大鼠肾下型腹主动脉瘤模型的建立及方法改良

Establishment of Experimental Abdominal Aortic Aneurysm Model in Rats

中文关键词:  腹主动脉瘤 动物模型 弹力蛋白酶 氯化钙

英文关键词:Abdominal aortic aneurysm Animal model Elastase Calcium chloride

中文摘要:

      目的 建立稳定的大鼠肾下型腹主动脉瘤模型，提高大鼠存活率及成瘤率，使成瘤过程及病理学特征更符合人腹主动脉瘤。方法 健康成年SD大鼠24只，按雌雄比例1∶1随机分为A、B两组，每组12只。设立A组为生理盐水灌注组，B组为弹力蛋白酶灌注结合氯化钙涂抹组，两组均采用开腹腹主动脉穿刺插管加压灌注法，所有大鼠均术后饲养4周后开腹收集腹主动脉标本。术中术后均采用小血管测量尺测量腹主动脉直径，以术后4周腹主动脉扩张50%以上作为诊断腹主动脉瘤的标准。两组腹主动脉标本均行HE染色，观察其病理学变化。 结果 A组大鼠存活率为83.33%，手术成功率为91.67%，成瘤率为0%；B组大鼠存活率为91.67%，手术成功率为100%，成瘤率为90.91%，两组成瘤率差异具有统计学意义 （P<0.05）。两组大鼠灌注时腹主动脉扩张率分别为50.82%±4.11%和48.19%±3.89%，灌注后即时腹主动脉扩张率分别为29.55%±4.69%和27.89%±4.28%，两组间扩张率差异无统计学意义。术后28 d两组腹主动脉扩张率分别为27.89%±4.28%和88.98%±42.33% （P<0.05）。B组腹主动脉呈梭形扩张，灌注段腹主动脉周围粘连较为明显，部分小鼠血管壁周围出现肉眼可见的钙化斑。镜下可见内膜明显增厚，中膜结构紊乱，基质降解，弹力纤维失去连续性，中膜有核平滑肌细胞减少，透壁性炎性细胞浸润。A组没有上述表现。 结论 弹力蛋白酶加压灌注法结合氯化钙涂抹法建立的大鼠腹主动脉瘤模型，可通过术中手术细节的改进获得良好的手术成功率和成瘤率，适用于腹主动脉瘤发病机制及治疗等方面的实验研究。

英文摘要:

      Objective To establish a new reliable experimental abdominal aortic aneurysm (AAA) rat model that simulates human aneurysms and has high survival rate. Methods Twenty-four SD rats were randomly divided equally into two groups (male∶female=1∶1). Intraluminal saline infusion was given to rats in group A. Rats in group B were given intraluminal elastase infusion and extraluminal calcium chloride application. The diameter of abdominal aorta was measured and eventually harvested at 4 weeks. Successful AAA formation was defined as a dilation ratio >50%. HE stain was applied to evaluate the histology changes of aorta. Results Group A had a survival rate, technical success rate and AAA formation rate of 83.3%, 91.67%, and 0% respectively, compared with 91.67%, 100%, and 90.91% in group B. The AAA formation rate in group B was significantly higher than that in group A (P<0.05). The dilation ratio during infusion was 50.82%±4.11% in group A and 48.19%±3.89% in group B. The dilation ratio after infusion was 29.55%±4.69% in group A and 27.89%±4.28% in group B. The difference of dilation ratio between the two groups was not significant. The post-surgery (28 d) dilation ratio was 27.89%±4.28% in group A and 88.98%±42.33% in group B (P<0.05). Fusiform aneurysms, local adhesion and calcification were found in group B. Rats in group B also had thickening intimal, degenerated matrix in media, loss of elastin fiber, apoptosis of vascular smooth muscle cells and transmural inflammation, none of which was observed in group A. Conclusion With improved operative procedure, intraluminal elastase infusion and extraluminal calcium chloride application can create reliable AAA rat model.