Glucosyl hesperidin improves serum cholesterol composition and inhibits hypertrophy in vasculature

Long-term administration of hesperidin (HES) or glucosyl hesperidin (GHES), a water-soluble analogue of HES, brings about an antihypertensive effect on spontaneously hypertensive rats (SHR). In the present study, we investigated the effects of long-term administration of HES and GHES (corresponding to 30 mg/d/kg body weight) on serum lipid concentration and morphology of vasculature. Serum HDL cholesterol increased in both SHR and Wistar-Kyoto rats (WKY) fed a HES- or GHES-containing diet for 25 wk. Simultaneously, GHES administration reduced the vascular diameter and media-intimal cross-sectional area of the abdominal aorta in SHR. These results suggest that HES as well as GHES improves serum cholesterol composition and that GHES inhibits hypertrophy in vasculature as well.     

Effects of dietary administration of plant-derived anthocyanin-rich colors to spontaneously hypertensive rats

Anthocyanins have beneficial effects such as free radical scavenging activity. We investigated the effects of continuous administration of colors from purple corn (PCC), purple sweet potato (PSC) and red radish (RRC) to spontaneously hypertensive rats (SHR). These are rich in anthocyanins. Animals were fed with diets containing PCC, PSC or RRC (1 mass% of diets) for 15 wk. While the body weight and the daily food intake of administered rats were not different from those of the non-administered control rats through the experimental period, the blood pressure and the heart rate of SHR administered each color decreased as compared to the control group from the early stage of administration. These results suggest that plant-derived colors containing anthocyanins have anti-hypertensive effects on hypertensive animals.     

Effects of voluntary running exercise on blood pressure and renin-angiotensin system in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats

The effect of a voluntary running exercise on blood pressure and renin-angiotensin system (RAS) was studied in male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). SHR and WKY were assigned to either voluntary running exercise or sedentary control groups at 5 wk of age. The systolic blood pressure in the exercised group for both strains of rats was significantly lower than in the sedentary control group. The plasma renin activity (PRA) and plasma renin concentration (PRC) were significantly lower in voluntary running exercised SHR than in sedentary SHR, whereas the same exercise did not result in a lower PRA and PRC in WKY. These results suggested that the blood pressure lowering effect of voluntary running exercise is related to the suppression of RAS in SHR.     

A quercetin supplemented diet does not prevent cardiovascular complications in spontaneously hypertensive rats

Diets high in quercetin may decrease the risk of developing cardiovascular disease. We tested whether quercetin delays or reduces the severity of hypertension, vascular dysfunction, or cardiac hypertrophy in the spontaneously hypertensive rat (SHR). Normotensive, 5-wk-old SHR consumed standard (n = 18) or quercetin-supplemented diet (1.5 g quercetin/kg diet, n = 22, SHR-Q) for 5 or 11 wk. Wistar Kyoto rats (WKY, n = 19), fed a standard diet, served as controls. At 16 wk, plasma quercetin, measured by HPLC, was 2.09 +/- 0.33 micromol/L in SHR-Q and below assay detection limits in SHR and WKY rats. At 10 and 16 wk of age, arterial blood pressure and heart weight:body weight were not different between SHR and SHR-Q. At 16 wk, cardiac function (echocardiography), vascular morphology (hematoxylin and eosin staining of aortae), and resistance and conductance vessel reactivity (wire myography) was unchanged in SHR vs. SHR-Q. Thus, a quercetin-supplemented diet does not delay the onset or lessen the severity of cardiovascular complications that develop in SHR. These findings contrast with previous reports of cardiovascular protection when quercetin was delivered via oral gavage. To determine whether the efficacy of quercetin depends on its method of delivery, 15-wk-old SHR were given quercetin (10 mg/kg) once daily via oral gavage for 4 consecutive days. Arterial blood pressure (mm Hg) was lower in gavaged SHR (148 +/- 5) than in SHR-Q (162 +/- 2, P < 0.02) and SHR (168 +/- 3, P < 0.001). These data suggest that mode of delivery is a critical determinant in whether quercetin provides cardiovascular benefits.     

