Research Paper Volume 15, Issue 23 pp 13628—13645

Figure 4. Effect of SIRT6 activation and inhibition on chondrocyte repair rate. Chondrocytes from middle-aged donors were pre-treated with 20 μM MDL-800, 10 μM EX-527, or vehicle (DMSO) for 2 hours before trypsinization, gel encapsulation, and irradiation. Treatment continued during the repair phase. (A) The percentage of DNA in comet tails for all cells were averaged for each donor, and the mean of all donors per condition is shown (mean + SEM). Repair time, treatment, and their interaction were significant sources of variation (2-way repeated measures ANOVA). Significant differences between groups at each time point (Tukey’s multiple comparisons test, p < 0.05) are denoted by symbols: (^*) = DMSO vs. MDL, (^#) = MDL vs. EX, (^&) = DMSO vs. EX). (B) The repair rate of chondrocytes is improved by MDL-800 treatment and inhibited by EX-527 treatment. Statistics as in A (repair rate calculated by calculating linear regression of percent DNA in comet head over 240 minutes; mean + SEM).