内皮素参与溶血磷脂酸促血管平滑肌细胞的增殖

Involvement of endothelin in the proliferative effect of lysophosphatidic acid on vascular smooth muscle cells in rats

目的 :观察内皮素 (endothelin ,ET)对溶血磷脂酸 (lysophosphatidicacid ,LPA)诱导大鼠血管平滑肌细胞(VSMCs)增殖的作用。方法 :离体培养的VSMCs经不同浓度的LPA孵育后测定 [3 H] 胸腺嘧啶 (3 H TdR)掺入 ,ETmRNA含量及ET的合成和释放量。结果 :LPA(5、10和 2 0 μmol·L-1)增加VSMCsETmRNA表达 ,VSMCsETmRNA含量分别较对照组高 16 %、2 1%和 2 3%。LPA亦以浓度依赖的方式增加VSMCsET的合成释放。 5～2 0 μmol·L-1LPA处理组细胞培养上清中ET含量较对照组高 14 0 %～ 2 0 0 % (P <0 .0 1)。 5～ 2 0 μmol·L-1LPA以浓度依赖的方式促进VSMCsDNA合成 ,非选择性的ETA 受体拮抗剂BQ12 3显著拮抗LPA刺激的VSMCs的DNA合成增加。结论 :LPA可促进VSMCs的ET产生 ,LPA的促VSMCs增殖效应部分是通过ET/ETA 受体途径介导。

Objective: To observe the effects of lysophosphatidic acid (LPA) on production of endothelin (ET) in rat aorta vascular smooth muscle cells (VSMCs). Methods: Cultured VSMCs were used in the study. DNA synthesis of VSMCs was measured by 3H TdR incorporation. The amount of ET mRNA of VSMCs was determined by competitive quantitative RT PCR. The levels of synthesis and release of ET in VSMCs were determined by radioimmunoassay (RIA). Results: 5-20 μ mol·L -1 of LPA promoted VSMCs 3H TdR incorporation in a concentration dependent manner. The amount of ET mRNA in VSMCs treated by 5-20 μmol·L -1 of LPA was increased by 16%, 21%, and 23%, respectively, compared with the control. After 8 hours of incubation, 5-20 μmol·L -1 of LPA elevated the ET production in a concentration dependent manner. After 8 hours of VSMCs incubated with LPA (5-20 μmol·L -1 ), the content of ET in medium was increased by 140%-200%, respectively, compared with the control. In addition, it was found that BQ123, a non selective ET receptor antagonist, greatly decreased the VSMCs DNA synthesis induced by LPA. Conclusion: LPA stimulated the ET mRNA expression and ET production in VSMCs. The effects of LPA on VSMCs DNA synthesis were partly mediated by ET/ET A receptor pathway. It suggests that LPA and ET interact and exert biological effects as endogenous active peptides.