Detection of levels of VEGF and IL-6 in the aqueous humor of patients with diabetic retinopathy and its clinical significance

Abstract

Objective To explore the relationship between diabetic retinopathy (DR) and vascular endothelial growth factor (VEGF), interleukin-6 (IL-6) levels in the aqueous humor. Methods Aqueous humor samples were collected from diabetic patients with cataracts or without retinopathy, and aqueous humor samples from non-diabetic patients with cataracts were chosen as controls. The content of VEGF in the aqueous humor was determined by using the ELISA technique. Results The level of VEGF in the aqueous humor samples of diabetic patients without retinopathy (NDR), background diabetic retinopathy (BDR) and proliferative diabetic retinopathy (PDR) were (240.29± 26.14) pg/ml, (292.32± 58.43) pg/ml and (477.65± 90.08) pg/ml respectively. The level of IL-6 in the aqueous humor from NDR, BDR and PDR were (160.81± 33.40) pg/ml, (238.82±62.01) pg/ml and (389.42± 90.08) pg/ml respectively. The levels of VEGF and IL-6 in the aqueous humor from the control group were (140.56± 26.24) pg/ml, (82.74± 21.51) pg/ml respectively. Compared with the control,the level of VEGF and IL-6 in the aqueous humor of diabetic patients increased significantly (P<0.01). The level of VEGF and IL-6 in the aqueous of the NDR, BDR and PDR also increased significantly (P <0.01). The level of VEGF significantly correlated with the level of IL-6 in the aqueous humor (r=0.995, P<0.01). The level of VEGF and IL-6 in the aqueous humor also significantly correlated with the severity and prolongation of DR (r=0.869, P <0.01 ;r=0.865, P <0.01). Conclusions VEGF and IL-6 play active roles in the generation and development of DR, and the level of VEGF in the aqueous humor closely correlates with the level of IL-6 in the aqueous humor of diabetic patients. Key words: Vascular endothelial growth factor; Interleukin-6; Diabetic retinopathy