Effects of different physical training protocols on ventricular oxidative stress parameters in infarction-induced rats

The Regulatory Role of Oxygen Metabolism in Exercise-Induced Cardiomyocyte Regeneration

During heart failure, the heart is unable to regenerate lost or damaged cardiomyocytes and is therefore unable to generate adequate cardiac output. Previous research has demonstrated that cardiac regeneration can be promoted by a hypoxia-related oxygen metabolic mechanism. Numerous studies have indicated that exercise plays a regulatory role in the activation of regeneration capacity in both healthy and injured adult cardiomyocytes. However, the role of oxygen metabolism in regulating exercise-induced cardiomyocyte regeneration is unclear. This review focuses on the alteration of the oxygen environment and metabolism in the myocardium induced by exercise, including the effects of mild hypoxia, changes in energy metabolism, enhanced elimination of reactive oxygen species, augmentation of antioxidative capacity, and regulation of the oxygen-related metabolic and molecular pathway in the heart. Deciphering the regulatory role of oxygen metabolism and related factors during and after exercise in cardiomyocyte regeneration will provide biological insight into endogenous cardiac repair mechanisms. Furthermore, this work provides strong evidence for exercise as a cost-effective intervention to improve cardiomyocyte regeneration and restore cardiac function in this patient population.

Improvement of Cardiac Function in Rats With Myocardial Infarction by Low-Intensity to Moderate-Intensity Endurance Exercise Is Associated With Normalization of Klotho and SIRT1

ABSTRACT

Exercise training (Ex) has beneficial effects on cardiovascular diseases by increasing Klotho and SIRT1. This study aimed to investigate whether the beneficial impact of Ex on myocardial infarction (MI) is mediated through Klotho and SIRT1. Fifty-six Wistar rats were divided into 4 main groups of Sham, MI, Ex, and MI + Ex. MI was induced by the closure of the left anterior descending. Animals were trained by endurance exercise for 4 weeks. In the end, hemodynamic and heart contractility indices were assessed. The levels of Klotho and SIRT1 in the serum and heart were measured by enzyme-linked immunosorbent assay and Western blot, respectively. The ADAM17 level in the heart and kidneys was assessed by enzyme-linked immunosorbent assay. The infarct size and fibrosis area were assessed by triphenyltetrazolium chloride and Masson trichrome staining, respectively. Ex recovered the reduction of dp/dt max and dp/dt min and decreased myocardial infarct size and fibrotic area in the MI group. Ex normalized the increase in heart rate, systolic blood pressure, left ventricular systolic pressure, and left ventricular end diastolic pressure in the MI group. Ex also normalized the reduction of the levels of Klotho and SIRT1 in serum and heart in the MI group. The changes of Klotho and SIRT1 in serum were positively correlated. Ex also restored ADAM17 levels in the MI group. Ex improved cardiac function in the MI group and is associated with reduction of the infarct size and normalization of Klotho and SIRT1 levels. Regarding unidirectional changes in Klotho and SIRT1, these proteins may play a role in beneficial effects of Ex on MI recovery.

Effects of Different Exercise Interventions on Cardiac Function in Rats With Myocardial Infarction

BACKGROUND

High-intensity interval training (HIIT) and aerobic training (AT) both improve cardiac function; however, their effects on cardiac function after myocardial infarction (MI) and the molecular mechanisms are unclear. In this study, HIIT, AT and sedentary (SED) interventions were performed for 4 weeks to compare the effects on cardiac function after MI and explore a more suitable approach for clinical application and the potential mechanisms.

METHODS

Twenty-four (24) male rats were randomly divided into a control group (CON), MI-sedentary group (MI-SED), MI-aerobic training group (MI-AT), and MI-high-intensity interval training group (MI-HIIT). After 4 weeks of intervention the exercise capacity, heart rate (HR), left ventricular end-diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), left ventricular ejection fraction (LVEF), AMP-activated protein kinase α1 (AMPKα1), cardiomyocyte morphology, and cardiac mitochondria were assessed.

