Interval and continuous exercise enhances aerobic capacity and hemodynamic function in CHF rats

HIIT may ameliorate inter-organ crosstalk between liver and hypothalamus of HFD-induced MAFLD rats; A two-phase study to investigate the effect of exercise intensity as a stressor

Previous studies demonstrate that GDF15 and its related signaling activators may be affected by exercise training, leading to the suppression of inflammatory factors and the promotion of immune-metabolic balance. Therefore, the purpose of the study was to evaluate the effect of high-intensity interval training (HIIT) on amelioration of inter-organ crosstalk between liver and hypothalamus of the high-fat diet (HFD)-induced metabolic dysfunction-associated fatty liver disease (MAFLD) rats in a two-phase study. In this regard, rats were initially divided into two groups, the normal diet-inactive (NS) and the HFD groups. HFD course lasted 12 weeks to induce MAFLD in the latter group. After ensuring the induction of MAFLD, 25 rats were divided into three groups: the HFD-inactive group (HS), the HFD-HIIT group (HH), as well as the HFD-aerobic group (HA). The training interventions were consistently applied over a period of eight weeks, five days a week, with each session lasting 40-60 min, and the duration of the whole research was 21 weeks. The results of this study displayed that HIIT intervention promotes hypothalamic Gdf15 gene expression and there were similar alterations in genes expression of Foxo1 and Akt2. Moreover, our results confirmed that HIIT ameliorated hypothalamic NFKB gene expression and there was a similar trend in genes expression of Tnfa and Il1b following both HIIT as well as aerobic training protocols. Taking these findings together, it is concluded that interventions, particularly exercise training, uniquely contribute to the reduction of hypothalamic-associated inflammatory responses that result in prolonged and chronic increases in GDF15.

Continuous exercise training rescues hippocampal long-term potentiation in the VPA rat model of Autism: Uncovering sex-specific effects

Long-term potentiation (LTP) impairment has been reported in many studies of autistic models. The aim of the present study was to investigate the effects of interval training (IT) and continuous training (CT) exercises on LTP in the hippocampal dentate gyrus (DG) neurons of valproic acid (VPA) rat model of autism. To induce an autism-like model, pregnant rats were injected 500 mg/kg NaVPA (intraperitoneal) on the embryonic day 12.5. IT and CT aerobic exercises started on postnatal day 56 in the offspring. Four weeks after IT and/or CT exercises, the offspring were urethane-anesthetized and placed into a stereotaxic apparatus for surgery, electrode implantation, and field potential recording. In the DG region, excitatory post synaptic potentials (EPSP) slope and population spike (PS) amplitude were measured. Sex differences in LTP were evident for control rats but not for VPA-exposed offspring. LTP was significantly smaller in VPA-exposed male offspring compared with control male rats. In contrast to males, there was no difference between VPA-exposed female offspring and control female rats. Interestingly, we observed a sex difference in the response to exercise between VPA-exposed male and female offspring. CT exercise training (but not IT) increased LTP in VPA-exposed male offspring. Both IT and CT exercise trainings had no effect on intact LTP in VPA-exposed female offspring. Our work suggests that there may be differences in the benefits of exercise interventions based on sex, and CT exercise training could be more beneficial for LTP improvements.

Interval training suppresses nod-like receptor protein 3 inflammasome activation to improve cardiac function in myocardial infarction rats by hindering the activation of the transforming growth factor-β1 pathway

OBJECTIVE

Myocardial infarction (MI) -induced cardiac dysfunction can be attenuated by aerobic exercises. This study explored the mechanism of interval training (IT) regulating cardiac function in MI rats, providing some theoretical basis for clarifying MI pathogenesis and new ideas for clinically treating MI.

METHODS

Rats were subjected to MI modeling, IT intervention, and treatments of the Transforming growth factor-β1 (TGF-β1) pathway or the nod-like receptor protein 3 (NLRP3) activators. Cardiac function and hemodynamic indicator alterations were observed. Myocardial pathological damage and fibrosis, reactive oxygen species (ROS) level, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities, MDA content, inflammasome-associated protein levels, and inflammatory factor levels were assessed. The binding between TGF-β1 and receptor was detected.

