Lu Guanyi, Su Gang, Davis John P, Schaheen Basil, Downs Emily, Roy R Jack, Ailawadi Gorav, Upchurch Gilbert R
Department of Surgery, University of Virginia, Charlottesville, Va.
Molecular Imaging Core, Department of Radiology, University of Virginia, Charlottesville, Va.
J Vasc Surg. 2017 Jul;66(1):232-242.e4. doi: 10.1016/j.jvs.2016.07.105. Epub 2017 Mar 6.
The purpose of this study was to establish a reliable, chronic model of abdominal aortic aneurysm (AAA).
Wild-type 8-week-old C56BL/6 male mice (n = 120) were equally divided into three groups: (1) BAPN group: 0.2% 3-aminopropionitrile fumarate salt (BAPN) drinking water was provided to mice 2 days before surgery until the end of study. Sham aneurysm induction surgery was performed using 5 μL of heat deactivated elastase. (2) Elastase group: mice were given regular drinking water without BAPN. During aneurysm induction surgery, 5 μL of the active form of elastase (10.3 mg protein/mL, 5.9 U/mg protein) was applied on top of the infrarenal abdominal aorta adventitia for 5 minutes. (3) BAPN+elastase group: mice were given BAPN drinking water and the active form of elastase application, as above. On postoperative days 7, 14, 21, 28, and 100, aortic samples were collected for histology, cytokine array, and gelatin zymography after aortic diameter measurement.
Compared with the elastase group, the BAPN+elastase group had a higher AAA formation rate (93% vs 65%; P < .01) with more advanced AAAs (25 of 42 vs 1 of 40 for stage II and III; P < .001). Aneurysms from the BAPN+elastase group demonstrated persistent long-term growth (221.5% ± 36.6%, 285.8% ± 78.6%, and 801% ± 160% on days 21, 28, and 100, respectively; P < .001), with considerable thrombus formation (54%) and rupture (31%) at the advanced stages of AAA development. Cytokine levels (pro-matrix metalloproteinase 9, interleukin-1β, interleukin-6, chemokine [C-C motif] ligand 5, triggering receptor expressed on myeloid cells 1, monocyte chemotactic protein 1, and tissue inhibitor of metalloproteinase 1) in the BAPN+elastase group were higher than in the elastase group on day 7. After day 7, cytokine levels returned to baseline, with the exception of elevated matrix metalloproteinase 2 activity. By histology, CD3-positive T cells in the BAPN+elastase group were elevated on days 28 and 100.
A combination of oral BAPN administration and periaortic elastase application induced a chronic, advanced-stage AAA with characteristics of persistent aneurysm growth, thrombus formation, and spontaneous rupture. Future studies should use this model, especially for examining tissue remodeling during the late stages of aneurysm development.
本研究旨在建立一种可靠的腹主动脉瘤（AAA）慢性模型。
将8周龄野生型C56BL/6雄性小鼠（n = 120）平均分为三组：（1）BAPN组：在手术前2天给小鼠提供0.2%富马酸3-氨基丙腈盐（BAPN）饮用水，直至研究结束。使用5 μL热失活弹性蛋白酶进行假动脉瘤诱导手术。（2）弹性蛋白酶组：给小鼠提供不含BAPN的常规饮用水。在动脉瘤诱导手术期间，将5 μL活性形式的弹性蛋白酶（10.3 mg蛋白质/mL，5.9 U/mg蛋白质）涂抹于肾下腹主动脉外膜上5分钟。（3）BAPN + 弹性蛋白酶组：给小鼠提供BAPN饮用水并按上述方法应用活性形式的弹性蛋白酶。在术后第7、14、21、28和100天，测量主动脉直径后收集主动脉样本进行组织学、细胞因子阵列分析和明胶酶谱分析。
与弹性蛋白酶组相比，BAPN + 弹性蛋白酶组的AAA形成率更高（93%对65%；P <.01），且AAA更严重（II期和III期分别为42个中的25个对40个中的1个；P <.001）。BAPN + 弹性蛋白酶组的动脉瘤表现出持续的长期生长（分别在第21、28和100天为221.5% ± 36.6%、285.8% ± 78.6%和801% ± 160%；P <.001），在AAA发展的晚期有大量血栓形成（54%）和破裂（31%）。BAPN + 弹性蛋白酶组的细胞因子水平（前基质金属蛋白酶9、白细胞介素-1β、白细胞介素-6、趋化因子[C-C基序]配体5、髓样细胞表达的触发受体1、单核细胞趋化蛋白1和金属蛋白酶组织抑制剂1）在第7天高于弹性蛋白酶组。第7天后，除基质金属蛋白酶2活性升高外，细胞因子水平恢复至基线。通过组织学检查，BAPN + 弹性蛋白酶组的CD3阳性T细胞在第28天和第100天升高。
口服BAPN与主动脉周围应用弹性蛋白酶相结合可诱导出具有持续动脉瘤生长、血栓形成和自发破裂特征的慢性晚期AAA。未来的研究应使用该模型，特别是用于检查动脉瘤发展后期的组织重塑。
