VEGFA and diabetic retinopathy: Regarding diabetic retinopathy, previous studies have reported that increased endothelial/pericyte ratio [12], subretinal accumulation of activated microglia/macrophages [13], increased vascular endothelial growth factor (VEGF) production in certain ocular tissue [14], and increased number of acellular capillaries [15], known as early histological changes of diabetic retinopathy, were confirmed in GK rats.