Abstract: Wang Cui *, Zhu Yiping, Xu Ai′e. *Hangzhou Clinical College Affiliated to Anhui Medical University, Hangzhou 310009, China Corresponding author: Xu Ai′e, Email: xuaiehz@msn.com 【Abstract】 Objective To study the effect of epigallocatechin gallate （EGCG） and fructus psoraleae on the induction of vitiligo-like depigmentation by monobenzone in mice. Methods Forty C57BL/6 mice were included in this study. Hairs in an area measuring 2 cm × 2 cm in size were shaved on the back of each of these mice. Then, the mice were randomly and equally divided into four groups to be topically treated with vaseline cream （negative control group）, monobenzone 40% cream （model group）, EGCG 5% cream followed by monobenzone 40% cream （EGCG group）, fructus psoraleae 7% cream followed by monobenzone 40% cream （fructus psoraleae group）, on the shaved area, respectively, for 50 consecutive days. Depigmentation of skin and hairs was observed daily by naked eyes for 15 days after drug withdrawal. At the end of the study, all the mice were sacrificed, and skin specimens were resected from the tested regions in them. Hematoxylin and eosin （HE） staining was performed to observe lymphocyte infiltration, and immunofluorescence assay to estimate the frequency of CD8+ T cells. Results Depigmentation was observed in monobenzone-induced and -uninduced sites in the model group, and in monobenzone-induced sites in all the mice in the EGCG group and fructus psoraleae group, but in neither monobenzone-induced nor -uninduced sites ih the negative control group. The average time for the appearance of depigmentation at monobenzone-induced sites was 16.7, 29.3 and 19.9 days in the model group, EGCG group and fructus psoraleae group respectively. The depigmentation area index at monobenzone-induced sites was 4.00 ± 0.00 in the model group, significantly different from that in the EGCG group and fructus psoraleae group （2.11 ± 0.54 and 2.84 ± 0.79, both P < 0.05）. Significant differences were also observed in depigmentation area index at monobenzone-induced sites among the model group, EGCG group and fructus psoraleae group （F = 14.173, P < 0.05）, and at monobenzone-uninduced sites between fructus psoraleae group and EGCG group （P < 0.05）. The frequency （expressed as fluorescence intensity） of CD8+ T cells was significantly lower in the EGCG group and fructus psoraleae group than in the model group, and significantly different between EGCG group and fructus psoraleae group （P < 0.05）. Conclusions Both EGCG and fructus psoraleae, especially EGCG, can interfere with the induction of vitiligo-like depigmentation of skin and hairs by monobenzone in mice. The mouse model of vitiligo-like depigmentaion in this study shows higher similarity to human vitiligo.

Key words: Vitiligo, Propyl gallate, PSORALEA CORYLIFOLIA, Disease models, animal