Key Findings:
In this study, dietary ALA exerted an antihypertensive effect in spontaneously hypertensive rats (SHR) through effects on angiotensin-converting enzyme (ACE) activity. Blood pressure is regulated mainly by ACE. Both ACE activity and mRNA expression were lower in SHR fed ALA than in SHR fed a control diet. The results indicate that the blood pressure-lowering mechanism of dietary ALA in SHR may involve a reduction of ACE levels in the aorta.
ABSTRACT:
Several studies have shown that dietary alpha-linolenic acid (ALA) is associated with a reduced risk of cardiovascular disease and has an antihypertensive effect. Blood pressure is regulated mainly by angiotensin-converting enzyme. In the present study, we investigated the effect of dietary ALA on ACE to clarify the mechanism of the antihypertensive effect in spontaneously hypertensive rats. Six-week-old SHR were fed a diet containing either 10% ALA-rich flaxseed oil or high oleic safflower off as a control for four weeks. Systolic blood pressure was measured by the tall cuff method once weekly. At the end of the feeding period, ACE activity was determined in the heart, aorta, lung and kidney. ACE mRNA in these organs was also measured by real time PCR analysis. SBP in the ALA group was significantly lower than in the control group at 2, 3 and 4 weeks. The ACE activity and mRNA expression levels in the ALA group were significantly lower than in the control only in the aorta. In conclusion, in the reduction of ACE activity and mRNA expression levels in the aorta of SHR. (Authors Abstract)