Intravitreous injection of PLGA microspheres encapsulating GDNF promotes the survival of photoreceptors in the rd1/rd1 mouse.
OBJECTIVE
To evaluate the potential delay of the retinal degeneration in rd1/rd1 mice using recombinant human glial cell line-derived neurotrophic factor (rhGDNF) encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) microspheres.


METHODS
rhGDNF-loaded PLGA microspheres were prepared using a water in oil in water (w/o/w) emulsion solvent extraction-evaporation process. In vitro, the rhGDNF release profile was assessed using radiolabeled factor. In vivo, rhGDNF microspheres, blank microspheres, or microspheres loaded with inactivated rhGDNF were injected into the vitreous of rd1/rd1 mice at postnatal day 11 (PN11). The extent of retinal degeneration was examined at PN28 using rhodopsin immunohistochemistry on whole flat-mount retinas, outer nuclear layer (ONL) cell counting on histology sections, and electroretinogram tracings. Immunohistochemical reactions for glial fibrillary acidic protein (GFAP), F4/80, and rhodopsin were performed on cryosections.


RESULTS
Significant delay of rod photoreceptors degeneration was observed in mice receiving the rhGDNF-loaded microspheres compared to either untreated mice or to mice receiving blank or inactivated rhGDNF microspheres. The degeneration delay in the eyes receiving the rhGDNF microspheres was illustrated by the increased rhodopsin positive signals, the preservation of significantly higher number of cell nuclei within the ONL, and significant b-wave increase. A reduction of the subretinal glial proliferation was also observed in these treated eyes. No significant intraocular inflammatory reaction was observed after the intravitreous injection of the various microspheres.


CONCLUSIONS
A single intravitreous injection of rhGDNF-loaded microspheres slows the retinal degeneration processes in rd1/rd1 mice. The use of injectable, biodegradable polymeric systems in the vitreous enables the efficient delivery of therapeutic proteins for the treatment of retinal diseases.
Andrieu-Soler
Charlotte
C
INSERM, U598, Paris, France.
Aubert-Pouëssel
Anne
A
Doat
Marc
M
Picaud
Serge
S
Halhal
Mounia
M
Simonutti
Manuel
M
Venier-Julienne
Marie-Claire
MC
Benoit
Jean-Pierre
JP
Behar-Cohen
Francine
F
D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers; D004596:Electroretinography; D019084:Fluorescent Antibody Technique, Indirect; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000008:administration & dosage*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007267:Injections; D019344:Lactic Acid; D051379:Mice; D008809:Mice, Inbred C3H; D008817:Mice, Mutant Strains; D008863:Microspheres; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011994:Recombinant Proteins / Q000008:administration & dosage; D012162:Retinal Degeneration / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D012243:Rhodopsin / Q000378:metabolism; D014822:Vitreous Body
D000943:Antigens, Differentiation; D004337:Drug Carriers; D051100:Glial Cell Line-Derived Neurotrophic Factor; D005904:Glial Fibrillary Acidic Protein; D011108:Polymers; D011994:Recombinant Proteins; C036763:monocyte-macrophage differentiation antigen; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D012243:Rhodopsin