The role of metformin in the prevention of diabetic nephropathy in experimental type 2 diabetes

Abstract

Introduction and purpose. A number of landmark trials have demonstrated clear benefits of metformin therapy in the prevention of macrovascular outcomes. Nevertheless, there is a lack of robust evidence to suggest whether metformin therapy will have similar beneficial outcomes in one of the most serious type 2 diabetes-related renal microvascular complications known as diabetic nephropathy. The study aimed to evaluate the effects of ten-week metformin treatment on renal morphofunctional changes in rats with non-genetic type 2 diabetic nephropathy. Materials and methods. Starting at 3 weeks after unilateral nephrectomy, adult male Wistar rats were fed the high-fat diet for 5 weeks, and then successively received nicotinamide (230 mg/kg) and streptozotocin (65 mg/kg) intraperitoneally in 15-min interval. Results. Starting at 11 weeks after confirmation of diabetes, metformin treatment did not attenuate routine renal dysfunction markers such as creatinine, creatinine clearance and albuminuria compared to placebo-treated diabetic group, and glomerulosclerosis index and glomerular expression of type IV collagen didn't significantly change either. Nevertheless, level of urinary kidney injury molecule-1, considered to be the marker of tubular damage in diabetes, was significantly lower in metformin-treated animals. Moreover, reduction of tubulointerstitial lesion tended to be significant. Conclusions. Under conditions of diabetic nephropathy modeling, metformin has shown direct protective effects against diabetic tubular disturbance. To assess long-term renal outcomes of these findings, more pre-clinical studies and clinical trials are required.