ObjectiveTo study the changes and correlation of cytokines in aqueous humor before and after intravitreal injection of conbercept (IVC) treatment in patients with proliferative diabetic retinopathy (PDR).MethodsA prospective clinical study. From March to December 2019, 36 patients (42 eyes) of PDR patients treated with IVC combined with pars plana vitrectomy (PPV) (the observation group) and 27 patients (31 eyes) underwent cataract surgery in the same period (control group) in Department of Ophthalmology of the First Affiliated Hospital of Guangzhou University of Chinese Medicine were included in this study. Before PPV 5-7 days, IVC treatment was performed, and the aqueous humor were extracted during IVC and second-stage PPV in the observation group. The aqueous humor was extracted during cataract surgery in the control group. Luminex assay was used to detect VEGF-A, placental growth factor (PLGF), platelet-derived growth factor-AA (PDGF-AA), platelet-derived growth factor-BB (PDGF-BB), angiopoietin-like protein 4 (ANGPTL4), IL-6, IL-8, IL-1β, monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α) cytokine expression. For normally distributed data, the independent sample t test was used for comparison between two independent samples; for non-normally distributed data, the Wilcoxon rank sum test was used for comparison between two independent samples. The correlation analysis used Spearman rank correlation test.ResultsBefore IVC treatment, the concentrations of VEGF-A, PLGF, PDGF-AA, ANGPTL4, IL-6, IL-8, MCP-1 and ICAM-1 in the aqueous humor of PDR patients were significantly higher than those in the control group (P＜0.05). After IVC treatment, the concentration of VEGF-A in the aqueous humor was significantly lower than that before treatment, and the concentrations of ANGPTL4 and IL-8 were significantly higher than those before treatment (P＜0.05). There were no significant differences in the concentrations of PLGF, PDGF-AA, PDGF-BB, IL-6, IL-1β, MCP-1, ICAM-1 and TNF-α before and after IVC treatment (P＞0.05). Before IVC treatment, the concentration of VEGF-A was positively correlated with PLGF, PDGF-AA, PDGF-BB, ANGPTL4, IL-6, IL-8, MCP-1 and TNF-α (P＜0.05).ConclusionsIVC treatment can reduce the concentration of VEGF-A and increase the concentrations of ANGPTL4 and IL-8 in aqueous humor in PDR patients before PPV.