Abstract: Objective:To determine the effect of narrow-band UVB  (NB-UVB)on the biological characteristics of melanocytes from the lesions of patients with vitiligo. Methods: Melanocytes from the skin lesions of 34 patients with vitiligo were cultured in vitro. Then the melanocytes were divided into 6 groups with different  radiation doses (0, 20, 40, 60, 80, 100 mJ/cm2). The levels of microtubule associated protein light chain 3 II/I (LC3 II/I), acidified mammalian rapamycin target protein (p-mTOR), autophagy signal phosphorylated adenosine monophosphate protein kinase (p-AMPK) and P26 protein in melanocytes were detected by Western blot at 1 day after radiation. The proliferation activity of melanocytes was measured by MTT at 2 day, 3 day and 4 day after radiation. The content of melanin in melanocytes was determined by NaOH staining method. Results: The expression levels of LC3 II/I and p-AMPK increased after NB-UVB treatment in a dose-dependent manner, while the expression levels of p-mTOR and P26 decreased. The proliferation activity of melanocytes increased after treated by NB-UVB, but the degree of increase reduced gradually with the increasing doses of NB-UVB. The level of melanin increased in a dose-dependent manner. Conclusion: NB-UVB can effectively regulate the expression of autophagy-related proteins in melanocytes and activate autophagy signal pathways. At the same time, it can promote the proliferation of melanocytes and melanin.

Key words: NB-UVB, vitiligo, melanocytes, biological characteristics