scholarly journals Physical Training as a Blood Pressure Reducer and a Remodeler of Cardiac Fibers in Spontaneously Hypertensive Rats (SHR)

2021 ◽  
pp. 22-30
Author(s):  
Mariana Molinar Mauad Cintra ◽  
Matheus Ribeiro Bizuti ◽  
Octávio Barbosa Neto ◽  
Marlene Antônia dos Reis ◽  
Lenaldo Branco Rocha ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Physical Training ◽  
Spontaneously Hypertensive Rats ◽  
Cardiac Fibrosis ◽  
Left Ventricular ◽  
Type Iii Collagen ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Type Iii

Background: Hypertension is the most prevalent of all cardiovascular diseases, reaching target organs such as the heart. Blood pressure control is critical for preventing organ damage induced by hypertension. Objective: To analyze blood pressure, heart rate, left ventricular thickness, the percentage of cardiac fibrosis and the percentage of type III collagen in Spontaneously Hypertensive Rats (SHR) submitted to swimming physical training. Methods: The experimental groups were composed of male Wistar Kyoto (WKY) rats (309-311g), which were divided into: 1) Normotensive Sedentary group (SN) (n = 6); 2) Trained Normotensive group (TN) (n = 6); 3) Sedentary Hypertensive group (SH) (n = 6); 4) Trained Hypertensive group (TH) (n = 6). After the end of the protocol, the animals were initially anesthetized to measure blood pressure. Results: Physical training was responsible for decreasing blood pressure (F = 16,968; p <0.001) and heart rate (F = 10.710; p = 0.004) in the trained groups (normotensive and hypertensive). Moreover, training was responsible for providing an increase in the thickness of the left ventricle (F = 7,254; p = 0.014) and a reduction in the percentage of cardiac fibrosis (F = 16,081; p <0.001). Furthermore, it was observed that the trained group had lower values of type III collagen (F = 13,166; p = 0.002). Conclusions: Physical swimming training triggered a decrease in blood pressure, heart rate, the percentage of fibrosis and the percentage of type III collagen. In addition, there was also a cardiac remodeling due to the increase in left ventricular hypertrophy.

scholarly journals Effects of Chronic Cholinergic Stimulation Associated With Aerobic Physical Training on Cardiac Morphofunctional and Autonomic Parameters in Spontaneously Hypertensive Rats

2021 ◽  
Author(s):  
Camila B. Gardim ◽  
Ana Catarine V. Oliveira ◽  
Bruno Augusto Aguilar ◽  
Stella V. Philbois ◽  
Hugo C. D. Souza
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Physical Training ◽  
Spontaneously Hypertensive Rats ◽  
Low Frequency ◽  
Pyridostigmine Bromide ◽  
Cholinergic Stimulation ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Pharmacological Blockade

Abstract We investigated in spontaneously hypertensive rats (SHR) the hemodynamic, cardiac morphofunctional, and cardiovascular autonomic adaptations after a protocol of aerobic physical training associated with chronic cholinergic stimulation. Fifty-four SRH were divided into two groups: trained and untrained. Afterward, each group was subdivided into three smaller groups: vehicle, treated with pyridostigmine bromide at 5mg/kg/day, and at 15mg/kg/day. The following protocols were assessed: echocardiography, autonomic double pharmacological blockade, analysis of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS). Physical training and pyridostigmine bromide reduced blood pressure and heart rate and increased vagal participation in cardiac tonic autonomic balance. Associated the responses were potentialized. Pyridostigmine bromide increased the oscillation of low frequency (LF:0.2-0.75Hz) and high frequency (HF:0.75-3Hz) of HRV. However, the association with physical training attenuated HF oscillations. Pyridostigmine bromide also increased LF oscillations of BPV. Both treatments promoted morphofunctional adaptations and associated increased the ejection volume, ejection fraction, cardiac output, and cardiac index. In conclusion, the association of pyridostigmine bromide and physical training promoted greater benefits in hemodynamic parameters and increase vagal influence on cardiac autonomic tonic balance. Nonetheless, pyridostigmine bromide alone seems to negatively affect BPV, while the association of treatment negatively influences HRV.

Abstract 1378: NFkb Blockade Attenuate Cytokines And Oxidative Stress In The Paraventricular Nucleus And Decreases Neurohumoral Excitation In Spontaneously Hypertensive Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Nithya Mariappan ◽  
Carrie Elks ◽  
Masudul Haque ◽  
Philip J Ebnezer ◽  
Elizabeth McIIwain ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Paraventricular Nucleus ◽  
Spontaneously Hypertensive Rats ◽  
Left Ventricular ◽  
Oxidative Stress Markers ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Stress Markers ◽  
And Oxidative Stress

