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Search Results: 1 - 10 of 3267 matches for " Spontaneously hypertensive rats "
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Enalapril alters the formation of the collagen matrix in spontaneously hypertensive rats
Bomfim, Alfredo de Souza;Mandarim-de-Lacerda, Carlos Alberto;
Arquivos Brasileiros de Cardiologia , 2003, DOI: 10.1590/S0066-782X2003000900006
Abstract: objective: to assess the effect of the inhibition of the angiotensin-converting enzyme on the collagen matrix (cm) of the heart of newborn spontaneously hypertensive rats (shr) during embryonic development. methods: the study comprised the 2 following groups of shr (n=5 each): treated group - rats conceived from shr females treated with enalapril maleate (15 mg. kg-1.day-1) during gestation; and nontreated group - offspring of nontreated females. the newborns were euthanized within the first 24 hours after birth and their hearts were removed and processed for histological study. three fields per animal were considered for computer-assisted digital analysis and determination of the volume densities (vv) of the nuclei and cm. the images were segmented with the aid of image pro plus? 4.5.029 software (media cybernetics). results: no difference was observed between the treated and nontreated groups in regard to body mass, cardiac mass, and the relation between cardiac and body mass. a significant reduction in the vv[matrix] and a concomitant increase in the vv[nuclei] were observed in the treated group as compared with those in the nontreated group. conclusion: the treatment with enalapril of hypertensive rats during pregnancy alters the collagen content and structure of the myocardium of newborns.
The antihypertensive effect of ethyl acetate extract from red raspberry fruit in hypertensive rats
Jia Han,Liu Ji,Ufur Halmurat,He Geng
Pharmacognosy Magazine , 2011,
Abstract: Objectives: To evaluate the antihypertensive effect of Xinjiang red raspberry fruit ethyl acetate extract (EER) on spontaneously hypertensive rats (SHR) and its possible mechanism from antioxidant perspective. Materials and Methods: The SHR rats were randomly divided into 3 groups, and treated with EER low dose (EERL, 100 mg/kg/d), high dose (EERH, 200 mg/kg/d), and water (SHR) through gastric gavage daily for 5 weeks. Another 8 age-matched male Wistar-Kyoto rats were used as normotensive group (WKY). The systolic blood pressure (SBP) was measured by noninvasive tail-cuff method once a week. At the end of the treatment, blood samples were collected and serum concentrations of nitric oxide (NO), superoxide dismutase (SOD), malondialchehyche (MDA), and plasma endothelin (ET) were determined. Results: Treatment of SHR rats with EER lowered the blood pressure compared with that treated with water (SHR), and the high dose showed more significant reduction in blood pressure. Treatment of SHR rats with EER increased serum NO and SOD levels and lowered ET and MDA levels. As compared with control group, NO levels were increased significantly in EERL (P < 0.01), SOD was elevated more significantly in both EERL and EERH (P < 0.01); MDA was decreased significantly in EERH group (P < 0.05), whereas plasma ET decreased more significantly in the EERH group (P < 0.05). Conclusions: The red raspberry extracts demonstrated a dose-dependent antihypertensive effects in SHR and this may be related to increased NO activation and improved vascular endothelial dysfunction via antioxidation. These results confirmed that raspberries rich in polyphenols have potential cardiovascular protective effects.
Enalapril alters the formation of the collagen matrix in spontaneously hypertensive rats
Bomfim Alfredo de Souza,Mandarim-de-Lacerda Carlos Alberto
Arquivos Brasileiros de Cardiologia , 2003,
Abstract: OBJECTIVE: To assess the effect of the inhibition of the angiotensin-converting enzyme on the collagen matrix (CM) of the heart of newborn spontaneously hypertensive rats (SHR) during embryonic development. METHODS: The study comprised the 2 following groups of SHR (n=5 each): treated group - rats conceived from SHR females treated with enalapril maleate (15 mg. kg-1.day-1) during gestation; and nontreated group - offspring of nontreated females. The newborns were euthanized within the first 24 hours after birth and their hearts were removed and processed for histological study. Three fields per animal were considered for computer-assisted digital analysis and determination of the volume densities (Vv) of the nuclei and CM. The images were segmented with the aid of Image Pro Plus 4.5.029 software (Media Cybernetics). RESULTS: No difference was observed between the treated and nontreated groups in regard to body mass, cardiac mass, and the relation between cardiac and body mass. A significant reduction in the Vv[matrix] and a concomitant increase in the Vv[nuclei] were observed in the treated group as compared with those in the nontreated group. CONCLUSION: The treatment with enalapril of hypertensive rats during pregnancy alters the collagen content and structure of the myocardium of newborns.
GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome
Natalia M Leguisamo, Alexandre M Lehnen, Ubiratan F Machado, Maristela M Okamoto, Melissa M Markoski, Graziela H Pinto, Beatriz D Schaan
Cardiovascular Diabetology , 2012, DOI: 10.1186/1475-2840-11-100
Abstract: Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-α and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age.MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p?=?0.001, 9-mo: p?=?0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-α were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32?±?2, H: 42?±?2, C: 45?±?2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%).MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.Metabolic syndrome is a highly prevalent condition [1] and a determinant of increased cardiovascular risk [2] and type 2 diabetes [3]. Insulin resistance is the key factor that leads to several of the abnormalities associated with the syndrome [4]. The link between insulin resistance and metabolic syndrome was suggested to be inflammation [5], which is the most widely accepted hypothesis for its development [5-9]. Besides, hypertension is related to insulin resistance [4], a feature that can be genetically induced [10,11].GLUT4 is the insulin-sensitive glucose transporter which main role is to provide the insulin-stimulated glucose uptake by adipose tissue, skeletal muscle and the heart, tissues that specifically express this protein [12]. It has been extensively reported that transgenic mice lacking or overexpressing GLUT4 respecti
Treatment with captopril abrogates the altered expression of alpha1 macroglobulin and alpha1 antiproteinase in sera of spontaneously hypertensive rats
Norhaniza Aminudin, Nur-Atiqah H Abdullah, Hasni Misbah, Saiful A Karsani, Ruby Husain, See Z Hoe, Onn H Hashim
Proteome Science , 2012, DOI: 10.1186/1477-5956-10-17
Abstract: Five proteins of high abundance were found to be significantly altered when the 2-DE serum profiles of the SHR were compared to those that were similarly generated from the SDR. Analysis by mass spectrometry and database search identified the proteins as retinol binding protein 4, complement C3, albumin (19.9 kDa fragment), alpha1 macroglobulin and alpha1 antiproteinase, which are all known to be associated with hypertension. The altered expression of the two latter proteins was found to be abrogated when similar analysis was performed on sera of the SHR that were treated with captopril.Our data suggests that serum alpha1 macroglobulin and alpha1 antiproteinase are potentially useful complementary biomolecular indicators for monitoring of hypertension.Spontaneously hypertensive rats (SHR) have been widely used as an animal model to investigate primary hypertension and its relationship to cardiovascular diseases. The SHR strain was generated in the 1960s by Okamoto et al. by selective breeding of the Wistar-Kyoto rats with high blood pressure [1]. The blood pressure of SHR usually rises at around 5-6 weeks of age and the systolic pressure of an adult SHR may reach a value of between 180 and 200 mmHg. The SHR usually develops characteristics of cardiovascular diseases like hypertrophy of the heart and blood vessels, which start at around 40 weeks of age [2].Hypertension has been known to cause the altered levels of serum or plasma proteins. A considerable number of proteins have been previously reported to be altered in levels in the sera of both animals and human subjects [3-6]. While some of the proteins were thought to be involved as anti-inflammatory and protective response [4,7], others were related to endothelial vascular repair [5], arterial smooth muscle cell growth [6] and some may instead be the contributing factors of hypertension.In the present study, we have investigated the simultaneous expression of the high abundant serum proteins in the normotensive S
Alveolar bone healing process in spontaneously hypertensive rats (SHR): A radiographic densitometry study
Manrique, Natalia;Pereira, Cassiano Costa Silva;Garcia, Lourdes Maria Gonzáles;Micaroni, Samuel;Carvalho, Antonio Augusto Ferreira de;Perri, Sílvia Helena Venturoli;Okamoto, Roberta;Sumida, Doris Hissako;Antoniali, Cristina;
Journal of Applied Oral Science , 2012, DOI: 10.1590/S1678-77572012000200017
Abstract: hypertension is one of the most important public health problems worldwide. if undiagnosed or untreated, this pathology represents a systemic risk factor and offers unfavorable conditions for dental treatments, especially those requiring bone healing. objectives: the purpose of this study was to demonstrate, by analysis of bone mineral density (bmd), that the alveolar bone healing process is altered in spontaneously hypertensive rats (shrs). material and methods: wistar rats and shrs were submitted to extraction of the upper right incisor and were euthanized 7, 14, 21, 28 and 42 days after surgery. right maxillae were collected, radiographed and analyzed using digora software. bmd was expressed as minimum (min), middle (med) and maximum (max) in the medium (mt) and apical (at) thirds of the dental alveolus. results: the results were compared across days and groups. wistar showed difference in med and max bmd in the mt between 7 and 28 and also between 14 and 28 days. the at exhibited significant difference in med and min bmd between 7 and 28 days, as well as difference in min bmd between 28 and 42 days. shrs showed lower med bmd in the mt at 28 days when compared to 21 and 42 days. differences were observed across groups in med and min bmd at day 28 in the mt and at; and in max bmd at 14, 21 and 42 days in the mt. conclusions: these results suggest that the alveolar bone healing process is delayed in shrs comparing with wistar rats.