RESULTS

After intervention: 1) exercise capacity in the MI-AT (49.08±3.141 m; p<0.001) and MI-HIIT (51.70±7.572 m; p<0.001) groups was significantly more increased than the MI-SED group; there was no significant difference between the MI-AT and MI-HIIT group (p=0.33). 2) LVEDD and LVESD in the MI-SED (p<0.01) and MI-HIIT (p<0.01) groups was significantly more increased than the CON group; the MI-AT group showed no significant difference in LVEDD and LVESD compared with the CON group; LVEF in the MI-AT (53.47±7.913%; p=0.03) and MI-HIIT (56.20±7.224%; p=0.006) groups was significantly more increased than the MI-SED group, and there was no statistical difference between the MI-AT and MI-HIIT groups. 3) AMPKα1 expression was significantly increased in the MI-AT (1.15±0.264; p=0.001) and MI-HIIT (1.04±0.238; p=0.003) groups and decreased in the MI-SED group (0.71±0.257; p<0.001) when compared with the CON group. 4) The MI-SED group exhibited sarcoplasmic dissolution and fibrous hyperplasia in the myocardium, cardiac mitochondrial damage and reduced mitochondrial numbers; the MI-HIIT group displayed swollen and vacuolated cardiac mitochondria with disrupted cristae; the MI-AT and MI-HIIT groups had significantly increased cardiac mitochondrial numbers than the MI-SED group; there was no statistical difference between the MI-AT and MI-HIIT groups.

CONCLUSIONS

Aerobic training and HIIT for 4 weeks had similar cardioprotection and were superior to SED intervention. Both AT and HIIT improved cardiac function and exercise capacity by upregulating AMPKα1 expression. However, 4 weeks of intervention resulted in left ventricular dilation and cardiac myocardial mitochondrial injury in the MI-HIIT group.

Short-term exercise training improves cardiac function associated to a better antioxidant response and lower type 3 iodothyronine deiodinase activity after myocardial infarction

Aims

We assessed the effects of a short-term exercise training on cardiac function, oxidative stress markers, and type 3 iodothyronine deiodinase (D3) activity in cardiac tissue of spontaneously hypertensive rats (SHR) following experimental myocardial infarction (MI).

Methods

Twenty-four SHR (aged 3 months) were allocated to 4 groups: sham+sedentary, sham+trained, MI+sedentary and MI+trained. MI was performed by permanent ligation of the coronary artery. Exercise training (treadmill) started 96 hours after MI and lasted for 4 weeks (~60% maximum effort, 4x/week and 40 min/day). Cardiac function (echocardiography), thioredoxin reductase (TRx), total carbonyl levels, among other oxidative stress markers and D3 activity were measured. A Generalized Estimating Equation was used, followed by Bonferroni’s test (p<0.05).

Results

MI resulted in an increase in left ventricular mass (p = 0.002) with decreased cardiac output (~22.0%, p = 0.047) and decreased ejection fraction (~41%, p = 0.008) as well as an increase in the carbonyl levels (p = 0.001) and D3 activity (~33%, p<0.001). Exercise training resulted in a decrease in left ventricular mass, restored cardiac output (~34%, p = 0.048) and ejection fraction (~20%, p = 0.040), increased TRx (~85%, p = 0.007) and reduced carbonyl levels (p<0.001) and D3 activity (p<0.001).

Conclusions

Our short-term exercise training helped reverse the effects of MI on cardiac function. These benefits seem to derive from a more efficient antioxidant response and lower D3 activity in cardiac tissue.

