Voluntary Wheel Running Exercise Research Articles

Voluntary wheel running reduces tumor growth and increases capillarity in the heart during doxorubicin chemotherapy in a murine model of breast cancer.

Introduction: The possible beneficial effects of physical activity during doxorubicin treatment of breast cancer need further investigation as many of the existing studies have been done on non-tumor-bearing models. Therefore, in this study, we aim to assess whether short-term voluntary wheel-running exercise during doxorubicin treatment of breast cancer-bearing mice could induce beneficial cardiac effects and enhance chemotherapy efficacy. Methods: Murine breast cancer I3TC cells were inoculated subcutaneously to the flank of female FVB mice (n = 16) that were divided into exercised and non-exercised groups. Two weeks later, doxorubicin treatment was started via intraperitoneal administration (5mg/kg weekly for 3weeks). Organs were harvested a day after the last dose. Results: The tumor volume over time was significantly different between the groups, with the exercising group having lower tumor volumes. The exercised group had increased body weight gain, tumor apoptosis, capillaries per cardiomyocytes, and cardiac lactate dehydrogenase activity compared to the unexercised group, but tumor blood vessel density and maturation and tumor and cardiac HIF1-α and VEGF-A levels did not differ from those of the non-exercised group. Discussion: We conclude that even short-term light exercise such as voluntary wheel running exercise can decrease the subcutaneous mammary tumor growth, possibly via increased tumor apoptosis. The increase in cardiac capillaries per cardiomyocytes may also have positive effects on cancer treatment outcomes.

Voluntary exercise preserves visual function and reduces inflammatory response in an adult mouse model of autosomal dominant retinitis pigmentosa

Whole-body physical exercise has been shown to promote retinal structure and function preservation in animal models of retinal degeneration. It is currently unknown how exercise modulates retinal inflammatory responses. In this study, we investigated cytokine alterations associated with retinal neuroprotection induced by voluntary running wheel exercise in a retinal degeneration mouse model of class B1 autosomal dominant retinitis pigmentosa, I307N Rho. I307N Rho mice undergo rod photoreceptor degeneration when exposed to bright light (induced). Our data show, active induced mice exhibited significant preservation of retinal and visual function compared to inactive induced mice after 4 weeks of exercise. Retinal cytokine expression revealed significant reductions of proinflammatory chemokines, keratinocyte-derived chemokine (KC) and interferon gamma inducible protein-10 (IP-10) expression in active groups compared to inactive groups. Through immunofluorescence, we found KC and IP-10 labeling localized to retinal vasculature marker, collagen IV. These data show that whole-body exercise lowers specific retinal cytokine expression associated with retinal vasculature. Future studies should determine whether suppression of inflammatory responses is requisite for exercise-induced retinal protection.

Exercise mitigates flow recirculation and activates metabolic transducer SCD1 to catalyze vascular protective metabolites.

Exercise promotes pulsatile shear stress in the arterial circulation and ameliorates cardiometabolic diseases. However, exercise-mediated metabolic transducers for vascular protection remain under-investigated. Untargeted metabolomic analysis demonstrated that wild-type mice undergoing voluntary wheel running exercise expressed increased endothelial stearoyl-CoA desaturase 1 (SCD1) that catalyzes anti-inflammatory lipid metabolites, namely, oleic (OA) and palmitoleic acids (PA), to mitigate NF-κB-mediated inflammatory responses. In silico analysis revealed that exercise augmented time-averaged wall shear stress but mitigated flow recirculation and oscillatory shear index in the lesser curvature of the mouse aortic arch. Following exercise, endothelial Scd1-deleted mice (Ldlr-/- Scd1EC-/-) on high-fat diet developed persistent VCAM1-positive endothelium in the lesser curvature and the descending aorta, whereas SCD1 overexpression via adenovirus transfection mitigated endoplasmic reticulum stress and inflammatory biomarkers. Single-cell transcriptomics of the aorta identified Scd1-positive and Vcam1-negative endothelial subclusters interacting with other candidate genes. Thus, exercise mitigates flow recirculation and activates endothelial SCD1 to catalyze OA and PA for vascular endothelial protection.

Age-Dependent Effects of Voluntary Wheel Running Exercise on Voiding Behavior and Potential Age-Related Molecular Mechanisms in Mice.

