Forced mild physical training-induced effects on cognitive and locomotory behavior in old mice

Aged gastrocnemius muscle of mice positively responds to a late onset adapted physical training

Introduction: A regular physical training is known to contribute to preserve muscle mass and strength, maintaining structure and function of neural and vascular compartments and preventing muscle insulin resistance and inflammation. However, physical activity is progressively reduced during aging causing mobility limitations and poor quality of life. Although physical exercise for rehabilitation purposes (e.g., after fractures or cardiovascular events) or simply aiming to counteract the development of sarcopenia is frequently advised by physicians, nevertheless few data are available on the targets and the global effects on the muscle organ of adapted exercise especially if started at old age. Methods: To contribute answering this question for medical translational purposes, the proteomic profile of the gastrocnemius muscle was analyzed in 24-month-old mice undergoing adapted physical training on a treadmill for 12 weeks or kept under a sedentary lifestyle condition. Proteomic data were implemented by morphological and morphometrical ultrastructural evaluations. Results and Discussion: Data demonstrate that muscles can respond to adapted physical training started at old age, positively modulating their morphology and the proteomic profile fostering protective and saving mechanisms either involving the extracellular compartment as well as muscle cell components and pathways (i.e., mitochondrial processes, cytoplasmic translation pathways, chaperone-dependent protein refolding, regulation of skeletal muscle contraction). Therefore, this study provides important insights on the targets of adapted physical training, which can be regarded as suitable benchmarks for future in vivo studies further exploring the effects of this type of physical activity by functional/metabolic approaches.

Modulatory Effect of Aerobic Physical Activity on Synaptic Ultrastructure in the Old Mouse Hippocampus

Aerobic physical exercise (APE) leads to improved brain functions. To better understand the beneficial effect of APE on the aging brain, a morphometric study was carried out of changes in hippocampal synapses of old (>27 months) Balb/c mice undergoing treadmill training (OTT) for 4 weeks in comparison with old sedentary (OS), middle-aged sedentary (MAS) and middle-aged treadmill training (MATT) mice. The inner molecular layer of the hippocampal dentate gyrus (IMLDG) and the molecular stratum of Ammon’s horn1 neurons (SMCA1) were investigated. The number of synapses per cubic micron of tissue (numeric density, Nv), overall synaptic area per cubic micron of tissue (surface density, Sv), average area of synaptic contact zones (S), and frequency (%) of perforated synapses (PS) were measured in electron micrographs of ethanol-phosphotungstic acid (E-PTA) stained tissue. Data were analyzed with analysis of variance (ANOVA). In IMLDG, an effect of age was found for Nv and Sv, but not S and %PS. Similar results were found for exercise and the interaction of age and exercise. In post hoc analysis Nv was higher (60.6% to 75.1%; p < 0.001) in MATT vs. MAS, OS and OTT. Sv was higher (32.3% to 54.6%; p < 0.001) in MATT vs. MAS, OS and OTT. In SMCA1, age affected Nv, Sv and %PS, but not S. The effect of exercise was significant for Sv only. The interaction of age and exercise was significant for Nv, Sv and %PS. In post hoc analysis Nv was lower in OS vs. MAS, MATT and OTT (−26.1% to −32.1%; p < 0.038). MAS and OTT were similar. Sv was lower in OS vs. MAS, MATT and OTT (−23.4 to −30.3%, p < 0.004). MAS and OTT were similar. PS frequency was higher in OS vs. MAS, MATT and OTT (48.3% to +96.6%, p < 0.023). APE positively modulated synaptic structural dynamics in the aging hippocampus, possibly in a region-specific way. The APE-associated reduction in PS frequency in SMCA1 of old mice suggests that an increasing complement of PS is a compensatory phenomenon to maintain synaptic efficacy. In conclusion, the modulation of synaptic plasticity by APE gives quantitative support to the concept that APE protects from neurodegeneration and improves learning and memory in aging.

High Intensity Interval Training Improves Physical Performance and Frailty in Aged Mice

Sarcopenia and frailty are highly prevalent in older individuals, increasing the risk of disability and loss of independence. High intensity interval training (HIIT) may provide a robust intervention for both sarcopenia and frailty by achieving both strength and endurance benefits with lower time commitments than other exercise regimens. To better understand the impacts of HIIT during aging, we compared 24-month-old C57BL/6J sedentary mice with those that were administered 10-minute uphill treadmill HIIT sessions three times per week over 16 weeks. Baseline and end point assessments included body composition, physical performance, and frailty based on criteria from the Fried physical frailty scale. HIIT-trained mice demonstrated dramatic improvement in grip strength (HIIT 10.9% vs -3.9% in sedentary mice), treadmill endurance (32.6% vs -2.0%), and gait speed (107.0% vs 39.0%). Muscles from HIIT mice also exhibited greater mass, larger fiber size, and an increase in mitochondrial biomass. Furthermore, HIIT exercise led to a dramatic reduction in frailty scores in five of six mice that were frail or prefrail at baseline, with four ultimately becoming nonfrail. The uphill treadmill HIIT exercise sessions were well tolerated by aged mice and led to performance gains, improvement in underlying muscle physiology, and reduction in frailty.