Abnormalities of glucose metabolism in spontaneously hypertensive rats
Gouveia, L.M.F.B.;Kettelhut, I.C.;Foss, M.C.;
Brazilian Journal of Medical and Biological Research , 2000, DOI: 10.1590/S0100-879X2000001100015
Abstract: abnormalities in glucose metabolism and insulin action are frequently detected in patients with essential hypertension. spontaneously hypertensive rats (shr) have been used as an experimental model to understand this pathological condition. the objective of the present study was to assess glucose metabolism and insulin action in shr and wistar rats under fed and fasting conditions. peripheral glucose utilization was estimated by kinetic studies with [6-3h]-glucose and gluconeogenetic activity was measured during continuous [14c]-bicarbonate infusion. plasma glucose levels were higher in the shr group. plasma insulin levels in the fed state were higher in the shr group (99.8 ± 6.5 μm) than in the control group (70.4 ± 3.6 μm). muscle glycogen content was reduced in shr compared to control under the various experimental conditions. peripheral glucose utilization was slightly lower in the shr group in the fed state (8.72 ± 0.55 vs 9.52 ± 0.80 mg kg-1 min-1 in controls). serum free fatty acid levels, hepatic glycogen levels, hepatic phosphoenolpyruvate carboxykinase activity and gluconeogenetic activity were similar in the two groups. the presence of hyperglycemia and hyperinsulinemia and the slightly reduced peripheral glucose utilization suggest the presence of resistance to the action of insulin in peripheral tissues of shr. hepatic gluconeogenesis does not seem to contribute to the metabolic alterations detected in these animals.
Effects of losartan combined with exercise training in spontaneously hypertensive rats
Azevedo, L.F.;Brum, P.C.;Mattos, K.C.;Junqueira, C.M.;Rondon, M.U.P.B.;Barretto, A.C.P.;Negrao, C.E.;
Brazilian Journal of Medical and Biological Research , 2003, DOI: 10.1590/S0100-879X2003001100018
Abstract: we investigate whether combined treatment with losartan, an angiotensin ii receptor blocker, and exercise training (et) in spontaneously hypertensive rats (shr) would have an additive effect in reducing hypertension and improving baroreflex sensitivity when compared with losartan alone. male shr (8 weeks old) were assigned to 3 groups: sedentary placebo (sp, n = 16), sedentary under losartan treatment (sl, n = 11; 10 mg kg-1 day-1, by gavage), and et under losartan treatment (tl, n = 10). et was performed on a treadmill 5 days/week for 60 min at 50% of peak vo2, for 18 weeks. blood pressure (bp) was measured with a catheter inserted into the carotid artery, and cardiac output with a microprobe placed around the ascending aorta. the baroreflex control of heart rate was assessed by administering increasing doses of phenylephrine and sodium nitroprusside (iv). losartan significantly reduced mean bp (178 ± 16 vs 132 ± 12 mmhg) and left ventricular hypertrophy (2.9 ± 0.4 vs 2.5 ± 0.2 mg/g), and significantly increased baroreflex bradycardia and tachycardia sensitivity (1.0 ± 0.3 vs 1.7 ± 0.5 and 2.0 ± 0.7 vs 3.2 ± 1.7 bpm/mmhg, respectively) in sl compared with sp. however, losartan combined with et had no additional effect on bp, baroreflex sensitivity or left ventricular hypertrophy when compared with losartan alone. in conclusion, losartan attenuates hypertension and improves baroreflex sensitivity in shr. however, et has no synergistic effect on bp in established hypertension when combined with losartan, at least at the dosage used in this investigation.
