Saacke R G, DeJarnette J M, Bame J H, Karabinus D S, Whitman S S
Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
Theriogenology. 1998 Jul 1;50(1):117-28. doi: 10.1016/s0093-691x(98)00119-8.
The collective efficiency of barriers in the female tract against spermatozoa with abnormal heads was studied. In Experiment 1, Day 6 ova/embryos were recovered nonsurgically from superovulated (n = 24) and single-ovulating (n = 44) cows following artificial insemination with semen of bulls selected for normal spermatozoal motility (> or = 50%) and high content (> 30%) of spermatozoa with misshapen heads, random nuclear vacuoles or the diadem defect. To assess characteristics of spermatozoa capable of traversing barriers in the female tract, accessory spermatozoa were classified morphologically (x 1250) and compared with those of the inseminate. Superovulated cows proved inadequate for assessment of accessory spermatozoa due to evidence of poor sperm retention in the zona pellucida; thus, only single-ovulating cows were used. Accessory spermatozoa (n = 479) from 31 ova/embryos recovered from 44 cows were more normal in head shape than those in the inseminate (76 vs 62%; P < 0.05). Spermatozoa with normal head shape, but with nuclear vacuoles appeared as accessory spermatozoa at the same frequency as they were found in the inseminate (20 vs 17%, respectively). Only sperm cells with subtly misshapen heads appeared as accessory spermatozoa. In Experiment 2, semen pooled from 4 bulls having large numbers of spermatozoa exhibiting a gradation from severely asymmetrically misshapen heads to subtly misshapen heads was evaluated. Again, the accessory sperm population (960 sperm cells recovered from 64 ova/embryos) was enriched with spermatozoa of normal head shape relative to the inseminate (53 vs 26%, respectively; P < 0.05). Sperm cells with only nuclear vacuoles and those with subtly misshapen heads were not different between the accessory and inseminate populations (11 vs 8%, and 20 vs 25%, respectively). We conclude that morphologically abnormal spermatozoa are excluded from the accessory sperm population based upon severity of head shape distortion.
研究了雌性生殖道中屏障对头部异常精子的总体作用效率。在实验1中，在人工授精后，从超排（n = 24）和单排（n = 44）母牛中通过非手术方法回收第6天的卵子/胚胎，所用公牛精液的精子活力正常（≥50%），但头部畸形、有随机核空泡或有王冠缺陷的精子含量高（>30%）。为了评估能够穿越雌性生殖道屏障的精子特征，对副精子进行形态学分类（×1250），并与输精精子进行比较。由于有证据表明透明带中精子保留不佳，超排母牛不适合用于评估副精子；因此，仅使用单排母牛。从44头母牛回收的31个卵子/胚胎中获得的479个副精子，其头部形状比输精精子更正常（分别为76%和62%；P<0.05）。头部形状正常但有核空泡的精子作为副精子出现的频率与输精精子中相同（分别为20%和17%）。只有头部稍有畸形的精子细胞作为副精子出现。在实验2中，对来自4头公牛的精液进行了评估，这些公牛有大量精子，其头部畸形程度从严重不对称到稍有畸形呈梯度变化。同样，相对于输精精子，副精子群体（从64个卵子/胚胎中回收的960个精子细胞）中头部形状正常的精子有所富集（分别为53%和26%；P<0.05）。只有核空泡的精子细胞和头部稍有畸形的精子细胞在副精子群体和输精精子群体中没有差异（分别为11%和8%，以及20%和25%）。我们得出结论，形态异常的精子根据头部形状畸变的严重程度被排除在副精子群体之外。
