Moderate-Intensity Intermittent Training Alters the DNA Methylation Pattern of PDE4D Gene in Hippocampus to Improve the Ability of Spatial Learning and Memory in Aging Rats Reduced by D-Galactose

Time-resolved map of serum metabolome profiling in D-galactose-induced aging rats with exercise intervention

Exercise, an intervention with wide-ranging effects on the whole body, has been shown to delay aging. Due to aging and exercise as modulator of metabolism, a picture of how exercise delayed D-galactose (D-gal)-induced aging in a time-resolved manner was presented in this paper. The mapping of molecular changes in response to exercise has become increasingly accessible with the development of omics techniques. To explore the dynamic changes during exercise, the serum of rats and D-gal-induced aging rats before, during, and after exercise was analyzed by untargeted metabolomics. The variation of metabolites was monitored to reveal the specific response to D-gal-induced senescence and exercise in multiple pathways, especially the basal amino acid metabolism, including glycine serine and threonine metabolism, cysteine and methionine metabolism, and tryptophan metabolism. The homeostasis was disturbed by D-gal and maintained by exercise. The paper was expected to provide a theoretical basis for the study of anti-aging exercise.

Effects of exercise-targeted hippocampal PDE-4 methylation on synaptic plasticity and spatial learning/memory impairments in D-galactose-induced aging rats

Physical exercise reduces the effects of aging and cognitive decline by improving synaptic plasticity and spatial learning. However, the underlying neurobiological mechanisms are unclear. A total of 45 Male SPF Sprague-Dawley rats were acclimatized and then allocated into three groups, 15 in each group: the saline control (DC) group, D-gal-induced aging (DA) group, and D-gal-induced aging + exercise (DE) group. Six weeks of intraperitoneal injections of D-gal at a concentration of 100 mg/kg body weight/d was injected to establish model of aging in the DA and DE groups. Morris water maze test was implemented to evaluate the hippocampus related cognition. SOD activity and MDA was tested to assess the aging in all groups. H&E and Nissl staining was used to observe the histopathological changes of hippocampal neurons in aging rats. Quantitative real-time polymerase chain reaction, western blotting and immunofluorescence staining techniques were used to investigate the expression of synaptic genes and proteins in the hippocampus. Massarray methylation system was employed to measure the PDE-4 gene methylation level in rat hippocampal tissues. Our results demonstrated that exercise intervention improves cognitive function in D-gal-induced aging rats. The methylation of CpG sites in PDE-4 in the hippocampus was significantly increased. The physical exercise significantly increased PDE-4 gene methylation and effectively decreased PDE-4 gene and protein expression. These beneficial behavioral and morphological effects were attributed to PDE-4 methylation, which was activated cAMP/PKA/CREB pathway and improved synaptic plasticity. Exercise induced PDE-4 methylation is key mechanism underpinning the amelioration of learning/memory impairment, suggesting the potential efficacy of physical exercise training in delaying brain aging.

Long-term lifestyle intervention is superior to transient modification for neuroprotection in D-galactose-induced aging rats

AIMS

To investigate whether transient dietary restriction or aerobic exercise in young adulthood exert long-lasting protection against brain aging later in life.

MAIN METHODS

Seven-week-old male Wistar rats were divided into 2 groups and given either normal saline as a vehicle (n = 8) or 150 mg/kg/day of D-galactose (n = 40) for 28 weeks, the D-galactose being used to induce aging. At week 13 of the experiment, D-galactose-treated rats were further divided into 5 groups, 1) no intervention, 2) transient dietary restriction for 6 weeks (week 13-18), 3) transient exercise for 6 weeks (week 13-18), 4) long-term dietary restriction for 16 weeks (week 13-28), and 5) long-term exercise for 16 weeks (week 13-28). At the end of week 28, cognitive function was examined, followed by molecular studies in the hippocampus.

KEY FINDINGS

Our results showed that either long-term dietary restriction or aerobic exercise effectively attenuated cognitive function in D-galactose-treated rats via the attenuation of oxidative stress, cellular senescence, Alzheimer's-like pathology, neuroinflammation, and improvements in mitochondria, brain metabolism, adult neurogenesis, and synaptic integrity. Although transient interventions provided benefits in some brain parameters in D-galactose-treated rats, an improvement in cognitive function was not observed.

SIGNIFICANCE

Our findings suggested that transient lifestyle interventions failed to exert a long-lasting protective effect against brain aging. Hence, novel drugs mimicking the neuroprotective effect of long-term dietary restriction or exercise and the combination of the two since young age appear to be more appropriate treatments for the elderly who are unable to engage in long-term dietary restriction or exercise.