Renin angiotensin system and cardiac hypertrophy after sinoaortic denervation in rats
Piratello, Aline Cristina;Moraes-Silva, Ivana;Paulini, Janaina;Souza, Pamella Ramona;Sirvente, Raquel;Salemi, Vera;Flues, Karin;Moreira, Edson Dias;Mostarda, Cristiano;Cunha, Tatiana;Casarini, Dulce Elena;Irigoyen, Maria Claudia;
Clinics , 2010, DOI: 10.1590/S1807-59322010001200019
Abstract: objective: the aim of this study was to evaluate the role of angiotensin i, ii and 1-7 on left ventricular hypertrophy of wistar and spontaneously hypertensive rats submitted to sinoaortic denervation. methods: ten weeks after sinoaortic denervation, hemodynamic and morphofunctional parameters were analyzed, and the left ventricle was dissected for biochemical analyses. results: hypertensive groups (controls and denervated) showed an increase on mean blood pressure compared with normotensive ones (controls and denervated). blood pressure variability was higher in denervated groups than in their respective controls. left ventricular mass and collagen content were increased in the normotensive denervated and in both spontaneously hypertensive groups compared with wistar controls. both hypertensive groups presented a higher concentration of angiotensin ii than wistar controls, whereas angiotensin 1-7 concentration was decreased in the hypertensive denervated group in relation to the wistar groups. there was no difference in angiotensin i concentration among groups. conclusion: our results suggest that not only blood pressure variability and reduced baroreflex sensitivity but also elevated levels of angiotensin ii and a reduced concentration of angiotensin 1-7 may contribute to the development of left ventricular hypertrophy. these data indicate that baroreflex dysfunction associated with changes in the renin angiotensin system may be predictive factors of left ventricular hypertrophy and cardiac failure.
Role of NADPH Oxidase in the Endothelial Dysfunction and Oxidative Stress in Aorta of Aged Spontaneous Hypertensive Rats
Ashraf Taye,Sven Wind
Iranian Journal of Basic Medical Sciences , 2010,
Abstract: Objective(s)Increased reactive oxygen species (ROS) production is implicated in the pathogenesis of arterial hypertension and the development of endothelial dysfunction. NADPH oxidase type enzyme family has been suggested to form ROS and to interfere with endothelium-dependent relaxation. However, the specific isoform of NADPH oxidases that may predominantly contribute to these events remains to be clarified. Materials and MethodsHere we investigated the expressional regulation of NADPH oxidase isoforms (NOX1, NOX2 and NOX4) in aorta of aged spontaneously hypertensive rats (SHR) in comparison to age matched Wistar Kyoto rats (WKY). Moreover, we examined the effect of in vitro inhibition of NADPH oxidase by apocynin or the novel NADPH oxidase inhibitor, VAS2870 on the vascular reactivity and ROS production.ResultsOur results showed that ROS formation was largely increased in aorta of SHR as measured by dihydroethidine (DHE) fluorescence and inhibited by apocynin or VAS2870. NADPH oxidase activity, measured by lucigenin-enhanced chemiluminescence and of NOX1 and NOX2 protein levels were increased in aortic homogenates from SHR compared to WKY. However, NOX4 protein expression was not significantly changed. Furthermore, the impaired acetylcholine-induced relaxation of SHR aorta was significantly improved in the presence of either apocynin or VAS2870. ConclusionCollectively, our data suggest that NADPH oxidases, particularly NOX1 and NOX2 are relevant sources of ROS in the aorta of aged SHR thereby cause endothelial dysfunction, and VAS2870 is effective as apocynin in reversing these consequences.Aorta, Endothelial dysfunction, Oxidative stress, Spontaneously hypertensive rats
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