Cardioprotective effects of physical exercise on redox biology in mice exposed to hand-rolled cornhusk cigarette smoke

The present study sought to evaluate the effects of physical training on histological parameters and oxidative stress in the myocardium of mice chronically exposed to hand-rolled cornhusk cigarette (HRCC) smoke. Male Swiss mice (60 days old, 30-35 g) were either exposed to ambient air or passively exposed to the smoke of 12 cigarettes daily over 3 sessions (4 cigarettes per session) for 60 consecutive days with or without physical training for 8 weeks. Forty-eight hours after the last training session, the heart was surgically removed for histological analysis and measurement of oxidative stress parameters. Histological imaging revealed cell disruption, with poorly defined nuclei, in the mice exposed to HRCC smoke, but not in the control group. However, mice exposed to HRCC smoke with physical training displayed signs of tissue repair and improved tissue integrity. Biochemical analysis revealed decreased production of superoxide, 2',7'-dichlorofluorescein (DCF), and nitrite, as well as decreased protein carbonylation, in the physical training groups, likely due to the exercise-induced increase in glutathione peroxidase (GPX) activity and glutathione (GSH) content. Taken together, our results suggest that physical exercise exerts cardioprotective effects by modulating the redox responses in animals exposed to HRCC smoke.

Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice

The present study aimed to compare the effects of moderate-intensity continuous and high-intensity interval exercise training (ET) on exercise tolerance, cardiac morphometry and function, hemodynamic, and cardiac autonomic modulation in myocardial infarcted mice. Wild-type mice (WT) were divided into four groups: sedentary WT (S); WT myocardium infarction sedentary (IS); WT myocardium infarction underwent to moderate-intensity continuous ET (MICT), and WT myocardium infarction underwent to high-intensity interval ET (MIIT). After 60 days of descending coronary artery ligation, moderate-intensity continuous ET consisted of running at 60% of maximum, while the high-intensity interval training consisted of eight sprints of 4 min at 80% of maximum and a 4-min recovery at 40% of maximum. Both exercises were performed 1 hr a day, 5 days a week, during 8 weeks. Results demonstrated that IS showed elevated exercise tolerance, as well as decreased hemodynamic and heart function, and autonomic control. On the other hand, both programs of ET were equally effective to increase all parameters, without further differences between the groups. In conclusion, the results of the present study showed that myocardial infarction leads to damage in both investigated strains and the two types of physical exercise attenuated the major impairments provoked by myocardial infarction in exercise tolerance, cardiac structure, cardiac function, hemodynamic and cardiac autonomic modulation.

The IGF1-PI3K-Akt Signaling Pathway in Mediating Exercise-Induced Cardiac Hypertrophy and Protection

Regular physical activity or exercise training can lead to heart enlargement known as cardiac hypertrophy. Cardiac hypertrophy is broadly defined as an increase in heart mass. In adults, cardiac hypertrophy is often considered a poor prognostic sign because it often progresses to heart failure. Heart enlargement in a setting of cardiac disease is referred to as pathological cardiac hypertrophy and is typically characterized by cell death and depressed cardiac function. By contrast, physiological cardiac hypertrophy, as occurs in response to chronic exercise training (i.e. the 'athlete's heart'), is associated with normal or enhanced cardiac function. The following chapter describes the morphologically distinct types of heart growth, and the key role of the insulin-like growth factor 1 (IGF1) - phosphoinositide 3-kinase (PI3K)-Akt signaling pathway in regulating exercise-induced physiological cardiac hypertrophy and cardiac protection. Finally we summarize therapeutic approaches that target the IGF1-PI3K-Akt signaling pathway which are showing promise in preclinical models of heart disease.

Oxidative status of the myocardium in response to different intensities of physical training

The intensity of exercise determines the metabolic pathway and the energetic substrate that is spent. Our study sought to identify the effects of different intensities of swimming on myocardial oxidative status and the blood lipid profile. Eighty Wistar rats (male and female) submitted to different intensities of a swimming regimen (low, LS; moderate, MS; or high, HS) for 16 weeks. Samples of blood and myocardium from the left ventricle were collected to determine lipid profiles and oxidative status. Reactive oxygen species (ROS) and antioxidant capacity against peroxyl radicals (ACAP), lipid profiles and lipid peroxidation was analyzed. ROS levels and ACAP were higher in male rats than in female rats overall (p<0.05). However, ACAP in the myocardium was significantly elevated in LS female rats compared to the MS and HS female rats, which had a significantly lower ACAP compared to all other groups. LS and MS training in both sexes and HS training (in females) led to significant decreases in the heart's lipid peroxidation. Amelioration of the lipid profile and reduction in oxidative damage contributed to a physiological state that benefits cardiovascular function in exercised animals. The results show that low and moderate intensity exercise promotes beneficial adaptations.

