Phototoxicity of Ultraviolet (UV) Radiation: Evaluation of UV-Blocking Efficiency of Intraocular Lens (IOL) Materials Using Retinal Cell Culture and in vitro Bioassays~!2009-06-08~!2010-02-10~!2010-03-26~!

Abstract

This work involves the evaluation of UV blocking efficiency of commercially available intraocular lens (IOL) materials using a retinal cell culture and a biological in vitro model that was developed in a previous study, as an effort to examine the sensitivity of this in vitro approach for evaluating toxicity of UV radiation on the retinal pigment epithelial cells. The human retinal pigment epithelial (RPE) cell line, ARPE-19, was cultured, and cells were irradiated with broadband UVB radiations at energy levels of 0.2 and 0.4 J/cm. Some treated cells were not shielded from the radiation while others were shielded using two thicknesses (0.9 and 1.5 mm) of IOL material. After irradiation, cellular viability, mitochondrial distribution, nuclei morphology, and phagocytotic activity were analyzed using the Alamar blue assay, Rhodamine 123 staining, the Hoechst assay, and a phagocytotic activity assay. The results demonstrate that UVB radiation can cause significant decreases in RPE cell viability as well as in phagocytotic activity. Also, the results show that UVB radiation can induce the degradation of DNA and mitochondria in cultured RPE cells. However, the two different thickness IOL material sheets (0.9 and 1.5 mm) showed very effective UV blocking ability, allowing no cellular damage at all. Thus, the finding suggest that these four assays together can be used as a sensitive, and meaningful in vitro biomarker method for evaluating toxicity of UV radiation on RPE cells, and also for examining IOL effectiveness.

Detrimental Effects of UVB on Retinal Pigment Epithelial Cells and Its Role in Age-Related Macular Degeneration

“…As discovered, UVB exposure does induce a dose-dependent decrease in phagocytotic activity in RPE cells. The same decrease in phagocytotic activity was also reported by Youn et al [ 45 ] after the application of 0.2 and 0.4 J/cm 2 UVB on ARPE-19, while DrRPE cells displayed suppressed phagocytotic activity after exposing the cells to 4.2 J/cm 2 UVB [ 33 ]. This is cause for concern as the renewal of the photoreceptor outer segments (POS) is key in maintaining vision.…”

“…However, immediately after irradiation, the morphology of mitochondria was shortened and no longer moving with very few branched mitochondria remaining within the cells [114]. Comparable conditions were also reported by Youn et al [45], whereby fewer, shorter, fragmented, and merged mitochondria were seen after UVB exposure.…”

“…A similar effect was also seen in ARPE-19 cells that were irradiated with UVB. The cells were seen to decrease in cell viability in proportion with the increase in the energy level [45]. This increase in cell death and DNA damage after irradiation is due to the ability of UVB in forming cyclobutane pyrimidine primers and pyrimidine-pyrimidone (6-4) photoproducts [46].…”

Oxidative Stress Measures of Lipid and DNA Damage in Human Tears

“…8 However, to our knowledge human studies showing UV-induced ocular surface oxidative stress are not found in the literature. This void in our knowledge base and the scientific literature is a barrier to progress in the field for development of viable effective methods to reduce or eliminate ocular disease induced by UV exposure.…”

Synthesis and Ultraviolet Absorption Characteristics of 4-Arylidene Isopinocamphones from a-Pinene

“…Nowadays, the increased ultraviolet radiation has been becoming one of the global environmental problems in recent years is very harmful to human health [1][2][3] , which leads to sunburn cells, premature skin aging, tanning, DNA and an increased risk for skin cancers [4][5][6][7][8][9][10][11][12] . Sensitive skin in the sun after continuous UV-B and UV-A radiation can damage DNA to decreased immunity and even cause skin cancer.…”