1 Introduction Hair follicles are key accessory organs in mammalian skin, and their growth and development are influenced by genetic factors, hormones, and the local microenvironment. A hair follicle consists of several structures, including the inner root sheath, outer root sheath, connective tissue sheath, hair bulb, and dermal papilla. The dermal papilla, located at the base of the hair bulb, is rich in blood vessels and nerves, which supply nutrients to support hair growth.