Older men frequently develop lower urinary tract symptoms attributed to benign prostatic hyperplasia (LUTS/BPH). Risk factors for LUTS/BPH include sedentary lifestyle, anxiety/depression, obesity, and frailty, which all increase with age. Although physical exercise may reduce the progression and/or severity of LUTS/BPH, the age-related mechanisms responsible remain unknown. Voiding symptoms, body mass, and frailty were assessed after 4-weeks of voluntary wheel running in 2-month (n = 10) and 24-month (n = 8) old C57Bl/6J male mice. In addition, various social and individual behaviors were examined in these cohorts. Finally, cellular and molecular markers of inflammation and mitochondrial protein expression were assessed in prostate tissue and systemically. Despite running less (aged vs young X¯ = 12.3 vs 30.6 km/week; p = .04), aged mice had reduced voiding symptoms (X¯ = 67.3 vs 23.7; p < .0001) after 1 week of exercise, which was sustained through week 4 (X¯ = 67.3 vs 21.5; p < .0001). Exercise did not affect voiding symptoms in young mice. Exercise also increased mobility and decreased anxiety in both young and aged mice (p < .05). Exercise decreased expression of a key mitochondrial protein (PINK1; p < .05) and inflammation within the prostate (CD68; p < .05 and plasminogen activator inhibitor-1; p < .05) and in the serum (p < .05). However, a frailty index (X¯ = 0.17 vs 0.15; p = .46) and grip strength (X¯ = 1.10 vs 1.19; p = .24) were unchanged after 4 weeks of exercise in aged mice. Voluntary aerobic exercise improves voiding behavior and mobility, and decreases prostatic mitochondrial protein expression and inflammation in aged mice. This promising model could be used to evaluate molecular mechanisms of aerobic exercise as a novel lifestyle intervention for older men with LUTS/BPH.

Hypothalamic Orexinergic Neurons Projecting to the Mesencephalic Locomotor Region Are Activated by Voluntary Wheel Running Exercise in Rats.

Cardiovascular changes during exercise are regulated by a motor volitional signal, called central command, which originates in the rostral portions of the brain and simultaneously regulates somatomotor and autonomic nervous systems. Whereas we recently elucidated mesencephalic locomotor region (MLR) neurons projecting to the rostral ventrolateral medulla as a crucial component of the central circuit responsible for transmitting central command signals, upstream circuits that regulate the MLR neurons remain unknown. Orexinergic neurons, which primarily originate from the perifornical area (PeFA) of the hypothalamus and reportedly play roles in eliciting locomotion and elevating sympathetic activity, send axonal projection to the MLR. The knowledge led us to investigate whether central command signals are relayed through orexinergic neurons projecting to the MLR. We performed anterograde transsynaptic tagging with AAV1 encoding Cre to confirm the presence of MLR neurons postsynaptic to the PeFA in rats. We also conducted retrograde neural tracing with retrograde AAV, combined with immunohistochemical staining, to examine the excitability of MLR-projecting orexinergic neurons in rats that were allowed to freely run on the wheel for 90 min. A significant number of MLR neurons were labeled with Cre, indicating that PeFA neurons make synaptic contacts with MLR neurons. Moreover, immunoreactivities of Fos, a marker of neuronal excitation, were found in many MLR-projecting orexinergic neurons by voluntary wheel running exercise, compared to non-exercising control rats, especially in the intermediate-posterior, rather than anterior, and medial, rather than lateral, portions within the orexinergic neuron-distributing domain. The findings suggest that specifically located orexinergic neurons transmit central command signals onto the MLR for running exercise. Elucidating the role of these MLR-projecting orexinergic neurons in somatomotor control and autonomic cardiovascular control deserves further study to unveil central circuit mechanisms responsible for central command function.

Voluntary exercise during puberty promotes spatial memory and hippocampal DG/CA3 synaptic transmission in mice.

Physical exercise has been shown to have an impact on memory and hippocampal function across different age groups. Nevertheless, the influence and mechanisms underlying how voluntary exercise during puberty affects memory are still inadequately comprehended. This research aims to examine the impacts of self-initiated physical activity throughout adolescence on spatial memory. Developing mice were exposed to a 4-wk voluntary wheel running exercise protocol, commencing at the age of 30d. After engaging in voluntary wheel running exercise during development, there was an enhancement in spatial memory. Moreover, hippocampal dentate gyrus and CA3 neurons rather than CA1 neurons exhibited an increase in the miniature excitatory postsynaptic currents and miniature inhibitory postsynaptic currents. In addition, there was an increase in the expression of NR2A/NR2B subunits of N-methyl-D-aspartate receptors and α1GABAA subunit of gamma-aminobutyric acid type A receptors, as well as dendritic spine density, specifically within dentate gyrus and CA3 regions rather than CA1 region. The findings suggest that voluntary exercise during development can enhance spatial memory in mice by increasing synapse numbers and improving synaptic transmission in hippocampal dentate gyrus and CA3 regions, but not in CA1 region. This study sheds light on the neural mechanisms underlying how early-life exercise improves cognitive function.