Aerobic exercise combined with chlorogenic acid exerts neuroprotective effects and reverses cognitive decline in Alzheimer's disease model mice (APP/PS1) via the SIRT1/ /PGC-1α/PPARγ signaling pathway

Alzheimer's disease (AD) is a prevalent neurodegenerative disease account for 60-80% of the total number of people with dementia, but its treatment and prevention strategies are still in a long process of exploration. It has been reported that a healthy lifestyle may be an effective non-pharmacological intervention for the prevention and treatment of AD, including increased physical activity and the consumption of polyphenol-rich foods. This study, therefore, investigated the effects of 8 weeks of moderate-intensity aerobic exercise (EX), administration of chlorogenic acid administration (GCA), and a combination of both (EX+GCA) on β-amyloid (Aβ) deposition, inflammatory factors, oxidative stress markers, neuronal damage, and cognitive performance in the brains of AD model mice (APP/PS1) and which signaling pathways may be responsible for these effects. The study used Western blot to detect the expression of signaling pathway-related proteins, enzyme-linked immunosorbent assay to detect the expression of inflammatory factors, hematoxylin-eosin staining to detect hippocampal neuronal morphology, immunohistochemistry to detect changes in Aβ deposition in the hippocampus, an oxidative stress marker kit to detect oxidative stress status and the Morris water maze to detect changes in cognitive performance. This study showed that an 8-week intervention (EX/GCA/EX+GCA) activating the SIRT1/PGC-1α signaling pathway improved oxidative stress, neuroinflammation, Aβ deposition, and cognitive performance in mice. However, there was no obvious difference between the EX and GCA groups. In contrast, the combined EX+GCA intervention was significantly better than phase EX or GCA. Our study suggests that although relief of Aβ deposition, neuroinflammation, oxidative stress, neuronal damage, and cognitive decline could also be achieved with EX or GCA, the combined EX+GCA intervention showed better results. These relief effects on AD-related conditions may be obtained by mediating the activation of the SIRT1/PGC-1α signaling pathway. This study is the first to explore the improvement of AD-related conditions with a combined lifestyle of EX+GCA. This healthy lifestyle could be a candidate option for the treatment of AD.

Mass Spectrometry Chromatography-Based Metabolomics: The Effect of Long-Term Aerobic Exercise on Learning Ability and the Metabolism of Intestinal Contents in Mice with Alzheimer's Disease

This study aimed to investigate the effect of long-term aerobic exercise on the metabolism of intestinal contents in APP/PS1 mice was studied using a non-targeted metabolomics technique based on high-performance liquid chromatography-mass spectrometry (HPLC-MS) coupling, providing a theoretical basis for exercise to regulate the metabolism of Alzheimer's disease (AD) organisms. Three-month-old male C57BL/6JNju mice, six wild-type (NC, n = 6); 12 APP/PS1 double transgenic species in total, were randomly divided into AD model (AM, n = 6) and AD model exercise (AE, n = 6) groups. The mice in the NC group were fed naturally, the mice in the AM group were statically placed on a running platform, and the mice in the AE group received a 20-week long-term moderate intensity running platform exercise intervention. Following the exercise intervention, the cecum contents of the mice in each group were collected and analyzed using the HPLC-MS technique, with those meeting both variable important in projection (VIP)> 1.5 and p < 0.05 being screened as differential metabolites. A total of 32 different metabolites were detected between the AM and NC groups, with 19 up-regulated in the AM group such as phosphatidic acid (PA) (18:4(6Z,9Z,12Z,15Z)/21:0) and 13 down-regulated in the AM group, such as 4,8-dimethylnonanoyl, compared to the NC group; 98 different metabolites were found between the AM and AE groups, 41 of which were upregulated such as Lyso phosphatidylcholine (LysoPC) and 57 of which were downregulated compared to the AM group such as Phosphatidylinositol (PI). The regulation of linoleic acid metabolism, glycerophospholipid metabolism, bile secretion, phenylalanine metabolism, and other pathways was predominantly regulated by nine metabolites, which were subsequently identified as indicators of exercise intervention to enhance metabolism in AD mice. The metabolomic technique can identify the metabolic problems of intestinal contents in AD mice and initially screen the biomarkers of exercise to improve the metabolic disorders in AD. These findings can help us better understand the impact of aerobic exercise on AD metabolism.

Bioinformatics Analysis and Experimental Verification of Exercise for Aging Mice in Different Brain Regions Based on Transcriptome Sequencing

PURPOSE

Physical exercise mitigates the effects of aging and cognitive decline. However, the precise neurobiological mechanisms underlying this phenomenon remain unclear. The primary aim of this study was to investigate the protective effect of exercise on age-related memory deficits in the prefrontal cortex (PFC) and hippocampus using bioinformatic analysis and biochemical verification.

METHODS

Young and aging mice were subjected to natural feeding or treadmill exercise (12 m/min, 8 weeks). Cognitive function was accessed using the Barnes maze and novel object recognition. Bioinformatic analysis was performed to identify co-expressed genes in different groups and brain regions. The selected genes and pathways were validated using RT-qPCR.

RESULTS

Regular exercise significantly ameliorated age-related cognitive deficits. Four up-regulated targets (Ifi27l2a, Irf7, Oas1b, Ifit1) and one down-regulation (Septin2) were reversed by exercise, demonstrating the underlying mechanisms of cognitive functions induced by aging with exercise in the hippocampus and PFC. The Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses indicated that the NOD-like receptor signaling pathway was inhibited in the neuroinflammation effects of exercise in aging mice in both brain regions.

CONCLUSION

Exercise enhances age-related learning and memory deficits. This beneficial effect may be attributed to the changes in five up/down-regulated genes and the NOD-like receptor signaling pathway in both the hippocampus and PFC. These findings establish the modulation of neuroinflammation as a pivotal molecular mechanism supporting exercise intervention in the brain aging process.