To evaluate the correlation between OCT changes and fundus autofluorescence (FAF) with immunohistochemistry (ICC) findings in an animal model of RP, the P23H rat and to investigate retinal and choroidal vascularization using fluorescein and indocianin green angiographyMethods
Twenty albino homozigous P23H line 1 rats aging from P18 to 27 months and wild-type albino Sprague-Dawley (SD rats) (2 and 11 months old) were used for this study. Normal pigmented Long Evans (LE) 2 months old were used to compare FAF findings. SLO imaging and OCT were acquired using an Spectralis system (Heidelberg Engineering, Germany). For checking FAF, fluorescence was excited using diode laser at 488 nm. Thickness measurements were evaluated avoiding the ones close to the optic nerve. ICC was performed to correlate with the findings of OCT and AF changesResults
During the course of P23H degeneration, the FAF pattern varied from not findings in young animals, some spotting at 2 months old to a mosaic of hyperfluorescent dots in the rats of 6 months or older. Retinal thicknesses diminished during the time. P23H rats showed great changes in morphology in advanced ages. Mean retinal thickness values varied from 189.88 μm at P60 to 58.15 μm at 27 months old. Retinal vascular plexus were diminished with time, and vessels exhibiting an abnormal, tortuous morphology could be observed.Conclusion
FAF is a non-invasive procedure that can detect changes in metabolic activity at the RPE in animal models of retinal degeneration in vivo. OCT and ICC show a good correlation. Retinal vascular plexus changes with aging.