Short-term effects of glucosyl hesperidin and hesperetin on blood pressure and vascular endothelial function in spontaneously hypertensive rats

Glucosyl hesperidin (G-hesperidin) is a water-soluble derivative of hesperidin. In the present study, the short-term effects of G-hesperidin and hesperetin, a putative metabolite of G-hesperidin, in spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto rats (WKY) were investigated. Single oral administration of G-hesperidin (10 to 50 mg/kg) induced a dose-dependent reduction in systolic blood pressure (SBP) in SHR, but had no effects in WKY. Intraperitoneal injection of hesperetin (50 mg/kg) into SHR also caused a significant reduction in SBP. The depressor effect was significantly inhibited by a nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester. Moreover, hesperetin (10(-5) M) enhanced endothelium-dependent relaxation induced by acetylcholine, but had no effect on endothelium-independent relaxation induced by sodium nitroprusside in isolated aortas from SHR. These data suggest that the hypotensive effect of hesperetin in SHR is associated with nitric oxide-mediated vasodilation. Therefore, this effect may be involved in the mechanisms by which G-hesperidin lowers blood pressure in hypertension.     

Mineral balance and blood pressure in the young spontaneously hypertensive rat

To evaluate factors that might be related to the pathogenesis of hypertension in spontaneously hypertensive rats (SHR), mineral balance studies were conducted in SHR and control Wistar-Kyoto (WKY) rats at the ages of 9, 13 and 16 wk. During the first balance period, before onset of hypertension, Na, Ca, Mg and P balances were all significantly more positive in SHR than in WKY rats. Percentage of absorbed Na excreted in urine was correlated with the rise in blood pressure of SHR but not of WKY rats during the first 4 wk of the study. At 13 wk balances of all four nutrients still tended to be higher in SHR. During the 16th wk of life, after onset of hypertension, Na, Ca and P balances were similar in SHR and WKY rats, but Mg balance was significantly lower in SHR. The percent urinary excretion of absorbed Na was lower in SHR at 9 wk of age, but after onset of hypertension it was similar to that in WKY rats. Food intake was always greater in SHR, whereas growth during the study was less, and absorption of Ca, Mg and P declined more rapidly with age in SHR than in WKY rats. The data suggest that nutrient malabsorption in SHR, if it occurs at all, is most likely an effect of, rather than a cause of, hypertension.     

The effect of nutrient profiles of the Dietary Approaches to Stop Hypertension (DASH) diets on blood pressure and bone metabolism and composition in normotensive and hypertensive rats

Hypertension has been associated with abnormalities of Ca and bone metabolism. Consequently, dietary strategies aimed at reducing blood pressure may also benefit bone health; however, this issue has received little attention. Therefore, the objective of the present study was to investigate the effect of two antihypertensive-type diets on blood pressure and bone metabolism and composition in normotensive (Wistar-Kyoto NHsd, WKY) and hypertensive (spontaneously hypertensive NHsd, SHR) rats. Thirty WKY and thirty SHR male rats, 14 weeks old, were separately randomized by weight into three groups of ten rats each. One group from each strain was given a control diet while the other two groups were fed two anti-hypertensive (high fruit and vegetable (F/V) and high fruit and vegetable and low-fat dairy produce (combination)) diets for 8 weeks. SHR rats were significantly (P<0.01) heavier than WKY rats. Blood pressure and femoral length, width, dry weight, ash, Ca, Mg, P and bone mineral mass were significantly (P<0.0001) greater in SHR than WKY rats, but were unaffected by diet, irrespective of strain. While markers of bone formation (serum osteocalcin) and bone resorption (urinary pyridinoline and deoxypyridinoline) were similar in both strains, these markers were significantly (P<0.05) lower (28-31, 16-23, 31-33 % respectively) in the SHR rats fed the combination diet relative to those fed the control and F/V diets. Bone turnover in WKY rats was unaffected by diet. In conclusion, these findings suggest that the combination diet may benefit bone metabolism in hypertensive animals. However, as blood pressure was unaffected by this diet, the mechanism by which it reduced bone turnover requires further investigation.     

