Huszar G, Patrizio P, Vigue L, Willets M, Wilker C, Adhoot D, Johnson L
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut 06525, USA.
J Androl. 1998 Jan-Feb;19(1):11-20.
Although in several species there is a relationship between epididymal sperm transport and fertility, in human in vitro fertilization (IVF), spermatozoa recovered from the caput epididymidis or even the rete testis are fertile. We studied two objective markers of sperm maturity in the sperm of men and stallions: creatine kinase (CK) concentrations, which are a measure of cytoplasmic retention in immature spermatozoa, and the ratio of CK-M and CK-B isoforms (% CK-M/[CK-M + CK-B]), which is proportional to the incidence of mature sperm. The CK markers and the fertilizing function are closely related: Immature sperm with cytoplasmic retention do not bind to the zona, because during cytoplasmic extrusion, the sperm plasma membrane is also remodeled. We examined whether changes in sperm CK values are still ongoing during epididymal transport, or if cellular maturation is completed prior to the arrival of sperm in the caput epididymidis. The incidences of mature sperm in human caput and corpus epididymidis (studied in six men with obstructive azoospermia of various pathogeneses) were (mean+/-SEM) 55.7+/-2.2 and 49.3+/-7.6%, respectively; and the sperm CK-M ratios in the caput epididymidis of three men were 72, 75, and 70%, values that are similar to those of ejaculated sperm. In four segments of the proximal and distal epididymis of three stallions (the origin of sperm was also verified by the position of the cytoplasmic droplet) and in ejaculate of five stallions, the incidences of mature sperm were 88.2+/-6.2, 89.0+/-6.7, 90.3+/-7.8, 87.6+/-5.9, and 86.7+/-0.8%, and the respective CK-M ratios were 75.0+/-8.7, 84.2+/-2.9, 87.9+/-1.2, 92.5+/-1.5, and 69.3+/-3.5%. There were no differences in the incidences of mature and immature spermatozoa or in CK-M ratios among sperm arising from the various epididymal regions or from the ejaculate in men or stallions. Thus, the cellular maturation events in sperm, as detected by the CK markers, are completed by the time the sperm commences epididymal transport. These findings are in agreement with the IVF fertility of sperm aspirated from the male reproductive tract. The data may also suggest that the primary role of sperm epididymal transport in men is to remodel the plasma membrane to enhance sperm functional integrity in the diverse environments of the male and female reproductive tracts prior to fertilization.
虽然在几个物种中附睾精子运输与生育能力之间存在关联，但在人类体外受精（IVF）中，从附睾头甚至睾丸网回收的精子具有生育能力。我们研究了男性和种马精子中精子成熟的两个客观标志物：肌酸激酶（CK）浓度，它是未成熟精子中细胞质保留情况的一种度量，以及CK-M和CK-B同工型的比例（%CK-M/[CK-M + CK-B]），该比例与成熟精子的发生率成正比。CK标志物与受精功能密切相关：具有细胞质保留的未成熟精子不与透明带结合，因为在细胞质挤出过程中，精子质膜也会重塑。我们研究了在附睾运输过程中精子CK值的变化是否仍在进行，或者细胞成熟是否在精子到达附睾头之前就已完成。人类附睾头和附睾体中成熟精子的发生率（在6名患有各种病因的梗阻性无精子症的男性中进行研究）分别为（平均值±标准误）55.7±2.2%和49.3±7.6%；三名男性附睾头中的精子CK-M比例分别为72%、75%和70%，这些值与射出精子的比例相似。在三只种马的附睾近端和远端的四个节段（精子的来源也通过细胞质滴的位置进行了验证）以及五只种马的射精中，成熟精子的发生率分别为88.2±6.2%、89.0±6.7%、90.3±7.8%、87.6±5.9%和86.7±0.8%，各自的CK-M比例分别为75.0±8.7%、84.2±2.9%、87.9±1.2%、92.5±1.5%和69.3±3.5%。在男性或种马中，来自不同附睾区域或射出的精子中，成熟和未成熟精子的发生率或CK-M比例没有差异。因此，通过CK标志物检测到的精子细胞成熟事件在精子开始附睾运输时就已完成。这些发现与从男性生殖道吸出的精子在体外受精中的生育能力一致。这些数据还可能表明，男性精子附睾运输的主要作用是重塑质膜，以在受精前增强精子在男性和女性生殖道不同环境中的功能完整性。
