FIGURE 2.

Physiological changes associated with the development of DR. Hexosamine pathway, polyol pathway, PKC pathway and AGEs accumulation lead to the occurrence of oxidative stress. Oxidative stress, inflammation, neovascularization, neurodegeneration, NVU, and gut microbiota are all involved in the pathogenesis of DR. ROS, Nrf2, SOD, IL-1β, VEGF, CSGIII, LPS and other substances also directly or indirectly lead to the occurrence of DR, resulting in the appearance of Microaneurysm, Fibrotic membrane, and New blood vessels and so on in the retina. These factors are interrelated and thus contribute to the development of DR.