Background
Dissecting aortic aneurysm (DAA) is a tear in the wall of the aorta that causes blood to flow, or “dissect,” between the medial layers of the media.
Methods
Pregnant rats (dams) were treated with the industrial chemical n‐(2‐aminoethyl) ethanolamine (AEEA) by intraperitoneal injection or gavage. The histology and pathology of aorta in the thorax from newborn pups were examined. Aortas of fetuses of gestational day 20 from dams exposed to AEEA were harvested for immunohistochemical staining and native Western blot to study the changes of collagen type 1 and type 3 in aorta.
Results
Dissecting aortic aneurysm of newborn rats was induced by treating with AEEA through intraperitoneal injection or gavage. The incidence of DAA reached 100% in live pups at the high dose by means of gavage of AEEA, but without lethality compared with intraperitoneal injection. A grading system for the dose‐response of DAA lesions associated with AEEA by gavage was established. Gestational day 20 fetuses from treated dams showed a decreased content and altered distribution of medial and adventitial collagen type 1 and 3 in aorta by immunohistochemistry; this decrease was confirmed by native Western blot.
Conclusion
This in vivo model of spontaneous aortic dissection bears striking similarities histologically to human aortic dissection. As such, the model conceivably could contribute to elucidating the mechanisms of DAA formation and to exploring diagnostic and therapeutic strategies. The pathogenesis of AEEA‐induced DAA may be related to defects in the normal developmental progression of collagen types 1 and 3 in the vascular wall. Birth Defects Research (Part A), 2014. © 2014 Wiley Periodicals, Inc. Birth Defects Research (Part A) 100:924–933, 2014. © 2014 Wiley Periodicals, Inc.