Abstract
Introduction. Abdominal aortic aneurysm (AAA) is associated with vascular inflammation, localised dilation and increased risk of aortic rupture. Impaired aortic relaxation to Ach has been reported in an angiotensin II-infused, apolipoprotein E-deficient (ApoE-/) mouse model of AAA (Seto et al., 2013). Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) have BP-lowering and anti-inflammatory effects, making them a potential treatment option for AAA. Aim. To investigate whether dietary supplementation of ApoE-/- mice with LC n-3 PUFAs can preserve vascular reactivity after 2-week infusion with angiotensin II. Methods. ApoE-/- mice were fed a low (n=12) or high (n=13) LC n-3 PUFA diet for 10 weeks, with infusion of saline or angiotensin II (1000 ng/kg/min) for the last 2 weeks. BP was measured using a non-invasive tail-cuff method. Wire myography was performed on isolated thoracic aorta. Results. Mean arterial pressure (MAP) was higher in low diet/angiotensin II-infused mice (93.7±4.3 mmHg) compared to saline-infused mice (86.9±6.8 mmHg, P<0.05). MAP was not different between high diet/angiotensin II-infused (85.4±6.4 mmHg) or saline-infused (85.4±2.9 mmHg) mice. Ach stimulated a relaxant response in low diet/saline-infused mice (28.9±6.0%; EC50, 0.22±0.05 ����M). Relaxation was negligible in low diet/angiotensin II-infused mice (6.7±8.0%). A similar relaxant response was observed in high diet/saline-infused (13.2±2.1%, EC50, 0.49±0.24 ����M), and angiotensin II-infused mice (19.3±3.1%, EC50, 0.92±0.23 ����M). Discussion. A high LC n-3 PUFA diet was protective against increased BP and preserved Ach-mediated aortic relaxation in angiotensin II-infused ApoE-/- mice.