The current status and progress of the pathological changes and related molecular mechanisms of neuroretinal injury in diabetic retinopathy

Abstract

The neuroretinal injuries of diabetic retinopathy (DR) include retinal neuronal damage and reactive gliosis, both of which are induced by hyperglycemia and presented as early features of DR. They promote to develop mutually and accelerate the progression of DR. The molecular mechanisms study of neuronal damage mainly focuses on the alterations of extracellular environment and related signaling pathways, include inflammation, oxidative stress, endoplasmic reticulum stress, the formation of advanced glycation end products, glutamate toxicity and so on. These alterations mainly result in neuronal apoptosis and autophagy. The damaged neurons activate the glial cells with apparent changes in morphology, cell counts and the level of intracellular protein expression. In non-proliferative DR, glial cells are moderately hypertrophic and slightly increased in numbers. In proliferative DR, there is a significant rise in glial cell number with enhanced level of inflammatory factors and vascular active substances which lead a further neuronal damage. Signaling pathways of extracellular signal-regulated kinase 1/2, c-Fos and p38 mitogen-activated protein kinase are associated with their activation. Researches on the molecular mechanisms and signaling pathways of the DR will promote controlling the DR progression at the cellular level. Key words: Optic nerve injuries; Diabetic retinopathy/pathology; Apoptosis; Autophagy; Review