Effects of postnatal treadmill exercise on apoptotic neuronal cell death and cell proliferation of maternal-separated rat pups

Intervention effect of exercise on working memory in patients with depression: a systematic review

Background

This article aims to systematically evaluate the intervention effect of exercise on working memory in patients with depression.

Methods

Six Chinese and English databases were searched for randomized controlled trials (RCTs) about exercise on working memory in patients with depression. PEDro scale was adopted to evaluate the methodological quality of the included articles, GRADEpro scale was employed to evaluate the level of evidence for outcomes, and the Metafor Package in R 4.4.1 was used to analyze the combined effect size, subgroup analyses and publication bias.

Results

A total of 15 studies were included. The meta-analysis indicated that exercise had a statistically significant effect on working memory in patients with depression, with an effect size of 0.16 (95% CI [0.03-0.28], p = 0.02). Exercise type (F(3,34) = 1.99, p = 0.13), intervention content (F(1,36) = 1.60, p = 0.22), and exercise duration (F(1,36) = 0.05, p = 0.83) did not moderate the effect, whereas exercise intensity showed a moderating effect (F(2,35) = 8.83, p < 0.01). There was evidence of publication bias in the study results (t = 2.52, p = 0.02).

Conclusion

Exercise can improve the working memory of patients with depression, and its moderating effect is the best when having low-intensity and moderate-intensity. Research plan was registered in international system evaluation platform PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) (CRD42023475325).

Enhancing cognitive performance and mitigating dyslipidemia: the impact of moderate aerobic training on sedentary older adults

BACKGROUND

The present study aimed to evaluate the effects of 24 weeks of moderate aerobic exercise on lipids and lipoprotein levels; Lipo (a) markers, and their association with cognitive performance in healthy older adults.

METHODS

A total of 150 healthy subjects (100 males and 50 females; age range: 65-95 years) were recruited for this study. Based on the LOTCA test score, subjects were classified into two groups: the control group (n = 50) and the cognitive impairment group (n = 100). Cognitive functioning, leisure-time physical activity (LTPA), lipid profile, total cholesterol, TG, HDL-c, LDL-C, and lipo(a) were assessed at baseline and post-24-week aerobic exercise interventions using LOTCA battery, pre-validated Global Physical Activity Questionnaire (GPAQ) version II, colorimetric, and immunoassay techniques, respectively.

RESULTS

Significant improvements in cognitive function and modulation in lipid profile and lipoprotein (a) markers were reported in all older subjects following 24 weeks of moderate exercise. LOTCA-7-sets scores significantly correlated with physical activity status and the regulation of lipids and Lipo (a) markers. Physically active persons showed higher cognitive performance along with a reduction in the levels of T-Cholest., TG, LDL-C, Lipo (a), and an increase in the levels of HDL-C and aerobic fitness VO2max compared with sedentary participants. Cognitive performance correlated positively with increased aerobic fitness, HDL-C, and negatively with T-Cholest., TG, LDL-C, and Lipo (a). However, a significant increase in the improvement of motor praxis, vasomotor organization, thinking operations, attention, and concentration were reported among older adults.

CONCLUSIONS

The study findings revealed that supervised moderate aerobic training for 24 weeks significantly enhances cognitive functions via mitigating older adults' lipid profiles and lipoprotein (a). Cognitive performance is positively correlated with aerobic fitness and HDL-C level and negatively with T-Cholest., TH, LDL-C, and Lipo (a).

