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.