Activity of glucose-6-phosphate dehydrogenease and its correlation with inflammatory factors in diabetic retinopathy

This study aims to explore glucose-6-phosphate dehydrogenase (G6PD) activity in diabetic retinopathy (DR) and its correlation with inflammatory factors, elucidating the regulatory role of G6PD in DR pathology.

A total of 151 T2DM patients were divided into three groups: diabetes without retinopathy (DNR, n = 59), non-proliferative retinopathy (NPDR, n = 46) and proliferative retinopathy (PDR, n = 49). Plasma G6PD activity was measured by a Randox G6PD kit and compared between these groups. Then the G6PD activity was correlated with inflammatory cytokines and metabolic parameters in these patients. A STZ-induced diabetic rat model was established, G6PD activity was validated by western blot and immunofluorescence staining in the retina of this model.

Plasma G6PD activity decreased in the order of DNR, NPDR and PDR groups (P<0.01). G6PD activity was negatively correlated with IL-6, IL-8, TNF-α, cholesterol, and LDL (r = -0.1625, -0.1808, -0.1865, -0.1747, r = -0.1807, P<0.05). Multiple regression analysis showed TNF-α, IL-6, and LDL were independent related factors for G6PD. Logistic regression analysis showed G6PD, triglyceride, cholesterol, IL-8, TNF-α, and macular edema were influencing factors for T2DM with DR. Western Blot analysis indicated a significant reduction of G6PD expression in the retina, and immunofluorescence staining showed distribution of G6PD especially in the retinal endothelium cell decreased.

G6PD may play an important role in DR occurrence and progression, with decreased expression correlating closely with lipid metabolism and inflammatory factors.