Protective Effects of the Total Coumarin Fraction of Urtica dentata on Experimental Diabetic Nephropathy In Vitro and In Vivo.

We previously reported that total coumarins, the major active components of Urtica dentata Hand, exhibited substantial protection against the development of autoimmune diabetes. Diabetic nephropathy is one of the most serious complications of diabetes and is closely correlated with end-stage renal disease. We used the rat glomerular mesangial cell line (HBZY-1) and streptozotocin-induced diabetic rats to investigate the potential protective effects and mechanisms of total coumarins on diabetic renal disease. Our data revealed that total coumarins inhibited high glucose-induced HBZY-1 cell proliferation and hypertrophy, and produced its effects through downregulating transforming growth factor-β1, connective tissue growth factor, and toll-like receptor 4 activation. Consistent with those findings, total coumarins administration in a diabetic model had anti-renal lesion effects in vivo. Total coumarins, at a dose of 50 or 100 mg/kg: 1) significantly increased body weight; 2) ameliorated morphological evidence of renal pathology; 3) decreased blood levels of glucose and urea nitrogen; 4) decreased albuminuria and serum creatinine; and 5) reduced protein and gene levels of transforming growth factor-β1, connective tissue growth factor, and toll-like receptor 4 in the kidneys. These results support the view that total coumarins treatment can be substantially renoprotective in DN. Georg Thieme Verlag KG Stuttgart · New York.