Curcumin alleviates liver oxidative stress in type 1 diabetic rats

The aim of the present study was to determine the effects of curcumin on antioxidants using a rat model of type 1 diabetes. Seven-week-old male Sprague-Dawley rats were injected with Streptozotocin (STZ) intraperitoneally to induce this model, and then treated with 1.0% curcumin (weight ratio) mixed in their diet for 21 days. The present study included three groups: Control group (NC), diabetic rat model group (DC) and a curcumin treated group (Diab-Cur). The results demonstrated that curcumin treatment markedly decreased the blood glucose levels, plasma malondialdehyde concentration and plasma activity of glutathione peroxidase (GSH-Px) and catalase (CAT); however, it increased the plasma superoxide dismutase (SOD) and insulin levels. Curcumin treatment increased the expression of the CAT, GSH-Px, HO-1 and norvegicus NAD(P)H quinone dehydrogenase 1, and decreased the SOD1 expression, which, led to a diminished oxidative stress status. In addition, curcumin treatment significantly increased the protein expression of Keap1 in the Diab-Cur group when compared with the DC group, decreased cytosolic concentrations of Nrf2 while increasing nuclear accumulation of Nrf2. The results provide evidence that oxidative stress in the STZ-induced diabetic rat model may be attenuated by curcumin via the activation of the Keap1-Nrf2-ARE signaling pathway, as evidenced by a decrease in the blood glucose concentration and an increase in the transcription of several antioxidant genes.