Environmental light intensity determines the temporal progression of retinal degeneration in rd10 mice

Abstract

AbstractThe rd10 mouse is a model of autosomal recessive retinitis pigmentosa (RP). This animal model carries a mutation in the Pde6b gen that generates a progressive loss of photoreceptors which leads to complete blindness. The aim of this study was to evaluate the effect of environmental light intensity on the degenerative process of the rd10 model. Three rd10 mice groups have been exposed from birth to P30 to different environmental light intensities: low (5 lux), medium (50 lux) and high (300 lux) intensity. Age‐matching C57BL/6J mice were used as controls. At the end of the experimental procedure, retinal function was assessed by electroretinography (ERG) and optomotor test. In addition, OCT images, hematoxylin staining, and immunohistochemistry were performed to analyze the structural integrity of the retinas of the three experimental groups. The rd10 mice housed at 5 lux intensity showed better functional response that the rd10 mice maintained at 50 or 300 lux, exhibiting significantly higher amplitudes in a‐ and b‐waves, as well as higher visual acuity. In the same line, the rd10 mice at 50 lux presented higher responses than the mice at 300 lux. Furthermore, the thickness of the ONL showed differences between the three rd10 groups. As the light intensity is lower, the thickness of the measured ONL is greater. These findings correlated with the morphology of the cones where better‐preserved photoreceptor morphology was found in the dystrophic animals housed at 5 lux. No significant differences were found between normal C57BL/6J animals kept at different light intensities. Environmental light intensity accelerates or delays the degeneration in rd10 mice. These data indicate that light intensity is a key factor to consider in studies carried out in retinal degenerative animal models, determining the temporal progression of the disease.MINECO‐FEDER BFU2015‐67139‐R, RETICS‐FEDER RD16/0008/0016, Prometeo 2016/158, ACIF/2016/055, FPU16/04114.