Figure 1. Endothelin-1 induces senescence in mouse myoblasts (C2C12) through ETA receptor. Cells were grown on coverslips (A, C) and incubated with 1 nM ET-1 at different times (A, B), or incubated with 10 μM Bosentan (Bos), 100 nM BQ-123 (BQ123) or 100 nM BQ-788 (BQ788) added 30 min before ET-1 (1 nM), and then incubated for 72h (C) or 48h (D). Then, senescence was tested measuring SA-ß-GAL activity (panel A, C) and protein content from p16 (panel B, D). Representative microphotographs are shown on the left with 40x magnification and the densitometric analysis is shown on the right panel A, C. Scale bar, 50 μm. A representative Western blot of p16 is shown next to the densitometric analysis on the panel B, D. Values are the mean±SEM of 6 independent experiments, *p<0.05 vs. control cells (C or time 0), and **p<0.05 vs ET alone.