Abstract: Objective To investigate the effects of glycated albumin (GA) and oleanolic acid (OA) on the expression of kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL) and some molecules of Toll-like receptor (TLR) signaling pathway in human proximal tubular epithelial cells (HK-2 cells). Methods The HK-2 cells were treated with GA, GA and OA for 24 h. The mRNA levels of KIM-1, NGAL, p38 mitogen activated protein kinase (MAPK), interleukin-1 receptor-associated kinase 4 (IRAK4), TLR 1, TLR2, TLR7 and TLR9 were detected by real-time PCR. The releases of KIM-1 and NGAL in the supernatants were detected by ELISA. The protein levels of p38 MAPK, IRAK4, TLR1, TLR2, TLR7 and TLR9 were measured by Western blotting. Results Compared with control group, GA could significantly up-regulate the mRNA and the protein levels released in supernatants of KIM-1 and NGAL (P<0.05), and promoted the expression of p38 MAPK, IRAK4, TLR1, TLR2 mRNA and protein in HK-2 cells (P<0.05). OA treatment could significantly inhibit theses effects (P<0.05). Conclusion GA can up-regulate the expression and release of KIM-1 and NGAL, and activate the TLR signaling pathway, suggesting that GA could play an important role in regulating renal injury. OA had effective intervention effect on GA.

Key words: glycated albumin, oleanolic acid, Toll-like receptor signaling pathway, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin