Morphological and molecular differences between black hair follicles and gray hair follicles

Abstract

Immature hair graying is defined as an abnormal phenomenon occurring in patients younger than 30 years of age. However, study on this phenomenon is still limited. The authors studied on tissue speciments for the understanding of 3 stages of hair growth cycle: Anagen, Catagen and Telogen, as well as analysed the differences in follicle morphologies of black and gray hairs. In addition, the expression of important molecules contributing to melanine synthesis of melanocyte such as MC1R, MITF and Tyrosinase were then implemented through molecular techniques. Results showed that the mophology of gray hair follicle differed from that of black hair follicle in three important aspects, including dermal papillae structure, melanocyte cell shape and sebaseous structure. The expressions of MC1R, MITF and Tyrosinase at the transcription levels of follicles of gray hairs were lower than those of black hair follicles. The research results indicated that immature hair graying directly related to the reduction of MC1R expression followed by the reduction of MITF and Tyrosinase expression at the transcriptional levels.