Figure 1. Experimental set-up for C2C12 myotube contraction system.

A 4-well or 8-well plate was connected to an electrical stimulation apparatus that had a pair of carbon electrodes for each well. Two wells were for control (no contraction) and the other two were for electrical stimulation in order to induce C2C12 myotube contraction. On-off control was regulated by a switching controller placed between the electrical pulse generator and the apparatus. C2C12 myotubes were stimulated with electric pulses of 50 V at 1 Hz for 3 ms at 997-ms intervals for a given time period in an incubator at 37°C.