The Androgenic Alopecia Protective Effects of Forsythiaside‐A and the Molecular Regulation in a Mouse Model

This study examined the inhibitory effect of forsythiaside‐A, a natural substance derived from Forsythia suspensa ( F. suspensa ), on entry into catagen induced by dihydrotestosterone (DHT) in an androgenic alopecia mouse model. In vitro experiment comparing finasteride with forsythiaside‐A showed that forsythiaside‐A treatment resulted in a 30% greater inhibition of DHT‐induced apoptosis in human hair dermal papilla cell (HHDPCs) and human keratinocytes (HaCaTs). In vivo experiment showed that mouse hair density and thickness were increased by 50% and 30%, respectively, in the forsythiaside‐A‐treated group when compared to a DHT group. Tissue histological results revealed that the forsythiaside‐A‐treated group had an increase in size and shape of the hair follicles and a 1.5 times increase in the follicle anagen/telogen ratio when compared to the finasteride group. Western blot examination of TGF‐β2 expression related to apoptosis signaling in mouse skin verified that forsythiaside‐A reduced the expression of TGF‐β2 by 75% and suppressed apoptosis by reducing the expression of caspase‐9 by 40%, and caspase‐3 by 53%, which play an roles up‐regulator in the apoptosis signal. The forsythiaside‐A group also showed a 60% increase in the Bcl‐2/Bax ratio, which is a factor related to mitochondrial apoptosis. Our results indicated that forsythiaside‐A prevents apoptosis by similar mechanism with finasteride, but forsythiaside‐A is more effective than finasteride. In summary, forsythiaside‐A controlled the apoptosis of hair cells and retarded the entry into the catagen phase and therefore represents a natural product with much potential for use as a treatment for androgenic alopecia. Copyright © 2015 John Wiley & Sons, Ltd.