Avaliação do possível efeito antioxidante do arroz branco e do arroz parboilizado sobre o dano renal em ratos com diabetes induzido por estreptozotocina

Abstract

The antioxidant effect of diets supplemented with white rice and parboiled rice was investigated in the kidneys of rats with streptozotocin-induced diabetes (40 mg/kg, iv). These diets were offered after confirmed hyperglycemia 9 d after induction. Food consumption was monitored on a daily basis and body weight was determined weekly. The experimental groups (n=8) (control fed standard diet; control fed parboiled rice; control fed white rice; diabetic fed standard diet; diabetic fed parboiled rice; diabetic fed white rice), were anesthetized and exsanguinated before removal of kidneys, which were used to determine lipoperoxidation concentration (TBARS), enzymatic antioxidant activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) as well as non-enzymatic antioxidant levels of glutathione (GSH). Diabetes induced increase in lipid peroxidation (LPO), which was higher in the group treated with white rice (118% as compared to the control group and 26% as compared to the parboiled rice group). The white rice diet reduced SOD (30%), CAT (25%), GR (29%) activities and GSH (24%) levels as compared to the control group. The parboiled rice diet increased GPx (25%) and GSH (29%) values as compared to the control group. GSH values in diabetic rats were found to be higher in the parboiled rice group. Thus, rice consumption does not improve LPO in the renal tissue of diabetic rats, but parboiled rice improves antioxidant parameters much more than white rice does.