Quercetin attenuates the effects of H2O2 on endoplasmic reticulum morphology and tyrosinase export from the endoplasmic reticulum in melanocytes.

Swollen endoplasmic reticulum (ER) is commonly observed in the melanocytes of vitiligo patients; however, the cause and proteins involved in this remain to be elucidated. Oxidative stress has been reported to be involved in the pathogenesis of vitiligo and previous studies have demonstrated that hydrogen peroxide (H2O2) induced melanocyte apoptosis, whereas quercetin exhibited cytoprotective activities against the effects of H2O2. The aim of the present study was to further investigate the role of H2O2 in the ER of melanocytes as well as its role in the export of tyrosinase from ER; in addition, the present study aimed to determine the mechanism by which quercetin protects against the effects of H2O2. The results demonstrated that melanocyte cells treated with H2O2 presented with swollen ER; however, a normal ER configuration was observed in untreated cells as well as quercetin/H2O2‑treated cells. Furthermore, H2O2 inhibited tyrosinase export from the ER and decreased expression levels of tyrosinase; however, quercetin was found to attenuate the effects induced by H2O2. In conclusion, the results of the present study confirmed the hypothesis that H2O2 induced ER dilation and hindered functional tyrosinase export from the ER of melanocytes. It was also found that quercetin significantly weakened these effects mediated by H2O2, therefore it may have the potential for use in the treatment of vitiligo.