PDGF isoforms induce and maintain anagen phase of murine hair follicles

It is known that platelet-derived growth factor (PDGF) receptors are expressed in hair follicle (HF) epithelium.

The aim of the present study was to clarify the effects of PDGF-AA and -BB on the cyclic growth of HFs.

PDGF-AA or -BB was injected into the dorsal skin of C3H mice during the second telogen phase once daily for five consecutive days, or PDGF-AA or -BB dissolved in hyaluronic acid was injected only once. In order to confirm the effects of different PDGF isoforms, anti-PDGF-AA antibody or anti-PDGF-BB antibody was injected just after each injection of PDGF-AA or -BB. In addition, anti-PDGF antibodies were injected into the skin of C3H mice during the second anagen phase once daily for 5 days. We studied expression of signaling molecules in the skin where anagen phase had been induced by PDGF injection by real-time RT-PCR.

Both PDGF-AA and -BB injection experiments immediately induced the anagen phase of the hair growth cycle at the injection sites. The induction of anagen was interfered by anti-PDGF antibody treatment. Real-time RT-PCR using extracted RNA from the PDGF injected sites of skin samples showed upregulated expression of HF differentiation-related key signaling molecules, Sonic hedgehog (Shh), Lef-1 and Wnt5a.

These results indicate that both PDGF-AA and -BB are involved in the induction and maintenance of the anagen phase in the mouse hair cycle. Local application of PDGF-AA and -BB might therefore prove to be an effective treatment option for alopecia associated with early catagen induction and elongated telogen phase.