DNA Damage in Human Spermatozoa Is Highly Correlated with the Efficiency of Chromatin Remodeling and the Formation of 8-Hydroxy-2′-Deoxyguanosine, a Marker of Oxidative Stress
DNA Damage in Human Spermatozoa Is Highly Correlated with the Efficiency of Chromatin Remodeling and the Formation of 8-Hydroxy-2′-Deoxyguanosine, a Marker of Oxidative Stress
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DOI：
10.1095/biolreprod.109.076836
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发表时间：
2009-09-01
影响因子：
3.6
通讯作者：
Aitken, R. John
中科院分区：
文献类型：
--
作者：
De Iuliis, Geoffry N.;Thomson, Laura K.;Aitken, R. John
人类精子中的DNA损伤与一系列不良临床结果相关，包括不育、流产和后代疾病。我们提出了一个两步假说来解释这种损伤，包括精子发生过程中受损的染色质重塑，随后是自由基攻击诱导DNA链断裂。本研究的目的是通过确定受损的染色质污染是否与人类精子中的氧化碱基损伤和DNA片段化相关来验证这一假设。通过流式细胞术/荧光显微镜监测DNA片段化、染色质污染、线粒体膜电位和氧化碱加合物8-羟基-2 '-脱氧鸟苷（8 OHdG）的形成。精子发生晚期DNA污染程度与精子DNA损伤程度高度相关（P < 0.001）。染色质重塑的破坏也与8 OHdG水平的显著升高相关（P < 0.001），而后者本身与DNA片段化高度相关（P < 0.001）。氧化应激在8 OHdG形成中的重要性通过使用H2 O2/Fe 2+以及通过该碱加合物与超氧化物生成之间观察到的相关性（P < 0.001）实验证明。8 OHdG的形成与线粒体膜电位呈负相关（P < 0.001），提示这些细胞器可能在氧化应激的产生中起作用。这些结果清楚地强调了氧化应激在诱导精子DNA损伤中的重要性，并对这种情况的临床管理具有重要意义。
DNA damage in human spermatozoa has been associated with a range of adverse clinical outcomes, including infertility, abortion, and disease in the offspring. We have advanced a two-step hypothesis to explain this damage involving impaired chromatin remodeling during spermiogenesis followed by a free radical attack to induce DNA strand breakage. The objective of the present study was to test this hypothesis by determining whether impaired chromatin protamination is correlated with oxidative base damage and DNA fragmentation in human spermatozoa. DNA fragmentation, chromatin protamination, mitochondrial membrane potential, and formation of the oxidative base adduct, 8-hydroxy-2'-deoxyguanosine (8OHdG), were monitored by flow cytometry/fluorescence microscopy. Impairment of DNA protamination during late spermatogenesis was highly correlated (P < 0.001) with DNA damage in human spermatozoa. The disruption of chromatin remodeling also was associated with a significant elevation in the levels of 8OHdG (P < 0.001), and the latter was itself highly correlated with DNA fragmentation (P < 0.001). The significance of oxidative stress in 8OHdG formation was demonstrated experimentally using H2O2/Fe2+ and by the correlation observed between this base adduct and superoxide generation (P < 0.001). That 8OHdG formation was inversely associated with mitochondrial membrane potential (P < 0.001) suggested a possible role for these organelles in the creation of oxidative stress. These results clearly highlight the importance of oxidative stress in the induction of sperm DNA damage and carry significant implications for the clinical management of this condition.