Cataract type in mouse exposed to moderate doses of ionizing radiation depends on mouse age at irradiation

Abstract

AbstractOne noxious agent for cataract formation is ionizing radiation (IR). For doses till or equal 2 Gy it is still unclear, whether opacification occurs and if, how cataract type depends on the animals age at irradiation. Wild‐type and heterozygous Ercc2+/‐ mice were whole‐body irradiated by 0.5 Gy, 1 Gy and 2 Gy of γ‐radiation (dose rate = 0.3 Gy/min), 10 weeks after birth (P70). Another cohort was exposed to 2 Gy, 2 days after birth (P2). All cohorts were investigated by optical coherence tomography (OCT) and eyes were collected for histology after death. OCT revealed frequent lens alteration in the mice irradiated at P2 and P70. These lesions were only subcapsular located in P70 mice and are dose‐dependent in size. Mice irradiated at P2 showed scattering structures within the posterior cortex, 8.5 mth after irradiation. At least 80% of the irradiated animals displayed at least mild posterior cortical cataracts. Histology of irradiated eyes (P70) unravelled the OCT‐detected lesions as cataractous accumulations of enlarged fibre cells, accompanied by subcapsular placed cells with nuclei. Lesions of P2 mice displayed no correlate to the in vivo data. Therefore, we conclude that IR leads to lens opacification in a dose‐dependent manner and its magnitude correlates strongly with age at irradiation. These results help to assess the sensibility of eye lenses to IR in case of exposure. The LDLensRad project received funding from Euratom in the framework of CONCERT, grant No 662287.