Effects of mechanical stress on ERK1/2 and AKT phosphorylation. ERK1/2 (A) and AKT (B) phosphorylation levels were analyzed by western blot in HC11 cells subjected to 20% RSA for the indicated times. Analysis was performed by triplicate in three independent experiments. Data are expressed as means ± SE. Significant differences: (*) p < 0.05 compared with 0 min and (**) p < 0.05 compared with 60 min. Six-hour stretched cells have their own corresponding un-stretched control (grey bar).