Abstract: Objective To investigate the effects of skin micro-needling in the treatment of alopecia areata (AA) using a dermaroller of 1.5 mm sized needles and in the stimulation of mouse dorsal hair growth using a dermaroller of 0.5 mm sized needles. Methods Fifty-two patients with AA were recruited from the outpatient department of Renmin Hospital of Wuhan University (Mar 2018 to Aug 2019) and further divided into two group, 5% minoxidil spray and 0.05% halomethasone cream were applied topically to the control group. The micro-needling group received micro-needling treatment combined with 5% minoxidil spray and 0.05% halomethasone cream. Moreover, the dorsal hair of C57BL/6 mouse was removed and then divided into model group, minoxidil group and micro-needling group. From the next day, the corresponding treatment was given to the mice for 14 consecutive days. Anagen-associated pigmentation changes and hair growth were recorded using a digital camera. The morphology and number of anagenic hair follicles were observed using HE staining, the expression of K15 in the hair follicle was detected by an immunohistochemistry staining. Results The effective rate of the micro-needling group was superior to that of the control group (P＜0.05), after 12 weeks of treatment. As compared with the model group, the skin darkening appeared earlier and the hair length longer in the micro-needling group (P＜0.05), the number of hair follicles and the K15 expression level were greatly increased in the micro-needling group compared with those in the model group (P＜0.05). Conclusions The hair follicle epithelial stem cells may be activated by micro-needling and thus stimulates hair growth and treats AA.

Key words: alopecia areata, micro-needling, efficacy, epithelial hair follicle stem cells