Autophagy Impairment in Retinal Ganglion Cells Following Hypoglycemia in Mice.

(1) Background: Diabetic retinopathy (DR), caused by hypo- and hyperglycaemia, is the leading cause of blindness. Hypoglycemia induces endoplasmic reticulum stress and retinal cell death in mice, and low-glucose conditions induce macroautophagy/autophagy defects in 661W photoreceptor cells and retinal explants. Very few studies have analyzed the effect of hypoglycemia on retinal autophagy, so we decided to fill this gap. (2) Methods: We use C57BL/6 and GFP-LC3 mice and isolated retinal ganglion cells (RGCs) from both mouse models to study the autophagy process. (3) Results: Intraocular injection of rapamycin and 5 h hypoglycemia showed an increase in autophagosomes formation, specifically in the RGCs. Isolated GFP-LC3 RGCs showed an increase in autophagosome formation under low-glucose conditions. In contrast, infection of isolated C57BL/6 RGCs with the RFP-GFP-LC3 lentivirus revealed a defect in autophagosome/lysosome fusion under these conditions. (4) Conclusions: This study showed that 5 h hypoglycemia induces autophagosomes formation in mouse RGCs; however, a defect in the fusion process inhibits the protective effect of autophagy. Therefore, modulating both autophagic and apoptotic pathways might be important to avoid complications associated with DR.