RESULTS

MI rats exhibited decreased left ventricle ejection fraction (LVEF), left ventricle fractional shortening  (LVFS), left ventricular systolic pressure  (LVSP), positive and negative derivates max/min (dP/dt max/min) and increased left ventricular end-systolic pressure (LVEDP), a large number of scar areas in myocardium, disordered cell arrangement and extensive fibrotic lesions, increased TGF-β1 and receptor binding, elevated ROS level and MDA content and weakened SOD, CAT and GSH-Px activities, and up-regulated NLRP3, apoptosis-associated speck-like protein containing a CARD  (ASC) and cleaved-caspase-1 levels, while IT intervention caused ameliorated cardiac function. IT inactivated the TGF-β1 pathway to decrease oxidative stress in myocardial tissues of MI rats and inhibit NLRP3 inflammasome activation. Activating NLRP3 partially reversed IT-mediated improvement on cardiac function in MI rats.

CONCLUSION

IT diminished oxidative stress in myocardial tissues and suppressed NLRP3 inflammasome activation via inactivating the TGF-β1 pathway, thus improving the cardiac function of MI rats.

MicroRNA-30a-5p Promotes Chronic Heart Failure in Rats by Targeting Sirtuin-1 to Activate the Nuclear Factor-κB/NOD-Like Receptor 3 Signaling Pathway

OBJECTIVE

MicroRNA-30a-5p (miR-30a-5p) has been identified as a marker of heart failure; however, its functional mechanisms in chronic heart failure (CHF) remain unknown. We aim to investigate the role of miR-30a-5p targeting sirtuin-1 (SIRT1) in myocardial remodeling in CHF via the nuclear factor-κB/NOD-like receptor 3 (NF-κB/NLRP3) signaling pathway.

METHODS

CHF rat models were established using aortic coarctation. The expression of miR-30a-5p, SIRT1, and the NF-κB/NLRP3 signaling pathway-related factors in CHF rats was determined. The CHF rats were then respectively treated with altered miR-30a-5p or SIRT1 to explore their roles in cardiac function, myocardial function, inflammatory response, pathological changes, and cardiomyocyte apoptosis. The binding relation between miR-30a-5p and SIRT1 was confirmed.

RESULTS

MiR-30a-5p was upregulated whereas SIRT1 was downregulated in myocardial tissues of CHF rats. MiR-30a-5p inhibition or SIRT1 overexpression improved cardiac and myocardial function, and suppressed the inflammatory response, alleviated pathological changes and inhibited cardiomyocyte apoptosis in CHF rats. MiR-30a-5p targeted SIRT1 to regulate the NF-κB/NLRP3 signaling pathway. In CHF rats, downregulated miR-30a-5p and silenced SIRT1 could reverse the beneficial effects of downregulated miR-30a-5p.

CONCLUSION

Inhibited miR-30a-5p inhibits CHF progression via the SIRT1-mediated NF-κB/NLRP3 signaling pathway.

MOTS-c and aerobic exercise induce cardiac physiological adaptation via NRG1/ErbB4/CEBPβ modification in rats

AIMS

To determine the effects of the mitochondrial open reading frame of the 12S ribosomal RNA type-c (MOTS-c) and aerobic exercise on cardiac structure and function and explore the role of neuregulin-1 (NRG1)- ErbB2 receptor tyrosine kinase 4(ErbB4)- CCAAT-enhancer binding protein β (C/EBPβ) in cardiac physiological adaptation induced by MOTS-c and aerobic training.

MAIN METHODS

We used Hematoxylin-Eosin staining(HE)and Transmission Electron Microscope (TEM) to observe the cardiac myocardial structure, carotid artery catheterization to test cardiac function, and real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting to describe the changes of NRG1, ErbB4, C/EBPβ, and Gata in cardiac physiological adaptation.