Voluntary running wheel exercise induces cognitive improvement post traumatic brain injury in mouse model through redressing aberrant excitation regulated by voltage-gated sodium channels 1.1, 1.3, and 1.6

Traumatic brain injury (TBI) leads to disturbed brain discharge rhythm, elevated excitability, anxiety-like behaviors, and decreased learning and memory capabilities. Cognitive dysfunctions severely affect the quality of life and prognosis of TBI patients, requiring effective rehabilitation treatment. Evidence indicates that moderate exercise after brain injury decreases TBI-induced cognitive decline. However, the underlying mechanism remains unelucidated. Our results demonstrate that TBI causes cognitive impairment behavior abnormalities and overexpression of Nav1.1, Nav1.3 and Nav1.6 proteins inside the hippocampus of mice models. Three weeks of voluntary running wheel (RW) exercise treatments before or/and post-injury effectively redressed the aberrant changes caused by TBI. Additionally, a 10% exercise-conditioned medium helped recover cell viability, neuronal sodium current and expressions of Nav1.1, Nav1.3 and Nav1.6 proteins across cultured neurons after injury. Therefore, the results validate the neuroprotection induced by voluntary RW exercise treatment before or/and post-TBI. The RW exercise-induced improvement in cognitive behaviors and neuronal excitability could be associated with correcting the Nav1.1, Nav1.3, and Nav1.6 expression levels. The current study proves that voluntary exercise is an effective treatment strategy against TBI. The study also highlights novel potential targets for rehabilitating TBI, including the Navs proteins.

Abstract 16975: Wheel-Running Exercise Abrogates Enhanced Sympathetic Neural-Immune Interface in Aortic Adventitia of Angiotensin II-Infused Hypertensive Mice

Background: Artery stiffness causes cardiovascular pathology. Although mechanisms underlying endothelial dysfunction and arterial stiffness are well characterized, it is unknown if neural-immune interaction in aortic adventitia (AA) influences arterial stiffness. We hypothesized that sympathetic innervation and CD68 + macrophages are increased in AA of Angiotensin II (Ang II)-infused mice leading to increased arterial fibrosis and stiffness, and that voluntary wheel-running exercise (VWR) mitigates these effects. Methods and Results: In eight-week-old C57BL/6 male mice, Ang II was infused at 1.5 μg/g/day for 4 weeks with and without VWR. Mean arterial blood pressure [MAP] measured by tail-cuff averaged 135±11 mmHg in Ang II-infused mice (n=5) and 90±10 mmHg in vehicle-infused mice (n=4). Staining for markers of nerve fibers/bundles with Neurofilament A (NF200), sympathetic nerves with tyrosine hydroxylase (TH), nerve endings in AA with synapsin, and CD68 + macrophages were all increased in AA removed from Ang II-infused mice compared with vehicle-infused mice. The increases in CD68 + macrophages and extracellular matrix (ECM) were associated with elevated pulse wave velocity (PWV), an index for arterial stiffness (Ang II: p &lt; 0.05 vs. vehicle). scRNA-seq analyses further corroborated that Ang II infusion promoted fibrosis and macrophage-associated genes in AA. VWR significantly attenuated the Ang II-induced increases in MAP, sympathetic innervation, CD68 + expression, ECM, and PWV (Ang II+VWR: all p&lt;0.05 vs. Ang II). To chemically “denervate” the sympathetic nervous system, we injected 6-hydroxydopamine (6-OHDA, 100 mg/kg on day 0 and 250 mg/kg on day 2, then weekly for 4 weeks) or vehicle in Ang II-infused mice. 6-OHDA decreased MAP, sympathetic innervation, macrophage expression, ECM accumulation, and PWV (Ang II+6-OHDA: p&lt;0.05 vs. Ang II+vehicle, n=3). Conclusion: Ang II-induced hypertensive mice develop increases in sympathetic innervation and macrophages in close proximity within AA that define an enhanced sympathetic neural-immune interface in association with vascular fibrosis, arterial stiffness, and hypertension. VWR significantly mitigates these pathophysiological responses.

Short-term treatment of Agastache rugosa extract combined with voluntary wheel running exercise alters the size and type of skeletal muscle fibers and improves anabolic resistance in middle-aged mice

Short-term treatment of Agastache rugosa extract combined with voluntary wheel running exercise alters the size and type of skeletal muscle fibers and improves anabolic resistance in middle-aged mice

Maternal exercise improves markers of metabolic signaling and reduces inflammation in brown adipose tissue of offspring

Maternal obesity impacts approximately one-third of pregnant people and impacts offspring through the transmission of obesogenic and diabetic traits. Pregnant patients often spend considerable time sedentary, which has been associated with harmful cardiometabolic changes. Our recent data show that compared with sedentary conditions, voluntary exercise during pregnancy in mice shifts adipose distribution of offspring away from energy storing white adipose tissue towards energy burning brown adipose tissue (BAT), which could improve energy metabolism over the lifespan. The objective of this study was to test the hypothesis that voluntary exercise in pregnant mice improves metabolic signaling pathways and reduces markers of inflammation in BAT from offspring. To test this, female C57BL/6J mice were placed on control diet and allocated to sedentary versus voluntary running wheel exercise cages. Voluntary wheel running was allowed for two weeks prior to breeding and throughout weaning. When offspring were 16 weeks of age, they were euthanized for collection of BAT. The study groups were male sedentary (n=9), female sedentary (n=11), male exercise (n=12), female exercise (n=8). Quantitative real-time polymerase chain reaction was used to measure mRNA of fibroblast-growth factor receptors (β-klotho, Fgfr1, Fgfr2) and inflammation markers (IL10, IL1β, TNFα) in BAT. Outcomes were analyzed by two-way ANOVA to assess effects of exercise, sex, and their interaction. Offspring from exercised mothers had a significant decrease in mRNA of IL1β (1.4±0.4 male sedentary vs. 0.4±0.1 male exercise vs. 1.1±0.2 female sedentary vs. 0.8 ±0.2 female exercise; PSex=0.668, PEX=0.006, PInt=0.098) and TNFα (0.9±0.1 male sedentary vs. 0.5±0.1 male exercise vs. 1.3±0.3 female sedentary vs. 0.6 ±0.1 female exercise; PSex=0.126, PEX=0.007, PInt=0.562) and an increase in Fgfr2 (1.1±0.2 male sedentary vs. 1.7±0.3 male exercise vs. 1.3±0.3 female sedentary vs. 3.8 ±1.2 female exercise; PSex=0.063, PEX=0.011, PInt=0.096) in BAT, which was largely independent of sex. There was no significant main effect of either sex or exercise on IL10, Fgfr1, or β-klotho mRNA in BAT. These data suggest that maternal exercise is associated with decreased inflammation and increased protective metabolic signaling in BAT. This could impact energy metabolism given increasing evidence for advantageous metabolic adaptations with increased BAT health and signaling. Additional studies are needed to further understand the impact of maternal exercise on adipose health, energy metabolism, and cardiovascular outcomes in offspring over the lifespan. American Heart Association Undergraduate Summer Fellowship, Department of Obstetrics and Gynecology at Penn State Milton S Hershey Medical Center, and Dani Peress MD Memorial Fund from the Society of Maternal Fetal Medicine This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Chronic voluntary wheel running exercise ameliorates metabolic dysfunction via PGC-1α expression independently of FNDC5/irisin pathway in high fat diet-induced obese mice

Exercise is an effective intervention to ameliorate metabolic diseases including obesity and insulin resistance, but the mechanisms involved in the metabolic amelioration have not yet been fully elucidated. This study aimed to determine whether AMPK–SIRT1–PGC-1α–FNDC5/Irisin-UCP1 expression is activated and whether metabolic dysfunction is ameliorated by chronic voluntary wheel running (VWR) in high-fat diet (HFD) induced obese mice. C57BL6J mice were randomly assigned into three groups at the age of 7 weeks for 10 weeks: normal chow diet (CON) group, HFD group, and HFD + VWR group. Chronic VWR ameliorates metabolic parameters and leads to increases in the expression of PGC-1α in the gastrocnemius muscle in HFD-induced obese mice. In contrast, the expression of AMPKα, SIRT1, and FNDC5, or circulating irisin levels did not lead to alteration. Improvement of metabolic health was partly mediated via PGC-1α expression by chronic VWR, but not FNDC5/Irisin pathway in HFD-induced obese mice.

Effects of Voluntary Wheel Running Exercise on Chemotherapy-Impaired Cognitive and Motor Performance in Mice.

