Figure 4. CHK2 inhibition affected DNA damage and oxidative stress during early embryonic development in mice. (A) Embryos at the 2-cell stage were stained with anti-γ-H2A.X (green). The γ-H2A.X signal was stronger in embryos in the CHK2 inhibition group. Bar = 30 μm. (B) The fluorescence intensity of γ-H2A.X in embryos in the 25 μM and control groups (108.8 ± 9.46, n = 28, 25μM vs. 50.7 ± 3.05, n = 32, control, p < 0.0001). (C) Embryos at the 2-cell stage were stained for ROS (green). The ROS signal was stronger in embryos in the CHK2 inhibition group. (D) The fluorescence intensity of ROS in embryos in the 25 μM treatment group and control group (25.9 ± 2.41, n = 43, 25 μM vs. 12.2 ± 5.0, n = 33, control, p < 0.05). (E) The expression of ROS-related genes in the 25 μM group and control group. (F) The ROS signal of embryos in the CHK2 inhibition group decreased after supplementation with an antioxidant. (G) ROS fluorescence intensity analysis. ***significant difference (p < 0.001). **significant difference (p < 0.01). *significant difference (p < 0.05).