Adapted physical exercise enhances activation and differentiation potential of satellite cells in the skeletal muscle of old mice

During ageing, a progressive loss of skeletal muscle mass and a decrease in muscle strength and endurance take place, in the condition termed sarcopenia. The mechanisms of sarcopenia are complex and still unclear; however, it is known that muscle atrophy is associated with a decline in the number and/or efficiency of satellite cells, the main contributors to muscle regeneration. Physical exercise proved beneficial in sarcopenia; however, knowledge of the effect of adapted physical exercise on the myogenic properties of satellite cells in aged muscles is limited. In this study the amount and activation state of satellite cells as well as their proliferation and differentiation potential were assessed in situ by morphology, morphometry and immunocytochemistry at light and transmission electron microscopy on 28-month-old mice submitted to adapted aerobic physical exercise on a treadmill. Sedentary age-matched mice served as controls, and sedentary adult mice were used as a reference for an unperturbed control at an age when the capability of muscle regeneration is still high. The effect of physical exercise in aged muscles was further analysed by comparing the myogenic potential of satellite cells isolated from old running and old sedentary mice using an in vitro system that allows observation of the differentiation process under controlled experimental conditions. The results of this ex vivo and in vitro study demonstrated that adapted physical exercise increases the number and activation of satellite cells as well as their capability to differentiate into structurally and functionally correct myotubes (even though the age-related impairment in myotube formation is not fully reversed): this evidence further supports adapted physical exercise as a powerful, non-pharmacological approach to counteract sarcopenia and the age-related deterioration of satellite cell capabilities even at very advanced age.

Forced mild physical training improves blood volume in the motor and hippocampal cortex of old mice

OBJECTIVES

To assess the effect of mild forced physical training on cerebral blood volume (CBV) and other brain parameters in old mice.

SETTING

Treadmill in the animal house.

PARTICIPANTS

Thirty old (>25 mo) male mice were randomly assigned to one of three groups, exercise (E), exercise plus testosterone (T) (ET), and rest (C).

INTERVENTION

Mild physical training on treadmill (30 min a day at belt speed = 8 m/min, five days a week) with or without one weekly injection of testosterone.

MEASUREMENTS

CBV, quantitative transverse relaxation time (T2) maps, and cortical thickness were measured by magnetic resonance imaging.

RESULTS

A significant increase of CBV was found in the motor and hippocampal cortex of E and ET mice; cortical thickness was not affected. T2 maps analysis suggested that water distribution did not change. T administration did not add to the effect of physical training.

CONCLUSION

This work provides first quantitative evidence that exercise initiated at old age is able to improve the hemodynamic status of the brain cortex in key regions for movement and cognition without inducing edema.

Antidepressant-like effects of essential oil and asarone, a major essential oil component from the rhizome of Acorus tatarinowii

CONTEXT

Depression is one of the most common psychiatric diseases. Acorus tatarinowii Schott (Araceae) has shown many bioactivities in treatment of senile dementia and epilepsy. However, there is no report on antidepressant-like effects of the essential oil (EO) and its major components on animals under standardized experimental procedures.

OBJECTIVE

This study was designed to investigate the antidepressant properties of EO and asarones from the rhizomes of A. tatarinowii.

MATERIALS AND METHODS

Gas chromatography-mass spectrometry (GC/MS) was used to determine the composition of EO. The forced swimming test (FST), tail suspension test (TST) and open-field test (OFT) were used to evaluate the antidepressant-like effects of EO and asarones. EO [30, 60, 120 or 240 mg/kg, per os (p.o.)], asarones (α-asarone and β-asarone) [5, 10 and 20 mg/kg, intraperitoneal (i.p.)] and imipramine (15 mg/kg, i.p.) were administered at 1 h, 30 min and 30 min before the test, respectively.

RESULTS

From the results of GC/MS, it was found that the main components of the EO were α-asarone (9.18%) and β-asarone (68.9%). From the results of FST and TST, the immobility time can be reduced to 166 ± 17 s (p < 0.01) and 146 ± 15 s (p < 0.05) by EO at the dose of 120 mg/kg. Moreover, significant antidepressant-like effects were shown by α-asarone with the immobility time of 178 ± 15 s (p < 0.05) and 159 ± 17 s (p < 0.01) in FST, or 147 ± 12 (p < 0.05) and 134 ± 12 s (p < 0.01) in TST at the dose of 10 and 20 mg/kg. β-Asarone also displayed antidepressant-like effects with an immobility time of 179 ± 18 s (p < 0.05) in FST or 142 ± 14 (p < 0.05) in TST at 20 mg/kg. However, no change in ambulation was observed in the OFT.

