Figure 3. Effects of Nrf2 knockdown on oocyte maturation. Fully-grown oocytes injected with Nrf2-siRNA were arrested at the GV stage with milrinone for 20 hours, and were then cultured in milrinone-free medium to evaluate the maturational progression. Negative control siRNA was injected as a control. (A) Western blot analysis showing the reduced expression of Nrf2 after siRNA injection. (B) Immunostaining showing the loss of Nrf2 in oocytes with siRNA injection. Scale bar, 20 μm. (C) The relative mRNA level of Nrf2, Nrf1 and Keep1 were determined by RT-qPCR in control- and Nrf2-siRNA-injected oocytes. mRNA levels in control oocytes were set to 1. (D) Quantitative analysis of the GVBD rate and Pb1 extrusion rate in control and Nrf2-siRNA oocytes. Data are expressed as the mean ± SD, *P<0.05 vs. control.