Figure 2. ClockΔ19 mice exhibit oxidative damage and DNA damage. (A) ROS activities were detected in the primary hepatocytes of WT and Clock∆19 mice (n=4 for all groups). (B) Relative expression of oxidation-related genes in WT and ClockΔ19 mice. Data were analyzed by Student’s t-test and displayed as the mean ± S.E.M. (n=4). **, P<0.01; *, P<0.05. (C) SOD, MDA, GSH and CAT activities were analyzed in liver tissue homogenate from WT and Clock∆19 mice (n=4). **, P<0.01; *, P<0.05. (D) Immunoblots of γ-H2AX and PARP in mouse liver tissues at ZT0 and ZT12. The spliced form of PARP (C-PARP) indicates DNA damage. Note that γ-H2AX was activated in Clock∆19 mice (n=4). **, P < 0.01 and *, P < 0.05 versus control. n=4 mice per group. (E) Immunoprecipitation of activated Caspase 3 (Cleaved-Caspase 3), which is activated in response to liver cell apoptosis activity. Mice had the same treatment as in (D). (n=4). **, P < 0.01; *, P < 0.05.