Erbium: YAG laser (2,940 nm) treatment stimulates hair growth through upregulating Wnt 10b and β-catenin expression in C57BL/6 mice

To evaluate the role of 2,940 nm erbium: YAG laser in hair growth in C57BL/6 mice.

Our findings showed that 2,940-nm Er: YAG laser could promote hair growth by inducing hair cycle transition from telogen to anagen phases in C57BL/6 mice through up regulating Wnt 10b and β-catenin. These results suggest that 2,940-nm Er: YAG laser may be a potential therapy for hair loss.

Anagen was experimentally induced by depilation. Healthy C57BL/6 mice (n=22) were randomly divided into four groups, with treatment of laser or minoxidil, or with combined laser and minoxidil treatments. The skin color of each mouse was observed each day. The time from telogen (pink skin color) to anagen (black coloration) phase and from anagen (black coloration) to catagen (all hairs grew out of the depilated skin) have been recorded. Hematoxylin and eosin (H&E) assay was done at fifteen days after the first treatment for each group to observe hair follicles and hair cycle score. Western blot analysis was utilized to detect the expression levels of Wnt 10-b and β-catenin.

Black pigmentation started significantly earlier both in the laser and combination group than in the control group. Moreover, the time from anagen to catagen in the laser, minoxidil and combination groups were all significantly shorter from the control group. Histopathology with H&E staining showed an obvious increase in the number of hair follicles in the anagen phase caused by the treatment of 2,940 nm erbium: YAG laser and minoxidil. Similarly, the percentage of hair follicles in anagen VI accounted for 19.5%, 37.5%, 41.5% and 44% in control, laser, minoxidil, and combination group, respectively. Western blot analysis showed that both the levels of Wnt 10b and β-catenin were significantly increased by the treatment of 2,940 nm erbium: YAG laser.