Site-specific elevation of interleukin-1β and matrix metalloproteinase-9 in the Willis circle by hemodynamic changes is associated with rupture in a novel rat cerebral aneurysm model

Document Type

Article

Abstract

The pathogenesis of subarachnoid hemorrhage remains unclear. No models of cerebral aneurysms elicited solely by surgical procedures and diet have been established. Elsewhere we reported that only few rats in our original rat aneurysm model manifested rupture at the anterior and posterior Willis circle and that many harbored unruptured aneurysms at the anterior cerebral artery-olfactory artery bifurcation. This suggests that rupture was site-specific. To test our hypothesis that a site-specific response to hemodynamic changes is associated with aneurysmal rupture, we modified our original aneurysm model by altering the hemodynamics. During 90-day observation, the incidence of ruptured aneurysms at the anterior and posterior Willis circle was significantly increased and the high incidence of unruptured aneurysms at the anterior cerebral artery-olfactory artery persisted. This phenomenon was associated with an increase in the blood flow volume. Notably, the level of matrix metalloproteinase-9 associated with interleukin-1β was augmented by the increase in the blood flow volume, suggesting that these molecules exacerbated the vulnerability of the aneurysmal wall. The current study first demonstrates that a site-specific increase in interleukin-1β and matrix metalloproteinase-9 elicited by hemodynamic changes is associated with rupture. Our novel rat model of rupture may help to develop pharmaceutical approaches to prevent rupture.

Keywords

Animal models, cerebral hemodynamics, inflammation, intracranial aneurysm, subarachnoid hemorrhage

Medical Subject Headings

Aneurysm, Ruptured (diagnostic imaging, etiology, metabolism, physiopathology); Animals; Cerebrovascular Circulation (physiology); Circle of Willis (diagnostic imaging, metabolism, physiopathology); Disease Models, Animal; Female; Hemodynamics (physiology); Interleukin-1beta (metabolism); Intracranial Aneurysm (diagnostic imaging, etiology, metabolism, physiopathology); Matrix Metalloproteinase 9 (metabolism); Rats, Sprague-Dawley; Ultrasonography, Doppler, Transcranial

Publication Date

8-1-2017

Publication Title

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism

E-ISSN

1559-7016

Volume

37

Issue

8

First Page

2795

Last Page

2805

PubMed ID

27798272

Digital Object Identifier (DOI)

10.1177/0271678X16675369

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