Long-Term Ultraviolet A Eye Irradiation Causes Retina Denaturation in Mice

BACKGROUND: Long-term ultraviolet (UV) A eye irradiation in mice initiates the induction of photoaging. However, the changes in the eye due to long-term exposure to UVA radiation are still unclear. METHODS: Male C57BL/6j (control) and inducible nitric oxide synthase knockout (iNOS(-/-)) mice were used in this study. The eyes of the mice were locally exposed to UVA radiation for 12 months. RESULTS: The expression of iNOS, matrix metalloproteinase-2 (MMP-2), MMP-9, vascular endothelial growth factor, β-amyloid, and macrophages in the retina all increased after UVA irradiation. Furthermore, in the iNOS(-/-) mice, no retinal changes were induced by UVA eye irradiation. CONCLUSIONS: These results indicated that long-term UVA eye irradiation led to iNOS-induced denaturation of the retina; however, further studies are needed to confirm these findings.