Objective To observe the effect of intra-abdominal aortic injection of pancreatic elastase combined with continuous subcutaneous injection of angiotensin Ⅱ on abdominal aortic aneurysm model in rabbits.Methods Twenty male New Zealand white rabbits were randomly divided into group A and group B,with 10 rabbits in each group.Group A was infused pancreatic elastase to make abdominal aortic aneurysm model;group B had abdominal aortic infusion of pancreatic elastase combined with subcutaneous pumping of angiotensin Ⅱ.Blood pressure and serum levels of matrix metalloproteinase(MMP)-2 and MMP-9 were measured before and 2,4,16 weeks after operation.The rabbits were executed 16 weeks after operation;vascular tissues were separated for hematoxylin eosin,EVG elastic fiber,Masson and immunohistochemical staining tests.Results Blood pressure in group B was significantly higher than that in group A at 2,4,16 weeks after operation[(92 ±9)mmHg vs (73 ± 7) mmHg,(105 ± 9) mmHg vs (74 ± 6) mmHg,(102 ± 10) mmHg vs (73 ± 7) mmHg] (P ＜ 0.05).Aneurysm formation rate and diameter expansion rate had no significant differences between group A and group B at 2 weeks after operation(P ＞ 0.05).At 4,16 weeks after operation,aneurysm formation rate and diameter expansion rat e in group A were significantly lower than those in group B(4 weeks:5/7 vs 10/10,68.0％ vs 96.0％;16 weeks:1/7 vs 10/10,12.0％ vs 104.0％) (P ＜ 0.05).Serum MMP-2 and MMP-9 levels 2 weeks after operation were significantly higher than those before operation in both groups;serum MMP-2 and MMP-9 levels 4,16 weeks after operation were significantly higher than those before operation in group B;serum MMP-2 and MMP-9 levels 4,16 weeks in group B were significantly higher than those in group A [4 weeks:(31.4 ± 0.7) μg/L vs (22.9 ±0.5)μg/L,(83.9 ±3.2)μg/L vs (58.6 ±2.5)μg/L;16 weeks:(29.2 ±0.9) μg/L vs (21.8 ±0.7)μg/L,(85.1 ±2.9)μg/L vs (53.1 ±2.0)μg/L] (P ＜0.05).Immunohistochemical test showed that CD68 positive cell cumulative absorbance value in group B was significantly lower than that in group A[(5 624 ±986) vs (8 937 ±1 021)] (P ＜ 0.05).Conclusion Intraluminal infusion of pancreatic elastase combined with subcutaneous pumping of angiotensin Ⅱ is a reliable method of making abdominal aortic aneurysm model in rabbits.%目的 观察胰弹力蛋白酶腔内灌注联合血管紧张素Ⅱ皮下持续泵入制作兔腹主动脉瘤模型的效果.方法 选取健康新西兰雄性白兔20只,随机分为A组和B组,每组10只.制备腹主动脉瘤模型,A组经导管给予腹主动脉内灌注弹力蛋白酶,B组给予腹主动脉内灌注弹力蛋白酶联合皮下持续泵注血管紧张素Ⅱ.分别于术前及术后2、4、16周测血压,行腹主动脉彩色超声检查,并检测血清基质金属蛋白酶2(MMP-2)和MMP-9水平;16周时处死兔,取血管标本行苏木精-伊红染色、EVG弹力纤维染色、Masson染色及免疫组织化学CD68巨噬细胞染色.结果 术后2、4、16周时,B组血压明显高于A组[(92 ±9) mmHg(1 mmHg =0.133 kPa)比(73±7)mmHg、(105±9) mmHg比(74±6)mmHg、(102±10) mmHg比(73±7) mmHg] (P ＜0.05).术后2周时,2组成瘤率及扩张率差异无统计学意义(P＞0.05);术后4、16周时,A组和B组成瘤率及瘤体直径扩张率差异有统计学意义(4周:5/7比10/10、68.0％比96.0％,16周:1/7比10/10、12.0％比104.0％)(P＜0.05).术后2周时2组MMP-2、MMP-9水平均明显高于术前,术后4、16周时仅B组MMP-2、MMP-9水平明显高于术前;术后4、16周时,B组MMP-2、MMP-9水平明显高于A组[4周:(31.4±0.7)μg/L比(22.9±0.5) μg/L、(83.9 ±3.2)μg/L比(58.6±2.5)μg/L;16周:(29.2±0.9) μg/L比(21.8 ±0.7) μg/L、(85.1±2.9) μg/L比(53.1±2.0) μg/L] (P ＜0.05).免疫组织化学染色结果显示,B组CD68阳性细胞染色累积吸光度值明显低于A组[(5 624±986)比(8 937±1 021)],差异有统计学意义(P＜0.05).结论 胰弹力蛋白酶腔内灌注联合皮下持续泵入血管紧张素Ⅱ是一种可靠的制作兔腹主动脉瘤模型的方法,可使腹主动脉瘤较长时间维持瘤体的形态.
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