Intravitreous injection of PLGA microspheres encapsulating GDNFpromotes the survival of photoreceptors in the rd1/rd1 mouse

[摘要] Purpose: To evaluate the potential delay of the retinal degenerationin rd1/rd1 mice using recombinant human glial cell line-derivedneurotrophic factor (rhGDNF) encapsulated inpoly(D,L-lactide-co-glycolide) (PLGA) microspheres.Methods: rhGDNF-loaded PLGA microspheres were prepared using a waterin oil in water (w/o/w) emulsion solvent extraction-evaporation process.In vitro, the rhGDNF release profile was assessed using radiolabeledfactor. In vivo, rhGDNF microspheres, blank microspheres, ormicrospheres loaded with inactivated rhGDNF were injected into thevitreous of rd1/rd1 mice at postnatal day 11 (PN11). The extent ofretinal degeneration was examined at PN28 using rhodopsinimmunohistochemistry on whole flat-mount retinas, outer nuclear layer(ONL) cell counting on histology sections, and electroretinogramtracings. Immunohistochemical reactions for glial fibrillary acidicprotein (GFAP), F4/80, and rhodopsin were performed on cryosections.Results: Significant delay of rod photoreceptors degeneration wasobserved in mice receiving the rhGDNF-loaded microspheres compared toeither untreated mice or to mice receiving blank or inactivated rhGDNFmicrospheres. The degeneration delay in the eyes receiving the rhGDNFmicrospheres was illustrated by the increased rhodopsin positivesignals, the preservation of significantly higher number of cell nucleiwithin the ONL, and significant b-wave increase. A reduction of thesubretinal glial proliferation was also observed in these treated eyes.No significant intraocular inflammatory reaction was observed after theintravitreous injection of the various microspheres.Conclusions: A single intravitreous injection of rhGDNF-loadedmicrospheres slows the retinal degeneration processes in rd1/rd1mice. The use of injectable, biodegradable polymeric systems in thevitreous enables the efficient delivery of therapeutic proteins for thetreatment of retinal diseases.

[学科分类] 生物化学/生物物理