106 Hair-inducing ability of cultured rat dermal papilla cells

Koh-ei Toyoshima1, Hitoshi Kuwamoto2, Yoso Sueyoshi1, Mutsumi Inamatsu2, and katsutoshi Yoshizato2,3; Bioart Laboratory1, Hiroshima Tissue Regeneration Project, Hiroshima Prefecture Collaboration of Regional Entities for Advancement of Technological Excellence, JST2, Dept. of Biological Science, Graduate School of Science, Hiroshima University3

The dermal papilla (DP) is a messenchymal component of the hair follicle and can induce ectopic hair follicles when it is implanted into the afollicular skin. Inamatsu et al. established serial cultivation of rat DP cells by maintaining them with the conditioned medium of kerationocytes and FGF2 (J. Invest. Dermatol., 111(5), 767-75, 1998). These cells sustained their hair follicle-inductive ability during the culture for more than 70 passages. However we could not observe the growth of hair shaft by transplantation of DP cells in rat sole skins. Combinations of cultured DP cells and epidermal cells freshly prepared from newborns of rat were grafted onto the back of nude mice to test the hair-inducing ability of cultured DP cells. The DP cells obtained from primary cultures induced the growth of dense hairs at the grafted sites, but macroscopical hair growth out of the skin was not seen for DP cells at passage number 21 and 51, although we confirmed microscopically the imduction of hair follicles and hair shafts in the intracutaneous regions for these passaged DP cells. Our results showed that cultured DP cells progressively lost the hair growth-inducing potential during serial cultivation, but retained hair follicle-inducing ability.