title: Activation of autophagy in a rat model of retinal ischemia following high intraocular pressure.
abstract: Acute primary open angle glaucoma is an optic neuropathy characterized by the elevation of intraocular pressure, which causes retinal ischemia and neuronal death. Rat ischemia/reperfusion enhances endocytosis of both horseradish peroxidase (HRP) or fluorescent dextran into ganglion cell layer (GCL) neurons 24 h after the insult. We investigated the activation of autophagy in GCL-neurons following ischemia/reperfusion, using acid phosphatase (AP) histochemistry and immunofluorescence against LC3 and LAMP1. Retinal I/R lead to the appearance of AP-positive granules and LAMP1-positive vesicles 12 and 24 h after the insult, and LC3 labelling at 24 h, and induced a consistent retinal neuron death. At 48 h the retina was negative for autophagic markers. In addition, Western Blot analysis revealed an increase of LC3 levels after damage: the increase in the conjugated, LC3-II isoform is suggestive of autophagic activity. Inhibition of autophagy by 3-methyladenine partially prevented death of neurons and reduces apoptotic markers, 24 h post-lesion. The number of neurons in the GCL decreased significantly following I/R (I/R 12.21±1.13 vs controls 19.23±1.12 cells/500 µm); this decrease was partially prevented by 3-methyladenine (17.08±1.42 cells/500 µm), which potently inhibits maturation of autophagosomes. Treatment also prevented the increase in glial fibrillary acid protein immunoreactivity elicited by I/R. Therefore, targeting autophagy could represent a novel and promising treatment for glaucoma and retinal ischemia.
authors.affiliation: Neuroscience Institute of the Cavalieri Ottolenghi Foundation, Orbassano, Torino, Italy. antonio.piras@unito.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Piras
authors.forename: Daniele
authors.initials: D
authors.lastname: Gianetto
authors.forename: Daniele
authors.initials: D
authors.lastname: Conte
authors.forename: Alex
authors.initials: A
authors.lastname: Bosone
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vercelli
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects / Q000473:pathology; D001343:Autophagy / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D002452:Cell Count; D015195:Drug Design; D004705:Endocytosis / Q000187:drug effects; D007429:Intraocular Pressure / Q000187:drug effects; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology* / Q000517:prevention & control; D012160:Retina / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000473:pathology; D013997:Time Factors
chemical_list: D000135:Acid Phosphatase; D000225:Adenine; D053148:Caspase 3; D008869:Microtubule-Associated Proteins; D018696:Neuroprotective Agents; C526109:Anxa3 protein, rat; C025946:3-methyladenine