This video shows how to induce abdominal aortic aneurysms (AAA) in mice via transient intraluminal infusion of porcine pancreatic elastase into the infrarenal segment of the abdominal aorta. The model has the ability to add broad insight into the pathobiology of AAA due to the emergence of numerous transgenic and gene knockout mice.
Transient intraluminal infusion of porcine pancreatic elastase into the infrarenal segment of the abdominal aorta is the most widely used animal model of abdominal aortic aneurysm (AAA) ever since it was first described in rats by Anidjar and colleagues.1 The rationale for its development was based on the disrupted nature of elastin observed in AAAs. This rat model has been modified to produce AAAs in the infrarenal aortic region of mice.2 The model has the ability to add broad insight into the pathobiology of AAA due to the emergence of numerous transgenic and gene knockout mice. Moreover, it is a viable platform to test potential therapeutic agents for AAA. In this video, we demonstrate the elastase infusion AAA procedure used in our laboratory.
Mice are anesthetized using 2.5% isoflurane, and a laparotomy is performed under sterile conditions. The abdominal aortais isolated with the assistance of an operating stereomicroscope (Leica). After placing temporary ligatures around the proximal and distal aorta, an aortotomy is created at the bifurcation with the tip of a 30-gauge needle. A heat-tapered segment of PE-10 polyethylene tubing is introduced through the aortotomy and secured. The aortic lumen is subsequently perfused for 5-15 minutes at 100 mm Hg with saline containing type I porcine pancreatic elastase (4.5 U/mL; Sigma Chemical Co.). After removing the perfusion catheter, the aortotomy is repaired without constriction of the lumen.
Figure 1.Representative Result of Elastase induced AAA.
Previous studies have noted significant lot-to-lot variation in AAA development from different commercial elastase preparations3. Thus, it is critical to monitor production lots as well as to have appropriate control groups in order to document the ability of the preparation to induce AAAs.
Interestingly, susceptibility to AAA development in this model is dependent on the mouse strain used3. The mouse used in the current video is of the C57Bl/6 strain which has consistent development of AAA using the outlined protocol. Elastase concentration and/or incubation time may be adjusted to accommodate other strains.
Although the technique of creation of AAA with elastase in mice is technically challenging, it is an important technique for studying the underlying molecular mechanisms of AAA formation and development. Practice and technical modifications have resulted in a success rate of over 90% in our laboratory. We believe that the video and the accompanying text will help reduce the learning curve for laboratories that wish to use this technique.
Troubleshooting
The authors have nothing to disclose.
This work was supported the SCCOR grant “AAA Disease: Mechanisms, Stratification, and Treatment” (P50 HL083800-03) from the National Institutes of Health
Material Name | Type | Company | Catalogue Number | Comment |
---|---|---|---|---|
Type I porcine pancreatic elastase | Reagent | Sigma | E1250 | |
polyethylene tubing (PE-10) | CLAY ADAMS | 427400 | ||
CHANGE-A-TIP | Bovie | 18010-00 (FST) | cautery knife | |
LEICA MZ6 | Leica | stereomicroscope | ||
LEICA DFC290HD | Leica | USB camera | ||
Image Pro Express ver. 6.0 | Media Cybernetics | software |