Differential gender- and species-specific formation of aneurysms using a novel method of inducing abdominal aortic aneurysms.
BACKGROUND
The objective of this study was to test a novel model of inducing abdominal aortic aneurysms (AAAs) in different mouse strains and genders.


METHODS
Male and female C57BL/6 and B6129 mice (n = 5 per group) underwent periaortic dissection and porcine pancreatic elastase (30 μL) or inactivated elastase application (5 min) to the aorta. Aortic measurements were taken on days 0 and 14. Aortic samples were analyzed for histology and zymography for matrix metalloproteinase (MMP) activity. Comparison statistics were performed using unpaired t-test.


RESULTS
AAA phenotype (50% aortic increase) occurred in external elastase-treated males (100%) and females (90%). No control animals developed AAAs. The aortic diameter was larger in C57BL/6 and B6129 elastase-treated versus control males (P = 0.0028 and P < 0.0001, respectively) and females (P < 0.0001 and P = 0.0458, respectively). Histology verified phenotype via disrupted internal elastic laminae. Macrophage counts in elastase-treated animals were >6-fold higher than in controls (all groups significant). MMP9 activity was greater in elastase-treated males and females in C57BL/6 (P = 0.0031, P = 0.0004) and B6129 (P = 0.025, P = 0.2) mice; MMP2 activity was greater in C57BL/6 versus B6129 male elastase-treated mice.


CONCLUSIONS
This rodent model produced AAAs in both genders and strains of mice. This model is simple, has little variability, and occurs in the infrarenal aorta, substantiating the external elastase model for future studies.
Section of Vascular Surgery, University of Michigan, Cardiovascular Center, Ann Arbor, Michigan, USA.
Adriana
A
Laser
Guanyi
G
Lu
Abhijit
A
Ghosh
Karen
K
Roelofs
Brendan
B
McEvoy
Paul
P
DiMusto
Castigliano M
CM
Bhamidipati
Gang
G
Su
Yunge
Y
Zhao
Christine L
CL
Lau
Gorav
G
Ailawadi
Jonathan L
JL
Eliason
Peter K
PK
Henke
Gilbert R
GR
Upchurch
D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000209:etiology*; D004195:Disease Models, Animal; D005260:Female; D008264:Macrophages / Q000502:physiology; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010196:Pancreatic Elastase; D010641:Phenotype; D012727:Sex Characteristics; D013045:Species Specificity; D013601:T-Lymphocytes / Q000502:physiology
D010196:Pancreatic Elastase; D020780:Matrix Metalloproteinase 9