Polyphenol-Containing Azuki Bean Extract Suppresses Blood Pressure, and Renal and Vascular Nitric Oxide Synthase Expression in Spontaneously Hypertensive Rats (SHR)

摘要

We investigated the effect of polyphenol-containing azuki bean extracts (ABE) on the elevation of systolic blood pressure (SBP) and the expression of endothelial nitric oxide synthase (eNOS) in the kidney and the thoracic aorta in SHR. Different male SHR groups were fed 0%, 0 05%, 0.2% and 0,8% ABE-containing diets for 8 weeks. Control normotensive Wistar Kyoto rats (WKY) were given the 0% and 0.8% diets. Tail SBP, expression of eNOS protein and its mRNA and immunohistochemical localization were examined. The SBP in SHR groups was markedly increased compared with WKY. The SBP of ABE-treated SHR was significantly lower (approximately 28 mmHg) than that of the untreated SHR. In immunoblotting and RT-PCR analyses, the levels of eNOS protein and its mRNA in the kidney and aorta of the ABE-treated SHR group were lower than those of the untreated SHR. These results suggest that ABE suppresses the elevation of SBP, and that ABE appears to modulate the levels of eNOS protein and mRNA expression in the kidney and aorta in SHR.