Department of Food and Nutritional Environment, College of Human Life and Environment, Kinjo Gakuin University, Nagoya, Japan.
Division of Physiology, School of Pharmaceutical Sciences, Faculty of Pharmaceutical Science, Josai University, Saitama, Japan.
Nitric Oxide. 2017 Jul 1;67:1-9. doi: 10.1016/j.niox.2017.04.009. Epub 2017 Apr 21.
Loss of nitric oxide (NO) bioavailability underlies the development of hypertensive heart disease. We investigated the effects of dietary nitrite on N-nitro-l-arginine methyl ester (l-NAME)-induced hypertension. Sprague-Dawley rats were divided into five groups: an untreated control group, an l-NAME-treated group, and three other l-NAME-treated groups supplemented with 10 mg/L or 100 mg/L of nitrite or 100 mg/L of captopril in drinking water. After the 8-week experimental period, mean arterial blood pressure was measured, followed by sampling of blood and heart tissue for assessment of nitrite/nitrate levels in the plasma and heart, the plasma level of angiotensin II (AT II), and the heart transcriptional levels of AT II type 1 receptor (ATR), transforming growth factor-β1 (TGF-β1), and connective tissue proteins such as type 1 collagen and fibronectin. Heart tissue was analyzed by histopathological morphometry, including assessments of ventricular and coronary vascular hypertrophy and fibrosis, as well as immunohistochemistry analyses of myocardial expression of ATR. l-NAME treatment reduced the plasma nitrate level and led to the development of hypertension, with increased plasma levels of AT II and increased heart transcriptional levels of ATR and TGF-β1-mediated connective tissue proteins, showing myocardial and coronary arteriolar hypertrophy and fibrosis. However, dietary nitrite supplementation inhibited TGF-β1-mediated cardiac remodeling by suppressing AT II and ATR. These results suggest that dietary nitrite levels achievable via a daily high-vegetable diet could improve hypertensive heart disease by inhibiting AT II-ATR-mediated cardiac remodeling.
一氧化氮(NO)生物利用度的丧失是高血压性心脏病发展的基础。我们研究了饮食中亚硝酸盐对 N-硝基-L-精氨酸甲酯(l-NAME)诱导的高血压的影响。将 Sprague-Dawley 大鼠分为五组:未处理的对照组、l-NAME 处理组和另外三组,它们的饮用水中分别补充 10mg/L 或 100mg/L 的亚硝酸盐或 100mg/L 的卡托普利。经过 8 周的实验期后,测量平均动脉血压,然后采集血液和心脏组织样本,以评估血浆和心脏中的硝酸盐/亚硝酸盐水平、血浆中血管紧张素 II(AT II)的水平以及心脏中 AT II 型 1 受体(ATR)、转化生长因子-β1(TGF-β1)和结缔组织蛋白(如 1 型胶原和纤维连接蛋白)的转录水平。通过组织病理学形态计量学分析心脏组织,包括评估心室和冠状动脉血管肥大和纤维化,以及心肌中 ATR 的免疫组织化学分析。l-NAME 处理降低了血浆硝酸盐水平,导致高血压的发生,同时增加了血浆中 AT II 的水平,以及心脏中 ATR 和 TGF-β1 介导的结缔组织蛋白的转录水平,表现为心肌和冠状动脉小动脉肥大和纤维化。然而,饮食中亚硝酸盐的补充通过抑制 AT II 和 ATR 抑制了 TGF-β1 介导的心脏重塑。这些结果表明,通过日常高蔬菜饮食可获得的饮食中亚硝酸盐水平可通过抑制 AT II-ATR 介导的心脏重塑来改善高血压性心脏病。