Cortical and hippocampal expression of inflammatory and intracellular signaling proteins in aged rats submitted to aerobic and resistance physical training

The microarchitecture and chemical composition of the femur neck of senescent female rats after different physical training protocols

A sedentary lifestyle, coupled with a decrease in estrogen, impairs bone homeostasis, favoring to the development of osteopenia and osteoporosis, both recognized as risk factors for fractures. Here, we investigated the quality of the femur, particularly the femur neck region, and the ambulation performance of senescent rats subjected to three different physical training protocols during the periestropause period. Forty-eight female rats, 18 months of age, were subjected to a 120-day training period, three times a week. The rats were distributed into four groups: aerobic training (AT), strength training (ST), concurrent training (CT), or no training (NT). After the experimental period, at 21 months of age, ambulation performance and femur were analyzed using microtomography, Raman stereology, densitometry, and mechanical strength tests. The results demonstrated greater remodeling activity and improvement in resistance and bone microarchitecture in the femur neck of senescent female rats after undergoing physical training. Our verified higher intensities of bands related to collagen, phosphate, amide III, and amide I. Furthermore, the analysis of the secondary collagen structures indicated alterations in the collagen network due to the exercise, resulting in increased bone strength. Both AT and strength-based training proved beneficial, with AT showing greater adaptations in bone density and stiffness in the femur, while strength-based training greater adaptations in trabecular and cortical structure. These insights contribute to the understanding of the potential interventions for preventing osteopenia and osteoporosis, which are critical risk factors for fractures.

Potential effect of physical exercise on the downregulation of BDNF mRNA expression in rat hippocampus following intracerebral hemorrhage

OBJECTIVES

Physical exercise is known to induce expression of the neuroprotective brain derived neurotrophic factor (BDNF) in the hippocampus. This study examined the effects of physical exercise on hippocampal BDNF expression and the potential benefits for preventing remote secondary hippocampal damage and neurological impairment following intracerebral hemorrhage (ICH).

MATERIALS AND METHODS

Wistar rats were randomly assigned to sham-operated, ICH, and ICH followed by exercise (ICH/Ex) groups. The two ICH groups were injected with type IV collagenase into the left basal ganglia, while sham animals were injected with equal-volume saline. The ICH/Ex group rats ran on a treadmill at 11 m/min for 30 min/day from day 3 to 16 post-ICH. All animals were examined for neurological function on day 2 pretreatment and from day 3 to 15 posttreatment, for spontaneous motor activity in the open field on day 15, and for cognitive ability using the object location test on day 16. Animals were then euthanized and bilateral hippocampi collected for gene expression analyses.

RESULTS

Experimental ICH induced neurological deficits that were not reversed by exercise. In contrast, ICH did not alter spontaneous activity or object location ability. Expression of BDNF mRNA of the ICH group was significantly downregulated in the ipsilateral hippocampus compared to the SHAM group, but this downregulation was not shown in the ICH/Ex group. The ICH/Ex group showed the downregulation of caspase-3 mRNA expression in the contralateral hippocampus compared to the SHAM group, while neither ICH nor exercise influenced toll-like receptor 4 mRNA expression.

CONCLUSIONS

ICH induced the secondary BDNF downregulation in the hippocampus remote from the lesion, whereas physical exercise might partially mitigate the downregulation.

Aerobic exercise training reduces deep-frying oil-induced apoptosis of hippocampal tissue by reducing oxidative stress in male rats