Cell Therapy in Ischemic Heart Disease: Interventions That Modulate Cardiac Regeneration

The incidence of severe ischemic heart disease caused by coronary obstruction has progressively increased. Alternative forms of treatment have been studied in an attempt to regenerate myocardial tissue, induce angiogenesis, and improve clinical conditions. In this context, cell therapy has emerged as a promising alternative using cells with regenerative potential, focusing on the release of paracrine and autocrine factors that contribute to cell survival, angiogenesis, and tissue remodeling. Evidence of the safety, feasibility, and potential effectiveness of cell therapy has emerged from several clinical trials using different lineages of adult stem cells. The clinical benefit, however, is not yet well established. In this review, we discuss the therapeutic potential of cell therapy in terms of regenerative and angiogenic capacity after myocardial ischemia. In addition, we addressed nonpharmacological interventions that may influence this therapeutic practice, such as diet and physical training. This review brings together current data on pharmacological and nonpharmacological approaches to improve cell homing and cardiac repair.

What can we learn about treating heart failure from the heart's response to acute exercise? Focus on the coronary microcirculation

Coronary microvascular function and cardiac function are closely related in that proper cardiac function requires adequate oxygen delivery through the coronary microvasculature. Because of the close proximity of cardiomyocytes and coronary microvascular endothelium, cardiomyocytes not only communicate their metabolic needs to the coronary microvasculature, but endothelium-derived factors also directly modulate cardiac function. This review summarizes evidence that the myocardial oxygen balance is disturbed in the failing heart because of increased extravascular compressive forces and coronary microvascular dysfunction. The perturbations in myocardial oxygen balance are exaggerated during exercise and are due to alterations in neurohumoral influences, endothelial function, and oxidative stress. Although there is some evidence from animal studies that the myocardial oxygen balance can partly be restored by exercise training, it is largely unknown to what extent the beneficial effects of exercise training include improvements in endothelial function and/or oxidative stress in the coronary microvasculature and how these improvements are impacted by risk factors such as diabetes, obesity, and hypercholesterolemia.

Perinatal low-protein diet alters brainstem antioxidant metabolism in adult offspring

BACKGROUND AND OBJECTIVES

Studies in humans and animal models have established a close relationship between early environment insult and subsequent risk of development of non-communicable diseases, including the cardiovascular. Whereas experimental evidences highlight the early undernutrition and the late cardiovascular disease relation, the central mechanisms linking the two remain unknown. Owing to the oxidative balance influence in several pathologies, the aim of the present study was to evaluate the effects of maternal undernutrition (i.e. a low-protein (LP) diet) on oxidative balance in the brainstem.

METHODS AND RESULTS

Male rats from mothers fed with an LP diet (8% casein) throughout the perinatal period (i.e. gestation and lactation) showed 10× higher lipid peroxidation levels than animals treated with normoprotein (17% casein) at 100 days of age. In addition, we observed the following reductions in enzymatic activities: superoxide dismutase, 16%; catalase, 30%; glutathione peroxidase, 34%; glutathione-S-transferase, 51%; glutathione reductase, 23%; glucose-6-phosphate dehydrogenase, 31%; and in non-enzymatic glutathione system, 46%.

DISCUSSION

This study is the first to focus on the role of maternal LP nutrition in oxidative balance in a central nervous system structure responsible for cardiovascular control in adult rats. Our data observed changes in oxidative balance in the offspring, therefore, bring a new concept related to early undernutrition and can help in the development of a new clinical strategy to combat the effects of nutritional insult. Wherein the central oxidative imbalance is a feasible mechanism underlying the hypertension risk in adulthood triggered by maternal LP diet.

