Protective effects of luteolin on STZ-induced diabetic kidneys

AIM: To explore the protective effects of luteolin on the diabetic kidneys. METHODS: Male Sprague-Dawley rats were randomly divided into 5 groups: normal control group, diabetic model group and the groups of diabetic rats treated with luteolin at a low dose, a middle dose and a high dose. The diabetic model was induced by a single intraperitoneal injection of streptozotocin (STZ,65 mg/kg). Blood glucose, urine protein, the activity of superoxide dismutase and catalase in serum and kidney, and the content of malonaldehyde(MDA) in kidney were analyzed by biochemical methods. Western blotting was used to detect the protein expression of transforming growth factor-β₁(TGF-β₁) and plasminogen activator inhibitor-1(PAI-1) in the renal cortex. The morphological changes of the renal tissues were observed under microscope. RESULTS: Compared with diabetic model group, luteolin significantly reduced the level of blood glucose (P<0.01), the content of urine protein (P<0.01) and MDA (P<0.01) in the kidneys, and increased the activity of superoxide dismutase and catalase (P<0.01) in serum and kidneys in the diabetic rats. The protein levels of TGF-β₁ and PAI-1 in the renal cortex were dramatically decreased as the rats were treated with luteolin. CONCLUSION: Luteolin may exert an important protective effect on diabetic kidneys by relieving oxidative stress and inhibiting the protein expression of TGF-β₁ and PAI-1 in the renal tissues of STZ-induced diabetic rats.