Figure 1. Quercetin prevented H₂O₂-induced fragmentation and retardation in blastocysts.

(A) Representative images of pre-implantation embryos cultured in the presence or absence of quercetin (Que) under H₂O₂-induced oxidative stress. Zygotes were pre-treated for 3 h with 5 μM Que followed by addition of 35 μM H₂O₂ for 15 min, and subsequently cultured in presence of Que until day 5.5. The morphology of pre-implantation embryos was imaged at D1.5 (2-cell), D4.5 (blastocyst) and D5.5 (hatched) after fertilization. In the H₂O₂-treated group, developmental retardation (arrow a) and fragmentation (arrow b) were observed in blastocysts. Normal development and high embryo quality were apparent in the Que-treated group at 5 μM. Bar, 50 μm. (B) Quantification of fragmented and retarded blastocysts. Data are presented as the mean ± SEM from three independent experiments. N shows the number of embryos and ^* P<0.05; ^*** P<0.001, compared with the control group (One-way ANOVA).