Effects of high-intensity interval versus continuous moderate-intensity aerobic exercise on apoptosis, oxidative stress and metabolism of the infarcted myocardium in a rat model

The optimal aerobic exercise training (AET) protocol for patients following myocardial infarction (MI) has remained under debate. The present study therefore aimed to compare the effects of continuous moderate-intensity training (CMT) and high-intensity interval training (HIT) on cardiac functional recovery, and to investigate the potential associated mechanisms in a post-MI rat model. Female Sprague Dawley rats (8-10 weeks old) undergoing MI or sham surgery were subsequently submitted to CMT or HIT, or kept sedentary for eight weeks. Prior to and following AET, echocardiographic parameters and exercise capacity of the rats were measured. Western blotting was used to evaluate the levels of apoptosis and associated signaling pathway protein expression. The concentrations of biomarkers of oxidative stress were also determined by ELISA assay. Messenger (m)RNA levels and activity of the key enzymes for glycolysis and fatty acid oxidation, as well as the rate of adenosine triphosphate (ATP) synthesis, were also measured. Compared with the MI group, exercise capacity and cardiac function were significantly improved following AET, particularly following HIT. Left ventricular ejection fraction and fraction shortening were further improved in the MI-HIT group in comparison to that of the MI-CMT group. The two forms of AET almost equally attenuated apoptosis of the post-infarction myocardium. CMT and HIT also alleviated oxidative stress by decreasing the concentration of malondialdehyde and increasing the concentration of superoxide dismutase and glutathione peroxidase (GPx). In particular, HIT induced a greater increase in the concentration of GPx than that of CMT. AET, and HIT in particular, significantly increased the levels of mRNA and the maximal activity of phosphofructokinase-1 and carnitine palmitoyl transferase-1, as well as the maximal ratio of ATP synthesis. In addition, compared with the MI group, the expression of signaling proteins PI3K, Akt, p38mapk and AMPK was significantly altered in the MI-CMT and MI-HIT groups. HIT was superior to CMT in its ability to improve cardiac function and exercise capability in a post-MI rat model. HIT was also superior to CMT with regard to attenuating oxidative stress and improving glucolipid metabolism of the post-MI myocardium.

High intensity interval and endurance training have opposing effects on markers of heart failure and cardiac remodeling in hypertensive rats

There has been re-emerging interest and significant work dedicated to investigating the metabolic effects of high intensity interval training (HIIT) in recent years. HIIT is considered to be a time efficient alternative to classic endurance training (ET) that elicits similar metabolic responses in skeletal muscle. However, there is a lack of information on the impact of HIIT on cardiac muscle in disease. Therefore, we determined the efficacy of ET and HIIT to alter cardiac muscle characteristics involved in the development of diastolic dysfunction, such as ventricular hypertrophy, fibrosis and angiogenesis, in a well-established rodent model of hypertension-induced heart failure before the development of overt heart failure. ET decreased left ventricle fibrosis by ~40% (P < 0.05), and promoted a 20% (P<0.05) increase in the left ventricular capillary/fibre ratio, an increase in endothelial nitric oxide synthase protein (P<0.05), and a decrease in hypoxia inducible factor 1 alpha protein content (P<0.05). In contrast, HIIT did not decrease existing fibrosis, and HIIT animals displayed a 20% increase in left ventricular mass (P<0.05) and a 20% decrease in cross sectional area (P<0.05). HIIT also increased brain natriuretic peptide by 50% (P<0.05), in the absence of concomitant angiogenesis, strongly suggesting pathological cardiac remodeling. The current data support the longstanding belief in the effectiveness of ET in hypertension. However, HIIT promoted a pathological adaptation in the left ventricle in the presence of hypertension, highlighting the need for further research on the widespread effects of HIIT in the presence of disease.

