实验性肺动脉高压与血浆内皮素和肺小动脉改变

CHANGES OF ENDOTHELIN DURING EXPERIMENTAL PULMONARY HYPERTENSION IN RABBITS

施行兔左肺动脉与降主动脉吻合术。术前及术后测定血浆内皮素（ＥＴ），发现ＥＴ分泌增加发生在肺动脉高压（ＰＨ）形成及肺血管病变发生之前。阿司匹林加硝苯地平（心痛定）可降低ＥＴ的峰值并减轻或延缓肺血管病变的发生，结果提示ＥＴ可能是ＰＨ形成的原因之一。

Potts'operation was performed to develop pulmonary hypertension on 16 rabbits which were then divided into 2 groups.Group A(n=11) received no medication while group B(n=5) received aspirin(5-7.5 mg.kg-1/d) and nifedipine(0.8-1.2 mg.kg-1/d)in drinking water.Plasma endothelin(ET) levels were determined before,20,40,60 and 90 days after the operation by radioimmunoassay in both groups.Aortic and pulmonary systolic pressures of group A were measured 30(n=4),60(n=3) and 90(n=4) days pOstoperatively,group B only 90 days(n=5) postoperatively and group C(n=3,unoperated controls).Pathological study of the lung tissues were undertaken during the hemodynamic measurements.The results revealed that plasma ET increased significantly(vs.preoperative levels) 20-day postoperatively in both group A(n=5) and B(n=5),while that in the former peaked significantly higher vs.group B at the 60th day after operation and in the latter at the 40th day,but the hemedynamic parameters increased only at the 60th day in both group A(n=3i and group B (n=5),Pathological changes showed similar trend as the hemodynamic data with delayed appearance of intimal thickening in group B.The earlier increase of plasma ET than the pulmonary systolic pressure distal to the anastomosis indicates that the latter might be caused by the former.Furthermore,plasma ET level could be lowered but nat kept at preoperatively level by the medication(aspirin + nifedipine)in group B.