Candesartan治疗对SHR大鼠心肌AngⅡ及其受体表达的影响

目的观察Candesartan早期治疗对SHR大鼠心肌纤维化及心肌AT1、AT2表达的影响,探讨其抗心肌纤维化的机制。方法选取4周龄的雄性自发性高血压大鼠SHR（Spontanous Hypertensive Rat,SHR）及与之年龄性别相配的正常大鼠WKY;动物分组：WKY组、SHR组、Candesartan治疗组（SHR—Can组,给药4周后停药,继续喂养至24周）;尾袖法测定大鼠血压,断头取血,称量全心与左心质量,计算心体比与左室质量指数;放免法测定血浆及心肌AⅡ水平;免疫组化法检测心肌组织中AT1、AT2的表达;Western blotting法测定心肌AT1、AT2的表达水平;天狼星红染色测定心肌胶原指数。结果8周龄后,与SHR组相比,SHR—Can组血压明显下降并持续24周（P〈0．05）;HR-Can组心体比及左室质量指数明显低于SHR组（P〈0．05）;SHR组血浆中AⅡ水平与WKY组相比明显增高（P〈0．01）,SHR—Can组与SHR组相比降低（P〈0．05）;心肌组织AⅡ含量SHR—Can组明显低于SHR组（P〈0．05）。心肌免疫组化染色示：与WKY相比,SHR大鼠AT1、AT2明显增高（P〈0．05）;与SHR相比,SHR-Can组心肌中AT1、AT2明显减少（P〈0．05）。Western blotting结果示：SHR组AT1、AT2表达水平明显高于WKY组（P〈0．05）;SHR—Can组AT1、AT2表达水平明显降低（P〈0．05）。天狼星红染色心肌胶原含量SHR—Can组明显低于SHR组（P〈0．05）。结论Candesartan早期治疗可抑制SHR大鼠高血压的形成与发展,也可抑制SHR心肌纤维化并降低心脏指数,还能降低SHR心肌AT1、AT2的表达,Candesartan抑制心肌纤维化可能与心肌局部AT1、AT2表达水平有关。     

Effects of kimchi supplementation on blood pressure and cardiac hypertrophy with varying sodium content in spontaneously hypertensive rats

We tested the effects of dietary intake of freeze-dried Korean traditional fermented cabbage (generally known as kimchi) with varying amounts of sodium on blood pressure and cardiac hypertrophy in spontaneously hypertensive rats (SHRs). Wistar-Kyoto rats (WKY), as a control group, received a regular AIN-76 diet, and the SHRs were divided into four groups. The SHR group was fed a regular diet without kimchi supplementation, the SHR-L group was fed the regular diet supplemented with low sodium kimchi containing 1.4% salt by wet weight, which was provided in a freeze-dried form, the SHR-M group was supplemented with medium levels of sodium kimchi containing 2.4% salt, and the SHR-H group was supplemented with high sodium kimchi containing 3.0% salt. Blood pressure was measured over 6 weeks, and cardiac hypertrophy was examined by measuring heart and left ventricle weights and cardiac histology. SHRs showed higher blood pressure compared to that in WKY rats, which was further elevated by consuming high sodium containing kimchi but was not influenced by supplementing with low sodium kimchi. None of the SHR groups showed significant differences in cardiac and left ventricular mass or cardiomyocyte size. Levels of serum biochemical parameters, including blood urea nitrogen, creatinine, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, sodium, and potassium were not different among the groups. Elevations in serum levels of aldosterone in SHR rats decreased in the low sodium kimchi group. These results suggest that consuming low sodium kimchi may not adversely affect blood pressure and cardiac function even under a hypertensive condition.     

