Lithospermic acid B ameliorates the development of diabetic nephropathy in OLETF rats

Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 diabetic animal models. In the present study we investigated the effects of LAB on the prevention of diabetic nephropathy in type 2 diabetic Otsuka Long-Evans-Tokushima Fatty (OLETF) rats. LAB (20 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. Treatment of OLETF rats with LAB had little effects on body weight and blood glucose levels. Treatment with LAB resulted in significant reduction in blood pressure. LAB markedly attenuated albuminuria and significantly lowered levels of lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta (TGF-beta1) expression in renal tissues of OLETF rats. In addition, LAB inhibited the progression of glomerular hypertrophy, mesangial expansion, and expansion of the extracellular matrix in the renal cortex. Collectively, these results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing blood pressure, oxidative stress, and MCP-1 expression. Our results suggest that LAB might be a new therapeutic agent for the prevention of nephropathy in type 2 diabetes.