血压在囊性动脉瘤增大中的作用及作用机制的实验研究

目的　研究血压在囊性动脉瘤增大中的作用及其病理机制。方法　将 4 8只SD大鼠随机分为A、B、C三组 ,每组 16只。以弹性蛋白酶处理右颈外动脉起始部 ,在距起始部 1mm处结扎并剪断 ,建立囊性动脉瘤模型。A组结扎双侧肾动脉后支、B组结扎单侧肾动脉后支以升高血压 ,C组不结扎肾动脉 ,作为对照组。各组分别在喂养 2周、8周时灌注固定取动脉瘤标本。测量 3组大鼠不同时间点的血压及动脉瘤大小 ,并应用免疫组化方法评价各组动脉瘤壁bFGF的表达情况。结果　各组动脉瘤的大小在 2周时无明显差异 ,8周时A组明显大于B组和C组 (P <0 0 1) ,B组和C组差异不显著。 2周时 ,各组bFGF均呈轻度表达 ,8周时A组bFGF表达强度明显高于B组和C组。结论　血压是影响动脉瘤增大的重要因素 ,动脉瘤壁在高血压及血流剪切力的作用下 ,bFGF表达上升 ,动脉瘤重新塑形 ,这可能是动脉瘤瘤体不断扩大的原因之一。

The effect of blood pressure elevation on the enlargement of saccular aneurysm and its mechanism: an experimental study

Objective to study the effect of blood pressure on the enlargement of saccular aneurysm and its mechanism. Methods Forty-eight SD rats were divided into 3 groups randomly(A, B and C; n=16 in each group). Saccular aneurysms of the carotid artery were induced by corrosion of the initial segment of the external carotid artery (1mm long) with elastase. In group A, the posterior branches of both renal arteries were ligated in order to produce a marlced blood pressure elevation. In group B, only unilateral renal artery was ligated, and a moderate hypertension was produced. In group C high blood pressure was not produced to serve as the control group. After 2 and 8 weeks, the blood pressure and the size of the aneurysms were measured. Then the aneurysms were fixed by intraarterial perfusion of formalin and were harvested for examinations. The expression of basic fibroblast growth factor (bFGF) in aneurismal wall was determined by immunohistochemical analysis. Results Two weeks after the beginning of the experiment, there was no difference in size of aneurysm among the 3 groups. But after 8 weeks, significant difference in aneurysmal size was found between group A and the other two groups. The expression of bFGF in group A was stronger than that in group B and C. Conclusion The elevation of blood pressure and enhancement of bFGF expression in aneurismal wall play an important role in enlargement of the aneurysm.