Treadmill exercise training prevents myocardial mechanical dysfunction induced by androgenic-anabolic steroid treatment in rats

Strength training improves heart function, collagen and strength in rats with heart failure

BACKGROUND/OBJECTIVES

Myocardial infarction (MI) frequently leads to cardiac remodeling and failure with impaired life quality, playing an important role in cardiovascular deaths. Although physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases, the effects of strength training (ST) on the structural and functional aspects of cardiac remodeling need to be further documented. In this study, we aimed to investigate the role of a linear block ST protocol in the rat model of MI.

METHODS AND RESULTS

After 6 weeks of MI induction or sham surgery, male adult rats performed ST for the following 12 weeks. The ladder-based ST program was organized in three mesocycles of 4 weeks, with one load increment for each block according to the maximal carrying load test. After 12 weeks, the infarcted-trained rats exhibited an increase in performance, associated with reduced cardiac hypertrophy and pulmonary congestion compared with the untrained group. Despite not changing MI size, the ST program partially prevented cardiac dilatation and ventricular dysfunction assessed by echocardiography and hemodynamics, and interstitial fibrosis evaluated by histology. In addition, isolated cardiac muscles from infarcted-trained rats had improved contractility parameters in a steady state, and in response to calcium or stimuli pauses.

CONCLUSIONS

The ST in infarcted rats increased the capacity to carry mass, associated with attenuation of cardiac remodeling and pulmonary congestion with improving cardiac function that could be attributed, at least in part, to the improvement of myocardial contractility.

Nandrolone Decanoate and Swimming Affects Cardiodynamic and Morphometric Parameters in the Isolated Rat Heart

(1) Background: The aim of this study was to show the effects of swimming and nandrolone administration on cardiodynamic and morphometric parameters of the isolated rat heart. (2) The study included 72 Wistar rats, divided into three groups, scheduled to be sacrificed after the second, third, and fourth week. Each group was divided into four subgroups: control (T-N-), nandrolone (T-N+), swimming training (T+N-), and swimming training plus nandrolone (T+N+) group. The rats from T+N- and T+N+ swam 1 h/day, 5 days/week while ones from T-N+ and T+N+ received weekly nandrolone decanoate (20 mg/kg). The isolated hearts were perfused according to the Langendorff technique and measured parameters: dp/dt max/min, SLVP, DLVP, heart rate, and coronary flow. Hearts were fixed and stained with H/E and Masson trichrome dyes. (3) dp/dt max and dp/dt min were increased in the T-N+ group at higher perfusion pressure compared to the T-N- group. SLVP and DLVP were increased in all groups after the 4th week. Collagen content was increased in T-N+ by 403% and in T+N+ by 357% groups, while it was decreased in T+N- compared to the control after 4th week. (4) Conclusions: Nandrolone alone or combined with swimming had a deleterious effect on myocardial function and perfusion.

Anti-Apoptotic Effects of Resistance Training and Tribulus Terrestris Consumption in the Heart Tissue of Rats Exposed to Stanozolol

Objective

Nowadays, the use of energetic substances has become a complex problem in sports, such that the role of anabolic-androgenic steroids is undeniable. This study aimed to investigate the antiapoptotic effect of resistance training and Tribulus terrestris in the heart tissue of rats exposed to stanozolol.

Materials and Methods

35 rats divided into 7 groups including (1) sham, (2) stanozolol-treated, (3) stanozolol+50 mg/kg Tribulus terrestris-treated, (4) stanozolol+100 mg/kg Tribulus terrestris-treated, (5) stanozolol+resistance training-treated, (6) stanozolol+resistance training+50 mg/kg Tribulus terrestris-treated, and (7) stanozolol+resistance training+100 mg/kg Tribulus terrestris-treated. During 8 weeks, groups 2-7 received 5 mg/kg stanozolol per day peritoneally; groups 5-7 performed resistance training for 3 sessions per week; and groups 3, 4, 6 and 7 received daily doses of Tribulus terrestris peritoneally.