A polyunsaturated fatty acid diet lowers blood pressure and improves antioxidant status in spontaneously hypertensive rats

gamma-Linolenic acid [GLA, 18:3(n-6)], eicosapentaenoic acid [EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)] have been reported to prevent cardiovascular diseases. However, they are highly unsaturated and therefore more sensitive to oxidation damage. We investigated the effects of a diet rich in these polyunsaturated fatty acids (PUFA) on blood pressure, plasma and lipoprotein lipid concentrations, total antioxidant status, lipid peroxidation and platelet function in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Five-week-old SHR and WKY rats were fed for 10 wk either a diet containing Isio 4 oil or a diet rich in GLA, EPA and DHA (5.65, 6.39 and 4.94 g/kg dry diet, respectively). The total antioxidant status was assayed by monitoring the rate of free radical-induced hemolysis. VLDL-LDL sensitivity to copper-induced lipid peroxidation was determined as the production of thiobarbituric acid reactive substances. After dietary PUFA supplementation, a significant decrease in blood pressure of SHR rats (-20 mm Hg) was observed and the total antioxidant status was enhanced. VLDL-LDL resistance to copper-induced peroxidation was increased in both strains. The PUFA supplementation did not change platelet maximum aggregation in SHR rats, but it decreased the aggregation speed. In hypertensive rats, GLA + EPA + DHA supplementation lowers blood pressure, enhances total anti-oxidant status and resistance to lipid peroxidation, diminishes platelet aggregation speed and lowers plasma lipid concentrations. Thus, it enhances protection against cardiovascular diseases. Therefore, nutritional recommendations for cardiovascular disease prevention should take into account the pharmacologic properties of GLA, EPA and DHA.     

Effects of deep-frying oil on blood pressure and oxidative stress in spontaneously hypertensive and normotensive rats

ObjectiveIngestion of deep-frying oil has been reported to cause physiologic and histologic changes in experimental animals' tissue, increase the oxidative stress, and possibly lead to death. The purpose of this study was to investigate the effect of deep-frying oil on oxidative stress and blood pressure in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats.MethodsDeep-frying oil was prepared by frying fresh soybean oil at 180 ± 5°C for 8 h each day, for 4 consecutive days. Male SHR and WKY rats were fed diets containing 15% fresh soybean oil or deep-frying oil (DO) for 10 wk.ResultsRats ingesting the DO diet had lower feed efficiency and higher relative liver and kidney weights but deep frying had no significant influence on blood pressure in WKY or SHR rats. The DO diet had no effect on plasma renin activity, aldosterone content, or tissue angiotension-I–converting enzyme activity. WKY rats fed the DO diet showed significantly increased urinary thromboxane B₂ and 8-iso-prostaglandin F_2α excretion, but not urinary 6-keto-prostaglandin F_1α excretion. Diets containing deep-frying oil resulted in increased plasma thiobarbituric acid-reactive substances and nitric oxide contents and decreased plasma total antioxidant capacity in SHR and WKY rats.ConclusionThe ingestion of deep-frying oil seemed not to influence blood pressure or its related parameters, but altered eicosanoid metabolism and elevated oxidative stress in SHR and WKY rats.     

Effect of a gamma-aminobutyric acid-enriched dairy product on the blood pressure of spontaneously hypertensive and normotensive Wistar-Kyoto rats

