Evidence has accumulated suggesting that various inflammatory cytokines are involved in the progress of diabetic retinopathy (DR), but there are few studies concerning the relationship between individual cytokines levels in the aqueous humor (AH) and the severity of DR. This study aimed to explore the differences of interleukin (IL)-23, IL-17, IL-10 and transforming growth factor (TGF)-β in AH form patients with different proliferative stages of DR.
From June 2016 to June 2019, patients for senile cataract surgery were enrolled with the informed consent. All cases were graded into 4 groups: the control group (patients without diabetes), non-retinopathy (NDR) group (diabetic patients without retinopathy), non-proliferative diabetic retinopathy (NPDR) group, and proliferative diabetic retinopathy (PDR) group. The concentrations of IL-23, IL-17, IL-10, and TGF-β in AH were measured using ELISA and compared them within four groups by ANOVA.
In this study, 20 (28.57%), 18 (25.71%), 17 (24.29%), and 15 (21.43%) patients were included in the control, NDR, NPDR, and PDR groups, respectively. There had no significant differences in demographic characteristics (P > 0.05). Comparison of these cytokines within four groups revealed: the IL-23 level was increased in NDR group initially and raised along with the progression of DR (P < 0.01). The IL-17 level was significantly higher in NPDR and PDR groups compared to NDR and the control groups, and positively correlated with more-severe DR (P < 0.01). By contrast, The IL-10 level was significantly lower in diabetic patients than in non-diabetic controls, and decreased as the severity of DR increased (P  0.05).
The over-expression of IL-23 and IL-17 in AH might have a synergistic effect on the pathogenesis well before the proliferative stage, and was typical positively correlated with the severity of DR. These results offer a novel early therapeutic target for DR.