Exercise training reduces cardiac dysfunction and remodeling in ovariectomized rats submitted to myocardial infarction

The aim of this study was to evaluate whether exercise training (ET) prevents or minimizes cardiac dysfunction and pathological ventricular remodeling in ovariectomized rats subjected to myocardial infarction (MI) and to examine the possible mechanisms involved in this process. Ovariectomized Wistar rats were subjected to either MI or fictitious surgery (Sham) and randomly divided into the following groups: Control, OVX+SHAM_SED, OVX+SHAM_ET, OVX+MI_SED and OVX+MI_ET. ET was performed on a motorized treadmill (5x/wk, 60 min/day, 8 weeks). Cardiac function was assessed by ventricular catheterization and Dihydroethidium fluorescence (DHE) was evaluated to analyze cardiac oxidative stress. Histological analyses were made to assess collagen deposition, myocyte hypertrophy and infarct size. Western Blotting was performed to analyze the protein expression of catalase and SOD-2, as well as Gp91phox and AT1 receptor (AT1R). MI-trained rats had significantly increased in +dP/dt and decreased left ventricular end-diastolic pressure compared with MI-sedentary rats. Moreover, oxidative stress and collagen deposition was reduced, as was myocyte hypertrophy. These effects occurred in parallel with a reduction in both AT1R and Gp91phox expression and an increase in catalase expression. SOD-2 expression was not altered. These results indicate that ET improves the functional cardiac parameters associated with attenuation of cardiac remodeling in ovariectomized rats subjected to MI. The mechanism seems to be related to a reduction in the expression of both the AT1 receptor and Gp91phox as well as an increase in the antioxidant enzyme catalase, which contributes to a reduction in oxidative stress. Therefore, ET may be an important therapeutic target for the prevention of heart failure in postmenopausal women affected by MI.

Effect of exercise training on oxidative stress and mitochondrial function in rat heart and gastrocnemius muscle

OBJECTIVE

This study aimed to explore the effect of endurance training on oxidative parameters and mitochondrial function in gastrocnemius and heart muscle.

METHODS

Male Wistar rats were trained by running for 6 weeks. In vitro measurements of the rates of hydroxyl radical ((•)OH) production, oxygen consumption (in either the absence, basal rate (V0), or the presence, maximal rate (Vmax), of adenosine diphosphate), and adenosine triphosphate (ATP) production were made simultaneously in permeabilized fibers. The mitochondrial function was explored after exposure or non-exposure to an in vitro generator system of reactive oxygen species (ROS).

RESULTS

Vmax was not affected by training, but V0 decreased. In conditions of maximal mitochondrial functioning, an increase in ATP rate and a decrease in (•)OH production occurred simultaneously. In vitro ROS exposure disturbed mitochondrial function, but training modified the vulnerability of Vmax and ATP rate to ROS in different ways.

DISCUSSION

We hypothesize that the part of Vmax devoted to proton leakage was decreased in trained rats, consequently improving ATP synthesis. The data suggest that, after training, there is more efficient use of electrons in respiratory chain energy production, rather than a greater ROS scavenging capacity.

Aerobic exercise training induces an anti-apoptotic milieu in myocardial tissue

This study evaluated modulators of apoptosis in the myocardium of rats subjected to exercise training. Rats were assigned to non-trained and exercise-trained groups, respectively. The animals ran for 1 h per day, 6 times per week and, for a total of 13 weeks. The left ventricle was processed for analysis of gene and protein anti- (Bcl-2, c-IAP1, c-IAP2, Survivin, ILK, Akt and pAkt) and pro- (Bad) apoptotic expression by real-time PCR (except for Akt and pAkt) and Western blot, respectively. The Bad mRNA (p<0.05), but not the protein expression (p = 0.19), was significantly lower after training. The exercise training significantly increased the gene and protein expression for all anti-apoptotic factors. However, a significant change in the c-IAP2 was seen only for gene expression (p<0.05). The present findings indicate that exercise can create a favorable milieu for the survival of cardiomyocytes when apoptosis is increased.