We investigated the blood-pressure-lowering effects of gamma-aminobutyric acid (GABA) and a GABA-enriched fermented milk product (FMG) by low-dose oral administration to spontaneously hypertensive (SHR/Izm) and normotensive Wistar-Kyoto (WKY/Izm) rats. FMG was a non-fat fermented milk product produced by lactic acid bacteria, and the GABA contained in FMG was made from the protein of the milk during fermentation. A single oral dose of GABA or FMG (5 ml/kg; 0.5 mg GABA/kg) significantly (P<0.05) decreased the blood pressure of SHR/Izm from 4 to 8 h after administration, but did not increase that of WKY/Izm rats. The hypotensive activity of GABA was dose-dependent from 0.05 to 5.00 mg/kg in SHR/Izm. During the chronic administration of experimental diets to SHR/Izm, a significantly slower increase in blood pressure with respect to the control group was observed at 1 or 2 weeks after the start of feeding with the GABA or FMG diet respectively (P<0.05) and this difference was maintained throughout the period of feeding. The time profile of blood-pressure change due to administration of FMG was similar to that of GABA. FMG did not inhibit angiotensin 1-converting enzyme. Furthermore, an FMG peptide-containing fraction from reverse-phase chromatography lacked a hypotensive effect in SHR/Izm rats. The present results suggest that low-dose oral GABA has a hypotensive effect in SHR/Izm and that the hypotensive effect of FMG is due to GABA.     

氯沙坦对自发性高血压大鼠肾组织钙离子浓度的影响及与肾小动脉重建的关系研究

目的探讨钙超负荷与高血压。肾小动脉重建的关系及氯沙坦（Losartan）的治疗作用。方法正常血压Wistar-Kyoto（WKY）大鼠和同种的16周龄自发高血压大鼠（spontaneously hyperten—siverat,SHR）大鼠随机分为WKY对照组、SHR对照组、高剂量losartan组（SHR＋HL）、低剂量losar—tan组（SHR＋LL）。每组6只动物。给予正常饮食,饲养至24周。losartan溶于10ml生理盐水中灌胃,余组等量生理盐水灌胃。测量尾动脉血压、肾组织钙离子浓度、肾小动脉内羟脯氨酸含量并观察肾脏病理测量肾人球小动脉中膜厚度、血管内径及中膜厚度与内径比值（MT／LR）。结果SHR组肾组织钙离子浓度[（18．42±2．34）μ mol／g]、肾小动脉内羟脯氨酸含量[（8．26±2．02）mg／g]均大于WKY组[（11．83±1．98）μmoL／g,（5．16±0．98）mg／g]（t=3．116,3．258,P〈0．05）,但两治疗组均有所降低,小于SHR组（t：2．946,P〈0．05）。SHR组肾内小动脉的壁厚[（5．25±1．13）μm]、壁厚内径比[（9．57±1．78）％]均大于WKY组相应比值[（4．03±0．16）斗m,（7．12±1．35）％]（t=2．836,3．425,P〈0．05）,但两治疗组壁厚内径比[（7．64±1．29）％,（7．85±1．32）％]小于SHR组（t=3．512,3．648,P〈0．05）。结论losartan可以通过抑制细胞内钙超负荷、降低纤维化程度来改善肾小动脉的血管阻力,对高血压大鼠的。肾小动脉重建有逆转作用。     

大气PM_(2.5)对大鼠心血管系统的急性毒性作用

目的观察大气PM2.5对机体心血管系统的影响,比较PM2.5对不同生理、病理状态下大鼠心血管系统毒性的差异。方法在上海市非工业区采集大气PM2.5,选取SH和WKY大鼠各24只,采用气管滴注染毒方法给大鼠肺灌注不同剂量PM2.5,观察PM2.5对不同机体心血管系统的急性毒作用,测量染毒后动物血清心肌酶学(乳酸脱氢酶LDH和肌酸激酶同工酶CK-MB)及血压、心率、心电图。结果大鼠PM2.5染毒后,测定大鼠血清心肌酶发现,WKY和SH大鼠血清LDH和CK-MB随染毒剂量增加而增加,且与对照组相比有统计学差异;同时SH大鼠各实验组心肌酶含量除CK-MB的低剂量组外均高于WKY大鼠的相应组含量,表明PM2.5对SHR的心血管毒性作用可能大于对WKY大鼠的作用。此外,两种大鼠肺灌注PM2.5后血压和心率与对照组相比有明显改变,且染毒后大鼠心电图ST段与T波发生改变。结论结果提示暴露于PM2.5对机体心血管系统有一定的损伤作用,心肌出现缺血缺氧反应。     

