Mechanisms of Protective Effect of Ramulus Mori Polysaccharides on Renal Injury in High-Fat Diet/Streptozotocin-Induced Diabetic Rats

Background: Diabetic nephropathy (DN) is the most important complication of diabetes and the most common cause of end-stage renal disease (ESRD). Aims: A recent study established that the Ramulus mori polysaccharides (RMP) exert antioxidant effects on DN in rats. Methods: The diabetic rats which induced by high-fat diet and streptozotocin injection were orally administered RMP by doses of 250, 500 and 1000 mg/kg daily for 8 weeks. The effects of RMP on hyperglycemia and other biochemical changes were examined in the sera and kidney tissues. Additionally, the pathological and ultrastructural changes and expressions of nuclear-factor kappa B (NF-κB) and transforming growth factor-ß1 (TGF-ß1) were assessed. Results: The results revealed that the serum levels of blood glucose, total cholesterol (TC) and triglycerides (TG) were significantly decreased by RMP. Furthermore, the blood urea nitrogen (BUN), serum creatinine (SCr) and 24-hour urine protein levels in the RMP-medicated rats were lower than those in untreated diabetic rats. Moreover, treatment of the DN rats with RMP normalized all biochemical changes, including the malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels in the serum and kidney tissues. In contrast, the protein expression levels of NF-κB and TGF-ß1, which were enhanced in the kidneys of DN rats, were reduced by RMP. Conclusion: These results suggest that RMP improving the renal function of diabeitc rats possibly via its ameliorating antioxidant activities