Guha Sujoy K
School of Medical Science and Technology, Indian Institute of Technology, Kharagpur 721302, India.
Asian J Androl. 2007 Mar;9(2):221-7. doi: 10.1111/j.1745-7262.2007.00244.x.
To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge.
Desired biophysical influences were obtained by injection of reversible inhibition of sperm under guidance (RISUG) into the lumen of the vas deferens of human subjects and the monkey. RISUG is a polyelectrolyte hydrogel complex of styrene maleic anhydride (SMA) and dimethyl sulfoxide (DMSO) which generates an electrostatic charge and also lowers in a near space of pH domain. The morphology of sperm was examined by light microscopy, scanning and transmission electron microscopy. Human study enabled semen collection by masturbation as early as 3 h after injection and studies extended up to 6 months. In the monkey, on vas excision after RISUG implantation, sperm characteristics were examined in serial sections.
Semenology in clinical studies and histological data of the monkey showed a time-sequenced sperm plasma membrane, tail mitochondria and nuclear decondensation alterations in sperm structural components, which beared marked similarity to changes in the sperm head and tail during capacitation and entry into the ovum.
The findings provide a means of causing such changes in the sperm that inhibit the fertilizing ability before the nucleus is affected. Therefore achieving non-obstructive vas-based contraception, without genotoxic or teratogenic effects caused by infertile sperm passing into the semen, is feasible.
确定输精管内pH值和电荷改变对精子造成的短期和长期形态学影响。
通过在人体受试者和猴子的输精管腔内注射可逆性精子抑制物（RISUG）来获得所需的生物物理影响。RISUG是苯乙烯马来酸酐（SMA）和二甲基亚砜（DMSO）的聚电解质水凝胶复合物，它会产生静电荷并在pH域的近空间内降低。通过光学显微镜、扫描电子显微镜和透射电子显微镜检查精子的形态。人体研究在注射后3小时即可通过手淫收集精液，研究持续长达6个月。在猴子身上，植入RISUG后进行输精管切除，在连续切片中检查精子特征。
临床研究中的精液学和猴子的组织学数据显示，精子结构成分的质膜、尾部线粒体和核去浓缩存在时间顺序的改变，这与精子在获能和进入卵子过程中头部和尾部的变化有显著相似性。
这些发现提供了一种在细胞核受到影响之前使精子发生此类变化从而抑制受精能力的方法。因此，实现基于输精管的非阻塞性避孕，且不会因不育精子进入精液而产生遗传毒性或致畸作用，是可行的。
