Investigation on the effect of hypoxia and cyclic stretch on recovery of damaged skeletal muscle cells using microfluidic system

Abstract

To develop the treatment to reduce muscle soreness, we tried to investigate the effect of hypoxia and cyclic stretch on the recovery of oxidative damaged skeletal muscle cells. C2C12 myoblast cells were differentiated and grown in the microfluidic device then induced oxidative stress by 1mM hydrogen peroxide. After the damage-inducing, damaged myotubes were repaired in four different environments, with and without cyclic stretch in normoxia (21% O2) and hypoxia (6% O2) to figure out the effect of hypoxia and cyclic stretch on recovery through comparing each condition. Reactive oxygen species, 8-hydroxydeoxyguanosine, and myosin heavy chain were chosen as recovery indicators. It was confirmed that hypoxia and cyclic stretch facilitated the recovery of muscle cells and the recovery was best performed in hypoxia with the cyclic stretch condition. To investigate the mechanism of the hypoxia and stretch intervened recovery, Hypoxia inducible factor -1$\alpha$ (HIF-1$\alpha$), Peroxiredoxin 2, Glutathione peroxidase 1, and Catalase were selected as candidates for the key factor of mechanism. HIF-1$\alpha$ and antioxidants seemed strongly related to enhanced recovery by hypoxia and cyclic stretch, and HIF-1$\alpha$ was speculated to play the most important role. By integrating the whole results, we were able to suggest the stretch and hypoxia triggered the pathway of cellular recovery.