The transcriptional factor, nuclear factor kappa B (NFkB) plays an important role in the regulation of cytokines. Among the cytokines, tumor necrosis factor-alpha (TNF) plays an important role in cardiovascular pathophysiology. This study was done to determine whether TNF-α blockade with etanercept (ETN) or NFkB blockade with dithiol pyrolidine thiocarbamate (PDTC) attenuate oxidative stress in the paraventricular nucleus (PVN) and contribute to neurohumoral excitation in spontaneously hypertensive rats. Method: Male 20 week old SHR rats were treated with ETN (1 mg/kg BW, sc) or PDTC (100mg/kg BW, ip) for 5 week period. Left ventricular function was measured at baseline (20 weeks) and at 25 weeks using echocardiography. Blood pressure was measured at weekly intervals throughout the study. At the end of the protocol rats were sacrificed the PVN was microdissected for the measurement of cytokines, oxidative stress markers using real time PCR (fold increase compared to WKY controls) and by immunohistochemistry. Superoxide, total reactive oxygen species and peroxynitrite were measured in the PVN and LV using electron paramagnetic resonance. Plasma norepinephrine and epinephrine an indicator of neurohumoral excitation was measured using HPLC-EC. Results: PVN data are tabulated. SHR animals had increased expression of protein and mRNA for cytokines and oxidative stress markers in the PVN and LV with increased MAP and cardiac hypertrophy when compared to WKY rats. Treatment with ETN and PDTC attenuated these increases with PDTC showing marked effect than ETN on hypertrophy and blood pressure responses. Conclusion: These findings suggest that cytokine activation in the PVN contributes to increased oxidative stress and neurohumoral excitation in hypertension.

Exercise training modifies myocardial mitochondria and myofibril growth in spontaneously hypertensive rats

1985 ◽  
Vol 248 (1) ◽  
pp. H8-H14
Author(s):  
R. P. Crisman ◽  
R. J. Tomanek
Keyword(s):  
Blood Pressure ◽  
Exercise Training ◽  
Spontaneously Hypertensive Rats ◽  
Pressure Overload ◽  
Volume Ratio ◽  
Volume Density ◽  
Left Ventricular ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

We tested the hypothesis that exercise training provides a stimulus that could modify the decrement in mitochondria-to-myofibril volume ratio characteristic of myocardial cells hypertrophied in response to a pressure overload. Spontaneously hypertensive rats (SHR) were trained 5 days/wk on a treadmill at 70-90% maximal VO2 between the ages of 6 and 16 wk corresponding to the development of hypertension and cardiac hypertrophy. The training program increased maximal VO2 and effected a resting bradycardia but did not alter blood pressure, left ventricular hypertrophy, or peak cardiac output. Our stereological data from electron micrographs shows that the decrement in mitochondrial volume density and the increase in myofibril volume density characteristic of SHR compared with their normotensive controls (WKY, Wistar-Kyoto rats) were reversed. Thus the relative volumes of mitochondria and myofibrils and their ratio in trained SHR were similar to those of the WKY group. The similarity was noted in myocytes from both the subepicardium and subendocardium. These data suggest that exercise training facilitates a proportional growth of energy-producing and energy-consuming organelles in SHR and that this effect is not secondary to modification of blood pressure or left ventricular mass.

Regression of myocardial hypertrophy and influence of adrenergic system

1983 ◽  
Vol 244 (1) ◽  
pp. H97-H101 ◽  
Author(s):  
S. Sen ◽  
R. C. Tarazi
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Regression Analysis ◽  
Arterial Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Myocardial Hypertrophy ◽  
Cardiac Response ◽  
Adrenergic System ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive

Studies of regression of myocardial hypertrophy in spontaneously hypertensive rats (SHR) suggest that the adrenergic system may play an important role in the reversal of hypertrophy. The effect of propranolol on reversal of hypertrophy, however, is still controversial. This study describes the effect of propranolol, given alone or in combination with hydralazine in different ratios for 4 wk, on blood pressure (BP), ventricular weight, and myocardial catecholamine (MC) concentrations. The data show that a certain ratio of propranolol to hydralazine (750:30) leads to moderate BP control (196-156 mmHg) without increased MC (634 vs. 552 ng/g) and moderately reduced hypertrophy. Reduction of BP alone with increased MC (hydralazine alone) or reduction of MC without BP control (propranolol alone) failed to reduce hypertrophy. A significant correlation between both ventricular weight and heart rate with MC (r = 0.6) was obtained by multiple regression analysis. This study suggests that adrenergic factors seem to play an important role in modulating structural cardiac response to variations in arterial pressure.

scholarly journals Effects of Concentrated Ambient Particles on Heart Rate, Blood Pressure, and Cardiac Contractility in Spontaneously Hypertensive Rats

2004 ◽  
Vol 16 (6-7) ◽  
pp. 421-429 ◽  
Author(s):  
Chuen-Chau Chang ◽  
Jing-Shiang Hwang ◽  
Chang-Chuan Chan ◽  
Peng-Yau Wang ◽  
Tsuey-Hwa Hu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spontaneously Hypertensive Rats ◽  
Cardiac Contractility ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Ambient Particles
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