Chemotherapy-induced cognitive impairment (chemobrain) and muscle wasting (cachexia) are persisting side effects which adversely affect the quality of life of cancer survivors. We therefore investigated the efficacy of physical exercise as a non-pharmacological intervention to reverse the adverse effects of chemotherapy. We examined whether physical exercise in terms of voluntary wheel running could prevent chemotherapy-induced cognitive and motor impairments in mice treated with the multi-kinase inhibitor sorafenib. Adult male BALB/c mice were subdivided into runner and non-runner groups and orally administered with sorafenib (60 mg/kg) or vehicle continuously for four weeks. Mice could freely access the running wheel anytime during sorafenib or vehicle treatment. We found that sorafenib treatment reduced body weight gain (% of change, vehicle: 3.28 ± 3.29, sorafenib: -9.24 ± 1.52, p = 0.0004), impaired hippocampal-dependent spatial memory in the Y maze (exploration index, vehicle: 35.57 ± 11.38%, sorafenib: -29.62 ± 7.90%, p < 0.0001), increased anhedonia-like behaviour in the sucrose preference test (sucrose preference, vehicle: 66.57 ± 3.52%, sorafenib: 44.54 ± 4.25%, p = 0.0005) and impaired motor skill acquisition in rotarod test (latency to fall on day 1: 37.87 ± 8.05 and day 2: 37.22 ± 12.26 s, p > 0.05) but did not induce muscle wasting or reduce grip strength. Concomitant voluntary running reduced anhedonia-like behaviour (sucrose preference, sedentary: 44.54 ± 4.25%, runners: 59.33 ± 4.02%, p = 0.0357), restored impairment in motor skill acquisition (latency to fall on day 1: 50.85 ± 15.45 and day 2: 168.50 ± 37.08 s, p = 0.0004), but failed to rescue spatial memory deficit. Immunostaining results revealed that sorafenib treatment did not affect the number of proliferating cells and immature neurons in the hippocampal dentate gyrus (DG), whereas running significantly increased cell proliferation in both vehicle- (total Ki-67+ cells, sedentary: 16,687.34 ± 72.63, exercise: 3320.03 ± 182.57, p < 0.0001) and sorafenib-treated mice (Ki-67+ cells in the ventral DG, sedentary: 688.82.34 ± 38.16, exercise: 979.53 ± 73.88, p < 0.0400). Our results suggest that spatial memory impairment and anhedonia-like behaviour precede the presence of muscle wasting, and these behavioural deficits are independent of the changes in adult hippocampal neurogenesis. Running effectively prevents body weight loss, improves motor skill acquisition and reduces anhedonia-like behaviour associated with increased proliferating cells and immature neurons in DG. Taken together, they support physical exercise rehabilitation as an effective strategy to prevent chemotherapy side effects in terms of mood dysregulation and motor deficit.

Voluntary Wheel Running Exercise Does Not Attenuate Circadian and Cardiac Dysfunction Caused by Conditional Deletion of Bmal1.

Circadian misalignment occurs with age, jet lag, and shift work, leading to maladaptive health outcomes including cardiovascular diseases. Despite the strong link between circadian disruption and heart disease, the cardiac circadian clock is poorly understood, prohibiting identification of therapies to restore the broken clock. Exercise is the most cardioprotective intervention identified to date and has been suggested to reset the circadian clock in other peripheral tissues. Here, we tested the hypothesis that conditional deletion of core circadian gene Bmal1 would disrupt cardiac circadian rhythm and function and that this disruption would be ameliorated by exercise. To test this hypothesis, we generated a transgenic mouse with spatial and temporal deletion of Bmal1 only in adult cardiac myocytes (Bmal1 cardiac knockout [cKO]). Bmal1 cKO mice demonstrated cardiac hypertrophy and fibrosis concomitant with impaired systolic function. This pathological cardiac remodeling was not rescued by wheel running. While the molecular mechanisms responsible for the profound cardiac remodeling are unclear, it does not appear to involve activation of the mammalian target of rapamycin (mTOR) signaling or changes in metabolic gene expression. Interestingly, cardiac deletion of Bmal1 disrupted systemic rhythms as evidenced by changes in the onset and phasing of activity in relationship to the light/dark cycle and by decreased periodogram power as measured by core temperature, suggesting cardiac clocks can regulate systemic circadian output. Together, we suggest a critical role for cardiac Bmal1 in regulating both cardiac and systemic circadian rhythm and function. Ongoing experiments will determine how disruption of the circadian clock causes cardiac remodeling in an effort to identify therapeutics to attenuate the maladaptive outcomes of a broken cardiac circadian clock.

