Research Paper Volume 11, Issue 3 pp 950—973

Replicative senescent human cells possess altered circadian clocks with a prolonged period and delayed peak-time

Figure 6. Alteration of circadian clock in the senescent cells was also observed by a Fsk-induced entrainment. (A) Relative oscillation patterns of luciferase in the proliferative (pro) and senescent (sen) cells entrained by Fsk were monitored by using a real-time luciferase monitoring system. Lowest intensity of each sample was set to -1. (B) Box-whisker plots of trough-times are displayed, n=8. Values are mean ± SEM. (C) Relative trough-time differences were measured, n=8. (D) Box-whisker plots of period lengths in the proliferative (pro) and senescent (sen) cells are displayed, n=8. Values are mean ± SEM. (E) Relative damping ratio in the proliferative (pro) and the senescent (sen) cells are analyzed. Data are mean ± SEM. **p<0.01, ***p<0.001, compared to each of the proliferative cells by Student’s two-tailed t test.