The Effect of Ultraviolet Irradiation on the Morphological Changes in Epidermal Keratinocytes

Chun, Soo Il; Kang, Won Hyoung

Abstract

A total of 40 adult black-mice was used and divided into two groups for expeiment. Group A was irradiated by UVB only and Group B had SPF 15 sunscreen a.pplied to the back followed by irradiation by UVB. Each group was divided again into 5 subgroups according to the days of UVB irradiation frcm 2 to 10 days. A Waldmann combination UVA+UVB Radiation Treatment Cabin 8001 was used as the light source and the UVB dosage was 50 mJ/cm2 daily. Skin specimens were taken 24 hours after the last irradiation. Histologic changes in epidermis were reviewed by the light microscope. In group A, the characteristic sunburn cells(SBC) were observed with 100 mJ/ cm2. SBC number was maximum with 400 mJ/cm2. The other epidermal changes were parakerat.osis, crusts, atypical cells, and mitoses of basal cells, which showed graded responses to the UVB doses. Pretreatment with the sunscreen completely prevented these changes.