Fig. 3. Stretch activation of p38 and myogenic differentiation markers are blocked by a TNF--neutralizing antibody. C2C12 myoblasts were stretched for the indicated periods in growth medium that contained an antibody that neutralizes TNF- or pre-immune IgG (5 µg/ml). Western blot analysis was performed to determine phosphorylation of p38, ERK1/2, JNK and AKT (A), as well as MEF2C phosphorylation and the expression of myogenin and p21 (B). Levels of total p38 or -actin are shown as the loading control.