Increased Expression of Toll-Like Receptor 2 in Rat Diabetic Nephropathy

Background/Aims: Inflammation is implicated in the pathogenesis of diabetic nephropathy (DN). This study examined the role of Toll-like receptor 2 (TLR2) in the progression of renal injury in a model of rat DN. Methods: DN was induced by intravenous injection of streptozotocin and rats were sacrificed at week 2, 4 and 8. Functional and pathologic markers, inflammatory infiltration, expression of TLR2, MCP-1, MyD88, HSP70, HMGB1 and activation of NF-kappa B were assessed. The effects of glucose on the expression of TLR2 by renal tubular epithelial cells were also examined in vitro. Results: The expression of TLR2 mRNA and protein level was significantly upregulated in the kidneys of diabetic rats (p < 0.01), which was associated with increased renal expression of MyD88 and MCP-1, activation of NF-kappa B and infiltration of macrophages. The expression of HSP70 and HMGB1, endogenous ligands of TLRs, was also significantly upregulated in the kidneys of diabetic rats. In human renal biopsy of DN, there was prominent expression of TLR2 in both the glomeruli and tubulointerstitium. In vitro study showed that high glucose induced the expression of TLR2 mRNA by NRK-52E cells (p < 0.01). Conclusions: Enhanced renal expression of TLR2 is associated with inflammatory infiltration in DN. Copyright (C) 2010 S. Karger AG, Basel