尿酸抑制人脐静脉内皮细胞合成一氧化氮

Uric acid inhibits the synthesis of nitric oxide in human umbilical vein endothelial cells

目的研究尿酸(UA)对人脐静脉内皮细胞(HUVEC)表达内皮型一氧化氮合酶(eNOS)及分泌一氧化氮(NO)的影响。方法不同浓度UA(0、0.5、1、1.5及2 mg/L)及50 mg/L ox-LDL(阳性对照)分别作用HUVEC 24、48及72 h,用real-time PCR法测定HUVEC eNOS mRNA;Western blot法检测细胞eNOS蛋白;酶法检测上清液NO的含量。结果 UA 0.5 mg/L组eNOS mRNA表达水平明显高于对照组(P<0.05);随着UA浓度升高(1、1.5及2 mg/L组),及其作用时间延长,HUVEC eNOS mRNA及蛋白表达水平及上清液NO分泌量相比对照均明显下降(72 h NO2-/NO3-2 mg/L组与对照组分别为0.52±0.18与1.00±0.10,P<0.05),且趋势与ox-LDL组相同。结论 0.5 mg/L以上浓度的UA呈浓度及时间依赖性抑制HUVEC eNOS表达及NO合成,提示高浓度的UA可能损伤血管内皮功能。

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.