title: Changes in the proliferative activity of epidermal melanocytes in serum-free primary culture during the development of ultraviolet radiation B-induced pigmented spots in hairless mice.
abstract: Long-term exposure to ultraviolet radiation B (UVB) induced pigmented spots in the dorsal skin of hairless mice of strain (HR-1 X HR/De)F1. To clarify the cellular mechanism for the development of these UVB-induced pigmented spots, we investigated changes in the proliferative activity of epidermal melanoblasts and melanocytes in the dorsal skin at various weeks after UVB irradiation. Epidermal cell suspensions from the dorsal skin of hairless mice were cultured in a serum-free medium supplemented with dibutyryl adenosine 3':5'-cyclic monophosphate (DBcAMP) and basic fibroblast growth factor (bFGF). The suspensions were prepared from dorsal skins of mice exposed to UVB for 4 weeks (the stage of hyperpigmentation). Suspensions were also prepared from mice at 3 (the stage of depigmentation), 8 (the stage of appearance of pigmented spots), 20 (the stage of development of small-sized pigmented spots) and 37 (the stage of development of medium-sized pigmented spots) weeks after the cessation of 8-week UVB exposure. At the stage of hyperpigmentation the proliferative activity of melanoblasts and melanocytes was suppressed. With the development of pigmented spots, the proliferative activity of undifferentiated melanoblasts gradually increased, and then followed the increase in the proliferative activity of differentiated melanocytes. These results suggest that the proliferative activity of epidermal melanoblasts and melanocytes in UVB-irradiated skin increases with the development of pigmented spots.
authors.affiliation: Shiseido Research Center, Hayabuchi, Kouhoku-ku, Yokohama, Japan.
authors.forename: Rikako
authors.initials: R
authors.lastname: Furuya
authors.forename: Satoru
authors.initials: S
authors.lastname: Akiu
authors.forename: Ritsuro
authors.initials: R
authors.lastname: Ideta
authors.forename: Masako
authors.initials: M
authors.lastname: Naganuma
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuda
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hirobe
mesh_terms: D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation / Q000502:physiology / Q000528:radiation effects*; D002455:Cell Division / Q000502:physiology / Q000528:radiation effects*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004295:Dihydroxyphenylalanine / Q000378:metabolism / Q000494:pharmacology; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism / Q000528:radiation effects*; D005260:Female; D008297:Male; D008543:Melanins / Q000378:metabolism / Q000528:radiation effects; D008544:Melanocytes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D051379:Mice; D008812:Mice, Hairless; D010859:Pigmentation Disorders / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D015854:Up-Regulation / Q000502:physiology / Q000528:radiation effects
chemical_list: D016895:Culture Media, Serum-Free; D008543:Melanins; D004295:Dihydroxyphenylalanine