Relationship Between Polymorphism Of Pro198Leu In GPx-1 Gene And Diabetic Microvascular Complications With Type 2 Diabetes

Background and Objective: Oxidative stress may play an important role in the pathogenisis of type 2 diabetes and its chronic complications. Glutathione peroxidase-1(GPx-1) is one of the most important antioxidant enzyme in defense against oxidative stress.There were studies showed that Pro198 Leu polymorphism in GPx-1 gene may influence the activity of GPx-1,so we speculate that Pro198 Leu polymorphism may play an important role in the pathogenisis of type 2 diabetes and its chronic complications. Studies have confirmed that Pro198 Leu polymorphism increased the risk of cardiovascular disease in patients with type 2 diabetes, but its relationship with microvascular lesions in type 2 diabetes are still unclear.This study aimed to investigate the relationship between GPx-1 gene Pro198 Leu polymorphism and diabetic microvascular complications(diabetic nephropathy and diabetic retinopathy) in Chinese Han patients with type 2 diabetes.Methods: 1028 patients with type 2 diabetes(T2DM) and 170 subjects with normal glucose tolerance(NGT) in Jiangxi region of China were enrolled in this study. According to 24 hours microalbuminuria,urinary albumin creatinine ratio, serum creatinine and endogenous creatinine clearance,the T2 DM patients were divided into two groups: without nephropathy group(NDN) and with nephropathy group(DN);According to the fundus examination, the T2 DM patients were divided into two groups: without retinopathy group(NDR) and with retinopathy group(DR). The genotype and allele frequencies of Pro198 Leu polymorphism in GPx-1 gene were detected by the polymerase chain reaction–restricted fragment length polymorphisms(PCR-RFLP) method.Results: 1. There are three genotypes CC,CT,TT of GPx-1 gene Pro198 Leu polymorphism in NGT group and T2 DM group. The differences There were no statistically significant differences in genotype and allele frequencies of Pro198Leu polymorphism between NGT group and T2 DM group(P>0.05). 2. There were statistically significant differences in genotype and allele frequencies of Pro198 Leu polymorphism between NDN group and DN group(P<0.05). 3. There were statistically significant differences in genotype and allelic frequencies of Pro198 Leu polymorphism between NDR group and DR group(P<0.05).Conclusions: 1. This study indicated that Pro198 Leu polymorphism in GPx-1 gene was associated with diabetic nephropathy and diabetic retinopathy in Chinese Han patients with type 2 diabetes. 2. Patients with T allele in the genotype(CT and TT) had higher incidences of DN and DR, which suggested that allele T may be a risk factor for diabetic microangiopathy.