Maternal exercise shifts adiposity distribution in offspring towards energy burning brown fat

Human epidemiological and animal studies show the maternal in utero environment significantly impacts offspring development. This includes sedentary lifestyle, which is linked to developmental programming of metabolic dysfunction. The aim of this study was to investigate metabolic outcomes in offspring of sedentary mice versus mice that exercised in pregnancy. C57BL/6J female mice were placed on control diet and allocated to sedentary (SED) versus voluntary running wheel exercise (EX) cages. Voluntary wheel running was allowed 2 weeks prior to breeding and throughout weaning. Offspring underwent body composition measurement and insulin and glucose tolerance tests at 6 and 12 weeks of age, were placed in an indirect calorimetry system to assess energy balance at 14 weeks, and were euthanized for collection of adipose depots at 16 weeks. Outcomes were analyzed by two-way ANOVA to assess effects of exercise, sex, and their interaction. We studied metabolic function in 11 male SED, 13 female SED, 15 male EX, and 13 female EX offspring. While body mass and adiposity were similar among groups, EX mice had less subcutaneous white adipose (% body mass: 1.26±0.09 male SED vs. 0.87±0.06 male EX vs. 1.15±0.11 female SED vs. 0.95 ±0.04 female EX; PSex=0.871, PEX=0.001, PInt=0.237) and more brown adipose (% body mass: 0.31±0.03 male SED vs. 0.47±0.05 male EX vs. 0.27±0.02 female SED vs. 0.48 ±0.05 female EX; PSex=0.704, PEX=0.001, PInt=0.527). There were no differences in fasting glucose and insulin levels, insulin sensitivity, glucose tolerance, or measures of energy balance (e.g., food intake, energy expenditure) among groups. These data suggest that despite no change in overall body mass or body composition, maternal exercise shifts adiposity distribution of offspring away from energy storing white fat towards energy burning brown fat. This change may impact energy metabolism over the lifespan given increasing evidence for advantageous metabolic adaptations with increased brown fat.

Effect of Voluntary Wheel-Running Exercise on the Endocrine and Inflammatory Response to Social Stress: Conditioned Rewarding Effects of Cocaine.

The present paper evaluates the effect of physical activity on the increase of the conditioned rewarding effects of cocaine induced by intermittent social stress and on the neuroinflammatory response that contributes to the enhancement of drug response. For that purpose, three studies were designed in which social stress was induced in different samples of mice through a social-defeat protocol; the mice underwent an increase of physical activity by different modalities of voluntary wheel running (continuous and intermittent access). The results showed that continuous access to running wheels prior to stress enhanced the establishment of cocaine place preference, whereas an intermittent access exerted a protective effect. Wheel running contingent to cocaine administration prevented the development of conditioned preference, and if applied during the extinction of drug memories, it exerted a dual effect depending on the stress background of the animal. Our biological analysis revealed that increased sensitivity to cocaine may be related to the fact that wheel running promotes inflammation though the increase of IL-6 and BDNF levels. Together, these results highlight that physical exercise deeply impacts the organism’s response to stress and cocaine, and these effects should be taken into consideration in the design of a physical intervention.

Agastache rugosa Extract Combined With Voluntary Wheel Exercise Affects the Improvement of Skeletal Muscle Homeostasis in Aged C57BL/6J Mice

ObjectivesThis study aimed to investigate the beneficial effects of Agastache rugosa (AR) combined with wheel running exercise on maintaining muscle homeostasis in aged skeletal muscle.MethodsMale 38-week-old C57BL/6J mice were divided into five groups (n = 8/group): control (CON), Low-dose AR-treated (ARL, 100 mg/kg/day), High-dose AR-treated (ARH, 200 mg/kg/day), exercise (EXC), and EXC + ARH (EXH) group. After 2 weeks of acclimation period, AR-treated groups were fed AR extract by oral administration for 4 weeks. The daily voluntary wheel running (VWR) distance was recorded using a counter machine. In the gastrocnemius (GAS) muscle sample, muscle homeostasis-related genes and protein were analyzed by qPCR and western blotting, respectively.ResultsThe weight of GAS in ARH and EXH increased significantly, compared to CON (p < 0.05). qPCR analysis showed that AR and exercise affected both oxidative and glycolytic muscle fibers. mRNA levels of Myh7 and Myh1 in EXH were remarkably higher than in CON (p < 0.05). Skeletal muscle atrophy (Atrogin-1 and MuRF-1) and hypertrophy (myogenin) related genes were up-regulated in EXC compared to CON (p < 0.05). Meanwhile, EXH dramatically down-regulated Atrogin-1 and MuRF-1 and up-regulated <> (p < 0.05). Western blotting analysis indicated that the hypertrophy-related protein p70S6 showed high levels in both exercise groups, but there was no statistically significant difference. In contrast, atrophy-related protein FOXO3a and MuRF-1 levels were remarkably lower in the EXC and EXH (p < 0.05).ConclusionsTaken together, this study demonstrated that AR with VWR exercise enhanced muscle homeostasis via regulation of skeletal muscle protein synthesis and degradation markers in aged hind-limb muscles. In conclusion, AR could be a promising candidate for maintaining muscle homeostasis and further alleviating sarcopenia.Funding SourcesThis work was supported by the BK21 FOUR (Fostering Outstanding Universities for Research) funded by the Ministry of Education (MOE, Korea) and National Research Foundation of Korea (NRF), and the Bio & Medical Technology Development Program of the National Research Foundation (NRF), funded by the Ministry of Science & ICT (2012M3A9C4048761).

