ABSTRACT
Hair is a ’lamentous biomaterial that grows from hair follicles found in the dermis, which is one of the de’ning characteristics of the mammalian class. A hair follicle is a very complex structure consisting of the hair shaft, dermal papilla cells, matrix, inner root sheath cells, outer root sheath cells, etc. Hair provides thermal regulation for many animals, and for some animals hair provides protection from environmental damage. Hair has a great social and sexual role in human beings (Randall 2008). Human hair follows a speci’c growth cycle with three distinct and concurrent phases: anagen, catagen, and telogen phases that occur simultaneously and are regulated by different genes and hormones (Stenn and Paus, 2001). Recent studies have reported the regulation of proliferation and function in hair follicle cells on the human hair cycle, aberrant action of androgen and testosterone, phsyical stress, and environment pollution related to human baldness (Elliott et al., 1990; Kaufman, 2002; Botchkarev, 2003; Winiarska et al., 2006).
