Enhanced In Vitro Hair Growth at the Air-Liquid Interface: Minoxidil Preserves the Root Sheath in Cultured Whisker Follicles

The study investigated the maintenance of hair follicles in culture, focusing on the effects of minoxidil on whisker follicles. By culturing follicles at the air-liquid interface on a modified collagen matrix, researchers observed a 2.7-fold increase in hair growth and an anagen-like morphology compared to submerged cultures. Minoxidil and its analogs were found to stimulate cysteine incorporation and specifically preserve the follicular root sheath, as indicated by increased TIMP expression and sulfotransferase activity. This preservation was not observed with the pinacidil analog, suggesting a unique action of minoxidil on the root sheath. The study concluded that the air-liquid interface culture method was superior for maintaining follicle morphology and promoting hair growth.