Deep-frying oil (DFO) contains high amounts of free radicals, and consuming foods prepared with this method causes damage to nervous tissue due to oxidative stress (OS). Since moderate-intensity aerobic exercise training (AT) reduces OS, the current search investigated the effects of AT on OS, apoptosis, and neurogenesis markers in the hippocampal tissue of DFO-fed rats. Eighteen Wistar male rats (200-280 gr) were randomly allocated to a control group fed with normal food (Con-ND), a control group receiving DFO (Con-DFO), and a group receiving DFO-aerobic exercise (EX-DFO) (n = 6 in each). DFO was gavaged for four weeks, five days a week, with a dose of 2 ml. AT included running on a treadmill for four weeks and five sessions per week (40 min per session). The expression of genes B-cell lymphoma 2 (BCL-2), Protein X associated with Bcl-2 (BAX), Caspase-3 (Casp-3), and Caspase-9 (Casp-9) was measured by PCR method. The ELISA method was used to calculate levels of Superoxide dismutase (SOD) and Catalase (CAT) activity, malondialdehyde (MDA), and Brain-Derived Neurotrophic Factor (BDNF). Also, the expression of the proteins Cannabinoid receptor type 1(CB1), Cannabinoid receptor type2 (CB2), Glial fibrillary acidic protein (GFAP), Neuronal nuclei (NeuN), and DNA fragmentation was evaluated by Immunohistochemical and TUNEL staining. DFO feeding led to a significant increase in apoptotic markers, such as BAX, Casp-3, and Casp-9 gene expression, and DNA fragmentation (p ≤ 0.05) while decreasing BDNF concentration SOD activity (p ≤ 0.05). AT significantly reduced the BAX, Casp-3, Casp-9, MDA, CB1, GFAP, and DNA fragmentation (p ≤ 0.05). In conclusion, AT can reduce the harmful effects of feeding with DFO on the hippocampal tissue.

Advancing Alzheimer's Therapeutics: Exploring the Impact of Physical Exercise in Animal Models and Patients

Alzheimer's disease (AD) is the main neurodegenerative disorder characterized by several pathophysiological features, including the misfolding of the tau protein and the amyloid beta (Aβ) peptide, neuroinflammation, oxidative stress, synaptic dysfunction, metabolic alterations, and cognitive impairment. These mechanisms collectively contribute to neurodegeneration, necessitating the exploration of therapeutic approaches with multiple targets. Physical exercise has emerged as a promising non-pharmacological intervention for AD, with demonstrated effects on promoting neurogenesis, activating neurotrophic factors, reducing Aβ aggregates, minimizing the formation of neurofibrillary tangles (NFTs), dampening inflammatory processes, mitigating oxidative stress, and improving the functionality of the neurovascular unit (NVU). Overall, the neuroprotective effects of exercise are not singular, but are multi-targets. Numerous studies have investigated physical exercise's potential in both AD patients and animal models, employing various exercise protocols to elucidate the underlying neurobiological mechanisms and effects. The objective of this review is to analyze the neurological therapeutic effects of these exercise protocols in animal models and compare them with studies conducted in AD patients. By translating findings from different approaches, this review aims to identify opportune, specific, and personalized therapeutic windows, thus advancing research on the use of physical exercise with AD patients.

Ex Vivo treatment of coronary artery endothelial cells with serum post-exercise training offers limited protection against in vitro exposure to FEC-T chemotherapy

Background: Chemotherapy treatment for breast cancer associates with well-documented cardiovascular detriments. Exercise has shown promise as a potentially protective intervention against cardiac toxicity. However, there is a paucity of evidence for the benefits of exercise on the vasculature. Objectives: This study aimed to determine the effects of chemotherapy on the vascular endothelium; and if there are protective effects of serological alterations elicited by an exercise training intervention. Methods and Results: 15 women participated in a 12-week home-based exercise intervention consisting of three high-intensity interval sessions per week. Human coronary artery endothelial cells (HCAEC) were exposed to physiological concentrations of 5-fluorouracil, epirubicin, cyclophosphamide (FEC) and docetaxel to determine a dose-response. Twenty-4 hours prior to FEC and docetaxel exposure, HCAECs were preconditioned with serum collected pre- and post-training. Annexin V binding and cleaved caspase-3 were assessed using flow cytometry and wound repair by scratch assays. Chemotherapy exposure increased HCAEC Annexin V binding, cleaved caspase-3 expression in a dose-dependent manner; and inhibited wound repair. Compared to pre-training serum, conditioning HCAECs with post-training serum, reduced Annexin V binding (42% vs. 30%, p = 0.01) when exposed to FEC. For docetaxel, there were no within-group differences (pre-vs post-exercise) for Annexin V binding or cleaved caspase-3 expression. There was a protective effect of post-training serum on wound repair for 5-flurouracil (p = 0.03) only. Conclusion: FEC-T chemotherapy drugs cause significant damage and dysfunction of endothelial cells. Preconditioning with serum collected after an exercise training intervention, elicited some protection against the usual toxicity of FEC-T, when compared to control serum.