Possible role of exercise therapy on depression: Effector neurotransmitters as key players

About 280 million people suffer from depression as the most common neurological disorder and the most common cause of death worldwide. Exercise with serotonin released in the brain by the 5-HT3-IGF-1 mechanism can lead to antidepressant effects. Swimming exercise has antidepressant effects by increasing the sensitivity of serotonin 5-HT2 receptors and postsynaptic 5-HT1A receptors, increasing 5-HT and 5HIAA levels, increasing TPH and serotonin, and decreasing inflammatory levels of IFN-γ and TNF-α. Anaerobic and aerobic exercises increase beta-endorphin, enkephalin, and dynorphin and have antidepressant effects. Exercise by increasing dopamine, D1R, and D2R leads to the expression of BDNF and activation of TrkB and has antidepressant behavior. Exercise leads to a significant increase in GABAAR (γ2 and α2 subunits) and reduces neurodegenerative disorders caused by GABA imbalance through anti-inflammatory pathways. By increasing glutamate and PGC1α and reducing glutamatergic neurotoxicity, exercise enhances neurogenesis and synaptogenesis and prevents neurodegeneration and the onset of depression. Irisin release during exercise shows an important role in depression by increasing dopamine, BDNF, NGF, and IGF-1 and decreasing inflammatory mediators such as IL-6 and IL-1β. In addition, exercise-induced orexin and NPY can increase hippocampal neurogenesis and relieve depression. After exercise, the tryptophan to large neutral amino acids (TRP/LNAA) ratio and the tryptophan to branched-chain amino acids (BCAA) ratio increase, which may have antidepressant effects. The expression of M5 receptor and nAChR α7 increases after exercise and significantly increases dopamine and acetylcholine and ameliorates depression. It appears that during exercise, muscarinic receptors can reduce depression through dopamine in the absence of acetylcholine. Therefore, exercise can be used to reduce depression by affecting neurotransmitters, neuromodulators, cytokines, and/or neurotrophins.

The effect of low- and moderate-intensity interval training on cognitive behaviors of male and female rats with VPA-induced autism

Introduction

This study was performed to evaluate the effects of low and moderate treadmill exercise for one month on social interaction, anxiety-like behaviors, and spatial learning and memory in male and female autistic rats.

Methods

Pregnant rats received valproic acid (VPA) (600 mg/kg/i.p) once on gestational day 12.5 to induce autism-like symptoms in the offspring. After delivery, the offspring were divided into six main groups, each with male and female subgroups: Control (CTL, prenatal normal saline), autism (prenatal VPA), low-intensity training (LIT,normal saline + low treadmill exercise), moderate -intensity training (MIT, normal saline + moderate treadmill exercise), VPA + LIT, and VPA + MIT. On the 60th day, the offspring were tested by the elevated plus maze (EPM), open field test (OFT), social interaction test (SIT), and Morris water maze (MWM).

Results

The results showed that both LIT and MIT could partly alleviate anxiety-like behaviors induced by prenatal VPA exposure in two sexes. Social impairment was observed in the autistic rats and was improved by LIT in both sexes and MIT in females. No significant change was seen in the spatial learning and memory of autistic rats by exercise.

Conclusion

The findings suggest that treadmill exercise can be helpful for improving some autism-like behaviors. Further studies are needed to investigate the involved mechanisms.

Postpartum depression: aetiology, pathogenesis and the role of nutrients and dietary supplements in prevention and management

Postpartum depression (PPD) is a challenging psychological disorder faced by 10-30% of mothers across the globe. In India, it occurs among 22% of mothers. Its aetiology and pathophysiology aren't fully understood as of today but multiple theories on the interplay of hormones, neurotransmitters, genetics, epigenetics, nutrients, socio-environmental factors, etc. exist. Nutrients are not only essential for the synthesis of neurotransmitters, but they may also indirectly influence genomic pathways that methylate DNA, and there is evidence for molecular associations between nutritional quality and psychological well-being. Increased behavioural disorders have been attributed to macro- and micronutrient deficiencies, and dietary supplementation has been effective in treating several neuropsychiatric illnesses. Nutritional deficiencies occur frequently in women, especially during pregnancy and breastfeeding. The aim of this study was to perform a comprehensive literature review of evidence-based research in order to identify, gather and summarize existing knowledge on PPD's aetiology, pathophysiology, and the role of nutrients in its prevention as well as management. The possible mechanisms of action of nutrients are also presented here. Study findings show that the risk of depression increases when omega-3 fatty acid levels are low. Both fish oil and folic acid supplements have been used to effectively treat depression. Antidepressant efficacy is lowered by folate insufficiency. Folate, vitamin B12, iron, etc. deficiencies are more prevalent in depressed people than in non-depressed people. Serum cholesterol levels and plasma tryptophan levels are found to be inversely correlated with PPD. Serum vitamin D levels were associated inversely with perinatal depression. These findings highlight the importance of adequate nutrition in the antepartum period. Given that nutritional therapies can be affordable, safe, simple to use, and are typically well-accepted by patients, more focus should be placed on dietary variables in PPD.