KEY FINDINGS

MOTS-c and aerobic training significantly increased heart weight and heart weight index (HWI) (all p < 0.05). Aerobic exercise and MOTS-c treatment thickened myocardial fibers, with a tendency of hypertrophy. Heart rate (HR) (p < 0.001, p = 0.010, p = 0.011), the isovolumic diastolic time constant (Tau) (p < 0.001, p < 0.001, p < 0.001) in exercised (E), MOST-c treated (M) and their combination (ME) decreased significantly, while the dP/dt_max (p < 0.001, p < 0.001, p = 0.039) and dP/dt_min (p < 0.001, p < 0.001, p = 0.001) in groups E, M and ME were significantly higher than those in group C, but EDP (p = 0.903, p = 0.708, p = 0.744) remained unchanged. Moreover, C/EBPβ gene levels were significantly decreased in the differential gene expression between groups C and M transcriptomics sequencing. The levels of ErbB4 mRNA (p < 0.001, p < 0.001, p < 0.001) and Gata4 mRNA (p < 0.001, p < 0.001, p = 0.001) in groups E, M and ME increased significantly, while C/EBPβ mRNA expression decreased significantly (p < 0.001, p = 0.002, p = 0.001), which was consistent with the results of transcriptome sequencing. NRG1 mRNA in group E was significantly higher than that in group C (p = 0.003), but there was no significant difference between groups M and ME (p = 0.804, p = 0.320). The protein expression of NRG1 (p = 0.026, p < 0.001, p < 0.001), ErbB4 (p < 0.001, p < 0.001, p < 0.001) and Gata4 (p = 0.014, p < 0.001, p = 0.006) in groups E, M and ME increased significantly, while C/EBPβ decreased significantly (p < 0.001, p = 0.001, p = 0.002).

SIGNIFICANCE

Our findings suggest that MOTS-c and aerobic exercise had similar effects, improving myocardial morphology and structure and enhancing cardiac function through activation of the NRG1-ErbB4-C/EBPβ pathway.

The effect of interval training on adipokine plasmatic levels in rats with induced myocardial infarction

Context: Exercise has been demonstrated to reduce pro-inflammatory while boosting anti-inflammatory adipokines; yet research in relation to Myocardial infarction (MI) is limited.Objective: The aim of this study was to investigate the effect of an interval exercise-training programme on concentrations of Lipocalin-2 and Adiponectin plasmatic levels in rats with induced MI.Materials and methods: The experimental study design comprised of three groups, including: a control group, MI control group and MI training group that participated in an interval training protocol for six weeks.Results: There was a significant increase in Lipocalin-2 levels in the MI interval training group when compared to the other groups.Discussion and conclusion: Although interval training has beneficial effects on adiponectin, it also increases Lipocalin-2 concentrations. Because Lipocalin-2 significantly contributes to the pathogenesis of atherosclerosis and adverse cardiac conditions, our findings suggest that interval training might be a counterproductive strategy to improve MI-related cardiac damage.

Sex Differences in Spatial Learning and Memory in Valproic Acid Rat Model of Autism: Possible Beneficial Role of Exercise Interventions

In the current study, we first tried to determine sex differences in spatial learning and memory in the valproic acid (VPA) rat model of autism. Second, the effects of interval training (IT) and continuous training (CT) exercises were examined in male and female offsprings. To induce autism-like animal model, the pregnant rats were injected 500 mg/kg NaVPA (intraperitoneal) at the embryonic day 12.5. IT and CT aerobic exercises were started at postnatal day 56. Then, on postnatal days 84–89, a Morris water maze (MWM) test was conducted on the separate groups of offsprings. Aerobic training was performed on a rodent treadmill with 0% slope for 8 weeks, 5 days/week, and 50 min/day. Unlike control animals, VPA-exposed female offspring had a better performance than VPA-exposed male offspring in MWM acquisition. In the case of MWM reference memory, we did not observe a sex difference between VPA-exposed male and VPA-exposed female offspring. Both IT and CT exercises in both control and VPA-exposed male rats significantly improved MWM acquisition. Moreover, both IT and CT exercises significantly improved MWM acquisition in control female rats. In addition, IT exercise (but not CT) significantly improved MWM acquisition in VPA-exposed female offsprings. Both IT and CT exercises in VPA-exposed that male and female offsprings improved the MWM reference memory. In conclusion, our observation demonstrated that prenatal exposure to VPA affects the spatial learning and memory in a sex dependent manner. We have shown that both IT and CT exercises are able to improve cognitive function in healthy and autistic rat offsprings.

Effects of aerobic and resistance exercise training associated with carnosine precursor supplementation on maximal strength and V̇O2max in rats with heart failure

BACKGROUND

Combined exercise training (CET) has been associated with positive responses in the clinical status of patients with heart failure (HF). Other nonpharmacological tools, such as amino acid supplementation, may further enhance its adaptation. The aim was to test whether CET associated with supplementing carnosine precursors could present better responses in the functional capacity and biochemical variables of rats with HF.

