Effects of FGF7/9 on hair induction in vivo hair reconstitution assay. a Representative time course of re-epithelization and hair regeneration after the removal of chamber in control and FGF7- and FGF9-treated groups were presented. b Representative histopathology of re-epithelized skin 6 weeks after the removal of chambers in three groups. Terminal hairs were remarkable in the FGF9-treated group, whereas hair follicles observed in the control and the FGF7-treated groups were comparatively immature. Scale bars = 10 μm. c Regenerated hair follicle (HF) density (total HF number per one vertical section) and the average HF diameter in three groups. FGF9 group presented increase in both the number and the diameter of newly formed HFs. *p < 0.05. **p < 0.01. The data were obtained from seven respective experiments.