Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA.
Departments of Obstetrics and Gynecology, the C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, USA Department of Biochemistry and Genetics, Faculty of Medicine, An-Najah National University, Nablus, Palestine.
Reprod Sci. 2016 Apr;23(4):498-507. doi: 10.1177/1933719115607993. Epub 2015 Oct 14.
We investigated the ability of reactive oxygen species (ROS), such as hydrogen peroxide (H(2)O(2)), hydroxyl radical ((·)OH), and hypochlorous acid (HOCl), to overcome the defensive capacity of cumulus cells and elucidate the mechanism through which ROS differentially deteriorate oocyte quality. Metaphase II mouse oocytes with (n = 1634) and without cumulus cells (n = 1633) were treated with increasing concentration of ROS, and the deterioration in oocyte quality was assessed by the changes in the microtubule morphology and chromosomal alignment. Oocyte and cumulus cell viability and cumulus cell number were assessed by indirect immunofluorescence, staining of gap junction protein, and trypan blue staining. The treated oocytes showed decreased quality as a function of increasing concentrations of ROS when compared to controls. Cumulus cells show protection against H(2)O(2) and (·)OH insult at lower concentrations, but this protection was lost at higher concentrations (>50 μmol/L). At higher H(2)O(2) concentrations, treatment dramatically influenced the cumulus cell number and viability with resulting reduction in the antioxidant capacity making the oocyte more susceptible to oxidative damage. However, cumulus cells offered no significant protection against HOCl at any concentration used. In all circumstances in which cumulus cells did not offer protection to the oocyte, both cumulus cell number and viability were decreased. Therefore, the deterioration in oocyte quality may be caused by one or more of the following: a decrease in the antioxidant machinery by the loss of cumulus cells, the lack of scavengers for specific ROS, and/or the ability of the ROS to overcome these defenses.
我们研究了活性氧（ROS），如过氧化氢（H(2)O(2)）、羟基自由基（(·)OH）和次氯酸（HOCl），以克服卵丘细胞的防御能力，并阐明 ROS 如何使卵母细胞质量恶化的机制。用不同浓度的 ROS 处理具有（n = 1634）和没有卵丘细胞（n = 1633）的中期 II 期小鼠卵母细胞，并通过微管形态和染色体排列的变化评估卵母细胞质量的恶化情况。通过间接免疫荧光、缝隙连接蛋白染色和台盼蓝染色评估卵母细胞和卵丘细胞活力以及卵丘细胞数量。与对照组相比，处理后的卵母细胞显示出随 ROS 浓度增加而质量下降的趋势。当 ROS 浓度较低时，卵丘细胞对 H(2)O(2)和(·)OH 损伤具有保护作用，但在较高浓度（>50 μmol/L）时这种保护作用丧失。在较高的 H(2)O(2)浓度下，处理会显著影响卵丘细胞数量和活力，导致抗氧化能力降低，使卵母细胞更容易受到氧化损伤。然而，在使用的任何浓度下，卵丘细胞对 HOCl 都没有提供显著的保护作用。在卵丘细胞不能为卵母细胞提供保护的所有情况下，卵丘细胞数量和活力都减少了。因此，卵母细胞质量的恶化可能是由于以下一个或多个原因造成的：卵丘细胞丧失导致抗氧化机制减少、缺乏特定 ROS 的清除剂，和/或 ROS 克服这些防御的能力。