METHODS

Twenty-one male Wistar rats were subjected to myocardial infarction and allocated to three groups: sedentary (SED, n = 7), CET supplemented with placebo (CETP, n = 7), and CET with HF supplemented with β-alanine and L-histidine (CETS, n = 7). The trained animals were submitted to a strength protocol three times per week. Aerobic training was conducted twice per week. The supplemented group received β-alanine and L-histidine orally (250 mg/kg per day).

RESULTS

Maximum oxygen uptake, running distance, time to exhaustion and maximum strength were higher in the CET-P group than that in the SED group and even higher in the CET-S group than that in the CET-P group (P < 0.01). CET-S showed lower oxidative stress and inflammation markers and higher heat shock protein 72 kDa content and mRNA expression for calcium transporters in the skeletal muscle compared to SED.

CONCLUSION

CET together with β-alanine and L-histidine supplementation in rats with HF can elicit adaptations in both maximum oxygen uptake, running distance, time to exhaustion, maximum strength, oxidative stress, inflammation and mRNA expression. Carnosine may influence beneficial adjustments in the cell stress response in the skeletal muscle and upregulate the mRNA expression of calcium transporters.

Aerobic exercise improves cardiac function in rats with chronic heart failure through inhibition of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)

Background

To explore the beneficial effects and underlying mechanisms of aerobic exercise on chronic heart failure (CHF).

Methods

A CHF rat model was induced via left anterior descending coronary artery ligation. Four weeks post-surgery, CHF rats received aerobic exercise training over an 8-week period and cardiac function indexes including xxx were analyzed. To investigate the mechanisms involved in the aerobic exercise-induced benefits on CHF, overexpression of the long non-coding RNA MALAT1 was examined both in vivo and in vitro. Furthermore, the interaction between MALAT1 and the microRNA miR-150-5p and the downstream PI3K/Akt signaling pathway was investigated.

Results

Compared to the control group, the CHF rats showed evidence of left ventricular dysfunction including aggravated cardiac function indexes and lung to body weight ratio. The Masson staining demonstrated a significant degree of blue-stained fibrotic myocardial tissue in CHF rats compared to control rats. Furthermore, the levels of collagen I and collagen II were also markedly increased in CHF rats. Aerobic exercise improved cardiac function and left ventricular remodeling in rats with CHF. There was a significant reduction in the levels of the reactive oxygen species (ROS), inflammatory cytokines including TNF-α, IL-6, and IL-1β, and inflammatory mediums containing the matrix metalloproteinases (MMPs) MMP-2 and MMP-9. Moreover, CHF rats receiving aerobic exercise showed decreased myocardial apoptosis and increased expression of autophagy-related proteins including beclin-1 and LC3B-II. Overexpression of the lncRNA MALAT1 eliminated all the beneficial effects related to aerobic exercise in CHF rats. Subsequent investigations demonstrated that miR-150-5p expression was up-regulated in CHF-Tr rats and down-regulated in CHF-Tr-MALAT1 rats. Furthermore, the downstream PI3K/Akt signaling pathway was re-activated in CHF-Tr-MALAT1 rats. In vitro experiments revealed that overexpression of MALAT1 reduced the miR-150-5p levels, resulting in increased cellular apoptosis and less autophagy. In addition, overexpression of MALAT1 suppressed the downstream PI3K/Akt signaling pathway. Restoring miR-150-5p level with a miR-150-5p mimic decreased the cellular apoptosis and increased autophagy, and the downstream PI3K/Akt signaling pathway was re-activated.

Conclusions

Aerobic exercise improved cardiac function through inhibition of the lncRNA MALAT1 in CHF, and the potential mechanisms may be mediated via the miR-150-5p/PI3K/Akt signaling pathway.

Exercise training reveals micro-RNAs associated with improved cardiac function and electrophysiology in rats with heart failure after myocardial infarction

AIMS

Endurance training improves aerobic fitness and cardiac function in individuals with heart failure. However, the underlying mechanisms are not well characterized. Exercise training could therefore act as a tool to discover novel targets for heart failure treatment. We aimed to associate changes in Ca²⁺ handling and electrophysiology with micro-RNA (miRNA) profile in exercise trained heart failure rats to establish which miRNAs induce heart failure-like effects in Ca²⁺ handling and electrophysiology.

