PPARs激动剂上调内皮细胞表达eNOS并增加NO生成

目的： 观察PPARα激动剂非诺贝特及PPARγ激动剂赛格列酮对人脐静脉内皮细胞（HUVECs）血管紧张素Ⅱ（AngⅡ）抑制NO生成的作用。 方法： 体外培养HUVECs，用1×10-7-1×10-4mol/L赛格列酮和10-5、10-4mol/L非诺贝特预处理HUVECs 24 h，再与10-6mol/L AngⅡ 共同孵育12 h，通过RT-PCR和Western blotting分别检测eNOS mRNA和蛋白表达水平；通过Griees反应测定NO2－/NO3－浓度。 结果： 与对照组相比，10-7mol/L AngⅡ刺激HUVEC 12 h下调eNOS mRNA（0.38±0.19 vs 0.13±0.18，P<0.01）和蛋白（35.90±3.18 vs 6.95±2.19，P<0.01）表达，减少NO生成（50.21 μmol/L vs 21.33 μmol/L，P<0.01）。用10-7、10-6、10-5、10-4 mol/L赛格列酮预处理24 h，上调eNOS mRNA表达（分别为0.36±0.03、0.36±0.14、0.37±0.16、0.43±0.06，与AngⅡ组比较，均P<0.01）和蛋白表达（分别为11.60±3.31、11.78±5.45、13.93±2.46、22.93±3.17，与AngⅡ组相比，均P<0.01），增加细胞培养液NO2-/NO3-浓度。非诺贝特也上调eNOS mRNA和蛋白表达，增加细胞培养液NO2-/NO3-浓度（P<0.01）。 结论： AngⅡ减少eNOS表达，从而减少NO生成。赛格列酮和非诺贝特预处理24 h，可拮抗AngⅡ对HUVECs eNOS mRNA和蛋白表达的抑制作用，增加NO的释放。

PPARs ligands antagonizes Ang-induced decrease in endothelial NO production by upregulating eNOS expression

AIM: We hypothesized that PPARγ ligands stimulate endothelial-derived nitric oxide (NO) release to protect the vascular wall. Thus, the purpose of this study is to investigate the effects of ciglitazone (Cig) and fenofibrate (Fen) on angiotensin Ⅱ (AngⅡ)-induced decrease in endothelial NO synthase (eNOS) expression and NO production in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were preincubated for 24 h with Cig (10-7, 10-6, 10-5, 10-4 mol/L) or Fen (10-5 and 10-4 mol/L), then incubated for 12 h with 10-7 mol/L AngⅡ. Total RNA was extracted, and the expression of mRNA and protein of eNOS was assessed by RT-PCR and Western blotting. NO production was measured by Griees method. RESULTS: In the presence of 10-7 mol/L AngⅡ for 12 h, NO production in cultured HUVECs was decreased (P<0.01). Cig and Fen pretreatments enhanced NO production (P<0.01) and antagonized Ang-induced decrease in eNOS mRNA and protein levels in HUVECs. CONCLUSION: PPARγ activator, ciglitazone, and PPARα activator, fenofibrate, antagonize Ang-induced decrease in endothelial NO production by directly upregulating eNOS expression.