Morphological and biochemical alteration by ultraviolet B irradiation in hairless mouse

Kook, Youn Keun; Won, Young Ho; Kim, Young Pio; Chun, Inn Ki

Abstract

BACKGROUND: It is well known that ultraviolet light(UVL) may cause skin cancer, decrease immune function and promote skin ageing. It is also known that an increase of chlorofluorocabons as air pollution, which csuses the depletion of ozone of the earth in ihe atmosphere, enables harmful ultraviolet-B(UVB) to reaeh the surface of the earth more easily: The purpose of this study is to determine the harmful effect of UVB on the skin by observing coicurrently the morphologieal snd biochemical changes in the UVB irradiated skin.
OBJECTIVE
The animal used was the hairless mouse(Hr+/Kud) which are considered to be the most suitable for a UVB irradiation experiment. The Fluorescent sunlamp(Toshiba FL, 20SE, Toshiba electrie Co., Tokyo, Japan) was used as a source of UVB. METHOD: The skin of the back and ear was irradiated by an increasing doses of UVB. In morphological changes, the slteration in keratinocytes and Langerhans cells in cell number and morphology were observed. In biochemical changes, activities of tte superoxide dismutase and eatalsse, which scsvanges reactive oxygen species(O and H) producec in the skin by UVB irradistion were assayed. RESULT: Sunburn cells appeared st 60mJ/cm of UVB and increased in number in proportion to the UVB irradiation with dose dependent pattern. The Langerhans cell decreased in number in proportion to UVB irrsdiation in dose dependent manner(half maximum dose was 60mJ/cm), and was not found at 1J/cm. The morphological changes of the Langerhans cells, such as a loss of dendrites and granulation, were noticed at 60mJ/cm of UVB irradiation. The enzyme activity of catalase decreased in proportion to UVB irradiation. The enzyme activity of SOD was not changed by UVB irradiation, however, it significantly increased at 1000mJ/cm UVB irradiation.
CONCLUSION
This study suggest that UVB irradiation to the skin causes a reduction in the immune funetion and alters the normal biochemical function of the skin.