Rats – ABC CARDIOL

IJCS

Original Article

Garlic Extract Reverses Ischemic Heart Disease in Female Rats Exposed to Combined Oral Contraceptive Pills

Onitsha Enebrayi Nelson et al. Gborienemi George Simeon Okutu Jackson Borobuebi Mie-Ebi Martin Wankasi Ezeiruaku Ferdinand Chukwuma

Abstract

Background

Garlic is an herbal medicinal plant with several pharmacological properties used for the management of various ailments. However, its potential in the reversal of ischemic heart disease induced by combined oral contraceptive pills is not well reported.

Objective

This study investigated the cardioprotective potential of aqueous garlic extract against cardiotoxicity induced by oral contraceptive pills.

Methods

Forty-six rats were used for this study. Six were used to determine the lethal dose (LD₅₀), and 40 rats were divided randomly into 5 groups of 8 rats each. Group A received feed and distilled water. Group B received 0.6 mg/kg of oral contraceptive pills. Group C received 500 mg/kg of garlic extract. Group D received 0.6 mg/kg of oral contraceptive pills + 500 mg/kg garlic extract. Group E received 0.6 mg/kg of oral contraceptive pills + 700 mg/kg garlic extract. The animals were sacrificed, and blood and tissue samples were collected for biochemical and histological analysis. Statistical analysis was done using SPSS, and p values < 0.05 were considered significant.

Results

The acute toxicity dose of combined oral contraceptive pills was 1.5 mg/kg for albino rats. Combined oral contraceptive pills induced ischemic necrosis as revealed by the photomicrographs, in addition to elevation of serum cardiac troponin-1, lactate dehydrogenase, creatine kinase, and malondialdehyde levels. Treatment with garlic extract demonstrated significant reduction in cardiac troponin-1 (p = 0.000), lactate dehydrogenase (p = 0.002), creatine kinase (p = 0.001), and malondialdehyde (p = 0.001) levels, as well as restoration of the cardiac cytoarchitecture changes caused by the combined oral contraceptive pills.

Conclusion

This study has demonstrated that aqueous garlic juice can reverse ischemic heart disease, lessen cytoarchitectural alterations of the heart caused by combined oral contraceptive pills, and thus ameliorate cardiac dysfunction.

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IJCS

Editorial

Hyperthyroidism and Cardiac Contractility

Dhiãnah Santini de Oliveira Chachamovitz

Much information is lacking on hyperthyroidism and cardiac function, especially in isolated muscles. Certainly, the time the heart muscle is exposed to elevated thyroid hormones (TH) influences the magnitude of their effects. The primary changes seem to be related to increases in the heart mass/body mass ratio and in relaxation kinetics.

These cardiac changes may also be related not only to the time of exposure to excess thyroid hormones, but to the level or intensity of hyperthyroidism, as well as the underlying cardiac condition, which may reflect exercise conditioning and overload. In this sense, the cellular mechanisms of muscle adaptation, energy and oxygen consumption, certainly make differences. As well as muscle strength and sarcoplasmic/endoplasmic reticulum calcium (SRCa) activity, they may also have different individual adaptive characteristics.

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IJCS

Original Article

Effects of Hyperthyroidism on Contractility and Na+/Ca2+ Exchanger Activity in the Isolated Papillary Muscle of Rats

Angela Mara Rambo et al. João Victor Capelli Peixoto Rebeca Alves Lins de Albuquerque Ilana Kassouf Silva Rosalvo Tadeu Hochmueller Fogaça

Abstract

Background:

Hyperthyroidism (Hy) is an endocrine disorder, in which the thyroid hormones markedly alter the cardiac function. Increased myocardial contractility and cardiac output, improvement in diastolic relaxation, changes in electrical activity, increments in ventricular mass, and arrhythmias have been reported. However, the influences of thyroid hormones upon molecular mechanisms of cardiac functions have not yet been fully understood.

Objectives:

To evaluate changes in cardiac contractile parameters and the Na+/Ca2+ exchanger (NCX) function in induced hyperthyroid rats.

Methods:

Hy was induced by intraperitoneal injections of T3 (15 μg/100 g) for 10 days. Contractile parameters and NCX function were evaluated in the isolated papillary muscle. Data normality was confirmed by the Shapiro-Wilk test. The comparison between groups was performed through an unpaired Student’s t-test. Results are expressed as mean ± SD. The accepted significance level was p < 0.05.

Results:

Our data revealed, in the Hy group, an increase of 30.98% in the maximum speed of diastolic relaxation (–284.64 ± 70.70 vs. –217.31 ± 40.30 mN/mm2/sec (p = 0.027)) and a boost of 149% in the NCX function in late phase of relaxation (20.17 ± 7.90 vs. 50.22 ± 11.94 minutes (p = 0.002)), with no changes in the maximum twitch force (p = 0.605) or maximum speed of systolic contraction (p = 0.208) when compared to the control.

