PDF(Pubmed)
Abstract：
Oxidative stress (OS) and disrupted antioxidant defense mechanisms play a pivotal role in the etiology of male infertility. The alterations in reactive oxygen species (ROS) production and calcium (Ca2+) homeostasis are the main activators for the mitochondrial permeability transition pore (mPTP) opening. The mPTP opening is one of the main mechanisms involved in mitochondrial dysfunction in spermatozoa. This alteration in mitochondrial function adversely affects energy supply, sperm motility, and fertilizing capacity and contributes to the development of male infertility. In human spermatozoa, the mPTP opening has been associated with ionomycin-induced endogenous oxidative stress and peroxynitrite-induced nitrosative stress; however, the effect of exogenous oxidative stress on mPTP opening in sperm has not been evaluated. The aim of this study was to determine the effect of exogenous oxidative stress induced by hydrogen peroxide (H2O2) on mPTP opening, mitochondrial function, motility, and cell death markers in human spermatozoa. Human spermatozoa were incubated with 3 mmol/L of H2O2 for 60 min, and intracellular Ca2+ concentration, mPTP opening, mitochondrial membrane potential (ΔΨm), ATP levels, mitochondrial reactive oxygen species (mROS) production, phosphatidylserine (PS) externalization, DNA fragmentation, viability, and sperm motility were evaluated. H2O2-induced exogenous oxidative stress caused increased intracellular Ca2+, leading to subsequent mPTP opening and alteration of mitochondrial function, characterized by ΔΨm dissipation, decreased ATP levels, increased mROS production, and the subsequent alteration of sperm motility. Furthermore, H2O2-induced opening of mPTP was associated with the expression of apoptotic cell death markers including PS externalization and DNA fragmentation. These results highlight the role of exogenous oxidative stress in causing mitochondrial dysfunction, deterioration of sperm motility, and an increase in apoptotic cell death markers, including PS externalization and DNA fragmentation, through the mPTP opening. This study yielded new knowledge regarding the effects of this type of stress on mitochondrial function and specifically on mPTP opening, factors that can contribute to the development of male infertility, considering that the role of mPTP in mitochondrial dysfunction in human sperm is not completely elucidated. Therefore, these findings are relevant to understanding male infertility and may provide an in vitro model for further research aimed at improving human sperm quality.
摘要：
氧化应激（OS）和破坏的抗氧化防御机制在男性不育的病因中起关键作用。活性氧（ROS）产生和钙（Ca2）稳态的变化是线粒体通透性过渡孔（mPTP）开放的主要活化剂。mPTP开放是精子线粒体功能障碍的主要机制之一。线粒体功能的这种改变会对能量供应产生不利影响，精子运动性,和受精能力，并有助于男性不育的发展。在人类精子中，mPTP开放与离子霉素诱导的内源性氧化应激和过氧亚硝酸盐诱导的亚硝化应激有关；然而，外源性氧化应激对精子mPTP开放的影响尚未评估。这项研究的目的是确定过氧化氢（H2O2）诱导的外源性氧化应激对mPTP开放的影响，线粒体功能，运动性,和人类精子中的细胞死亡标记。将人类精子与3mmol/L的H2O2孵育60分钟，和细胞内Ca2+浓度，mPTP开口,线粒体膜电位(ΔkW)，ATP水平,线粒体活性氧（mROS）的产生，磷脂酰丝氨酸（PS）外化，DNA片段化,生存能力，并对精子活力进行了评价。H2O2诱导的外源性氧化应激导致细胞内Ca2+增加,导致随后的mPTP开放和线粒体功能的改变，特征为ΔkW耗散，降低ATP水平,mROS产量增加，以及随后精子活力的改变。此外，H2O2诱导的mPTP开放与凋亡细胞死亡标志物的表达有关，包括PS外化和DNA片段化。这些结果强调了外源性氧化应激在引起线粒体功能障碍中的作用。精子活力恶化，凋亡细胞死亡标志物的增加，包括PS外化和DNA片段化，通过mPTP开口。这项研究获得了有关这种应激对线粒体功能，特别是对mPTP开放的影响的新知识，可能导致男性不育发展的因素，考虑到mPTP在人类精子线粒体功能障碍中的作用尚未完全阐明。因此,这些发现与了解男性不育有关，并可能为旨在改善人类精子质量的进一步研究提供体外模型。