Resistance Training Modulates Hippocampal Neuroinflammation and Protects Anxiety-Depression-like Dyad Induced by an Emotional Single Prolonged Stress Model

Stress is a triggering factor for anxious and depressive phenotypes. Exercise is known for its action on the central nervous system. This study aimed to evaluate the role of resistance exercise in an anxiety-depression-like dyad in a model of stress. Male Swiss mice (35-day-old) were exercised, three times a week for 4 weeks on nonconsecutive days. The resistance exercise consisted of climbing a 1-m-high ladder 15 times. After mice were subjected to an emotional single prolonged stress (Esps) protocol. Seven days later, they were subjected to anxiety and depression predictive behavioral tests. The results showed that exercised mice gain less weight than sedentary from weeks 3 to 5. Resistance exercise was effective against an increase in immobility time in the forced swim test and tail suspension test and a decrease in grooming time of mice subjected to Esps. Resistance exercise protected against the decrease in the percentage of open arms time and open arm entries, and the increase in the anxiety index in Esps mice. Four-week resistance exercise did not elicit an antidepressant/anxiolytic phenotype in non-stressed mice. Esps did not alter plasma corticosterone levels but increased the hippocampal glucocorticoid receptor content in mice. Resistance exercise protected against the decrease in hippocampal levels of tropomyosin kinase B (TRκB), the p-Akt/Akt, and the p-mTOR/mTOR ratios of Esps mice. Resistance exercise proved to be effective in decreasing hippocampal neuroinflammation in Esps mice. Resistance exercise protected against the increase in the hippocampal Akt/mTOR pathway and neuroinflammation, and anxiety/depression-like dyad in Esps exposed mice.

Adropin increases with swimming exercise and exerts a protective effect on the brain of aged rats

Adropin is a protein in the brain that decreases with age. Exercise has a protective effect on the endothelium by increasing the level of adropin in circulation. In this study, whether adropin, whose level in the brain decreases with age, may increase with swimming exercise, and exhibit a protective effect was investigated. Young and aged male Sprague Dawley rats were submitted to 1 h of swimming exercise every day for 8 weeks. Motor activity parameters were recorded at the end of the exercise or waiting periods before the animals were euthanized. Increased motor functions were observed in only the young rats that exercised regularly. Adropin levels in the plasma, and the adropin and VEGFR2 immunoreactivities and p-Akt (Ser473) levels in the frontal cortex were significantly increased in the aged rats that exercised regularly. It was also observed that the BAX/Bcl2 ratio and ROS-RNS levels decreased, while the TAC levels increased in the aged rats that exercised regularly. The results of the study indicated that low-moderate chronic swimming exercise had protective effects by increasing the level of adropin in the frontal cortex tissues of the aged rats. Adropin is thought to achieve this effect by increasing the VEGFR2 expression level and causing Akt (Ser473) phosphorylation. These results indicated that an exercise-mediated increase in endogenous adropin may be effective in preventing the destructive effects of aging on the brain.

Effect of the ACTN-3 gene polymorphism on functional fitness and executive function of elderly

During aging, physical integrity and cognitive abilities, especially executive function, become compromised, directly influencing the quality of life of the elderly. One good strategy to ensure healthy aging is the practice of physical exercise. Activities to improve aerobic capacity and muscle strength are extremely important in old age. However, some genetic factors can interfere both positively and negatively with these gains. In this context, the polymorphism rs1815739 (R577X) of the α-actinin 3 gene (ACTN-3) is commonly studied and related to muscle phenotype. Thus, the present study aimed to investigate the effect of the ACTN-3 gene polymorphism on the functional fitness (measured by the Senior Fit test) and cognitive capacity (evaluated by the Stroop test) of the elderly (n = 347), both men and women. We did not find the effect of genotype on functional fitness, but we did observed a positive effect of the ACTN-3 gene polymorphism on executive function. The presence of the X allele of the ACTN3 gene in the elderly was related to a better performance in the Stroop test (shorter answer time). Our results showed that ACTN-3 gene polymorphism affects the executive function of the elderly but not their functional fitness.

