PPAR-γ激动剂对AngⅡ刺激血管内皮细胞分泌血管活性因子的影响

目的 探讨过氧化物酶体增殖物激活受体γ(PPARγ)激动剂对AngⅡ刺激血管内皮细胞分泌血管活性因子的影响,并与AngⅡⅠ型受体(AT1R)拮抗剂losartan相对照,即从细胞水平进一步揭示PPARγ与高血压病的关系.方法 以脐静脉内皮细胞为研究对象,观察PPARγ激动troglitazone对内皮细胞分泌内皮素-1(ET-1)和NO的影响,及其对AngⅡ刺激内皮细胞分泌ET-1和NO的影响,并与losartan相对照.结果 10 μmol/L和50μmol/L troglitazone使人脐静脉内皮细胞分泌ET-1含量与对照组相比虽有下降但无统计学意义,而NO与对照组相比明显升高(P＜0.05);50μmol/L troglitazone可明显抑制AngⅡ(1×10-6 mol/L)刺激的ET的分泌(P＜0.05);两种浓度troglitazone均能抑制AngⅡ对内皮细胞生成NO的减低作用(P＜0.05);losartan抑制AngⅡ刺激内皮细胞合成和分泌ET-1增加和抑制AngⅡ减弱内皮细胞合成和分泌NO的作用比troglitazone更为明显(P＜0.05).结论 PPARγ激动剂troglitazone可抑制AngⅡ刺激内皮细胞合成和分泌ET-1的增加和NO的减少,但其作用并没有losartan明显,提示troglitazone通过影响血管活性因子的分泌而调节血压的作用并非完全是通过AT1R途径.

Peroxisome proliferator-activated receptor activator troglitazone inhibits angiotensin Ⅱ-stimulated secretion of vasoactive factors by endothelial cells

OBJECTIVE: To investigate the effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand on angiotensin II (AngII)-induced endothelin-1 (ET-1) and NO secretion by endothelial cells in comparison with AngII type I receptor (AT1R) antagonist losartan, so as to reveal the relationship between PPAR gamma and essential hypertension. METHODS: Cultured human umbilical vein endothelial cells (HUVECs) were treated with AngII, PPAR gamma ligand troglitazone, AngII plus troglitazone, and AngII plus AT1R antagonist losartan, respectively, and the concentrations of NO and ET-1 in the cell culture supernatant were measured to evaluate the effects of troglitazone and losartan on AngII-induced NO and ET-1 production by human endothelial cells. RESULTS: Treatment of the HUVECs with troglitazone at 10 micromol/L and 50 micromol/L did not produce significant changes in ET-1 concentration in the cell culture supernatants, but significantly increased NO concentration as compared with the control group (P<0.05). Triglitazone at the concentration of 50 micromol/L significantly inhibited AngII (1x10(-6) mol/L)-induced ET-1 production (P<0.05), and at both 10 and 50 micromol/L, troglitazone inhibited the NO release-lowering effect of AngII in the endothelial cells (P<0.05). Both troglitazone and losartan inhibited AngII-induced ET-1 production by the endothelial cells, but losartan showed more potent effect (P<0.05). Similarly, both troglitazone and losartan inhibited decreased NO production in response to AngII treatment, and again losartan showed stronger effect (P<0.05). CONCLUSION: PPAR gamma ligand troglitazone can inhibit AngII-induced ET-1 production enhancement and decreased NO release by the endothelial cells, but its effect is not so strong as losartan, suggesting that troglitazone modulates blood pressure not solely through AT1R pathway.