Abstract
Extrinsic injury can evoke intrinsic stimulation and subsequently initiate the physiological repair process. This study aims to investigate whether clinically acceptable micro-injury could be used to create local stimuli to induce hair regeneration and vitiligo repigmentation. A novel device was designed and manufactured to precisely control the micro-injury parameters. Then the most appropriate extent of micro-injury without over-damaging the skin was evaluated. Finally, the effects of micro-injury on hair regeneration and vitiligo repigmentation were examined by macroscopic observation, histological staining, gene and protein expression analysis. We discover that proper micro-injury effectively induces hair regeneration by activating the hair follicle stem cell proliferation and migration downwards to the hair matrix, finally shifting the hair follicle stage from telogen into anagen. On vitiligo model mice, micro-injury also induces the hair follicle melanocyte stem cells to migrate upwards to the interfollicular epidermis, activating and giving rise to melanocytes to repopulate the vitiligo lesion. Mechanistic analysis indicates that the canonical Wnt/β-catenin pathway plays a key role in the micro-injury-induced repair process. This study demonstrates that micro-injury has great potential in inducing hair regeneration and vitiligo repigmentation, laid a foundation to develop a micro-injury-based treatment method in alopecia and vitiligo.