Effects of thiamine treatment on oxidative stress in experimental diabetes

Hyperglycemia, oxidative stress and hyperlipidemia are features of diabetes mellitus. Thiamine has beneficial effects on carbohydrate metabolism and it was proposed that this vitamin has antihyperlipidemic and antioxidant effects. Our aim was to investigate the effects of thiamine on oxidative stress and metabolic changes in streptozotocin (STZ) induced diabetic rats.

Diabetes was induced by a single intraperitoneal injection of STZ. Thiamine (6 mg/kg) was added to drinking water for five weeks. The rats were divided into four groups: control rats; thiamine treated control rats; diabetic rats; thiamine treated diabetic rats. Plasma and tissue malondialdehyde (MDA) levels were measured by high-performance liquid chromatography and spectrophotometry, respectively. Paraoxonase (PON) and arylesterase (AE) activities were measured with spectrophotometric methods, and erythrocyte superoxide dismutase (SOD) and blood glutathione peroxidase (GSH-Px) activities were determined using commercial kits.

Thiamine treatment reduced plasma and tissue MDA levels, serum glucose, total cholesterol and triglyceride levels, and increased serum high density lipoprotein- cholesterol and insulin levels, serum PON and AE, erythrocyte SOD and blood GSH-Px activities.

Thiamine significantly improves oxidative stress and has hyperinsulinemic and antihyperlipidemic effects so we suggest that thiamine might be used as a supportive therapeutic agent in diabetes (Tab. 2, Fig. 3, Ref. 53).