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Extract of wine phenolics improves aortic biomechanical properties in stroke-prone spontaneously hypertensive rats
1Department of Environmental Preservation and Development, Graduate School of Human and Environmental Studies, Kyoto University, Japan. mizutani@helios.jinkan.kyoto-u.ac.jp
Abstract:
We studied the effect of the extract of wine phenolics (EWP) on blood pressure, vasorelaxing activity and aortic biomechanical properties in stroke-prone hypertensive rats (SHRSP). Thirty-six 4-week-old male SHRSP/Izm rats were divided into 6 equal groups fed one of the following 6 diets: A control diet (plain laboratory diet), the control diet substituted with 0.5 or 1.0% polyphenolic compounds derived from the extract of apple phenolics (EAP), the control diet substituted with 0.5 or 1.0% polyphenolic compounds derived from the extract of tea phenolics (ETP), or the control diet along with drinking water containing 1.0% polyphenolic compounds derived from EWP. Systolic blood pressure (SBP) and body weight (BW) were checked once a week. At the end of the 8th week of feeding, all of the rats were sacrificed and the heart weight and aortic biomechanical properties were measured. The relaxation effect of the addition of EWP on endothelium-intact aortic rings precontracted with prostaglandin (PG) F2 alpha was also measured. Only EWP, not EAP or ETP, significantly lowered the SBP values a compared with the control group at the 4th, 7th and 8th weeks of feeding (p < 0.05). The heart weight and ventricular weight, expressed as the percentage of BW, were significantly lower in the EWP group than in the control group (p < 0.05). The aortic maximum stress was significantly increased (p < 0.05), and the aortic incremental elastic modulus was significantly reduced (meaning higher elasticity) (p < 0.001) in the EWP group as compared with the control group. The aortic rings showed concentration-dependent relaxation induced by EWP, and the relaxation was significantly greater than that induced by a commercial red wine preparation. In conclusion, EWP attenuated the elevation of blood pressure in SHRSP possibly by increasing the vasorelaxation activity. The aortic fragility and elasticity were also improved in EWP-fed SHRSP.