Oxidative Mechanism of Uric Acid Induced CRP Expression in Human Umbilical Vein Endothelial Cells

Objective To explore the oxidative mechanism of uric acid (UA) induced CRP expression in human umbilical vein endothelial cells. Methods Different concentrations of UA (0 mg/dL, 4 mg/dL, 8 mg/dL, 12 mg/dL, 16 mg/dL) were incubated 12 h with HUVECs, and HUVECs were stimulated with 12 mg/dL UA for different times (6 h, 12 h, 24 h, 48 h). CRP mRNA and protein expression were determined by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot, respectively; the effects of uric acid on the intracellular reactive oxygen species (ROS) production in HUVECs were measured by fluorescence microscope and flow cytometric analysis using a 2', 7'-Dichlorofluorescin diacetate (DCF-DA) fluorescence probe. The effects of N-acetyl cysteine (NAC) on UA-induced levels of ROS, mRNA and protein of CRP in HUVECs were also observed. Results The results demonstrated that UA could significantly increase the mRNA and protein expression of CRP in HUVECs in time- and concentration-dependent manners. HUVECs were stimulated with 12 mg/dL UA at 6 h, mRNA and protein levels of CRP significantly higher than that of control level (P<0.05), reached a peak at 12 h (P<0.01). NAC reduced UA-induced levels of ROS, mRNA and protein of CRP in HUVECs compared with those of 12 mg/dL UA induced group(P<0.05). Conclusion Uric acid significantly increased mRNA and protein expression of CRP in HUVECs in time- and concentration-dependent manners. Its mechanism may be associated with uric acid induced increasing of ROS levels in endothelial cells, which suggested that the uric acid mediated oxidative stress and inflammation may be involved in the injury of endothelial cells.