Nephro-Protective Effect of Cortex Lycii Radicis Extracts in Streptozotocin- Induced Diabetic Rats

Abstract

Background: To evaluate the effects of aqueous Cortex Lycii Radicis (CLR) extracts on diabetic nephrology in a streptozotocin-induced diabetic nephropathy rat model, and to explore the underlying mechanisms of CLR action. Methods: We induced diabetes mellitus via a single intravenous streptozotocin injection (30 mg/kg) and subsequent high-fat diet for 3 weeks in male Sprague Dawley rats. Rats that developed diabetes mellitus were randomized to receive normal saline (vehicle, n=10), low-dose CLR (15 g/kg/day, n=10), or high-dose CLR (30 g/kg/day, n=10), and rosiglitazone (2 mg/kg/day, n=10) daily for 8 weeks. In addition, 10 normal rats served as controls. Kidneys were removed to evaluate histological renal glomeruli alterations using periodic acid–Schiff (PAS) staining. Results: Fructosamine, and blood urea nitrogen concentrations, as well as the urinary albumin excretion rate (AER), were increased in vehicle-treated diabetic rats compared to control rats (P<0.05). These parameters decreased upon CLR treatment, particularly at low-dosage CLR (P<0.05). Morphologic observations showed that high-dosage CLR markedly attenuated diabetes-associated renal injury. The renal protective effects of CLR may be mediated by downregulation of cytokine expression, including TGF-α and interleukin 6. Conclusion: CLR accelerates functional and histological kidney recovery, thereby delaying diabetic nephropathy progression. Therefore, it may be a novel therapeutic approach for the treatment of diabetic nephrology. Keywords: Chinese medicine, Cortex Lycii Radicis, diabetic nephropathy, traditional.