Retinal Astrocytes and Microglia Activation in Diabetic Retinopathy Rhesus Monkey Models

PURPOSE To assess the retinal neurodegeneration in type-1 diabetes mellitus (T1DM) and type-2 diabetes mellitus (T2DM) rhesus monkeys, and to investigate whether alterations of glial cells occur in the early stage of diabetic retinopathy (DR). MATERIAL AND METHODS T1DM rhesus monkeys were established by daily intravenous injections of streptozotocin (STZ, 25 mg/kg body weight) in citrate buffer (pH 4.5) for 5 days, while T2DM rhesus monkeys were induced by feeding with high-fat diet. The period of DR in rhesus monkeys was evaluated by fundoscopy and optical coherence tomography (OCT). Afterward, the morphological changes of inner neurons and glial cells in the retina were detected by immunofluorescence (IF). RESULTS When compared with the control groups, no difference was observed in both T1DM and T2DM by fundus photographs, while slight exudation and effusion in the blood vessels of retina of rhesus monkeys were found by OCT in DM rhesus monkeys. In addition, the expression of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule (Iba1) were significantly increased in both T1DM (P