METHODS AND RESULTS

Post-myocardial infarction (MI) heart failure was induced in Sprague Dawley rats. Rats with MI were randomized to sedentary control (sed), moderate (mod)- or high-intensity (high) endurance training for 8 weeks. Exercise training improved cardiac function, Ca²⁺ handling and electrophysiology including reduced susceptibility to arrhythmia in an exercise intensity-dependent manner where high intensity gave a larger effect. Fifty-five miRNAs were significantly regulated (up or down) in MI-sed, of which 18 and 3 were changed towards Sham-sed in MI-high and MI-mod, respectively. Thereafter we experimentally altered expression of these "exercise-miRNAs" individually in human induced pluripotent stem cell-derived cardiomyocytes (hIPSC-CM) in the same direction as they were changed in MI. Of the "exercise-miRNAs", miR-214-3p prolonged AP duration, whereas miR-140 and miR-208a shortened AP duration. miR-497-5p prolonged Ca²⁺ release whereas miR-214-3p and miR-31a-5p prolonged Ca²⁺ decay.

CONCLUSION

Using exercise training as a tool, we discovered that miR-214-3p, miR-497-5p, miR-31a-5p contribute to heart-failure like behaviour in Ca²⁺ handling and electrophysiology and could be potential treatment targets.

β-Alanine and l-histidine supplementation associated with combined training increased functional capacity and maximum strength in heart failure rats

NEW FINDINGS

What is the central question of the study? Does β-alanine with l-histidine supplementation associated with endurance and strength training improve echocardiographic parameters, functional capacity, and maximum strength in rats with chronic heart failure? What is the main finding and its importance? β-Alanine with l-histidine supplementation associated with endurance and strength training increased functional capacity and maximum strength through increasing exercise capacity peripherally but did not affect echocardiographic parameters in rats with chronic heart failure. Combined training (CT) has been associated with positive responses in the clinical status of patients with chronic heart failure (CHF). Other non-pharmacological tools, such as amino acid supplementation, may further enhance its adaptation. However, the effects of β-alanine and l-histidine supplementation in CHF remain unclear. In the present study, the aim was to test whether supplementing carnosine precursors with CT could give improved responses in the functional capacity and echocardiographic variables of rats with CHF. Twenty-four Wistar rats, were submitted to myocardial infarction and allocated to three groups: animals with CHF kept in sedentary conditions (SED, n = 8), animals with CHF submitted to CT in strength and aerobic exercise supplemented with placebo (CT-P, n = 8) and animals with CHF submitted to CT in strength and aerobic exercise supplemented with β-alanine and l-histidine (CT-S, n = 8). The trained animals were submitted to a strength protocol three times per week with intensity of 65-75% of one repetition maximum test. Aerobic training was conducted two times per week (50 min, 15 m min^-1 ). The supplemented group received β-alanine and l-histidine orally (each 250 mg kg^-1  day^-1 ). No changes in echocardiographic and morphological parameters were found among the groups (P > 0.05). Functional capacity, Δ V ̇ O 2 max and maximum strength were higher in CT-P than in SED and even higher in CT-S than in CT-P (P < 0.01). The CT was able to improve functional capacity, but the supplementation was shown to enhance these parameters even further in the CHF rats. We conclude that the increase in functional capacity and strength gained through CT and supplementation were associated with the improvement in peripheral parameters with no changes in cardiac variables.

Higher Concentration of Hypertonic Saline Shows Better Recovery Effects on Rabbits with Uncontrolled Hemorrhagic Shock

Background

Our previous study found a novel fluid combination with better resuscitation effects under hypotensive condition at the early stage of uncontrolled hemorrhagic shock (UHS). However, the optimal recovery concentration of hypertonic saline in this fluid combination remains unknown. This experiment aimed to explore the optimal concentration.

Material/Methods

New Zealand white rabbits (n=40) were randomly divided into 5 groups, including a sham-operated group (SO), a shock non-treated group (SNT), a normal saline group (NS), and hypertonic saline groups (4.5% and 7.5%). We established an UHS model and administered various fluid combinations (dose-related sodium chloride solution+crystal-colloidal solution) to the groups followed by monitoring indexes of hemodynamic and renal function, measuring infusion volume and blood loss, and analyzing pathological morphology by hematoxylin and eosin staining.

