LAUSR

ABSTRACT Although reactive oxygen species in semen are associated with unfavorable results with respect to assisted reproductive technology, their effects based on the detailed stages of embryo development are unclear. We investigated the relationship between reactive oxygen species in semen and the oocyte fertilization rate, cleavage rate, and blastulation rate of intracytoplasmic sperm injections. This retrospective study enrolled 77 couples who underwent intracytoplasmic sperm injection and analyzed 887 eggs from 141 cycles of intracytoplasmic sperm injection. The reactive oxygen species level in semen was compared between the fertilized and nonfertilized groups, between the good-cleavage-embryo and non-developed-embryo groups, and between the good-quality-blastocyst and poor-quality-blastocyst groups. The cut-off level of reactive oxygen species was calculated to predict good-cleavage-embryo and good-quality-blastocyst development. The fertilization rate was 65.4%, and the mean reactive oxygen species levels were not significantly different between the fertilized and nonfertilized groups. The reactive oxygen species level was significantly higher in the non-developed-embryo group than in the good-cleavage-embryo group (P = 0.0026) and was significantly lower in the good-quality-blastocyst group than in the poor-quality-embryo group (P = 0.015). Cleavage embryos and blastocysts were divided into high- and low-reactive-oxygen-species groups using a cut-off value of 6601 and 4926 relative light units, as calculated from the receiver operating characteristic curve. The rates of good-cleavage embryos and good-quality blastocysts were lower in the high-reactive-oxygen-species group than in the low-reactive-oxygen-species group, which were both statistically significant. To conclude, reactive oxygen species in semen is considered to have an adverse effect on both the early and late stages of embryo development in intracytoplasmic sperm injection. Abbreviations: GnRH, gonadotropin-releasing hormone; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilization; LPO, lipid peroxidation; NADPH, nicotinamide adenine dinucleotide phosphate; RLU, relative light units; ROC, receiver operating characteristic; ROS, reactive oxygen species