中文摘要：

目的：研究Na^＋／H^＋交换抑制剂阿米洛利对低氧刺激的大鼠肺动脉平滑肌细胞（PASMCs）增殖的影响，以及Na^＋／H^＋交挟体-l（NHE-1）活性和表达的变化.方法：常氧（21％O2）或低氧（2％O2）条件下培养PASMCs，并分别给予浓度为1．653、3．125、6．25、12．5、25和50μmol／L．等不同浓度的阿米洛利，培养24h，采用MTT比色实验和免疫组化检测PCNA阳性细胞率的方法反映细胞增殖情况，同时采用激光共聚焦检测细胞内pH以反映Na^＋／H^＋交换体-1活性，RT—PCR法检测Na^＋／H^＋交换体-1mRNA的表达量.结果：低氧培养的PASMCs细胞内pH升高，NHE—1mRNA的表达增多，而阿米洛利可以降低细胞内pH，减少NHE—1mRNA的表达量。同时低氧较常氧培养MTT光吸收值较常氧培养明显升高。PCNA阳性细胞率明显增高，而给予阿米洛利时上述两个指标随药物浓度增加而逐渐下降。结论：低氧可以激活PASMCs细胞膜上的E—1，增加其mRNA水平表达量，使细胞内碱化，促进细胞增殖，而Na^＋／H^＋交换抑制剂阿米洛利可以抑制其活性，减少mRNA水平的表达，导致细胞内酸化，从而抑制细胞增殖，并且此抑制作用在3．125～50μmol／L．浓度范围内呈现明显的浓度依赖性。

英文摘要：

To study the influence of Na^＋/H^＋ exchange inhibitor amiloride on hypoxia-induced proliferation in rats pulmonary artery smooth muscle cells（PASMC,s）, also observe the change of Na^＋/H^＋ exchanger- 1 （ NHE- 1 ） activity and expression. Methods： Rats PASMGs were cultured in normoxia（21% O2 ） or hypoxia（2 % O2 ）for 24 hours, as well as administered mniloride with various concentrations, cultured for 24 hours, then determined MTT OD values and rates of PCNA positive cells to investigate cells proliferation, moreover intracellular pH was determined by interactive Laser Cytometer, and Na^＋/H^＋ exchanger-1 mRNA expression was determined by RT-PCR. Results： Hypoxic exposure heightened intracellular pH and mRNA expression of NILE-1 in PASMCs, however, 3. 123-50 μmol/L, amiloride depressed them gradually. Additionally, hypoxic exposure raised MTT OD value and rates of PCNA positive cells, similarly, the above two indexes descended gradually with presence of 3.125- 50μmol/L. amiloride. Conclusion： Na^＋/H^＋ exchange inhibitor amiloride can suppress hypoxia-induced proliferation in pulmonary artery smooth muscle cells, which is due to depress activity and expression of NHE-1.