Results

Stanozolol administration significantly increased the BAX, BCL-2, P53, and caspase 3 and BAX/BCL-2 ratio (P < .001). Resistance training, 100 mg/kg Tribulus terrestris administration, 50 mg/kg Tribulus terrestris administration, resistance training+100 mg/kg Tribulus terrestris administration, and resistance training+50 mg/kg Tribulus terrestris administration significantly decreased BAX, BCL-2, P53, and caspase 3 levels and BAX/BCL-2 ratio (P < .001); however, stanozolol+resistance training+100 mg/kg Tribulus terrestris administration caused more decrease than stanozolol+resistance training+50 mg/kg Tribulus terrestris administration in BAX (P < .001).

Conclusion

Resistance training and Tribulus terrestris administration alone appear to have antiapoptotic effects; however, resistance training combined with Tribulus terrestris administration, especially at higher doses, have more desirable effects than resistance training or Tribulus terrestris administration alone on the apoptosis markers.

Delayed Reperfusion-Coronary Artery Reperfusion Close to Complete Myocardial Necrosis Benefits Remote Myocardium and Is Enhanced by Exercise

The present study aimed to analyze the effects of reperfusion of a distant coronary artery on cardiac function, the ultrastructure, and the molecular environment of the remote myocardium immediately after the completion of myocardial regional necrosis: delayed reperfusion (DR). Additionally, the effects of prior exercise on the outcomes of DR were investigated. Female rats with permanent occlusion or delayed reperfusion were randomly assigned to an exercise (swimming, 1 h/day, 5 days/week for 8 weeks) or sedentary protocol. Thus, the study included the following four groups: sedentary permanent occlusion, exercise permanent occlusion, sedentary delayed reperfusion, and exercise delayed reperfusion. The descending coronary artery was occluded for 1 h. Reperfusion was confirmed by contrast echocardiography, and the rats were observed for 4 weeks. Permanent occlusion and DR caused similar myocardial infarction sizes among the four groups. Interestingly, exercise significantly decreased the mortality rate. Delayed reperfusion resulted in significant benefits, including enhanced hemodynamics and papillary muscle contraction, as well as reduced apoptosis and collagen content. Protein calcium kinetics did not change. Meanwhile, developed tension and the Frank–Starling mechanism were enhanced, suggesting that calcium sensitivity was intensified in myofilaments. Remarkable remote myocardial benefits occurred after distant DR, and prior exercise intensified cardiac recovery. Our findings provide valuable information about DR. Our data might explain the better clinical outcomes in recent studies showing that late reperfusion could improve heart failure in patients with myocardial infarction. In conclusion, DR has remote myocardial benefits, including inotropism enhancement, pulmonary congestion reduction, and collagen and apoptosis attenuation, which are enhanced by prior exercise.

Differences of Matrix Metalloproteinase 2 Expression between Left and Right Ventricles in Response to Nandrolone Decanoate and/or Swimming Training in Mice

Background:

Matrix metalloproteinase (MMP)-2 plays an important role in the remodeling of left ventricles (LVs) and right ventricles (RVs). We investigated the differences of MMP-2 expression between LV and RV in response to nandrolone decanoate (ND), swimming training (ST), and combined ND and ST (NS) in mice, based on their structural, functional, and biochemical characteristics.

Methods:

Totally 28 male C57B1 mice (6 weeks old; 20–23 g) were divided into four groups, including the control (n = 7), ND (n = 6), ST (n = 8), and NS (n = 7) groups. After respective treatments for 8 weeks, echocardiographic examination was used to assess the cardiac structure and function. Van Gieson stain was used to examine the fibrosis of LV and RV in response to different treatments, and Western blotting analysis was performed to explore different MMP-2 expressions between LV and RV in response to ND and/or ST. Analysis of variance was used for comparing the four groups.

Results:

At 8 weeks, right ventricular dimension/body weight in the ND group was larger than the other three groups (F = 7.12, P < 0.05) according to the echocardiographic examination. Fibrosis induced by ND administration was increased more in RV (2.59%) than that in LV (2.21%). MMP-2 expression of the ND group in RV was significantly greater than the control and NS groups in RV and the corresponding ND group in LV.

Conclusion:

The experimental data support the hypothesis that ND administration induces greater MMP-2 expression increase in RV compared to LV, leading to consequent RV dilation.