Results

The hypertonic saline groups showed more stable hemodynamic indexes, reduced blood loss, fewer required infusions, and milder decreases in renal function than those of control groups (SNT and NS groups), and exhibited fewer pathological changes in the heart, lung, kidney, and liver. All indexes in the 4.5% and 7.5% groups were better than those of the NS group, and the hemodynamic indexes in the 7.5% group were more stable than those of the 4.5% group (P<0.05), with reduced blood loss and infusion volume and a milder decrease in renal function.

Conclusions

The novel fluid combination with 7.5% hypertonic saline group had a better recovery effect at the early stage of UHS before hemostasis compared to that of the 4.5% hypertonic saline group. This result may provide guidance for clinical fluid resuscitation.

Effect of Training with or without Ziziphus Jujuba Extract on Cardiokines in Heart Tissue of Myocardial Infarcted Rats

BACKGROUND

Today, the importance of physical activity as a preventative way for cardiovascular disease has attracted much attention.The aim of this study is to investigate the effect of 6 weeks of interval training with or without extract of Ziziphus jujuba on lipocalcin-2 (LCN2) and adiponectin levels in heart tissue in male Wistar rats with myocardial infarction.

METHODS

Thirty male Wistar rats (mean weight, 180-220 g and age, 2-3 months) were divided into five groups, including (1) Healthy control; (2) Isoprenaline-treated group (ISO); (3) ISO + jujube extracts (JE); (4) Trained ISO rats; and (5) Trained ISO rats + JE. Exercise was performed (5 days/week, for 6 week including 54-min cycles with speed of 23 m/min and 54-min cycles with speed of 15 m/min). After 48 h of the last training session, the rats were sacrificed, and their heart tissue was excised. The significant level of statistical data was analyzed by one-way ANOVA test.

RESULTS

LCN2 levels significantly decreased in trained ISO rats + JE group after 6 weeks of interval training with JE consumption, compared to ISO group. However, the consumption of jujuba extracts with and without interval training did not show any significant changes in adiponectin levels of rat's heart tissue, compared to ISO (P < 0.05).

CONCLUSIONS

Because the LCN2 inflammatory factor decreased after 6 weeks of exercise and consumption of the extract, it seems that performing interval training with JE consumption can be an effective method in the cardiac rehabilitation phase after a heart attack.

High-intensity resistance training alone or combined with aerobic training improves strength, heart function and collagen in rats with heart failure

BACKGROUND

Resistance training (RT) has been associated with positive responses in patients with cardiovascular disease, and when it is combined with continuous aerobic training (CAT), favorable adaptations appear to be even more pronounced. However, the effects of high-intensity RT alone or in combined with CAT in the case of heart failure (HF) is not completely elucidated.

METHODS

28 male Wistar rats with HF (90 days old) were allocated to 4 groups: high-intensity RT (RT, n=7), CAT (CAT, n=7), RT and CAT (RT+CAT, n=7) and sedentary (Sed, n=7). Trained animals were subjected to a RT protocol in an adapted squat apparatus for rats (4 bouts, 6-8 reps, 90 s interval, 3×/week, 75% to 85% of one maximum repetition (1RM) for 8 weeks). The animals subjected to CAT performed it 3×/week during 50 min/session at 16 m/min. The animals of the combined exercise regimen performed both the RT and CAT exercise protocols.

RESULTS

The left ventricular end-diastolic pressure (LVEDP), collagen volume fraction and right ventricular hypertrophy were lower in RT, CAT and RT+CAT groups when compared to Sed group (P<0.05) for all outcomes. Regarding the inflammatory profile, only the CAT group showed greater IL-10 concentrations.

CONCLUSION

We concluded that RT combined with CAT was able to improve the strength in animals with HF, which was associated to improvement in ventricular structure and function.

Effects of l-arginine supplementation associated with continuous or interval aerobic training on chronic heart failure rats

OBJECTIVE

Chronic heart failure (CHF) is related with exercise intolerance and impaired nitric oxide (NO) production, which can lead to several functional capacity alterations. Considering the possible superiority of aerobic interval training compared to continuous training and the capacity of l-arginine to restore the NO pathway, the aim of the present study was to investigate whether these treatments are beneficial to exercise capacity, muscle mass preservation and hemodynamic, inflammatory and oxidative stress parameters in CHF rats.

