Fig. 6. (A) Annexin V inhibits myotube formation in differentiating C2C12 and H9C2 myoblast cultures via an interaction with PS. C2C12 and H9C2 cells were induced to differentiate in DM (control), DM with PS binding-deficient M1234, or DM with 100 µg/ml annexin V (AnxV). The graphs depict myotube distribution as a function of the number of nuclei they contained on DMd5 in cultures of C2C12 cells that were induced to differentiate at 50% confluency, and on DMd11 in cultures of H9C2 cells that were induced to differentiate at 95% confluency. Data from 6 wells per group were combined. Statistical analysis of this data is shown in Table 1. (B) Annexin V inhibits myotube formation dose dependently. C2C12 cells were induced to differentiate in DM with indicated concentrations of annexin V and the number of myotubes were counted in each sample (n=6 per dose). The graph depicts the average number of myotubes per well as a percentage of control on DMd5 in myoblast cultures that were induced to differentiate at 50% confluency. A significant decrease in the number of myotubes formed was observed at a concentration of 40 µg/ml (**p=0.001) and 100 µg/ml (* p=0.002).