Black S M, Fineman J R, Steinhorn R H, Bristow J, Soifer S J
Department of Pediatrics, University of California, San Francisco, San Francisco, California 94143-0106, USA.
Am J Physiol. 1998 Nov;275(5):H1643-51. doi: 10.1152/ajpheart.1998.275.5.H1643.
Altered pulmonary vascular reactivity is a source of morbidity and mortality for children with congenital heart defects and increased pulmonary blood flow. Nitric oxide (NO) is an important mediator of pulmonary vascular reactivity. The objective of this study was to characterize potential early alterations in expression, localization, and activity of endothelial NO synthase (eNOS) induced by increased pulmonary blood flow and pulmonary hypertension. Utilizing aortopulmonary vascular graft placement in the fetal lamb, we have established a unique animal model of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. Ten fetal lambs underwent in utero placement of an aortopulmonary vascular graft (shunt). RNase protection assays and Western blotting were performed on lung tissue prepared from 4-wk-old shunt lambs and age-matched controls. eNOS mRNA (2.4:1, P < 0.05) and protein (2. 08:1, P < 0.05) were increased in lungs of shunt lambs. In situ hybridization and immunohistochemistry revealed that the increase was confined to the endothelium of pulmonary arteries. eNOS protein (1.55:1, P < 0.05) and tissue cGMP concentrations (2.1:1, P < 0.05) were also increased in isolated fifth-generation pulmonary arteries of shunt lambs. In addition, total lung eNOS activity was increased (2.9:1, P < 0.05). Thus we report a previously undescribed, early upregulation of eNOS gene expression and activity in lambs with increased pulmonary blood flow and pulmonary hypertension.
肺血管反应性改变是先天性心脏病和肺血流量增加患儿发病和死亡的一个原因。一氧化氮（NO）是肺血管反应性的重要介质。本研究的目的是描述由肺血流量增加和肺动脉高压诱导的内皮型一氧化氮合酶（eNOS）在表达、定位和活性方面潜在的早期改变。利用在胎羊中放置主肺动脉血管移植物，我们建立了一种独特的肺动脉高压动物模型，该模型模拟了伴有肺血流量增加的先天性心脏病。十只胎羊在子宫内接受了主肺动脉血管移植物（分流管）的放置。对4周龄分流羊和年龄匹配的对照羊的肺组织进行了核糖核酸酶保护分析和蛋白质印迹分析。分流羊肺中的eNOS mRNA（2.4:1，P<0.05）和蛋白质（2.08:1，P<0.05）增加。原位杂交和免疫组织化学显示，这种增加仅限于肺动脉内皮。分流羊分离的第五代肺动脉中的eNOS蛋白（1.55:1，P<0.05）和组织环鸟苷酸浓度（2.1:1，P<0.05）也增加。此外，全肺eNOS活性增加（2.9:1，P<0.05）。因此，我们报告了在肺血流量增加和肺动脉高压的羊中，eNOS基因表达和活性以前未被描述的早期上调。
