Comparison of topical application of tea polyphenol versus pimecrolimus versus tacrolimus for the treatment of monobenzone-induced vitiligo-like depigmentation in a mouse model

Abstract

Objective To compare the therapeutic effect of topical application of tea polyphenol versus pimecrolimus versus tacrolimus for monobenzone-induced vitiligo-like depigmentation in mice. Methods Twenty-five 3-week-old female C57BL/6 mice were randomly and equally divided into 5 groups: negative control group, model group, tea polyphenol group, pimecrolimus group, tacrolimus group. Monobenzone 45% cream was applied to the back of mice in all the five groups except the negative control group once daily for 40 consecutive days to establish a model of vitiligo-like depigmentation. During the induction of depigmentation, the tea polyphenol group, pimecrolimus group and tacrolimus group were topically treated with tea polyphenol, pimecrolimus and tacrolimus respectively, and the model group remaining untreated. The depigmentation of hairs and skin was observed by naked eyes on a daily basis. Tissue specimens were obtained for histological examination from depigmented skin at non-application sites in mice after the end of the experiment. Hematoxylin-eosin staining was conducted to analyze lymphocytic infiltration, reflectance confocal microscopy to observe melanin and melanocytes in skin, and immunofluorescence assay to detect CD8+ T cell infiltration. Results Depigmentation occurred in both application sites and non-application sites of mice in the model group. Compared with the model group, the tacrolimus, pimecrolimus and tea polyphenol groups showed delayed depigmentation, reduced degree and area index of depigmentation, and attenuated lymphocytic infiltration and CD8+ T cell infiltration in depigmented maculae at application sites. In addition, the therapeutic effect of tacrolimus was stronger than that of pimecrolimus and tea polyphenol. Conclusion Tea polyphenol, pimecrolimus and tacrolimus are all effective for the treatment of vitiligo-like depigmentation in mice. Key words: Monobenzone; Tea polyphenol; Tacrolimus; Pimecrolimus; Vitiligo, animal model