Voluntary Exercise Boosts Striatal Dopamine Release: Evidence for the Necessary and Sufficient Role of BDNF.

Physical exercise improves motor performance in individuals with Parkinson's disease and elevates mood in those with depression. Although underlying factors have not been identified, clues arise from previous studies showing a link between cognitive benefits of exercise and increases in brain-derived neurotrophic factor (BDNF). Here, we investigated the influence of voluntary wheel-running exercise on BDNF levels in the striatum of young male wild-type (WT) mice, and on the striatal release of a key motor-system transmitter, dopamine (DA). Mice were allowed unlimited access to a freely rotating wheel (runners) or a locked wheel (controls) for 30 d. Electrically evoked DA release was quantified in ex vivo corticostriatal slices from these animals using fast-scan cyclic voltammetry. We found that exercise increased BDNF levels in dorsal striatum (dStr) and increased DA release in dStr and in nucleus accumbens core and shell. Increased DA release was independent of striatal acetylcholine (ACh), and persisted after a week of rest. We tested a role for BDNF in the influence of exercise on DA release using mice that were heterozygous for BDNF deletion (BDNF+/-). In contrast to WT mice, evoked DA release did not differ between BDNF+/- runners and controls. Complementary pharmacological studies using a tropomyosin receptor kinase B (TrkB) agonist in WT mouse slices showed that TrkB receptor activation also increased evoked DA release throughout striatum in an ACh-independent manner. Together, these data support a causal role for BDNF in exercise-enhanced striatal DA release and provide mechanistic insight into the beneficial effects of exercise in neuropsychiatric disorders, including Parkinson's, depression, and anxiety.SIGNIFICANCE STATEMENT Exercise has been shown to improve movement and cognition in humans and rodents. Here, we report that voluntary exercise for 30 d leads to an increase in evoked DA release throughout the striatum and an increase in BDNF in the dorsal (motor) striatum. The increase in DA release appears to require BDNF, indicated by the absence of DA release enhancement with running in BDNF+/- mice. Activation of BDNF receptors using a pharmacological agonist was also shown to boost DA release. Together, these data support a necessary and sufficient role for BDNF in exercise-enhanced DA release and provide mechanistic insight into the reported benefits of exercise in individuals with dopamine-linked neuropsychiatric disorders, including Parkinson's disease and depression.

Melanoma Impairs Mouse Heart Function Which Short‐Term Exercise Cannot Restore

The aim of this study was to investigate whether melanoma impairs intrinsic heart function in mice and whether short‐term voluntary running wheel exercise could reduce the possible negative effects. Additionally, we investigated whether changes in cell size, capillary density, calcium channel levels, metabolic enzyme activities or oxidative stress could explain the possible changes in heart function. Advanced melanoma has been shown to cause cardiac muscle wasting and influence heart function in vivo, we hypothesized that melanoma would also impair intrinsic heart function, which has not been investigated previously. We also hypothesized that voluntary short‐term exercise could reduce the effects of melanoma on cardiac function since exercise training is known to improve cardiovascular function and reduce the negative effects of some cancers.Male mice were divided into untrained tumor‐free group (control) and untrained melanoma group and trained melanoma group. The mice did voluntary running‐wheel exercise until predetermined tumor size after which their hearts were isolated. The cardiac function was measured in retrograde perfusion at a constant pressure in multiple oxygen levels using Langendorff apparatus. The molecular and tissue level markers were measured afterwards.The melanoma animals were not cachectic as indicated lack of body weight loss. The rate of pressure production, pressure amplitude and rate of pressure decline were all significantly lower in the isolated hearts of the melanoma animals as compared to tumor‐free animals. However, the heart function did not differ between the untrained and trained melanoma groups. Furthermore, there were no differences between the groups in the calcium channel levels, reactive oxygen species, catalase activity, lipid peroxidation or citrate synthase and lactate dehydrogenase activity. However, mice from both melanoma groups had significantly lower superoxide dismutase activity as compared to tumor‐free animals, which might reduce the heart’s ability to respond to possible changes in oxidative stress. Exercise trained animals had higher capillary density, but their cell size and heart weights did not significantly differ from the untrained groups. Running wheel exercise did not affect the final tumor growth either even though there was tendency at the beginning of the experiment that running wheel exercise could slow down the tumor growth. One reason for this could be that when melanoma proceeded, the mouse running activity reduced significantly.In conclusion, melanoma is an aggressive cancer that impairs intrinsic heart function even when no cachexia is present. The aggressiveness of melanoma also prevented the short‐term voluntary exercise from alleviating the changes caused by melanoma. Future studies should combine the training to medical cancer treatment in order to estimate whether exercise training could be beneficial as adjunct therapy in melanoma treatment.

