The effects of PUVA on epidermal melanocytes in C57BL mice

Ree, Joo Heung; Youn, Jai Il

Abstract

The object of this study is to evaluate the effects of repeat,ed PUVA applications on epidermal melanocytes. The changes in the number of melanocyes is compared to the frequency of PUVA applications. 26 adult male C57BL mice were used. About an hour after appliction of 0.1% solution of 8-methoxypsoralen, UVA was delivered two or four times a weels on both ears of mice with blacklight fluorescent tube l,'Waldmann UV-800). Weekly examinations of melanocytes were made for 4 weeks on split epidermal sheets treated with DOPA solution. The results were as follows. 1. Repeated PUVA applications revealed a significant increase in the number of melanocytes. With PUVA, two times a week, the number of me anocytes was increased from 83.2+/-7.2/mm2 (unir radiated ear) to 250.6+/-34.7/mm2 after ore week and 525.5+/-66.7/mm2 after 4 weeks. With PUVA, four times a week, the number of melanocytes was increased from 83.2+/-7.. 2/mm2 (unirradiated ear) to 437.0+/-74.0/mm2 after one week and 686.3+/-27.8/mm2 after 4 weeks. 2. PUVA, four times a wcek, elicited higher melanocyte density than PUVA, two times a week, under the same period of treatment. 3. After two weeks, the same amount of irradiation increased the number of melanocytes more in PUVA, four times a week than in PUVA, t,wo times a week.