Oxidative stress and its association with TNF-α-308 G/C and IL-1α-889 C/T gene polymorphisms in patients with diabetes and diabetic nephropathy

Diabetic nephropathy is one of the major complications of type 2 diabetes and it is currently the leading cause of end-stage renal disease. The stimulus for the increase in inflammation in diabetes is still under investigation; however, reactive oxygen species might be a primary source. This study was conducted in four groups in West Indian population: control (235), type 2 diabetes (DM) (214), nephropathy with diabetes (DN) (188) and nephropathy without diabetes (NDN) (196). Oxidative stress markers such as malondialdehyde (MDA), glutathione (GSH), superoxide dismutase and catalase were measured in all the groups. TNF-α-308 G/C and IL-1α-889 C/T polymorphisms were analyzed using PCR-RFLP method. Correlations between genotype frequency and the level of oxidative stress markers were examined. MDA was significantly increased in the patient group in comparison to control group. GSH and SOD were significantly decreased in the patient group in comparison to control group. There was no significant difference observed in genotype frequency of TNF-α in the patient group compared with control group. IL-1α-889 C/T polymorphism may be associated with diabetic nephropathy. Moreover there was no association of TNF-α-308 G/C polymorphism with diabetic nephropathy in West Indian population. The higher serum levels of oxidative stress markers in diabetic patients with nephropathy suggest the possible role of oxidative stress.