Uric Acid Inhibits the Synthesis of Nitric Oxide in Human Umbilical Vein Endothelial Cells

Objective To investigate the effect of uric acid(UA) on the expression of endothelial nitric oxide synthase(eNOS) and the production of nitric oxide in cultured human umbilical vein endothelial cells(HUVECs).Methods HUVECs were incubated with different concentrations of UA(0,0.5,1,1.5,2 mg/L) and 50 mg/L ox-LDL(as positive control) for 24,48 and 72 h.Then,eNOS mRNA was detected by RT-PCR.The expression of eNOS protein was observed by Western blot.NO in supernatant medium was analyzed by enzymic method.ResultsUA 5 mg/dl group increased the expression of eNOS mRNA of HUVECs as compared with that from placebo control group(P0.05).While the concentration of UA increasing and time runing,the expression of eNOS and the production of NO and ox-LDL decreased significantly(72 h NO2-/NO3-is 0.52±0.18 versus 1.00±0.1 for 2 mg/L versus control,P0.05).Conclusion UA inhibits the expression of eNOS and the production of NO of HUVECs in a dose-dependent and time-dependent manner.It suggests that UA may damage the function of endothelial cells and may influence the genesis and development of cardiovascular diseases.