METHODS

Thirty-eight male Wistar rats post 6weeks of myocardial infarction (MI) surgery were randomly assigned into 6 CHF groups: sedentary (SED, n=6); SED+Arg (n=7); ACT (n=8); ACT+Arg (n=5); AIT (n=7); AIT+Arg (n=5). Exercise test capacity (ETC) was performed pre and post 8weeks of intervention. Supplemented rats received Arg (1g/kg) by oral gavage (7×/week). Exercise training was performed on a rat treadmill (5×/week). Hemodynamic variables, tissue collection, congestion, inflammatory cytokines, and oxidative parameters were evaluated at the end of protocols.

RESULTS

All trained groups showed a superior exercise capacity compared to SED groups on the post-intervention test (p<0.0001). Pulmonary congestion was attenuated in AIT and AIT+Arg compared with the SED group (p<0.05). Left ventricular end-diastolic pressure (LVEDP) was lower in ACT+Arg, AIT, and AIT+Arg groups than SED group (p<0.05). Association of AIT with Arg supplementation was able to improve hemodynamic responses (left ventricular systolic pressure (LVSP), systolic blood pressure (SBP), +dP/dt_max, and -dP/dt_max (p<0.05), likewise, decrease muscular and renal lipid peroxidation and tumor necrosis factor (TNF)-α, and increase interleukin (IL)-10/TNF-α plasmatic levels (p<0.01). Groups that associated aerobic exercise with Arg supplementation (ACT+Arg and AIT+Arg) revealed higher gastrocnemius mass compared to the SED group (p<0.01).

CONCLUSIONS

Both aerobic training protocols were capable to improve aerobic capacity, and the association with Arg supplementation was important to attenuate muscle loss. Moreover, interval training associated with Arg supplementation elicits greater improvements in hemodynamic parameters, contributing to reduction in pulmonary congestion, and demonstrated particular responses in the inflammatory profile and in the antioxidant status.

Exercise training improves the IL-10/TNF-α cytokine balance in the gastrocnemius of rats with heart failure

OBJECTIVE

This study examined the effects of exercise training (ExT) upon concentration of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) in the gastrocnemius of rats with heart failure (HF) induced by left coronary artery ligation.

METHODS

Adult male Wistar rats submitted to myocardial infarction (MI) or sham surgery were randomly allocated into one of four experimental groups: trained HF (Tr-HF), sedentary HF (Sed-HF), trained sham (Tr-Sham) and sedentary sham (Sed-Sham). ExT protocol was performed on treadmill for a period of 8 weeks (60m/days, 5×/week, 16m/min), which started 6 weeks after MI. Cardiac hemodynamic evaluations of left ventricular end-diastolic pressure (LVEDP) and morphometric cardiac were used to characterize HF. The hemodynamic variables were recorded and gastrocnemius muscle was collected. TNF-α, IL-6 and IL-10 protein levels were determined by multiplex bead array.

RESULTS

Sed-HF group presented increase of TNF-α level when compared with the Sed-Sham group (mean difference, MD 1.3; 95% confidence interval, CI -0.04 to 2.5). ExT reduced by 59% TNF-α level in Tr-HF group (MD -1.7; 95% CI -2.9 to -0.3) and increased IL-10 (MD 15; 95% CI 11-26) when compared with the Sed-HF group. Thus, the gastrocnemius muscle IL-10/TNF-α ratio was increased in Tr-HF rats (MD 15; 95% CI -8 to 47) when compared with the Sed-HF rats.

CONCLUSION

These results demonstrate that ExT not only attenuates TNF-α level but also improves the IL-10 cytokine level in skeletal muscle of HF rats.

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.

Effects of coordination and manipulation therapy for patients with Parkinson disease

PURPOSE

To determine the effects of a new exercise training regimen, i.e. coordination and manipulation therapy (CMT), on motor, balance, and cardiac functions in patients with Parkinson disease (PD).