Effects of stanozolol on apoptosis mechanisms and oxidative stress in rat cardiac tissue

Stanozolol is a widely used 17α-alkylated anabolic androgenic steroid (AAS) derivative. Despite stanozolol's adverse effects, its effect on oxidative stress parameters and mitochondrial apoptosis pathway is not clearly defined. In our study, thirty four male Sprague-Dawley rats were divided into 5 groups as control (C), vehicle control (VC), steroid (ST), vehicle control-exercise (VCE), and steroid-exercise (STE). Animals were subcutaneously administered stanozolol 5 mg/kg in steroid groups and propylene glycol 1 ml/kg in the vehicle-control groups. On the 28th day-after sacrification, oxidative stress (MDA, GSH, PC, SOD, CAT) and apoptosis parameters (TUNEL, Cytochrome-c) in cardiac tissue were evaluated. Also, blood vessel morphology of cardiac tissue was evaluated with Verhoeff-van Giesen staining. It has been demonstrated that stanozolol administration triggers apoptosis by using TUNEL assay and cytochrome-c immunohistochemical staining intensity, while this effect is significantly reduced in the presence of exercise. In conclusion, the present study demonstrated that stanozolol administration induces apoptosis with increasing PC and CAT levels, while GSH, MDA and SOD parameters do not reveal any significant change. Exercise has a protective role in stanozolol induced oxidative stress and apoptosis. According to Verhoeff-van Giesen staining results for blood vessel morphology assessment, it has been seen that exercise has a protective role on cardiac blood vessels. This mechanism needs further investigations with long term exposure studies for clarifying possible pathways.

Administration of anabolic steroid during adolescence induces long-term cardiac hypertrophy and increases susceptibility to ischemia/reperfusion injury in adult Wistar rats

Chronic administration of anabolic androgenic steroids (AAS) in adult rats results in cardiac hypertrophy and increased susceptibility to myocardial ischemia/reperfusion (IR) injury. Molecular analyses demonstrated that hyperactivation of type 1 angiotensin II (AT1) receptor mediates cardiac hypertrophy induced by AAS and also induces down-regulation of myocardial ATP-sensitive potassium channel (K_ATP), resulting in loss of exercise-induced cardioprotection. Exposure to AAS during adolescence promoted long-term cardiovascular dysfunctions, such as dysautonomia. We tested the hypothesis that chronic AAS exposure in the pre/pubertal phase increases the susceptibility to myocardial ischemia/reperfusion (IR) injury in adult rats. Male Wistar rats (26day old) were treated with vehicle (Control, n=12) or testosterone propionate (TP) (AAS, 5mgkg^-1 n=12) 5 times/week during 5 weeks. At the end of AAS exposure, rats underwent 23days of washout period and were submitted to euthanasia. Langendorff-perfused hearts were submitted to IR injury and evaluated for mechanical dysfunctions and infarct size. Molecular analysis was performed by mRNA levels of α-myosin heavy chain (MHC), βMHC and brain-derived natriuretic peptide (BNP), ryanodine receptor (RyR2) and sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) by quantitative RT-PCR (qRT-PCR). The expression of AT1 receptor and K_ATP channel subunits (Kir6.1 and SURa) was analyzed by qRT-PCR and Western Blot. NADPH oxidase (Nox)-related reactive oxygen species generation was assessed by spectrofluorimetry. The expression of antioxidant enzymes was measured by qRT-PCR in order to address a potential role of redox unbalance. AAS exposure promoted long-term cardiac hypertrophy characterized by increased expression of βMHC and βMHC/αMHC ratio. Baseline derivative of pressure (dP/dt) was impaired by AAS exposure. Postischemic recovery of mechanical properties was impaired (decreased left ventricle [LV] developed pressure and maximal dP/dt; increased LV end-diastolic pressure and minimal dP/dt) and infarct size was larger in the AAS group. Catalase mRNA expression was significantly decreased in the AAS group. In conclusion, chronic administration of AAS during adolescence promoted long-term pathological cardiac hypertrophy and persistent increase in the susceptibility to myocardial IR injury possible due to disturbances on catalase expression.

