时，精子的能力低于20％，在5°C时，TBM和TCM均达到50％。CASA分析表明，暴露于中药的精子的LIN和WOB高于TBM。在所研究的甘油浓度中,所有参数是相似的。这些结果表明，冷却过程可能会导致类似于沿冷却曲线的低温蒸发的效果。在17°C时开始微妙，在5°C时达到精子总数的50％，与甘油浓度无关。
