Induction of hair growth in hair follicle cells and organ cultures upon treatment with 30 kHz frequency inaudible sound via cell proliferation and antiapoptotic effects.

Androgenic alopecia is a hair loss disease mediated by dihydrotestosterone (DHT) and is currently treated using minoxidil, finasteride, or low-level laser therapy. However, these treatments have side-effects, indicating the need for an alternative treatment. In the present study, it was demonstrated that inaudible sound at 30 kHz significantly induced proliferative and anti-apoptotic effects in human dermal papilla cells (hDPCs) and outer root sheath keratinocytes. Cell viability assay, ELISA, reverse transcription quantitative PCR and TUNEL assays were performed to evaluate the effect of inaudible sound. Inaudible sound was also demonstrated to significantly inhibit the hair loss signals induced by DHT treatment in hDPCs. Furthermore, inaudible sound significantly induced hair follicle (HF) elongation and hair matrix keratinocyte proliferation in human HF organ culture. Overall, the results suggested that inaudible sound may be effective in treating hair loss and could be used to develop a new hair loss treatment approach.