Abstract

SA.15.11

Systemic effect of unilateral in vivo exposure to UVR-B 300nm – bilateral cataractogenesis and elevated pro-inflammatory cytokines

Meyer L. M.^1,2, Löfgren S.², Wegener A.¹, Dong X.², Mody², Holz F. G.¹, Söderberg P. G.^2
1University Eye Hospital, University of Bonn, Bonn, Germany; ²Department of Clinical Neuroscience, Karolinska Insitutet, St Erik's Eye Hospital, Stockholm, Sweden

Objective: To investigate if unilateral in vivo UVR-B exposure of one eye affects the contralateral eye in a sympathetic, cataractogenic reaction and to determine serum levels of pro-inflammatory cytokines IL-1b, IL-6, and TNF-a following unilateral UVR-B exposure.
Methods: Eighty six weeks old female C57BL/6 mice were divided into four dose groups (n=20). Depending on dose group animals were unilaterally exposed in vivo to UVR-B for 15 minutes to 0/ 2/ 3/ or 4 times cataract threshold dose (MTD_2.3:16) UVR-B. The radiation output of the UVR- source had l_MAX at 302.6 nm with 4.5 nm [FWHM]. 48 hours following UVR-B exposure experimentally induced cataract was quantified as forward lens light scattering in the exposed and the contralateral not exposed lenses with a light dissemination meter (LDM meter). Evolution of cataract morphology was documented using grid and dark field illumination photography. Blood samples were taken from all animals via heart puncture. IL-1b, IL-6 and TNF-a serum concentration was quantified with ELISA.
Results: Exposed lenses scattered light higher than non-exposed lenses. The difference was significant at 2 & 4 MTD _2.3:16 exposure dose. Mean light scattering in contralateral lenses in 2/ 3/ 4 MTD group was increased as compared to the control group that had received identical treatment than the other groups but no radiation (95% CI for mean light scattering in contralateral eyes: 0 MTD=0.227±0.02 tEDC; 2 MTD=0.261±0.02 tEDC; 3 MTD=0.303±0.04 tEDC; 4 MTD=0.319±0.04 tEDC). Serum pro-inflammatory cytokine levels were increased with increasing UVR-B dose for IL-1b and IL-6 but not for TNF-a.
Conclusions: Unilateral UVR-B exposure increases light scattering also in the contralateral eye and triggers a systemic inflammatory response mediated by IL-1b and IL-6. Age related cataract is almost exclusively a bilateral event. Since a systemic inflammatory response might be an important factor in the pathogenesis of the disease our results might contribute new approaches to cataract research.

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