Núñez-Martínez I, Moran J M, Peña F J
Veterinary Teaching Hospital Service of Reproduction and Obstetrics, Faculty of Veterinary Medicine, University of Extremadura Avd de la Universidad s/n, Cáceres, Spain.
Reprod Domest Anim. 2006 Oct;41(5):408-15. doi: 10.1111/j.1439-0531.2006.00685.x.
Strong evidences suggest that many different sperm subpopulations co-exist within the mammalian ejaculate. These subpopulations have been identified in a number of species; however, to the best of our knowledge, no data exist regarding the existence of sperm subpopulations within the canine ejaculate. Ejaculates were obtained by masturbation from four mongrels and processed using a standard freezing protocol. Motility data were analysed before and after cryopreservation using a computer assisted sperm analysis (CASA) system ISAS. On raw data, a principal component analysis (PCA) was performed to reduce the number of motility descriptors to a few informative variables, and then a K-means cluster procedure was performed and then a regression analysis to validate the clusters obtained in the second analysis. ANOVAs and chi-squared analyses were used to compare clusters and males. PCA revealed that two principal components represented more that the 88% of the variance with eigenvalues of 3.25 and 3.02, respectively. The clustering and discriminant analysis using curvilinear velocity and linear velocity as variables revealed the existence of 11 sperm subpopulations--four of them characterized by high velocities, two by medium values and five by low velocities. After freezing-thawing, nine subpopulations were found--four of high velocities, two of medium and three of low velocities. It is concluded that freezing-thawing not only impairs sperm motility but also produces changes in the sperm subpopulation structure in the canine ejaculate, that the evaluation of the sperm structure subpopulations is a better indicator of semen quality and freezeability than the use of mean values, and that two sperm motility quality indexes can be used to resume of the variables obtained from the CASA analysis.
有力证据表明，哺乳动物射精精液中存在许多不同的精子亚群。这些亚群已在多个物种中得到鉴定；然而，据我们所知，尚无关于犬射精精液中精子亚群存在情况的数据。通过手淫从四只杂种犬获取精液，并采用标准冷冻方案进行处理。使用计算机辅助精子分析（CASA）系统ISAS分析冷冻保存前后的活力数据。对原始数据进行主成分分析（PCA），以将活力描述符的数量减少到几个信息变量，然后进行K均值聚类程序，接着进行回归分析以验证在第二次分析中获得的聚类。使用方差分析和卡方分析来比较聚类和雄性。主成分分析表明，两个主成分分别代表了超过88%的方差，特征值分别为3.25和3.02。以曲线速度和直线速度为变量进行聚类和判别分析，结果显示存在11个精子亚群——其中四个以高速度为特征，两个以中等速度为特征，并五个以低速度为特征。冻融后，发现有九个亚群——四个高速度亚群，两个中等速度亚群和三个低速度亚群。得出的结论是，冻融不仅会损害精子活力，还会导致犬射精精液中精子亚群结构发生变化；精子结构亚群的评估比使用平均值更能作为精液质量和冷冻能力的指标；并且可以使用两个精子活力质量指标来概括从CASA分析中获得的变量。
