Moderate oxidative stress induces temporal impairment in mitochondrial
ATP production. As
glutathione (GSH) content is reduced to eliminate oxidative stress by oxidation-reduction reaction, intracellular GSH content is crucial for maintaining mitochondrial function under oxidative stress. GSH precursors such as N-acetyl
cysteine (NAC) and
cysteine are known to suppress oxidative stress based on the supply of
cysteine residues being rate-limiting for GSH synthesis. However, it remains unclear whether
cystine (Cys2) can suppress
mitochondrial dysfunction under oxidative stress conditions. Therefore, we examined whether Cys2 could attenuate
mitochondrial dysfunction under moderate oxidative stress without scavenging
reactive oxygen species (ROS) in the medium. C2C12 myotubes were incubated for 120 min in a Cys2-supplemented medium and subsequently exposed to
hydrogen peroxide (H2O2).
Heme oxygenase-1 (HO-1) gene expression, intracellular
cysteine and GSH content, intracellular
ATP level, and maximal mitochondrial respiration were assessed. Cys2 treatment significantly increased GSH content in a dose-dependent manner under oxidative stress. Cys2 treatment significantly decreased HO-1 expression induced by H2O2 exposure. In addition, maximal mitochondrial respiration rate was decreased by H2O2 exposure, but improved by Cys2 treatment. In conclusion, Cys2 treatment mitigates oxidative stress-induced
mitochondrial dysfunction by maintaining GSH content under moderate oxidative stress without scavenging ROS in the medium.