Circadian rhythm disorder impairs the radioresistance of mice. (A–C) The expression level of Clock (A), Bmal1 (B), and Per1 (C) was examined by qRT-PCR using the peripheral blood of mice from different cohorts after irradiation; (D) Kaplan-Meier survival analyses of mice from the three cohorts, after irradiation, were performed. p < 0.05 using a log-rank test between the 12 h dark/12 h light group and the 8 h dark/16 h light (or 16 h dark/8 h light) group, n = 10 per group; (E) The body weight of mice from the three groups, after irradiation, were measured every 5 days, n = 10 per group; (F) The food intake of five mice was assessed every five days. Statistically significant differences are indicated: *** p < 0.005; ** p < 0.01; Student’s t-test. TBI, total body irradiation.