Abstract
Purpose :
Investigation of unilateral UVR-B irradiation effects to the exposed eye in comparison to the unexposed contralateral eye in vivo in the mouse model. Characterization of inflammatory reactions which lead to cataract formation in the unexposed eye with a certain latency period. Identification of immunological pathways responsible for propagation of the radiation effect to the unexposed eye.
Methods :
Six-week-old C57Bl/6 mice (pigmented) and ABCA4 mice (albino) were unilaterally exposed in vivo to a triple threshold dose (9,4 kJ/m2 pigmented) and double threshold dose (6,5 kJ/m2 albino) of UVR-B. The other eye was covered with aluminium foil. UVR-B irradiation in the 300-nm wavelength region (UVR-B peak at 312nm) was performed in mydriasis using a Bio-Spectra system (Vilber Lourmat, Germany). After a latency period of 3 and 7 days following UVR-B exposure, morphological changes in the lenses were photographed with a Leica dark-field microscope. Thereafter lenses were fixed in 4 % Paraformaldehyde, embedded in paraffin, sectioned and stained with fluorescence coupled antibodies for substance P receptor, NKR-1 and DAPI for cell nuclei. All animal experiments were done according to the regulations of the German Tierschutzgesetz and the ARVO declaration of the use of animals in eye and vision research.
Results :
UVR-B exposure induced corneal edema anterior subcapsular cataract in the exposed eye after a latency period of 3 days. At day 7 a triangular-shaped opacity had developed in the area of anterior suture. After a latency period of 3 to 7 days, unexposed lenses showed opacities in the lens nucleus and also diffuse opacities in the anterior superficial suture of the lens. Histological examination revealed positive staining for NK-1 receptor in the corneal epithelium, the nuclear bow epithelium of the lens, the ciliary body epithelium and in the inner plexiform layer of the retina in pigmented animals. The albino mice additionally showed positive staining in the iris vessels which could be due to the absence of pigmentation.
Conclusions :
Unilateral UVR-B exposure of the eye affects the unexposed eye in a sympathetic reaction. To explain the inflammation in the contralateral eye, the role of substance p, and other neuro-inflammatory peptides needs further investigation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.