Effect Of Antioxidant To Progression Of Diabetic Nephropathy In Diabetic Rat

Abstract

Reactive oxygen species play critical roles in the development and progression of diabetic nephropathy (DN). To evaluate the effect of antioxidant therapy on renal damage, we investigated the effect of green tea catechin on oxidative stress-induced renal cell damage in LLC-PK cells and DN induced by subtotal nephrectomy plus streptozotocin injection in rats, Antioxidant activities of 6 green tea catechins were evaluated by 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging activity test. Protective effect of (-)-epigallocatechin 3-O-gallate (EGCG) as a representative tea catechin against oxidative renal cell damage was measured in LLC-PK cells. EGCG showed the strongest DPPH radical scavenging activity and protected renal epithelial LLC-PK cells from oxidative damage in the dose-dependent manner. Hyperglycemia, proteinuria and the elevated lipid peroxidation levels were reduced by EGCG administration. The renal protein expressions related to diabetic nephropathy such as iNOS, COX-2, NF-κB, phosphorylated IκB-α, TGF-β1 and fibronectin were significantly decreased after EGCG treatment. In conclusion, EGCG has beneficial effects on DN by suppressing hyperglycemia and related oxidative stress in kidney.