Conclusion:

The improvement in relaxation parameters is hypothetically attributed to an increase in Sarco-Endoplasmic Reticulum Ca2+ATPase isoform 2 (SERCA2) expression and an increased calcium flow through L-type channels that boosted the NCX function.

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IJCS

Original Article

Radioprotective Effect of Nigella Sativa Oil on Heart Tissues of Rats Exposed to Irradition

Mehmet Kaplan et al. Elif Demir Fethi Yavuz Gizem Ilgin Kaplan … Mehmet Resit Taysi Seyithan Taysi Mehmet Murat Sucu

Abstract

Background

Various studies are ongoing related to the radioprotective agents. Herbal preparations are currently becoming popular because of their beneficial effects with fewer side effects compared to the synthetic/semi-synthetic medicines, and Nigella sativa oil (NSO) is only one of them.

Objective

To investigate NSO for its antioxidant effects on the heart tissue of rats exposed to ionizing radiation (IR).

Methods

Thirty six male albino Wistar rats, divided into four groups, were designated to group I (IR plus NSO group) that received both 5 Gray of gamma IR to total cranium and NSO; group II (IR alone group) that received IR plus saline, group III (control group of NSO) that received saline and did not receive NSO or IR; group IV (control group) that received only sham IR. Alterations in Total antioxidant status (TAS) and Total oxidant status (TOS), Oxidative stres index (OSI), Sulhydryl group (SH), Lipid hydroperoxide (LOOH), Paraoxonase (PON) levels, Arylesterase (ARE) and Ceruloplasmin (CER) activities in homogenized heart tissue of rats were measured by biochemical methods.

Results

In heart tissue of the rats in the IR alone group (group II) LOOH, TOS and OSI levels were found to be higher, ARE activity and TAS level were found to be lower than all of the other groups (p < 0.01). These results also support that IR increases oxidative stress and NSO's protective effect.

Conclusion

NSO would reduce the oxidative damage in the irradiated heart tissue in the experimental rat model.

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Original Article

Maternal Intake of Flaxseed During Lactation and Exercise Training Protect Against Salt Overload-Induced Aortic Remodeling in Adult Offspring

Simoni Silva-Couto et al. André Manoel Correia-Santos Gabriela Câmara Vicente Caroline Luiza Codonho Castro … Vanessa de Lana Melo Barreto Joyce Eduarda Campos Martins Queila Lenzi Gilson Teles Boaventura Maurício Alves Chagas

Abstract

Background

High dietary sodium intake can induce endothelial stiffness even without changes in blood pressure.

Objectives

To evaluate the effects of exercise training and chronic intake of sodium chloride solution on aortic morphology of male offspring of rat dams who consumed flaxseed during lactation.

Methods

Female rats were fed with a control diet or a flaxseed diet during lactation. At weaning, two male offspring of each rat dam were allocated into eight groups for 180 days: four groups received a control diet e four received a flaxseed diet, with /without exercise and with/without NaCl solution supply. Aorta was collected for histomorphometric analysis. The one-way analysis of variance was used and P value < 0.05 was considered statistically significant.

Results

The chronic use of 1% NaCl solution led to changes in aortic histoarchitecture in the control group: increase in aortic intima-media thickness (10,4%, p<0.0001) and reduced number of elastic lamellae (-8,1%, p<0.0001). Groups of offspring of mother that consumed flaxseed during lactation, the chronic use of 1% NaCl alone did not lead to an increase in the aortic intima-media thickness. Exercise training of adult offspring increased aortic intima-media thickness (13.3%, p<0.0001), with preservation of elastic components and aortic flexibility.

Conclusion

Chronic salt overload caused adverse effects on the aorta of rats, and maternal consumption of the flaxseed diet during lactation protected against aortic remodeling. Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0

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Editorial

Relevance of Animal Models and Echocardiogram for Hypertensive Disease Studies

Karyne Pollo de Souza et al. Christianne Brêtas Viera Scaramello

Hypertension is the main risk factor for the development of cardiovascular diseases, such as cerebrovascular and ischemic heart diseases, as well as for premature death worldwide. The prevalence of this condition was about 30% in low-, middle- and high-income countries in 2010. Cardiovascular pharmacotherapy and lifestyle changes constitute important measures to manage cardiovascular diseases, and the reduction of blood pressure is a fundamental strategy to prevent and treat them. Systemic arterial hypertension is a clinical multifactorial condition. The underlying mechanisms of hypertensive disease are complex, which is why it is essential to elucidate them. Many animal models of hypertension can serve this purpose, most of which were developed considering the probable causes of this condition, such as high salt intake and renin-angiotensin-aldosterone system overactivity. It is important that each model exploit a single pathway to hypertension development.