Effect of Voluntary Ethanol Consumption Combined with Testosterone Treatment on Cardiovascular Function in Rats: Influence of Exercise Training

This study evaluated the effects of voluntary ethanol consumption combined with testosterone treatment on cardiovascular function in rats. Moreover, we investigated the influence of exercise training on these effects. To this end, male rats were submitted to low-intensity training on a treadmill or kept sedentary while concurrently being treated with ethanol for 6 weeks. For voluntary ethanol intake, rats were given access to two bottles, one containing ethanol and other containing water, three 24-hour sessions per week. In the last two weeks (weeks 5 and 6), animals underwent testosterone treatment concurrently with exercise training and exposure to ethanol. Ethanol consumption was not affected by either testosterone treatment or exercise training. Also, drug treatments did not influence the treadmill performance improvement evoked by training. However, testosterone alone, but not in combination with ethanol, reduced resting heart rate. Moreover, combined treatment with testosterone and ethanol reduced the pressor response to the selective α₁-adrenoceptor agonist phenylephrine. Treatment with either testosterone or ethanol alone also affected baroreflex activity and enhanced depressor response to acetylcholine, but these effects were inhibited when drugs were coadministrated. Exercise training restored most cardiovascular effects evoked by drug treatments. Furthermore, both drugs administrated alone increased pressor response to phenylephrine in trained animals. Also, drug treatments inhibited the beneficial effects of training on baroreflex function. In conclusion, the present results suggest a potential interaction between toxic effects of testosterone and ethanol on cardiovascular function. Data also indicate that exercise training is an important factor influencing the effects of these substances.

Nandrolone decanoate negatively reverses the beneficial effects of exercise on cardiac muscle via sarcolemmal, but not mitochondrial K(ATP) channel

ATP-sensitive potassium channels are supposed to have a substantial role in improvement of cardiac performance. This study was performed to evaluate whether nandrolone decanoate (ND) and (or) exercise training could affect the expression of cardiac K(ATP) channel subunits. Thirty-five male albino Wistar rats were randomly divided into 5 groups, including sedentary control (SC), sedentary vehicle (SV), sedentary ND (SND), exercise control (EC), and exercise and ND (E+ND). Exercise training was performed on a treadmill 5 times per week. ND was injected (10 mg/kg/week, i.m.) to the rats in the SND and E+ND groups. Following cardiac isolation, the expression of both sarcolemmal and mitochondrial subunits of K(ATP) channel was measured using Western blot method. The expression of sarcolemmal, but not mitochondrial, subunits of K(ATP) channel (Kir6.2 and SUR2) of EC group was significantly higher compared with SC group while ND administration (SND group) did not show any change in their expression. In the E+ND group, ND administration led to decrease of the over-expression of sarcolemmal Kir6.2 and SUR2 which was previously induced by exercise. There was no significant association between the mitochondrial expression of either Kir6.2 or SUR2 proteins and administration of ND or exercise. Supra-physiological dosage of ND negatively reverses the effects of exercise on the cardiac muscle expression of sarcolemmal, but not mitochondrial, K(ATP) channel subunits.

Testosterone modulates cardiac contraction and calcium homeostasis: cellular and molecular mechanisms

The incidence of cardiovascular disease rises dramatically with age in both men and women. Because a woman's risk of cardiovascular disease rises markedly after the onset of menopause, there has been growing interest in the effect of estrogen on the heart and its role in the pathophysiology of these diseases. Much less attention has been paid to the impact of testosterone on the heart, even though the levels of testosterone also decline with age and low-testosterone levels are linked to the development of cardiovascular diseases. The knowledge that receptors for all major sex steroid hormones, including testosterone, are present on individual cardiomyocytes suggests that these hormones may influence the heart at the cellular level. Indeed, it is well established that there are male-female differences in intracellular Ca(2+) release and contraction in isolated ventricular myocytes. Growing evidence suggests that these differences arise from effects of sex steroid hormones on processes involved in intracellular Ca(2+) homeostasis. This review considers how myocardial contractile function is modified by testosterone, with a focus on the impact of testosterone on processes that regulate Ca(2+) handling at the level of the ventricular myocyte. The idea that testosterone regulates Ca(2+) handling in the heart is important, as Ca(2+) dysregulation plays a key role in the pathogenesis of a variety of different cardiovascular diseases. A better understanding of sex hormone regulation of myocardial Ca(2+) homeostasis may reveal new targets for the treatment of cardiovascular diseases in all older adults.