Figure 5. Metformin treatment reduces calcium influx induced by CTX.

(A) Assessment of time dependent calcium influx induced by incubation with 1 µM CTX in differentiated C2C12 myotubes. Two samples of C2C12 differentiated myotubes were one treated with 5 mM metformin for 22 hours (dashed line) while the other was left untreated (solid lines). Cells were loaded with Fluo4-AM and emission of fluorescence light at 488 nm was monitored every 10 seconds under a fluorescence confocal microscope, with a 10× objective and 2× optical zoom for a total magnification of 20×, to monitor calcium uptake. 50 seconds after the acquisition start point CTX was added to the cell culture (arrow) and the changes in fluorescence monitored for a total of 500 seconds. Each condition was normalized to the measurements prior to stimulation. Data were expressed as fold change vs control. (B) The bar graph illustrates the mean of FLUO4-AM fluorescence intensity maximal peaks. Data represent the mean of three experiments ± SE, (*p<0.05).