CCL2 and diabetes mellitus: Photoreceptors comprise rod and cone cells and they are also involved in retinal inflammation through the secretion of proinflammatory proteins, including iLs (1α, 1β, 6, and 12), CXCLs (1 and 12a), CCL25, MCP-1/CCL2, and TNF-α in the mouse model of diabetes, resulting in retinal vascular permeability [330,331].