The relationship of serum 8-hydroxydeoxyguanosin to diabetic retinopathy

Objective To investigate the relationship of the levels of serum 8-hydroxydeoxyguanosin (8-OHdG) to diabetic retinopathy (DR) in subjects with type 2 diabetes (T2DM).Methods The patients were classified into groups according to retinopathy (no signs of diabetic retinopathy [DM],nonproliferative diabetic retinopathy [NPDR],and proliferative diabetic retinopathy [PDR]).The concentration of serum 8-OHdG were measured with enzyme-linked immunosorbent assay (ELISA) in all 49 patients with diabetes mellitus and 22 normal control subjects.The correlation between 8-OHdG and diabetic retinopathy were analyzed in all patients with T2DM.Results The concentration of serum 8-OHdG in patients with T2DM were significantly higher than those in the control subjects (Willcoxon W Test,Z =-6.70,P =0.00; Mean Rank of T2DM group and normal control subjects are 47.00 and 11.50 respectively).There was statistical difference in the levels of serum 8-OHdG in the PDR,NPDR,and DM groups (Kruskal Wallis Test,x2=59.50,P =0.00).The levels of serum 8-OHdG was much higher in the patients with PDR than that in patients with diabetes without retinopathy and with NPDR,The concentration of serum 8-OHdG was higher in the patients with NPDR than that in patients with diabetes without retinopathy.The degree of 8-OHdG was correlated with the degree of DR (Spearman correlation coefficients=0.94,P =0.00).Conclusions The elevated serum 8-OHdG may be one of probable risk factors in the diabetic retinopathy in the patients with T2DM. Key words: Type 2 diabetes mellitus;  8-hydroxydeoxyguanosin;  Diabetic retinopathy