DIFFERENTIATION OF HISTOLOGICAL CHANGES INDUCED BY ULTRAVIOLET-A AND -B LIGHT IRRADIATION IN THE AURICULAR SKIN AND EYE OF ALBINO BALB/C MICE

Abstract

We differentiated the histological changes induced by irradiation with ultraviolet-A (UVA) and -B (UVB) light in the auricular skin and eye in female Balb/c mice. The animals were irradiated (1.30mW/cm2) with UVA for 1, 3, or 7 days, or with UVB for 2, 4, or 8 hr or 1, 3, or 7 days. Irradiation with UVA and UVB induced inflammation in the auricular skin, but the early changes were different. UVA-irradiation caused neutrophil infiltration without apparent edema, while UVB-irradiation induced marked edema with degranulation of mast cells and enlargement of endothelial cells of blood vessels in the dermis. These lesions became more severe with time progression, with the auricle showing partial necrosis at the later stage. UVA-irradiation caused retinal degeneration with vesiculation of the photoreceptor outer segment as an early change. In contrast, UVB-irradiation initially induced degeneration of corneal cells, followed by degeneration of lens epithelial cells. Although the incidence of retinal changes induced by UVB-irradiation was much lower than that by UVA, the number of migrating cells in the photoreceptor segments with UVB significantly increased at the later stage.