The effect of Nrf2 knockout on the immune organ coefficients of mice after exposure to abdominal irradiation. (A) The spleens were collected and weighted after Nrf2+/+ mice and Nrf2−/− mice were euthanized 1, 2, 3.5, 4, and 5 days post-abdominal irradiation. The spleen coefficient was calculated by spleen weight (mg)/mice weight (g). The data were expressed as mean ± SD (n = 4 mice/group); (B) the thymus were collected and weighted after Nrf2+/+ mice and Nrf2−/− mice were euthanized 1, 2, 3.5, 4, and 5 days post-abdominal irradiation. The thymus coefficient was calculated by thymus weight (mg)/mice weight (g). The data were expressed as mean ± SD (n = 4 mice/group). *** p < 0.001, Nrf2−/− group versus Nrf2+/+ group.