High level of intracellular sperm oxidative stress negatively influences embryo pronuclear formation after intracytoplasmic sperm injection treatment

Summary This study evaluates the relationship between sperm intracellular reactive oxygen species (ROS; H2O2, O2), DNA fragmentation (DF), low mitochondria membrane potential (MMP) of sperm and normal pronuclear formation among intracytoplasmic sperm injection (ICSI) patients. Semen samples were obtained from 62 infertile male who were candidates for ICSI treatment. After sperm processing, metaphase II (MII) oocytes were injected, and the mean percentages of intracellular ROS, MMP and DF were evaluated using flow cytometry. The mean percentages of pronuclear formation and zygote score (Z) were also recorded, and Pearson, Spearman's rank correlation coefficient and Kruskal–Wallis tests were applied to analyse the data. The amounts of sperm intracellular H2O2 and O2−˙ had significant positive correlation with low MMP (P