Photoreceptor rescue of pigment epithelium-derived factor-impregnated nanoparticles in Royal College of Surgeons rats

PURPOSE: To investigate the protective effect of intravitreal injection of pigment epithelium-derived factor-impregnated nanoparticles (PEDF-NPs) against photoreceptor degeneration in Royal College of Surgeons (RCS) rats. METHODS: Three-week-old RCS rats received an intravitreal injection of PBS, blank NPs, PEDF (2.5 μg), or PEDF-NPs (2.5 μg). Eyes were assessed with morphological, immunohistochemical, and physiologic analysis over the following 8 weeks. Cell death was examined using the terminal deoxynucleotidyl transferase-mediated uridine 5′-triphosphate-biotin nick end labeling (TUNEL) assay. RESULTS: In RCS rats, the a- and b-wave amplitudes on electroretinograms in eyes treated with PEDF-NPs were greater than those in retinas receiving other treatment. Immunocytochemistry showed consistently greater opsin preservation in eyes treated with PEDF-NPs. A significantly higher number of photoreceptors and significantly fewer TUNEL-positive cells were present after treatment with PEDF-NPs, compared to PEDF-treated eyes. CONCLUSIONS: The results suggest that intravitreally injected PEDF-NPs delayed photoreceptor degeneration by inhibiting apoptosis in the RCS rat retina due to targeting and sustained release of PEDF.