Interval and continuous exercise training produce similar increases in skeletal muscle and left ventricle microvascular density in rats

Interval training (IT), consisting of alternated periods of high and low intensity exercise, has been proposed as a strategy to induce more marked biological adaptations than continuous exercise training (CT). The purpose of this study was to assess the effects of IT and CT with equivalent total energy expenditure on capillary skeletal and cardiac muscles in rats. Wistar rats ran on a treadmill for 30 min per day with no slope (0%), 4 times/week for 13 weeks. CT has constant load of 70% max; IT has cycles of 90% max for 1 min followed by 1 min at 50% max. CT and IT increased endurance and muscle oxidative capacity and attenuated body weight gain to a similar extent (P > 0.05). In addition, CT and IT similarly increased functional capillary density of skeletal muscle (CT: 30.6 ± 11.7%; IT: 28.7 ± 11.9%) and the capillary-to-fiber ratio in skeletal muscle (CT: 28.7 ± 14.4%; IT: 40.1 ± 17.2%) and in the left ventricle (CT: 57.3 ± 53.1%; IT: 54.3 ± 40.5%). In conclusion, at equivalent total work volumes, interval exercise training induced similar functional and structural alterations in the microcirculation of skeletal muscle and myocardium in healthy rats compared to continuous exercise training.

Moderate physical activity from childhood contributes to metabolic health and reduces hepatic fat accumulation in adult rats

BACKGROUND

Obesity, oxidative stress and inflammation, by triggering insulin resistance, may contribute to the accumulation of hepatic fat, and this accumulation by lipotoxicity can lead the organ to fail. Because obesity is growing at an alarming rate and, worryingly, in a precocious way, the present study aimed to investigate the effects of moderate physical training performed from childhood to adulthood on liver fat metabolism in rats.

METHODS

Twenty rats that were 28 days old were divided into two groups: control (C) and trained (T). The C Group was kept in cages without exercise, and the T group was submitted to swimming exercise for 1 hour/day, 5 days/week from 28 to 90 days of age (8 weeks) at 80% of the anaerobic threshold determined by the lactate minimum test. At the end of the experiment, the body weight gain, insulin sensitivity (glucose disappearance rate during the insulin tolerance test), concentrations of free fatty acids (FFA) and triglycerides (TG) and hepatic lipogenic rate were analyzed. For the statistical analysis, the Student t-test was used with the level of significance preset at 5%.

RESULTS

The T group showed lower body weight gain, FFA concentrations, fat accumulation, hepatic lipogenic rate and insulin resistance.

CONCLUSION

The regular practice of moderate physical exercise from childhood can contribute to the reduction of obesity and insulin resistance and help prevent the development of accumulation of hepatic fat in adulthood.

Therapeutic action of physical exercise on markers of oxidative stress induced by chronic kidney disease

AIMS

To investigate the effects physical training exerts on markers of oxidative stress in rats with chronic kidney disease (CKD).

MAIN METHODS

Twenty-four male Wistar rats were divided into four groups (n=6): sham, CKD, exercise-sham and exercise-CKD. Surgical reduction of the renal mass was performed (5/6 nephrectomized) and exercise was conducted on a treadmill (50 min/day up to 1 km/h for, 5 days/week for eight weeks). Forty-eight hours after the last exercise session, blood (1 mL) was collected from the abdominal aorta and animals were decapitated. The left kidney was surgically removed and stored at -70 °C for subsequent analysis.

KEY FINDINGS

An increase was observed in creatinine and urea levels, superoxide production, antioxidant enzymes, and oxidative damage in the CKD group, as compared to sham animals (p<0.05). Physical training made superoxide production and oxidative damage decrease in the CKD group (p<0.05), increasing SOD and GPX activity, though it did not increase the antioxidant effects of CAT, and renal parameters.

SIGNIFICANCE

Even without altering renal function in animals induced to CKD model, the results show that physical training is an important component in the treatment of CKD, because it exerted a positive influence on oxidative stress parameters, especially on the reduction in superoxide production and oxidative damage, as well as an improvement in the antioxidant defense system, like SOD and GPX.