CCL2 and macular retinal edema: At the same time, this study also found that the levels of VEGF, MCP-1, and ANGPTL4 in the two groups decreased after treatment, and the levels of VEGF, MCP-1, and ANGPTL4 in the observation group were lower than those in the control group, suggesting that intravitreal injection of aflibercept in the treatment of DR with macular edema can improve the cytokine levels in the aqueous humor.