Hair Growth-Promoting Effect of a Horse Oil-Folium Isatidis Topical Preparation via Modulation of VEGF, TGF-β1, and β-Catenin Signaling in C57BL/6 Alopecia Mice: A Pilot Study.

Wnt/β-catenin signaling is a key regulator of hair follicle cycle progression, and aberrant activation or suppression of this pathway has been implicated in the pathogenesis of alopecia. Horse oil (HO) and Folium Isatidis (FI) have been traditionally used in East Asian medicine for hair growth, but their combined molecular mechanism remains unclear. We evaluated a topical preparation combining HO and FI (HOFI) in two C57BL/6 mouse models: physiological depilation (telogen-to-anagen transition) and testosterone-induced seborrheic alopecia. Hair growth was assessed by gross appearance, hair length, and histomorphometry (follicle number, size, dermal thickness). Plasma and skin levels of vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) were measured by ELISA. Protein expression of β-catenin, Bcl-2, and Bax in skin tissue was analyzed by Western blotting. Compared with NC, HO, FI, and HOFI significantly increased hair length, follicle density and size, and dermal thickness (p < 0.05). All three treatments upregulated VEGF and β-catenin, suppressed TGF-β1, elevated Bcl-2, and reduced Bax expression. HOFI exhibited significantly greater effects than either monotherapy across all endpoints (p < 0.05). HOFI promotes hair growth by activating the VEGF/β-catenin signaling axis, inhibiting TGF-β1, and shifting the Bcl-2/Bax balance toward follicular cell survival. These findings provide a molecular rationale for developing HO-FI combinations as topical agents for alopecia.