Resumen de The skin injury induced by high energy dose of ultraviolet in hairless descendants of Mexican hairless dogs

Y. Ishii, T. Kimura, S. Itagaki, K. Doi

• Histopathological 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 rtific ia l irradi a ti o n w ith hi g h e ne rgy d ose (180 kJ/ m2) o f ultrav io le t (U V) rays (UVA+B) were investigated.

  Ma crosco pi ca ll y, e ry th e ma a nd e d e ma we re observed in the irradi ated skin at 1 day after irradiation (OAI), and blister fo rmation occurred except one dog at 2 OAI. Erythema almost disappea red 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 blister fo rmation 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 slig ht epide rma l thi ckening, but me lanin granul es, which we re distributed in almost the who le leng th of the epide rmis before UV irradi a tio n, we re detected only in cells which seemed to be melanocytes exce pt one dog. Oih ydroxy ph e nyla lanin e (OOPA)- positive melanocytes almost disappeared at 1 and 2 OAI, and a t 6 OA I, th e numb e r o f DOPA -positi ve me la nocy tes in c reased ove r th e leve l befo r e UV irradiation. The ultrastructural fea tures of melanocytes were characteri zed by vacuolated cytoplasm, decreased me lanosomes, irregul ar-s haped nuc le i and shortened dendrites at 1 OAI, and returned to norma l 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, seve re fo rm of UV-induced skin injury see n in hum a ns co uld be re pr o du ce d in ha irl ess descendants of MH