Sivashanmugam P, Rajalakshmi M
Department of Reproductive Biology, All India Institute of Medical Sciences, New Delhi, India.
Anat Rec. 1997 Jan;247(1):25-32. doi: 10.1002/(SICI)1097-0185(199701)247:1<25::AID-AR4>3.0.CO;2-E.
The changes in ultrastructure, lipid organization, chromatin decondensation, and denaturation of rhesus monkey spermatozoa during epididymal maturation were studied. This study would provide background information that would be useful to evaluate adverse effects, if any, caused by the use of contraceptive agents.
Adult sexually mature rhesus monkeys were castrated under ketamine anesthesia. The epididymis was divided into initial segment, caput, corpus, and cauda epididymides. To study changes in lipid organization of the sperm plasma membrane during epididymal transit, spermatozoa from different epididymal segments and ejaculated spermatozoa were exposed to merocyanine 540 (MC 540). The changes in chromatin denaturation and decondensation were assessed by using the nucleic acid-specific fluorochromes, acridine orange, and ethidium bromide, respectively, prior to and after exposure to dithiothreitol (DTT).
Testicular spermatozoa (approximately 40%) showed localization of MC 540 mainly in the midpiece, whereas remaining sperm did not localize MC 540. Spermatozoa from the initial segment of the epididymis showed uniform distribution of MC 540 localization in the head and midpiece. A pattern of localization of MC 540 similar to mature caudal and ejaculated sperm in which the staining was restricted to the acrosome and the midpiece first appeared in a small percentage of caput spermatozoa and was completed during transit through the corpus epididymidis. Mature spermatozoa from cauda epididymidis, vas deferens, and ejaculate did not undergo chromatin denaturation even after exposure to 10 mM DTT, unlike sperm from testis, initial segment, and caput epididymidis. Spermatozoa exposed to DTT showed chromatin decondensation; maximum decondensation was seen in testicular sperm and a decrease in the percentage of sperm, showing decondensation, occurred during epididymal transit. Ultrastructural studies showed that spermatozoa undergo structural changes during sperm maturation.
The present study shows that rhesus monkey spermatozoa undergo reorganization of the plasma membrane lipids and stabilization of disulfide linkages during epididymal transit. The results would be of use in evaluating the action of potential male contraceptive drugs on epididymal spermatozoa.
研究了恒河猴精子在附睾成熟过程中超微结构、脂质组织、染色质解聚和变性的变化。本研究将提供背景信息，有助于评估使用避孕药具可能产生的任何不良影响。
成年性成熟恒河猴在氯胺酮麻醉下进行去势手术。附睾分为起始段、头部、体部和尾部。为研究精子在附睾转运过程中质膜脂质组织的变化，将来自不同附睾段的精子和射出的精子暴露于部花青540（MC 540）。在暴露于二硫苏糖醇（DTT）之前和之后，分别使用核酸特异性荧光染料吖啶橙和溴化乙锭评估染色质变性和解聚的变化。
睾丸精子（约40%）显示MC 540主要定位于中段，而其余精子未定位MC 540。附睾起始段的精子显示MC 540在头部和中段均匀分布。MC 540的定位模式类似于成熟的尾部和射出精子，其中染色仅限于顶体和中段，首先出现在一小部分头部精子中，并在通过附睾体部的过程中完成。来自附睾尾部、输精管和射出物的成熟精子即使在暴露于10 mM DTT后也不会发生染色质变性，这与来自睾丸、起始段和附睾头部的精子不同。暴露于DTT的精子显示染色质解聚；睾丸精子中可见最大程度的解聚，并且在附睾转运过程中显示解聚的精子百分比下降。超微结构研究表明，精子在成熟过程中会发生结构变化。
本研究表明，恒河猴精子在附睾转运过程中经历质膜脂质的重组和二硫键的稳定。这些结果将有助于评估潜在男性避孕药对附睾精子的作用。
