Investigation on the Effect of Cyclic Stretch and Hypoxia on Recovery of Damaged Skeletal Muscle Cells Using Microfluidic System

To develop an effective treatment for muscle recovery, costimuli effect of cyclic stretch and hypoxia on the recovery of oxidative damaged skeletal muscle cells is investigated. C2C12 myoblast cells are differentiated into myotube in culture dish followed by seeding the myotubes in the microfluidic device for further growth. Hydrogen peroxide is used to induce oxidative stress on myotubes for mimicking intracellular muscle damage. Afterward, the damaged myotubes are recovered in either normoxia or hypoxia environment with or without cyclic stretch, to elucidate the effect of the stretch and hypoxia on recovery. For analysis, reactive oxygen species, 8‐hydroxydeoxyguanosine, and myosin heavy chain are chosen as recovery indicators and it is shown that cyclic stretch and hypoxia facilitate the recovery of muscle to the greatest extent when both cyclic stretch and hypoxia are applied. To investigate the mechanism of the stretch and hypoxia intervened recovery, hypoxia inducible factor‐1α (HIF‐1α), peroxiredoxin 2, glutathione peroxidase 1, and catalase are selected as candidates for the key factor of recovery acceleration. There is evidence that HIF‐1α and antioxidants contributed to stretch‐/hypoxia‐induced recovery, and HIF‐1α is speculated to play the most important role. Hence, the stretch and hypoxia triggered pathways of cellular recovery are suggested. By using in vitro microfluidic system‐based experiments where a damage model with increased ROS in muscle cells is generated, the combination of stretch and hypoxia condition is turned out to increase the recovery rate of muscle. Also, HIF1‐α plays a causal role in the stretch‐/hypoxia‐enhanced recovery.