Therapeutic effects of growth hormone in a rat model of total sleep deprivation: Evaluating behavioral, hormonal, biochemical and electrophysiological parameters

OBJECTIVE

Total sleep deprivation (TSD) causes several harmful changes in the brain, including memory impairment, increased stress and depression levels, as well as reduced antioxidant activity. Growth hormone (GH) has been shown to boost antioxidant levels while improving memory and depression. The present study was conducted to explain the possible effects of exogenous GH against behavioral and biochemical disorders caused by TSD and the possible mechanisms involved.

MAIN METHODS

To induce TSD, rats were housed in homemade special cages equipped with stainless steel wire conductors to induce general and inconsistent TSD. They received a mild repetitive electric shock to their paws every 10 min for 21 days. GH (1 ml/kg, sc) was administered to rats during induction of TSD for 21 days. Memory retrieval, anxiety, depression-like behaviors, pain behaviors, antioxidant activity, hippocampal level of BDNF, and simultaneously brain electrical activity were measured at scheduled times after TSD.

KEY FINDINGS

The results showed that GH treatment improved memory (p < 0.001) in the PAT test of rats exposed to TSD. These beneficial effects were associated with lowering the level of anxiety and depression-like behavior (p < 0.001), rising the pain threshold (p < 0.01), increasing the activity of antioxidants (p < 0.01), hippocampal BDNF (p < 0.001), and regular brain electrical activity.

SIGNIFICANCE

Our findings show that GH plays a key role in modulating memory, anxiety and depression behaviors, as well as reducing oxidative stress and improve hippocampal single-unit activity in the brain during TSD.

Antibiotic-induced microbiota depletion in normally-reared adult rats mimics the neuroendocrine effects of early life stress

Early life stress induced by maternal separation (MS) causes neuroendocrine, behavioral, and metabolic alterations that are related to gut dysbiosis. MS also increases microglial activation and decreases neurogenesis. Whether these long-term alterations are maintained or worsened in the absence of gut microbiota remains unknown. Hence, this study evaluated the effect of MS symptomatology after antibiotic-induced microbiota depletion (AIMD) in adult rats. Control and maternally separated (3 h per day from postnatal day one to 14, MS180) rats were subjected to AIMD for one month, then assessed for behavioral, metabolic, and neuroendocrine responses. Effects of MS180 and AIMD on gut microbiota were confirmed by qPCR. The data indicate that MS180 caused a passive coping strategy in the forced swimming test and decreased hippocampal neurogenesis. In addition, fasting glucose, cholesterol, and corticosterone levels increased, which correlated with a decrease in Lactobacillus spp counts in the caecum. AIMD also increased immobility in the forced swimming test, decreased hippocampal neurogenesis, and augmented corticosterone levels. However, it had no effects on glucose homeostasis or plasma lipid levels. Furthermore, the MS180-induced long-term effects on behavior and neurogenesis were not affected by microbiota depletion. Meanwhile, the metabolic imbalance was partially reversed in MS180 + AIMD rats. These results show that AIMD mimics the behavioral consequences of MS180 but may prevent metabolic imbalance, suggesting that gut dysbiosis could be part of the mechanisms involved in the maintenance of the long-term consequences of early life stress.

