Thurston L M, Watson P F, Mileham A J, Holt W V
Institute of Zoology, Regent's Park, London, United Kingdom.
J Androl. 2001 May-Jun;22(3):382-94.
This study investigated two hypotheses: 1) that consistent between-boar variation in frozen semen quality exists and is genetically determined, and 2) that morphologically distinct subpopulations of spermatozoa exist within fresh boar ejaculates and that the incidence of these subpopulations is correlated with semen quality following cryopreservation. Five ejaculates were collected from each of 15 boars (5 boars from each of 3 breeds). An objective sperm morphology analyzer used Fourier shape descriptors to describe variation in the morphology of 300 spermatozoa per ejaculate before freezing. Semen was diluted into a commercial freezing buffer (700 mOsm/kg, 3% glycerol) and 5 straws (0.5 mL) per ejaculate were cryopreserved (to -5 degrees C at 6 degrees C/min, then -5 degrees C to -80 degrees C at 40 degrees C/min). Semen was assessed for percentage of motile cells and motility characteristics (with computer-aided sperm analysis), plasma membrane integrity (SYBR-14 positive), and acrosome integrity (fluorescein-labeled peanut agglutinin positive). Consistent between-boar variability was detected for post-thaw sperm motility (P < .01), membrane integrity (P < .01), acrosome integrity (P < .01), curvilinear velocity (P < .01), straight-line velocity (P < .05), beat cross-frequency (P < .05), and amplitude of lateral head displacement (P < .01). Three morphologically distinct subpopulations of spermatozoa, defined by Fourier descriptors, were detected. The proportion of these subpopulations within the fresh ejaculate correlated with semen quality assessments made following cryopreservation. These findings support the hypothesis that consistent interindividual variation in sperm freezability is genetically determined and may relate to processes that occur during spermatogenesis. Subsequent characterization of these genetic differences between "good" and "poor" freezers may ultimately identify biophysical components of the spermatozoa that are essential for successful cryopreservation.
1）冻精质量存在公猪间的一致性差异，且由基因决定；2）新鲜公猪射精中存在形态上不同的精子亚群，且这些亚群的发生率与冷冻保存后的精液质量相关。从15头公猪中每头采集5次射精样本（3个品种，每个品种5头公猪）。使用客观精子形态分析仪，通过傅里叶形状描述符来描述冷冻前每次射精中300个精子的形态变化。精液被稀释到商业冷冻缓冲液（700 mOsm/kg，3%甘油）中，每次射精的5支细管（0.5 mL）被冷冻保存（以6℃/分钟的速度降至-5℃，然后以40℃/分钟的速度从-5℃降至-80℃）。通过计算机辅助精子分析评估精液的活动细胞百分比和运动特征、质膜完整性（SYBR-14阳性）和顶体完整性（荧光素标记的花生凝集素阳性）。解冻后精子活力（P <.01）、膜完整性（P <.01）、顶体完整性（P <.01）、曲线速度（P <.01）、直线速度（P <.05）、拍频交叉频率（P <.05）和头部侧向位移幅度（P <.01）均检测到公猪间的一致性差异。通过傅里叶描述符定义，检测到三种形态上不同的精子亚群。这些亚群在新鲜射精中的比例与冷冻保存后的精液质量评估相关。这些发现支持了这样的假设，即精子冷冻能力的个体间一致性差异是由基因决定的，并且可能与精子发生过程中发生的过程有关。随后对“好”和“差”冷冻公猪之间这些基因差异的表征最终可能会确定精子中对成功冷冻保存至关重要的生物物理成分。
