Expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) in mouse uterus during the peri-implantation period.

Nuclear factor-erythroid 2-related factor- 2 (Nrf2) is a nuclear transcription factor that facilitates transcription of genes for detoxification enzymes and antioxidant proteins. We investigated the distribution and expression of Nrf2 during the peri-implantation period. We detected Nrf2 in uteri of mice during estrus (control) and on days 1, 4, 5, 6 and 8 of pregnancy using immunohistochemistry, quantitative real-time polymerase chain reaction and western blotting. Nrf2 immunostaining was significantly greater on days 1, 5 and 6 of pregnancy compared to controls, and on days 4 and 8 of pregnancy; western blotting results were consistent with immunohistochemical observations. Nrf2 mRNA levels on days 5 and 8 were significantly higher than for control uteri. Increased expression of Nrf2 on days 1, 5 and 6 of pregnancy may be important for uterine receptivity, implantation and decidualization by protecting the developing embryo and uterus from the adverse effects of oxidative stress.