高血压模型大鼠脂肪组织脂联素mRNA表达及福辛普利和氯沙坦干预的意义

目的 研究脂联素mRNA在自发性高血压模型大鼠脂肪组织中的表达及福辛普利和氯沙坦其表达的影响.方法 选用22周雄性高血压模型大鼠20只,随机分为高血压模型大鼠组、福辛普利干预组、氯沙坦干预组、福辛普利+氯沙坦干预组,同时选同周龄的WKY大鼠做对照组,每组动物5只,喂养8周后测大鼠尾动脉血压;留尿检测微量尿蛋白(Upm)和N-乙酰-β-D-氨基葡萄糖苷酶(NAG酶);取空腹血清检测肌酐(Scr)、尿素氮(Bun)水平;取肾周脂肪组织,RT-PCR检测脂联素mRNA表达.结果 高血压模型大鼠组血压、微量尿蛋白、NAG酶明显高于WKY组(P＜0.05),而脂联素mRNA表达明显低于WKY组(P＜0.05);药物干预组血压、微量尿蛋白、NAG酶明显低于高血压模型大鼠组(P＜0.05),而脂联素mRNA表达高于高血压模型大鼠组(P＜0.05).结论 高血压模型大鼠脂肪组织脂联素mRNA表达下降;经福辛普利和氯沙坦干预后血压下降,微量尿蛋白和NAG酶下降,肾功能改善,同时脂肪组织脂联素mRNA表达增加.提示脂联素在高血压的发生发展过程中起着重要作用.     

瑞士乳杆菌TUST005发酵乳对先天性高血压大鼠血压和心率影响

目的研究瑞士乳杆菌TUST005发酵乳对8w龄先天性高血压大鼠的尾部动脉血压和心率可能产生的影响。方法将雄性原发性高血压大鼠,随机分为5组,每组8只,分别用发酵乳及乳清、水、脱脂乳和普通酸奶,每天灌胃1次,每一试验样品实验期为3d,剂量逐渐升高。用ZH-HX-Z鼠尾无创动脉测量仪测定收缩压和心率。结果当瑞士乳杆菌TUST005发酵乳剂量1.5ml与乳清剂量为2ml,血压的下降和上升速度相对缓慢,维持最低血压水平时间较长分别为4h和6h,降压效果最好且降压值为20.5mmHg。当瑞士乳杆菌TUST005发酵乳乳清剂量为1ml,心率下降幅度为50bpm。结论用瑞士乳杆菌发酵乳喂养SHR大鼠,能明显降低血压和心率。     

Blood and tissue zinc levels in spontaneously hypertensive rats.

Zinc (Zn) determinations were performed on blood plasma and red cells, liver, heart, adrenals, and spleen of spontaneously hypertensive (SHR) and control normotensive (WKY) male rats, 20 weeks of age. SHR revealed higher red cell (p = 2 × 10(?5)) and heart (p = 0.007) Zn levels than WKY rats. The water content of organs was the same in the two strains. When compared with published data, these results suggest an association between high cell Zn levels and hypertension, the meaning of which is briefly discussed.     

Dietary (n-3) fat and cholesterol alter tissue antioxidant enzymes and susceptibility to oxidation in SHR and WKY rats

