Photobiomodulation (PBM) is now being used in regenerative medicine to treat alopecia caused by a variety of reasons. The mechanisms underlying its effects remain unclear.

The focus of a recent study published in the Wound Repair and Regeneration was to investigate the effects of PBM on hair regeneration in wounded skin and to investigate the underlying mechanisms.

For this experiment, scratched epidermis and dermis models were used. The findings demonstrated that scratched epidermis did not affect hair regeneration; however, the scratched dermis caused evident hair follicle atrophy which had a considerable impact on hair regeneration. Here, PBM (655 nm, 3 J/cm2 [10 min]) was used to treat wounds in scratched dermis models; hair regrowth and cell proliferation in hair follicles were measured. The level of hair coverage was dramatically increased following PBM therapy when compared to the control. Sox9+ and PCNA+ cells in hair follicles were could be visualized in the PBM-treated group but not in the control group.

Further, the effects of PBM on the function of dermal papilla cells (DPCs) were studied in vitro. The results showed that PBM (655 nm, 3 J/cm2 [10 min]) dramatically boosted DPC migration while having zero effect on proliferation. Additionally, researchers observed that PBM stimulated DPC exosome production, which was followed by activation of the Akt/GSK-3/-catenin pathway. MK-2206, an AKT inhibitor, significantly attenuated PBM-induced DPC migration and exosome secretion.

From the results, it was inferred that PBM promotes hair regeneration in wounded skin by increasing DPC migration and exosome secretion through the Akt/GSK-3/-catenin pathway.

Source: Wound Repair and Regeneration. 2021 Dec 18.  doi: 10.1111/wrr.12989.