Aitken R John, Wingate Jordana K, De Iuliis Geoffry N, Koppers Adam J, McLaughlin Eileen A
Discipline of Biological Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia.
J Clin Endocrinol Metab. 2006 Oct;91(10):4154-63. doi: 10.1210/jc.2006-1309. Epub 2006 Aug 8.
Defective sperm function is the largest defined cause of human infertility; however, the etiology of this condition is poorly understood. Although oxidative stress is acknowledged as a key contributor to this pathology, there are also data indicating that defective human spermatozoa contain abnormally high amounts of cis-unsaturated fatty acids. This study investigated whether a causative relationship exists between these two attributes of impaired semen quality.
The objective of this study was to determine whether polyunsaturated fatty acids can induce oxidative stress in human spermatozoa.
Dihydroethidium and SYTOX Green were used in conjunction with flow cytometry and HPLC to investigate reactive oxygen species (ROS) generation by human spermatozoa after fatty acid exposure.
Arachidonic acid (AA) induced a time- and dose-dependent increase in ROS generation by human spermatozoa that led to the promotion of peroxidative damage and a loss of sperm motility. This effect could not be blocked with inhibitors of the cyclooxygenase or lipoxygenase pathways of AA metabolism, rotenone, protein kinase C antagonists, or known inhibitors of plasma membrane redox systems. However, ROS generation could be triggered with other cis-unsaturated fatty acids including linoleic and docosahexaenoic acids. Saturated fatty acids, methyl esters of unsaturated fatty acids, or other amphiphiles were all ineffective. However in a cell-free system, AA could trigger a redox signal via mechanisms that were profoundly disrupted by diphenylene iodonium, a flavoprotein inhibitor.
The presence of excess unsaturated fatty acids in defective human spermatozoa may precipitate the oxidative stress encountered in male infertility.
精子功能缺陷是人类不育症中已明确的最大病因；然而，这种病症的病因却知之甚少。尽管氧化应激被认为是导致这种病理状况的关键因素，但也有数据表明，功能缺陷的人类精子含有异常大量的顺式不饱和脂肪酸。本研究调查了精液质量受损的这两个特征之间是否存在因果关系。
本研究的目的是确定多不饱和脂肪酸是否能在人类精子中诱导氧化应激。
利用二氢乙锭和SYTOX Green，结合流式细胞术和高效液相色谱法，研究脂肪酸暴露后人类精子中活性氧（ROS）的生成情况。
花生四烯酸（AA）可诱导人类精子中ROS生成呈时间和剂量依赖性增加，进而导致过氧化损伤加剧以及精子活力丧失。AA代谢的环氧化酶或脂氧合酶途径抑制剂、鱼藤酮、蛋白激酶C拮抗剂或已知的质膜氧化还原系统抑制剂均无法阻断这种效应。然而，其他顺式不饱和脂肪酸，包括亚油酸和二十二碳六烯酸，也能引发ROS生成。饱和脂肪酸、不饱和脂肪酸甲酯或其他两亲分子均无此作用。然而在无细胞系统中，AA可通过一种被黄素蛋白抑制剂二亚苯基碘鎓严重破坏的机制触发氧化还原信号。
功能缺陷的人类精子中存在过量不饱和脂肪酸可能会引发男性不育中所遇到的氧化应激。