Previously, 8% fish oil blend diets, compared to butter and soybean oil blend diets, reduced specific antioxidant enzyme activities and tissue susceptibility to in vitro oxidative stress in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. Moreover, high cholesterol (5.0 g/kg diet) diets protected against in vitro tissue lipid oxidation. In this study, we hypothesized that 160 g fat/kg diet as blends of (n-6) or (n-3) oils and cholesterol would alter antioxidant enzyme activities and thus increase tissue susceptibility to oxidation. The effects of diet blends of saturated (butter, B), (n-6) (soybean oil, SBO) or (n-3) (menhaden oil, MO) oils with cholesterol (0.5 or 5.0 g/kg) on systolic blood pressure (SBP), plasma lipids, antioxidant enzymes and susceptibility to oxidation were examined in SHR and WKY rats. SBP at 13 wk of age was greater (P < 0.001) in SHR than in WKY rats, but was not affected by diets. Plasma cholesterol and triacylglycerols were decreased (P < 0.001) by MO diets. Hepatic glutathione reductase activities were reduced (P < 0.001) in SBO-fed SHR and enhanced in SBO- and MO-fed WKY rats. Glutathione levels were reduced (P < 0.001) in RBC and enhanced (P < 0.001) in livers of MO-fed rats. Lipid oxidation was enhanced (P < 0.001) in red blood cells (RBC) from SBO groups, and hearts and livers of MO groups. High cholesterol diets reduced (P < or = 0.001) susceptibility to lipid peroxidation in RBC and liver of SHR and WKY rats. Greater amounts of dietary (n-3) fat enhance tissue susceptibility to oxidation, which can be modulated by increased dietary cholesterol in SHR and WKY rats.     

Blood Pressure-Lowering Effect of Wine Lees: Dose-Response Study,Effect of Dealcoholization and Possible Mechanisms of Action

The antihypertensive effect of wine lees (WL) has been previously evidenced. In this study, the antihypertensive properties of different doses of WL were evaluated in spontaneously hypertensive rats (SHR). In addition, the blood pressure (BP)-lowering effect of dried (dealcoholized) WL powder (WLPW) and the mechanisms involved in its functionality were investigated. Furthermore, a possible hypotensive effect of WLPW was discarded in Wistar–Kyoto (WKY) rats. The administration of WL at different doses caused a dose-dependent decrease in BP of SHR up to 5.0 mL/kg bw, exhibiting the maximum decrease at 6 h post-administration. WLPW caused a greater drop in BP than WL, showing an antihypertensive effect higher and more prolonged than the drug Captopril. Moreover, the BP-lowering effect of WLPW was specific to the hypertensive state since an undesirable hypotensive effect in normotensive WKY rats was ruled out. Finally, WLPW improved oxidative stress and increased the activity of the antioxidant endogen system of SHR. These results suggest that WLPW could be used as functional ingredient for foods or nutraceuticals to ameliorate hypertension. Nevertheless, further clinical studies are needed to evaluate its long-term antihypertensive efficiency.     

Short-term effect of egg-white hydrolysate products on the arterial blood pressure of hypertensive rats

In the present study we evaluate the blood pressure-lowering effect of the following products: the hydrolysate obtained from egg white (EW) by enzymatic treatment with pepsin (HEW), the peptide fraction of HEW with molecular mass lower than 3000 Da (HEW<3000 Da), and three peptide sequences isolated from HEW<3000 Da (Tyr-Ala-Glu-Glu-Arg-Tyr-Pro-Ile-Leu: YAEERYPIL); (Arg-Ala-Asp-His-Pro-Phe-Leu: RADHPFL); and (Ile-Val-Phe (IVF)). These peptides, and also HEW and HEW<3000 Da, had been characterized previously in vitro as potent inhibitors of angiotensin-converting enzyme (ACE). EW and the products mentioned earlier were orally administered by gastric intubation, to 17-20-week-old male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. We measured the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) of the rats by the tail cuff method before administration and also 2, 4, 6, 8 and 24 h post-administration. Distilled water served as negative control, and we used captopril (50 mg/kg) as positive control to carry out similar experiments with a known ACE inhibitor. HEW, HEW<3000 Da and the three peptide sequences decreased SBP and DBP in SHR but they did not modify these variables in WKY rats. The peptide sequences YAEERYPIL, RADHPFL and IVF showed a potency to decrease blood pressure greater than HEW or HEW<3000 Da. The results obtained suggest that the studied products could be used as a functional food with potential therapeutic benefit in the prevention and treatment of hypertension.