Bone marrow mesenchymal stem cells ameliorated kidney fibrosis by attenuating TLR4/NF-κB in diabetic rats

Diabetic nephropathy (DN) is a chronic inflammatory complication of diabetes mellitus, which becomes the most common cause of end-stage renal disease (ESRD). Recently, bone marrow mesenchymal stem cells (BMSCs) are considered as a promising therapy for DN. However, the protective mechanism of BMSCs on DN remains unclear. This study was done to explore the effect of a bone marrow stromal cell (BMSCs) transplant on DN rats and rat glomerular mesangial cells in high-glucose concentration. Diabetic rats were induced by a single intraperitoneal injection of streptozotocin (STZ) 65 mg/kg, then 4 × 106 BMSCs were transplanted in diabetic rats as the treatment group. Six weeks after BMSCs transplantation, blood serum creatinine (Scr) and blood urea nitrogen (BUN) were used to test renal function. Renal pathological examination was observed by HE staining, Masson staining, PAS staining and immunohistochemistry. The results demonstrated that BMSCs could dramatically improve renal function and collagen accumulation by reducing Scr, BUN, collagen I and IV expression and histopathological abnormalities in the diabetic kidneys. Furthermore, BMSCs could significantly attenuate the expression of TLR4/NF-κB and MCP-1 in vitro and in vivo (P < 0.05, vs diabetic groups). This study reported a novel finding that BMSCs play a protective role in inhibition of inflammatory and fibrotic cytokines by down-regulating TLR-4/NF-κB expression under diabetic condition.