Abstract: Objective To investigate the effect of bergapten (BG) on the inhibition of high glucose (HG) induced inflammatory factors expression and apoptosis in renal tubular epithelial cells by down-regulation of miR-503. Methods The renal tubular epithelial cells were divided into control (Con) group, high glucose ( HG) group, high glucose + BG low-, medium- and high concentration (HG + BG-L, -M, -H) group, HG + inhibitor-NC group, HG + miR-503 inhibitor group, HG + BG + miR-NC group, HG + BG + miR-503 group. Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of inflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), flow cytometry was used to monitor the cell apoptosis, and Western blotting was used to determine the expression levels of apoptotic proteins cleaved-caspase 3 and cleaved-caspase 9, and the expression level of miR-503 was determined by qRT-PCR. Results The apoptosis rate, the levels of TNF-α, IL-6, and the expression levels of cleaved-caspase 3, cleaved-caspase 9 protein and miR-503 in renal tubular epithelial cells in the HG group were all higher than those in the Con group (all P< 0. 05). The apoptosis rate, the levels of TNF-α, IL-6, and the expression levels of cleaved-caspase 3, cleaved-caspase 9 protein, miR-503 of renal tubular epithelial cells in the HG + BG-L group, the HG + BG-M group, and the HG + BG-H group were all lower than those in the HG group (all P < 0. 05), and the inhibitory effects of BG were concentration dependent. After interfering with miR-503, the expression levels of miR-503, cleaved-caspase 3 and cleaved-caspase 9, the levels of TNF-α, IL-6, and the apoptosis rate in renal tubular epithelial cells in the HG + miR-503 inhibitor group were lower than those in the HG + inhibitor-NC group (all P < 0. 05). The expression levels of miR-503, cleaved-caspase 3 and cleaved-caspase 9, the levels of TNF-α, IL-6, and the apoptosis rate in renal tubular epithelial cells in the HG + BG + miR-503 group were higher than those in the HG + BG + miR-NC group (all P< 0. 05). Conclusion BG inhibits the high glucose induced expression of inflammatory factors and apoptosis of renal tubular epithelial cells in a concentration-dependent manner by down-regulation of the miR-503 expression.

Key words: diabetic nephropathy, bergapten, renal tubular epithelial cells, miR-503, inflammatory factors, apoptosis