兔肺充血模型与血浆内皮素变化及内皮素受体表达的关系

The Expression and Its Pathogenetic of Endothelin Receptors in Systemic and Pulmonary Circulation in Rabbit Model with Left-to-Right Shunt

目的本实验建立动物左向右分流,当左向右分流导致血浆内皮素含量明显增高时,测定体、肺血管及组织中内皮素的表达,从而在分子生物学水平探讨内皮素与肺高压的发生发展机制。方法取新西兰兔18只,分为对照组6只,实验组12只。在主动脉与肺动脉间用人造血管建立左向右分流。分别于术前、术后1、2、5h抽血测内皮素含量。对照组采用相同方法建立分流不予开放。术后取肺、肾动脉各1.5cm,肺、肾组织各(1.5×1.5)cm2,采用逆转录、酶联免疫扩增法及ELISA法测定内皮素受体mRNA表达。结果实验组术后1、2h内皮素水平均无显著差异。术后5h内皮素水平较术前及术后2h明显升高(P<0.05)。实验组肺动脉、肺组织内皮素A受体mRNA表达分别高于肾动脉、肾组织与对照组(P<0.05,<0.01)。结论当肺血流量增加,血浆内皮素水平明显增高而尚未出现肺高压时,肺动脉及肺组织中内皮素A受体mRNA的表达即显著高于肾动脉及肾组织。说明在肺充血时内皮素A受体的缩血管作用占主导地位。

Purpose To investigate the expression of endothelin receptors in the systemic and pulmonary arterials and tissues, when plasma endothelin levels increase significantly in the left-to-right shunt animal model. Methods Eighteen New Zealand rabbits were divided into 2 groups： experimental group （ n = 8） and control group （ n = 6）. A duct between the ascending aorta and main pulmonary artery was established to form the animal model of left-to-right shunt. From artery 2 mL of blood sample were obtained before operation and at 1,2, and 5 hours after operation respectively, to assay the plasma endothelin levels. The pulmonary artery and renal artery 1.5 cm, pulmonary tissue and renal tissue （ 1.5 × 1.5） cm^2 were excised after operation. Results Endothelin levels at one hour, two hours after operation were no statistically difference. Whereas the endothelin levels 5 hours after operation was significantly higher than those before operation （P 〈 0.05）. In the experimental group：the expression of endothelin A receptor in pulmonary artery and tissue was higher than in the renal artery and tissue （ P 〈 0.05）. Between the experimental and control group： the expression of endothilin A receptor in pulmonary artery and tissue in experimental group is higher than in control group（ P 〈 0.01 ）. There was no difference expression of endothelin B receptor. Conclusions The expression of endothelin A receptor in the pulmonary artery and pulmonary tissue is significant increased when the volume of pulmonary blood flow increased, at the same time the plasma endothelin level is obviously high,whereas the pressure of pulmonary artery did not change. It is showed that endothelin A receptor is in the predominant position ot vascular systole,while pulmonary congested.