Spontaneously hypertensive rats (SHR) are genetically modified animals commonly chosen for several studies, including antihypertensive drugs screening. They provide an inexpensive experimental model and have a hypertensive phenotype similar to human patients. There are also endocrine models of hypertension, including the administration of deoxycorticosterone acetate (plus salt) and N-ω-nitro-L-arginine methyl- ester (L-NAME). According to the literature, both SHR and L-NAME models are related to sympathetic overactivity.^,

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Original Article

Electrocardiographic Abnormalities in Hypertension Models

Ana Gabriela Conceição-Vertamatti et al. Filipy Borghi Larissa Yuri Ishizu Gustavo Trevisan Costa … Luiz Alberto Ramos Miguel Arcanjo Areas Dora Maria Grassi-Kassisse

Abstract

Background:

Hypertensive condition can lead to abnormalities in heart structure and electrical activity. The electrocardiogram (ECG) is a recording of the electrical activity of the heart and widely used to diagnose and detect heart problem.

Objective:

We conducted a comparative ECG analysis between two hypertension models (L-NAME and SHR) and their controls (Wistar and Wistar-Kyoto) at six and 15 ^th week of age.

Methods:

Blood pressure was measured at the end of the 15 ^th week, and electrocardiography was performed at six and 15 weeks of age in anaesthetized rats. Data normality was confirmed by Kolmogorov-Smirnov test followed by unpaired Student’s t-test and the Mann-Whitney for parametric and non-parametric data, respectively. Results are expressed as mean ± SD. The accepted level of significance was set at p < 0.05.

Results:

L-NAME exhibited prolongation of JT and QT intervals and SHR showed a decrease in heart rate when compared to Wistar-Kyoto and L-NAME. Wistar-Kyoto exhibited short PR interval with increased QRS complex, and only QT prolongation at 15 weeks compared to Wistar.

Conclusions:

All the hypertension models used in this study featured an increase in blood pressure. However, while SHR showed cardiac dysfunction, L-NAME exhibited changes in ventricular performance. These results may guide future studies on different types and models of hypertension.

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Original Article

Protective Effects of Accumulated Aerobic Exercise in Infarcted Old Rats

Daniele Jardim Feriani et al. Hélio José Coelho-Júnior Maria Cláudia Irigoyen Bruno Rodrigues

Abstract

Background:

Aerobic exercise exerts cardioprotective effects on myocardial infarction. However, there is lack of information about the possible protective effects of continuous or accumulated aerobic exercise performed prior to myocardial infarction in aging.

Objective:

To evaluate the preventive effects of continuous or accumulated aerobic exercise on physical capacity, pulmonary congestion and ventricular weight in rats submitted to myocardial infarction.

Methods:

Old male Wistar rats were divided into four groups: sham control, sedentary infarcted, continuous aerobic exercise submitted to myocardial infarction, and accumulated aerobic exercise submitted to myocardial infarction. Body weight and maximum speed were evaluated at the beginning and at the end of the protocol. Trained groups performed continuous (1 h a day) or accumulated (30 minutes in the morning and 30 minutes in the afternoon) exercise. All groups, except the sham control, were submitted to myocardial infarction surgery at the end of the protocol. Heart, skeletal muscles, as well as wet and dry lung were weighed. The significance level in statistical analysis was established at p < 0.05.

Results:

Both continuous and accumulated exercise caused an increase in physical capacity in rats, as well as prevented its further impairment after myocardial infarction, and in the accumulated exercise group this prevention was greater. The continuous exercise group demonstrated an increase in lung water content, while the accumulated exercise group presented a reduction in body weight and an increase in left ventricle relative weight.

Conclusion:

In conclusion, the data of the present study indicate that accumulated aerobic exercise present a better protective effect than continuous aerobic training in the context of myocardial infarction and aging.

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ABC

Original Article

Lipid metabolism in rats fed diets containing different types of lipids

Márcia Barbosa Águila et al. Carla Cota Loureiro Alessandra da Rocha Pinheiro Carlos Alberto Mandarim-de-Lacerda

OBJECTIVE: To assess the effect of different types of lipid diets on the lipid metabolism of aging rats. METHODS: Fifty male Wistar rats were studied from the time of weaning to 12 and 18 months of age. Their diets were supplemented as follows: with soybean oil (S), canola oil (CA), lard and egg yolk (LE), and canola oil + lard and egg yolk (CA + LE). Blood pressure (BP) was measured every month, and the heart/body ratio (H/BR) was determined. The rats were euthanized at the age of 12 and 18 months, and blood samples were collected for lipid analysis as follows: total cholesterol (TC), LDL-C, VLDL-C, HDL-C, triglycerides (TG), and glucose. RESULTS: The type of oil ingested by the animals significantly altered BP, H/BR, and serum lipid levels in rats at 12 and 18 months. No difference was observed in the survival curve of the animals in the different groups. The LE group had the highest BP, and the CA group was the only one in which BP did not change with aging. A reduction in the H/BR was observed in the LE and CA+LE animals. At the age of 12 months, differences in TC, HDL-C, LDL-C, VLDL-C, TG, and glucose were observed. At the age of 18 months, a significant difference in TC, HDL-C, and glucose was observed. The highest TC value was found in the CA group and the lowest in the S group. CONCLUSION: No increase in BP occurred, and an improvement was evident in the lipid profile of rats fed a diet supplemented with CA, in which an elevation in HDL-C levels was observed, as compared with levels with the other types of diet.

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