Resistance exercise improves learning and memory and modulates hippocampal metabolomic profile in aged rats

Physical activity has been considered an important non-medication intervention to preserve mnemonic processes during aging. However, how resistance exercise promotes such benefits remains unclear. A possible hypothesis is that brain-metabolic changes of regions responsible for memory consolidation is affected by muscular training. Therefore, we analyzed the memory, axiety and the metabolomic of aged male Wistar rats (19-20 months old in the 1st day of experiment) submitted to a 12-week resistance exercise protocol (EX, n = 11) or which remained without physical exercise (CTL, n = 13). Barnes maze, elevated plus maze and inhibitory avoidance tests were used to assess the animals' behaviour. The metabolomic profile was identified by nuclear magnetic resonance spectrometry. EX group had better performance in the tests of learning and spatial memory in Barnes maze, and an increase of short and long-term aversive memories formation in inhibitory avoidance. In addition, the exercised animals showed a greater amount of metabolites, such as 4-aminobutyrate, acetate, butyrate, choline, fumarate, glycerol, glycine, histidine, hypoxanthine, isoleucine, leucine, lysine, niacinamide, phenylalanine, succinate, tyrosine, valine and a reduction of ascorbate and aspartate compared to the control animals. These data indicate that the improvement in learning and memory of aged rats submitted to resistance exercise program is associated by changes in the hippocampal metabolomic profile.

Possible Neuroprotective Mechanisms of Physical Exercise in Neurodegeneration

Physical exercise (PE) improves physical performance, mental status, general health, and well-being. It does so by affecting many mechanisms at the cellular and molecular level. PE is beneficial for people suffering from neuro-degenerative diseases because it improves the production of neurotrophic factors, neurotransmitters, and hormones. PE promotes neuronal survival and neuroplasticity and also optimizes neuroendocrine and physiological responses to psychosocial and physical stress. PE sensitizes the parasympathetic nervous system (PNS), Autonomic Nervous System (ANS) and central nervous system (CNS) by promoting many processes such as synaptic plasticity, neurogenesis, angiogenesis, and autophagy. Overall, it carries out many protective and preventive activities such as improvements in memory, cognition, sleep and mood; growth of new blood vessels in nervous system; and the reduction of stress, anxiety, neuro-inflammation, and insulin resistance. In the present work, the protective effects of PE were overviewed. Suitable examples from the current research work in this context are also given in the article.

Effects of Physical Exercise on Autophagy and Apoptosis in Aged Brain: Human and Animal Studies

The aging process is characterized by a series of molecular and cellular changes over the years that could culminate in the deterioration of physiological parameters important to keeping an organism alive and healthy. Physical exercise, defined as planned, structured and repetitive physical activity, has been an important force to alter physiology and brain development during the process of human beings' evolution. Among several aspects of aging, the aim of this review is to discuss the balance between two vital cellular processes such as autophagy and apoptosis, based on the fact that physical exercise as a non-pharmacological strategy seems to rescue the imbalance between autophagy and apoptosis during aging. Therefore, the effects of different types or modalities of physical exercise in humans and animals, and the benefits of each of them on aging, will be discussed as a possible preventive strategy against neuronal death.

Potential Involvement of Adiponectin Signaling in Regulating Physical Exercise-Elicited Hippocampal Neurogenesis and Dendritic Morphology in Stressed Mice

Adiponectin, a cytokine secreted by mature adipocytes, proves to be neuroprotective. We have previously reported that running triggers adiponectin up-regulation which subsequently promotes generation of hippocampal neurons and thereby alleviates depression-like behaviors in non-stressed mice. However, under the stressing condition, whether adiponectin could still exert antidepressant-like effects following exercise remained unexplored. In this study, by means of repeated corticosterone injections to mimic stress insult and voluntary wheel running as physical exercise intervention, we examined whether exercise-elicited antidepressive effects might involve adiponectin's regulation on hippocampal neurogenesis and dendritic plasticity in stressed mice. Here we show that repeated injections of corticosterone inhibited hippocampal neurogenesis and impaired dendritic morphology of neurons in the dentate gyrus of both wild-type and adiponectin-knockout mice comparably, which subsequently evoked depression-like behaviors. Voluntary wheel running attenuated corticosterone-suppressed neurogenesis and enhanced dendritic plasticity in the hippocampus, ultimately reducing depression-like behaviors in wild-type, but not adiponectin-knockout mice. We further demonstrate that such proneurogenic effects were potentially achieved through activation of the AMP-dependent kinase (AMPK) pathway. Our study provides the first evidence that adiponectin signaling is essential for physical exercise-triggered effects on stress-elicited depression by retaining the normal proliferation of neural progenitors and dendritic morphology of neurons in the hippocampal dentate gyrus, which may depend on activation of the AMPK pathway.

