Ricci M A, Slaiby J M, Gadowski G R, Hendley E D, Nichols P, Pilcher D B
Department of Surgery, University of Vermont College of Medicine, Burlington, USA.
Ann N Y Acad Sci. 1996 Nov 18;800:89-96. doi: 10.1111/j.1749-6632.1996.tb33301.x.
Propranolol has been suggested to slow aortic aneurysm (AAA) expansion by a mechanism independent of simple blood pressure (BP) reduction. To investigate this hypothesis, we designed a series of experiments to examine the effects of hypertension and propranolol upon AAA expansion. Using an established animal model, we induced AAA in normotensive and genetically hypertensive rats by perfusion of the isolated infrarenal aorta with elastase for two hours. Systolic tail BP was monitored with a plethysmograph. AAA size was measured directly with a micrometer on postoperative days 7 and 14. All data are expressed as the mean +/- standard deviation (SD). BP (mmHg) was significantly higher in hypertensive rats: 164 +/- 15 versus 119 +/- 7 (p < 0.001). AAA were also significantly larger in hypertensive rats with a mean expansion rate (mm/day) nearly twice that of normotensive animals: 0.13 +/- 0.09 versus 0.07 +/- 0.03. In a second series of animals, propranolol treatment was compared to placebo. In those animals, hypertensive propranolol-treated rats had significantly smaller AAA than placebo-treated controls (p < 0.05). There was no difference in normotensive animals but these rats had an unexplained paradoxical rise in BP with treatment. In this model, hypertension increases the expansion rate of AAA. Propranolol reduced the size of AAA in hypertensive animals, at least in part because of a decrease in BP. Other possible mechanisms of propranolol's action may be operative and require further study.
有人提出，普萘洛尔可通过一种独立于单纯降低血压（BP）的机制来减缓主动脉瘤（AAA）的扩张。为了研究这一假设，我们设计了一系列实验来检验高血压和普萘洛尔对AAA扩张的影响。利用一个已建立的动物模型，我们通过用弹性蛋白酶灌注分离的肾下腹主动脉两小时，在正常血压和遗传性高血压大鼠中诱导产生AAA。用体积描记器监测尾动脉收缩压。在术后第7天和第14天用千分尺直接测量AAA的大小。所有数据均表示为平均值±标准差（SD）。高血压大鼠的血压（mmHg）显著更高：164±15 对比 119±7（p<0.001）。高血压大鼠的AAA也显著更大，平均扩张率（mm/天）几乎是正常血压动物的两倍：0.13±0.09 对比 0.07±0.03。在第二组动物中，将普萘洛尔治疗与安慰剂进行了比较。在这些动物中，接受普萘洛尔治疗的高血压大鼠的AAA明显小于接受安慰剂治疗的对照组（p<0.05）。正常血压动物中没有差异，但这些大鼠在治疗后血压出现了无法解释的反常升高。在这个模型中，高血压会增加AAA的扩张率。普萘洛尔减小了高血压动物中AAA的大小，至少部分原因是血压降低。普萘洛尔作用的其他可能机制可能起作用，需要进一步研究。