MATERIALS AND METHODS

We divided 36 PD patients into the CMT (n = 22) and control (n = 14) groups. The patients in the CMT group performed dry-land swimming (imitation of the breaststroke) and paraspinal muscle stretching for 30 min/workday for 1 year. The control subjects did not exercise regularly. The same medication regimen was maintained in both groups during the study. Clinical characteristics, Unified Parkinson's Disease Rating Scale (UPDRS) scores, Berg balance scale (BBS) scores, mechanical balance measurements, timed up and go (TUG) test, and left ventricular ejection fraction (LVEF) were compared at 0 (baseline), 6, and 12 months. Biochemical test results were compared at 0 and 12 months. The primary outcome was motor ability. The secondary outcome was cardiac function.

RESULTS

In the CMT group, UPDRS scores significantly improved, TUG test time and step number significantly decreased, BBS scores significantly increased, and most mechanical balance measurements significantly improved after 1 year of regular exercise therapy (all p < 0.05). In the control group, UPDRS scores significantly deteriorated, TUG test time and step number significantly increased, BBS scores significantly decreased, and most mechanical balance measurements significantly worsened after 1 year (all P < 0.05). LVEF improved in the CMT group only (P = 0.01).

CONCLUSIONS

This preliminary study suggests that CMT effectively improved mobility disorder, balance, and cardiac function in PD patients over a 1-year period.

FSTL1 as a Potential Mediator of Exercise-Induced Cardioprotection in Post-Myocardial Infarction Rats

Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI), but the underlying mechanisms are poorly understood. Follistatin-like1 (FSTL1) is a cardioprotective factor against ischemic injury and is induced in cardiomyocytes and skeletal muscle in ischemic and hypoxic conditions. To test the hypothesis that FSTL1 may be a molecular link between exercise and improved heart function post MI, we subjected MI-rats, induced by left coronary artery ligation, to two modes of exercise: intermittent aerobic exercise (IAE) or mechanical vibration training (MVT), for four weeks and examined the relevance of FSTL1 to exercise-mediated cardiac effects. Exercise improved the functional performance, reduced fibrosis of MI-hearts and induced FSTL1 expression, the TGFβ-Smad2/3 signaling and angiogenesis in myocardium. In gastrocnemius, exercise increased the cross-sectional area of myocytes and FSTL1 expression. Importantly, exercise increased circulating FSTL1 levels, which were positively correlated with the skeletal muscle FSTL1 expression and negatively correlated with heart fibrosis. Overall, the IAE was more effective than that of MVT in cardioprotection. Finally, exogenous FSTL1 administration directly improved angiogenesis as well as functionality of post-MI hearts. Taken together, we have demonstrated that FSTL1 is a potential mediator of exercise-induced cardioprotection in post-MI rats.

Chronic heart failure modifies respiratory mechanics in rats: a randomized controlled trial

Objective

To analyze respiratory mechanics and hemodynamic alterations in an experimental model of chronic heart failure (CHF) following myocardial infarction.

Method

Twenty-seven male adult Wistar rats were randomized to CHF group (n=12) or Sham group (n=15). Ten weeks after coronary ligation or sham surgery, the animals were anesthetized and submitted to respiratory mechanics and hemodynamic measurements. Pulmonary edema as well as cardiac remodeling were measured.

Results

The CHF rats showed pulmonary edema 26% higher than the Sham group. The respiratory system compliance (Crs) and the total lung capacity (TLC) were lower (40% and 27%, respectively) in the CHF rats when compared to the Sham group (P<0.01). There was also an increase in tissue resistance (Gti) and elastance (Hti) (28% and 45%, respectively) in the CHF group. Moreover, left ventricular end-diastolic pressure was higher (32 mmHg vs 4 mmHg, P<0.01), while the left ventricular systolic pressure was lower (118 mmHg vs 130 mmHg, P=0.02) in the CHF group when compared to the control. Pearson’s correlation coefficient showed a negative association between pulmonary edema and Crs (r=–0.70, P=0.0001) and between pulmonary edema and TLC (r=–0.67, P=0.0034). Pulmonary edema correlated positively with Gti (r=0.68, P=0.001) and Hti (r=0.68, P=0.001). Finally, there was a strong positive relationship between pulmonary edema and heart weight (r=0.80, P=0.001).

Conclusion

Rats with CHF present important changes in hemodynamic and respiratory mechanics, which may be associated with alterations in cardiopulmonary interactions.