Subcutaneous B16 melanoma impairs intrinsic pressure generation and relaxation of the heart, which are not restored by short-term voluntary exercise in mice.

The aim of this study was to investigate whether subcutaneous melanoma impairs intrinsic cardiac function and hypoxia tolerance in mice. In addition, it was investigated whether these changes could be prevented by voluntary wheel-running exercise. The roles of different molecular pathways were also analyzed. Male mice (C57Bl/6NCrl) were divided into unexercised tumor-free group, unexercised melanoma group, and exercised melanoma group. The experiment lasted 2.7 ± 0.1 wk (determined by the tumor size) after which the heart function was measured in different oxygen levels ex vivo using Langendorff method. All the melanoma mice had lower pressure amplitude (50.3%), rate of pressure production (54.1%), and decline (52.5%) in hearts ex vivo when compared with tumor-free group. There were no functional differences between the two melanoma groups. All the groups had similar weight changes, heart weights, cardiomyocyte sizes, levels of Ca2+ channels, energy metabolism enzyme activities, lipid peroxidation, and reactive oxygen species in their cardiac tissue homogenates. However, all the melanoma mice had 7.4% lower superoxidase dismutase activity compared with the control animals, which might reduce the ability of the heart to react to changes in oxidative stress. The exercising melanoma group had a 28.6% higher average heart capillary density compared with the unexercised melanoma group. Short-term wheel running did not affect the tumor growth. In conclusion, subcutaneous melanoma seems to impair intrinsic heart function even before cachexia, and these functional alterations were not caused by any of the measured molecular markers. Short-term voluntary wheel-running exercise was insufficient to alleviate the intrinsic cardiac impairments caused by melanoma.NEW & NOTEWORTHY Melanoma has been shown to induce cardiac atrophy and impair cardiac function in vivo, however, it has not been investigated how melanoma affects the intrinsic heart function. Here, we showed that subcutaneous melanoma can impair intrinsic heart function in noncachectic mice, decreasing the heart's pressure production and relaxation. In addition, we investigated whether short-term voluntary wheel-running exercise could attenuate the impairment of intrinsic cardiac function. However, our results do not seem to support this hypothesis.

Hepatocyte-specific eNOS deletion impairs exercise-induced adaptations in hepatic mitochondrial function and autophagy.

Endothelial nitric oxide synthase (eNOS) is a potential mediator of exercise-induced hepatic mitochondrial adaptations. Here, male and female hepatocyte-specific eNOS knockout (eNOShep-/- ) and intact hepatic eNOS (eNOSfl/fl ) mice performed voluntary wheel-running exercise (EX) or remained in sedentary cage conditions for 10 weeks. EX resolved the exacerbated hepatic steatosis in eNOShep-/- male mice. Elevated hydrogen peroxide emission (~50% higher in eNOShep-/- vs. eNOSfl/fl mice) was completely ablated with EX. Interestingly, EX increased [1-14 C] palmitate oxidation in eNOSfl/fl male mice, but this was blunted in the eNOShep-/- male mice. eNOShep-/- mice had lower markers of the energy sensors AMP-activated protein kinase (AMPK)/phospho- (p)AMPK and mammalian target of rapamycin (mTOR) and p-mTOR, as well as the autophagy initiators serine/threonine-protein kinase ULK1 and pULK1, compared with eNOSfl/fl mice. Females showed elevated electron transport chain protein content and markers of mitochondrial biogenesis (transcription factor A, mitochondrial, peroxisome proliferator-activated receptor-gamma coactivator 1α). Collectively, this study demonstrates for the first time, to the authors' knowledge, the requirement of eNOS in hepatocytes in the EX-induced increases in hepatic fatty acid oxidation in male mice. Deletion of eNOS in hepatocytes also appears to impair the energy-sensing ability of the cell and inhibit the activation of the autophagy initiating factor ULK1. These data uncover the important and novel role of hepatocyte eNOS in EX-induced hepatic mitochondrial adaptations.