A Morphometric Study of Light-Induced Damage in Transgenic Rat Models of Retinitis Pigmentosa

Dana K. Vaughan, Sylvie F. Coulibaly, Ruth M. Darrow, Daniel T. Organisciak
2003 Investigative Ophthalmology and Visual Science  
PURPOSE. To determine relative susceptibility to, and regional variation of, light-induced retinal damage in two rhodopsinmutant rat models of retinitis pigmentosa, using slow-and fast-degenerating lines. METHODS. Transgenic S334ter (lines 4 and 9) and P23H (lines 2 and 3) rats were reared in dim cyclic light or darkness and then exposed to intense green light for 1 to 8 hours. Sections along the vertical meridian were collected for retinal morphology and photoreceptor morphometry 2 weeks
more » ... metry 2 weeks later. Unexposed transgenic and normal Sprague-Dawley rats served as the control. Mean outer segment lengths and outer nuclear layer thicknesses were analyzed as a function of position along the vertical meridian and as averages across that vector. RESULTS. Rapidly degenerating S334ter-4 retinas, reared in dim cyclic light, exhibited no light-induced damage, whereas retinas in the other sublines sustained damage within a sensitive region in the superior hemisphere. Light-induced damage always involved loss of outer segment membrane and photoreceptors. In some cases, the retinal pigment epithelium and inner nuclear layer were also affected. Potentiation of lightinduced damage by dark-rearing was increased by at least a factor of three, and in some sublines the sensitive region was enlarged to include the entire vertical meridian. CONCLUSIONS. A complex pattern of light-induced damage outcomes was identified in S334ter (sublines 4 and 9) and P23H (sublines 2 and 3) rats. The relative susceptibilities of each subline to damage by light were different, even within the same transgene, but consistent factors included a sensitive region in the superior hemisphere and potentiation by dark-rearing. (Invest Ophthalmol Vis Sci. 2003;44:848 -855)
doi:10.1167/iovs.02-0709 pmid:12556421 fatcat:l733hf24hrf3zp44kgectf5no4