2012 Fiscal Year Final Research Report
Evaluation of the effects of polyphenols in plant foods on the microcirculation in rats by In vivo intravital microscope.
| Project/Area Number |
22580146
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Food science
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| Research Institution | Shibaura Institute of Technology |
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Principal Investigator |
OSAKABE Naomi 芝浦工業大学, システム理工学部, 教授 (30554852)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBATA Masahiro 芝浦工業大学, システム理工学部, 教授 (60158954)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 微小循環 / in vivo / ボリフェノール / 生体顕微鏡 |
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| Research Abstract |
In this study, we developed the observation system for microcirculation in several tissues of experimental animals in order to evaluate the effect of polyphenols in plant foods. To observe the microcirculation, a midline abdominal incision was made and the mesentery or cremaster muscle exteriorized and spread carefully over a plastic chamber. The chamber was connected to a reservoir that allowed continuous superfusion of the mesentery with Krebs-Ringer bicarbonate buffer (pH 7.3-7.4) at 37C°. The Krebs-Ringer solution was aerated with 95% N2-5% CO2 using a peristaltic pump. In first study, the animals were allocated to 3 groups, and fed either a control diet, a high fat diet containing 15% lard, or the HFD with 2% cocoa (HFD-C) for 6 weeks. At the end of the experimental period, the mesentery was spread in a chamber, and the vessels were treated topically with phenylephrine, acetylcho- line, or papaverine. The vascular responses to phenylephrine, acetylcholine-dependent vasodilatation
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and endothelium-independent vasodilatation were calculated by the diameter of the mesentery artery with each treatment. Topical treatment of mesenteric arterioles with acetylcholine caused a significantly greater response in the control compared with the HFD group. In the HFD-C group, acetylcholine-dependent vasodilatation was decreased marginally. Similarly, rats in the HFD group showed a 機関番号：32619研究種目：基盤研究（C）研究期間：2010年度 ～ 2012年度 課題番号：22580146研究課題名（和文） In vivo生体顕微鏡を用いた植物ポリフェノールの微小循環に対する作用の検証研究課題名（英文） Evaluation of the effects of polyphenols in plant foods on the microcirculation in rats by In vivo intravital microscope.研究代表者越阪部 奈緒美（OSAKABE NAOMI）芝浦工業大学・システム理工学部・教授研究者番号：30554852significant reduction in vascular sensitivity to phenylephrine compared with the control group. However, there was no significant difference between the control and HFD-C groups. The induction of endothelial-independent artery dilation was re-duced slightly in the HFD group. Our results suggest that one of the hypotensive mechanisms of cocoa is due to amelioration of endothelial dysfunction in arterioles induced by an inappropriate diet.In the second animal study, we evaluated the effects of a single oral administration of flavan-3ols in rats on cremaster muscle microcirculation using intravital video microscopy.First, the cremaster was exteriorized under anesthesia and spread in a chamber. Animals were orally administered 100 mg/kg body weight of cocoa, 10 mg/kg of the flavan-3ol fractionand (-)-epicatechin, or a mixture of xanthine derivatives equivalent to 100 mg cocoa. Red blood cell velocity in arterioles increased soon after administration of cocoa or flavan-3ols, and a significant elevation was observed from 5 min after treatment to 20 min after treatment compared with vehicle. This change was not observed after treatment with (-)-epicatechin or xanthine derivatives. The number of newly recruited capillaries in cremaster muscle was significantly increased from 15 min after cocoa or flavan-3ol treatment. Similarly, blood flow in the cremasteric artery as measured by a laser Doppler flow meter was significantly increased by cocoa or flavan 3-ol treatment, but not by(-)-epicatechin or xanthine derivatives. Blood pressure and heart rate were also increased after administration of cocoa or flavan-3ols. Endothelial nitric oxide synthase (eNOS) in the aorta and NO metabolites levels in blood were also significantly elevated 30 min after treatment with flavan 3-ols. These results suggest that a single oral administration of flavan 3-ols increased blood flow, blood pressure, and heart rate, resulting in increased shear stress on vascular endothelial cells, resulting in eNOS expression. These acute effects of flavan 3-ols suggest that ingestion of chocolate may improve vascular endothelial function. These results suggested that the in vivo intravital video- microscopy analysis is the one of the most useful tool to detect of the effect of polyphenol on microcirculation. Less
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