Fibroblast growth factor influences the development and cycling of murine hair follicles

The effects of basic fibroblast growth factor (bFGF) on the development of hair follicles in neonatal mouse skin were examined. Newborn mice (B6C3-based strain) were given daily subcutaneous injections of bFGF and bovine serum albumin (BSA) for 7 days. By Day 9, distinct areas of hairless, unpigmented skin were observed surrounding the sites treated with bFGF. This phenomenon persisted until about 14-16 days of age when the emergence of hair in the bald patches was first seen. Hair growth continued in the treated regions until they were mostly covered at 18-20 days of postnatal age. Control sites injected with BSA only were indistinguishable from the surrounding pigmented, hairy skin at all ages. Histological examination of skin from various ages of bFGF-treated mice suggested that the growth factor had affected both the initiation and the development of the hair follicles. This resulted in a significant delay in the first and subsequent hair cycles when compared to control animals injected with BSA only.