Increased Sensitivity of Keratinocytes to Oxidative Stress in Vitiligo

Park, Dong Jae; Na, Gun Yeon; Lee, Seok Jong; Kim, Do Won; Chung, Sang Lip

Abstract

BACKGROUND
Vitiligo, a disease presenting as white patches on the skin, is caused by selective destruction of melanocytes, which are completely absent in established lesions. There are many theories about the etiology of vitiligo including the self-destruct, biochemical, neural, autoimmune and genetic hypotheses. Oxidative stress has been implicated in vitiligo as a causative factor. OBJECTIVE: To examine the susceptibility of vitiligo keratinocytes to external oxidative stress, H2O2, we compared survival rates in cultured keratinocytes according to the different concentration and exposure time of H2O2. METHODS: Keratinocytes were prepared from normal control volunteer, and the center of lesion and non-lesional skin of vitiligo patients. It was evaluated in cultures at the second and third passages. And, keratinocytes were exposed to various concentrations of hydrogen peroxide (H2O2) for 10, 20 and 40 minutes. Finally, the 96 wells plate containing cells were performed MTT assay. RESULTS: Compared to normal keratinocytes, vitiligo keratinocytes, both non-lesional and lesional, showed markedly lower survival rate. At the concentration of 0.01, 0.1 and 1 mM H2O2, survival rates did not significantly affect viability of keratinocytes after neither exposure times. On the contrary, vitiligo keratinocytes, both non-lesional and lesional, were more susceptible to the toxic effect of H2O2 after the period of exposure at concentration of 10mM H2O2 compared with normal keratinocytes. The survival rate of at concentration of 10mM H2O2 inversely correlated with the exposure period in all experiments. CONCLUSIONS: Our results demonstrate the presence of an imbalance in the anti-oxidant system in vitiligo keratinocytes and provide further support for oxidative damage as a pathogenic event in vitiligo.