Changes of Myogenic Reactive Oxygen Species and Interleukin-6 in Contracting Skeletal Muscle Cells

The aim of this study was to measure changes in myotube reactive oxygen species (ROS) and the production of interleukin (IL)-6 in electrically stimulated mouse C2C12 skeletal muscle cells. After five days of differentiation, myotubes were stimulated using an electrical stimulator set at 45 V at a frequency of 5 Hz, with a pulse width of 20 ms. Acute stimulations were performed for 45, 60, 75, 90, or 120 min in each dish. ROSs were detected in the extracted cells directly using a fluorescent probe. IL-6 mRNA expression in C2C12 myotubes and IL-6 concentration in C2C12 myotube supernatants were determined using realtime PCR and ELISA, respectively. Compared with control cells, ROS generation was significantly increased at 45 min after the onset of stimulation (P < 0.01) and continued to increase, reaching a maximum at 120 min. IL-6 mRNA expression and IL-6 concentration in C2C12 cells were significantly increased after 75 min (P < 0.01) and 120 min (P < 0.05) of electrical stimulation (ES) compared with the control cells. Our data show that a specific ES intensity may modulate ROS accumulation and affect IL-6 gene expression in contracting skeletal muscle cells.