The role of estrogen in the formation of experimental abdominal aortic aneurysm

ObjectiveThe current study sought to investigate the role of estrogen in the formation of experimental abdominal aortic aneurysm (AAA).MethodsElastase perfusion of infrarenal AAA animal model was performed in 20 female and 20 male Wistar rats that were randomly divided into an ovariectomized/sham-operated group and an estradiol (E2) experimental/saline control group, respectively. At day 14, E2 was detected, while the mRNA and protein expressions of matrix metalloproteinases 2 and 9 (MMP-2 and -9) in AAA tissue were detected by immunohistochemistry and polymerase chain reaction (PCR).ResultsThe ovariectomized group showed lower estrogen levels and a higher aneurysm dilatation rate and significantly higher MMP-2 and -9 expression compared with the sham-operated group (P < .01), which was in accordance with MMP-2 and -9 mRNA expression. The E2 group showed higher estrogen levels and a lower aneurysm dilatation rate and significantly lower MMP-2 and -9 expression than did the saline control group (P < .01), which was in accordance with MMP-2 and -9 mRNA expression.ConclusionsIn the pathogenesis of AAA, estrogen may play an inhibitory role by decreasing expression of MMP-2 and MMP-9 synthesis.