The skin injury induced by high energy dose of ultraviolet in hairless descendants of Mexican hairless dogs
Y. Ishii1, T. Kimura2, S. Itagaki1 and K. Doi1
1Department of Biomedical Science, Faculty of Agriculture, The University of Tokyo, Yayoi 1-1-1 , Bunkyo-ku and 2Research Center, Nihon Nosan Kogyo Co., Ltd., Tsukuba, Ibaraki, Japan
Offprint requests to: Dr. Y. Ishii, Department of Biomedical Science, Faculty of Agriculture, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan
Summary. His topathological changes in the dorsal skin of hai rl ess desce nd a nts of Mex ica n ha irl ess dogs (MHOs) ex posed to a rti f ic ial irradi a ti on with hi gh e ne rgy dose (180 kJ/m2) o f ultrav io le t (UV) rays (UVA+B) were investigated. Macrosco pi ca ll y, e ry th ema and e d ema we re observed in the irradi ated skin at 1 day after irradiation (OAI), and bl ister formation occurred except one dog at 2 OAI. Erythema almost disappeared at 5 OAI, and at 6 OAI, the skin recovered to almost normal state. Light microscopically, sunburn cells were obse rved at 1 OAI. Then intercellul ar edema and bli s ter fo rm ation in the epidermis and dermal edema were evident at 2 and 3 OAI. At 6 DAI, the skin showed almost normal fea tures except fo r s lig ht epidermal thi ckening, but me lanin granules, whic h we re di stributed in almost th e who le leng th of the epidermis before UV irradi a tio n, were detected only in cells which seemed to be melanocytes except one dog. Oih ydroxy phe nyla lanine (OOPA)positive melanocytes almost disappeared at 1 and 2 OAI, and a t 6 OA I, th e numbe r of DOPA-pos itive me la nocy tes in c reased ove r the leve l befo re UV irradiation. The ultrastru ctural fea tures of melanocytes were characteri zed by vacuolated cytoplasm, decreased me lanosomes, irregul ar-s haped nuc lei and shortened dendrites at 1 OAI, and return ed to normal at 6 OAI. These findings of melanocytes refl ect the severity of the skin injury and support weak suntan reaction in this case. In conclusion, severe form of UV-induced skin injury seen in hum a ns co uld be re pr odu ced in ha irl ess descendants of MHOs exposed to high energy dose of artificial UVA+B. Histol Histopathol 12, 383-389 (1997)
Key words: Melanocyte, Mexican hairless dog, Skin,
Ultraviolet ray
DOI: 10.14670/HH-12.383