CONCLUSION

The results obtained indicate that the EO and asarones from the rhizomes of A. tatarinowii can be considered as a new therapeutic agent for curing depression.

Intervening on spontaneous physical activity to prevent weight regain in older adults: design of a randomized, clinical trial

There is a need to identify evidenced-based obesity treatments that are effective in maintaining lost weight. Weight loss results in reductions in energy expenditure, including spontaneous physical activity (SPA) which is defined as energy expenditure resulting primarily from unstructured mobility-related activities that occur during daily life. To date, there is little research, especially randomized, controlled trials, testing strategies that can be adopted and sustained to prevent declines in SPA that occur with weight loss. Self-monitoring is a successful behavioral strategy to facilitate behavior change, so a provocative question is whether monitoring SPA-related energy expenditure would override these reductions in SPA, and slow weight regain. This study is a randomized trial in older, obese men and women designed to test the hypothesis that adding a self-regulatory intervention (SRI), focused around self-monitoring of SPA, to a weight loss intervention will result in less weight and fat mass regain following weight loss than a comparable intervention that lacks this self-regulatory behavioral strategy. Participants (n=72) are randomized to a 5-month weight loss intervention with or without the addition of a behavioral component that includes an innovative approach to promoting increased SPA. Both groups then transition to self-selected diet and exercise behavior for a 5-month follow-up. Throughout the 10-month period, the SRI group is provided with an intervention designed to promote a SPA level that is equal to or greater than each individual's baseline SPA level, allowing us to isolate the effects of the SPA self-regulatory intervention component on weight and fat mass regain.

Could dietary trans fatty acids induce movement disorders? Effects of exercise and its influence on Na⁺K⁺-ATPase and catalase activity in rat striatum

The influence of trans fatty acids (FA) on development of orofacial dyskinesia (OD) and locomotor activity was evaluated. Rats were fed with diets enriched with 20% soybean oil (SO; n-6 FA), lard (L; saturated FA) or hydrogenated vegetable fat (HVF; trans FA) for 60 weeks. In the last 12 weeks each group was subdivided into sedentary and exercised (swimming). Brains of HVF and L-fed rats incorporated 0.33% and 0.20% of trans FA, respectively, while SO-fed group showed no incorporation of trans FA. HVF increased OD, while exercise exacerbated this in L and HVF-fed rats. HVF and L reduced locomotor activity, and exercise did not modify. Striatal catalase activity was reduced by L and HVF, but exercise increased its activity in the HVF-fed group. Na(+)K(+)-ATPase activity was not modified by dietary FA, however it was increased by exercise in striatum of SO and L-fed rats. We hypothesized that movement disorders elicited by HVF and less by L could be related to increased dopamine levels in striatum, which have been related to chronic trans FA intake. Exercise increased OD possibly by increase of brain dopamine levels, which generates pro-oxidant metabolites. Thus, a long-term intake of trans FA caused a small but significant brain incorporation of trans FA, which favored development of movement disorders. Exercise worsened behavioral outcomes of HVF and L-fed rats and increased Na(+)K(+)-ATPase activity of L and SO-fed rats, indicating its benefits. HVF blunted beneficial effects of exercise, indicating a critical role of trans FA in brain neurochemistry.

Antidepressant-like activity of the aqueous extract of Allium macrostemon in mice

AIM OF THE STUDY

The aim of this study was to identify the effects of water extracts of Allium macrostemon Bunge (AM-W), a traditional herb, in mice.

MATERIALS AND METHODS

The antidepressant-like activities of AM-W were evaluated through behavioral despair in forced swimming test and tail suspension test. To elucidate the mode of action of the antidepressant-like effects of AM-W, new born cells in the subgranular zone and the granule cell layer were analyzed by immunostaining for incorporation of 5-bromo-2-deoxyuridine (BrdU). In addition, the effects of AM-W on the expression levels of brain-derived neurotrophic factor (BDNF) were investigated by western blotting and immunohistochemistry.

RESULTS

The administration of AM-W reduced the immobility duration in the forced swimming test and tail suspension test (100 or 200 mg/kg, P<0.05). Sub-chronic administration of AM-W (100 or 200 mg/kg, p.o., for 14 days) increased the number of BrdU-incorporating cells. The percentage of BrdU-incorporating cells co-localized with NeuN was significantly increased after AM-W administration (100 or 200 mg/kg, P<0.05). Moreover, the expression levels of BDNF which is reported to be associated with neurogenesis were significantly increased in the hippocampus after administration of AM-W.

CONCLUSIONS

These results suggest that AM-W may be a good antidepressant, and that its mechanism of action may be related to its positive effects on neurogenesis and BDNF release.