Voluntary wheel running protects against the increase in ethanol consumption induced by social stress in mice

Previous studies have shown that exposure to social defeat (SD), a model of social stress, produces a long-term increase in the consumption of ethanol, most likely through an increase in the neuroinflammation response. The aim of the present study was to evaluate whether exposure to physical activity in the form of voluntary wheel running (VWR) could block the increase in ethanol consumption and the neuroinflammatory response induced by social stress. Mice were exposed to either 4 sessions of repeated social defeat (RSD) or a non-stressful experience. During the whole procedure, half of the mice were exposed to controlled physical activity, being allowed 1 h access to a low-profile running wheel three times a week. Three weeks after the last RSD, animals started the oral self-administration (SA) of ethanol (6% EtOH) procedure. Biological samples were taken 4 h after the first and the fourth RSD, 3 weeks after the last RSD, and after the SA procedure. Brain tissue (striatum) was used to determine protein levels of the chemokines fractalkine (CX3CL1) and SDF-1 (CXCL12). RSD induced an increase in ethanol consumption and caused greater motivation to obtain ethanol. The striatal levels of CX3CL1 and CXCL12 were also increased after the last RSD. VWR was able to reverse the increase in ethanol intake induced by social stress and the neuroinflammatory response. In conclusion, our results suggest that VWR could be a promising tool to prevent and reduce the detrimental effects induced by social stress.

Exercising Immunity: Interleukin-13 Flexes Muscle

Endurance exercise drives physiological changes in the muscle to optimize performance. In a recent study in Science, Knudsen et al. report a role for the type 2 cytokine interleukin-13 in orchestrating metabolic reprogramming that drives adaptation to endurance exercise.

Effects of Resistance Exercise on Cerebral Redox Regulation and Cognition: An Interplay Between Muscle and Brain

This review highlighted resistance training as an important training type for the brain. Most studies that use physical exercise for the prevention or treatment of neurodegenerative diseases have focused on aerobic physical exercise, revealing different behavioral, biochemical, and molecular effects. However, recent studies have shown that resistance training can also significantly contribute to the prevention of neurodegenerative diseases as well as to the maintenance, development, and recovery of brain activities through specific neurochemical adaptations induced by the training. In this scenario we observed the results of several studies published in different journals in the last 20 years, focusing on the effects of resistance training on three main neurological aspects: Neuroprotective mechanisms, oxidative stress, and cognition. Systematic database searches of PubMed, Web of Science, Scopus, and Medline were performed to identify peer-reviewed studies from the 2000s. Combinations of keywords related to brain disease, aerobic/resistance, or strength physical exercise were used. Other variables were not addressed in this review but should be considered for a complete understanding of the effects of training in the brain.

A leucine-rich diet modulates the mTOR cell signalling pathway in the gastrocnemius muscle under different Walker-256 tumour growth conditions

Background

The exact signalling mechanism of the mTOR complex remains a subject of constant debate, even with some evidence that amino acids participate in the same pathway as used for insulin signalling during protein synthesis. Therefore, this work conducted further study of the actions of amino acids, especially leucine, in vivo, in an experimental model of cachexia. We analysed the effects of a leucine-rich diet on the signalling pathway of protein synthesis in muscle during a tumour growth time-course.

Methods

Wistar rats were distributed into groups based on Walker-256 tumour implant and subjected to a leucine-rich diet and euthanised at three different time points following tumour development (the 7th, 14th and 21st day). We assessed the mTOR pathway key-proteins in gastrocnemius muscle, such as RAG-A-GTPase, ERK/MAP4K3, PKB/Akt, mTOR, p70S6K1, Jnk, IRS-1, STAT3, and STAT6 comparing among the experimental groups. Serum WF (proteolysis-induced factor like from Walker-256 tumour) and muscle protein synthesis and degradation were assessed.

Results

The tumour-bearing group had increased serum WF content, and the skeletal-muscle showed a reduction in IRS-1 and RAG activation, increased PKB/Akt and Erk/MAP4K3 on the 21st day, and maintenance of p70S6K1, associated with increases in muscle STAT-3 and STAT-6 levels in these tumour-bearing rats.

Conclusion

Meanwhile, the leucine-rich diet modulated key steps of the mTOR pathway by triggering the increased activation of RAG and mTOR and maintaining JNK, STAT-3 and STAT-6 levels in muscle, leading to an increased muscle protein synthesis, reducing the degradation during tumour evolution in a host, minimising the cancer-induced damages in the cachectic state.