Neuroprotective Effects of Treadmill Exercise in Hippocampus of Ovariectomized and Diabetic Rats

To determine detrimental effects of estrogen and insulin deficiencies on hippocampus, we examined apoptosis-induced neuronal damage and cholinergic system in ovariectomized and/or diabetic rat hippocampus. Possible neuroprotective effects of treadmill exercise were also investigated. Adult female Wistar rats were randomly divided into four groups (n = 5 rats/group) as follows: control, ovariectomized (Ovx), diabetic (Dia, streptozotocin (STZ) 60 mg/kg; i.p.), and Ovx + Dia groups. Each group was further subdivided into exercise and non-exercise groups. Animals in exercise groups were subjected to treadmill training, while those in non-exercise groups were placed on the stationary treadmill for 4 weeks (5 days/week). Apoptosis-related protein levels (i.e. Bax, Bcl-2, and caspase-3), number of survived neurons, and acetylcholinesterase (AChE) activity in the hippocampus were measured using Western blotting, Cresyl Violet staining, and Ellman assay, respectively. Both ovariectomy and diabetes increased expression of Bax and caspase-3 and decreased expression of Bcl-2 at protein levels. In addition, a significant decrease in the number of survived neurons was observed in both Ovx and Dia groups, while AChE activity was lower only in the Dia group. The Ovx + Dia group showed stronger apoptosis-induced neuropathology and inhibition of AChE activity. Treadmill exercise attenuated apoptosis-induced neuropathology in the Ovx and Dia groups and recovered AChE activity in the Dia group. Neuroprotective effects of treadmill exercise were mediated by inhibition of apoptosis. Moderate exercise protocol had no beneficial anti-apoptotic and neuroprotective effects in ovariectomized-diabetic rats.

Impact of exercise training on symptoms of depression, physical activity level and social participation in people living with HIV/AIDS: a systematic review and meta-analysis

BACKGROUND

Symptoms of depression are prevalent in people living with human immune deficiency virus/acquired immune deficiency syndrome (PLWHA), and worsened by lack of physical activity/exercises, leading to restriction in social participation/functioning. This raises the question: what is the extent to which physical exercise training affected, symptoms of depression, physical activity level (PAL) and social participation in PLWHA compared to other forms of intervention, usual care, or no treatment controls?

METHOD

Eight databases were searched up to July 2020, according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol. Only randomised controlled trials involving adults who were either on HAART/HAART-naïve and reported in the English language, were included. Two independent reviewers determined the eligibility of the studies, extracted data, assessed their quality, and risk of bias using the Physiotherapy Evidence Database (PEDro) tool. Standardised mean difference (SMD) was used as summary statistics for the mean primary outcome (symptoms of depression) and secondary outcomes (PAL and social participation) since different measuring tools/units were used across the included studies. Summary estimates of effects were determined using a random-effects model (I2).

RESULTS

Thirteen studies met the inclusion criteria with 779 participants (n = 596 participants at study completion) randomised into the study groups, comprising 378 males, 310 females and 91 participants with undisclosed gender, and with an age range of 18-86 years. Across the studies, aerobic or aerobic plus resistance exercises were performed 2-3 times/week, at 40-60 min/session, and for between 6-24 weeks, and the risk of bias vary from high to low. Comparing the intervention to control groups showed significant difference in the symptoms of depression (SMD = - 0.74, 95% confidence interval (CI) - 1.01, - 0.48, p ≤ 0.0002; I2 = 47%; 5 studies; 205 participants) unlike PAL (SMD = 0.98, 95% CI - 0.25, 2.17, p = 0.11; I2 = 82%; 2 studies; 62 participants) and social participation (SMD = 0.04, 95% CI - 0.65, 0.73, p = 0.91; I2 = 90%; 6 studies; 373 participants).

CONCLUSION

Physical exercise training could have an antidepressant-like effect in PLWHA but did not affect PAL and social participation. However, the high heterogeneity in the included studies, implies that adequately powered randomised controlled trials with clinical/methodological similarity are required in future studies.

TRAIL REGISTRATION NUMBER

INPLASY202040048.

Effects of early life adversities upon memory processes and cognition in rodent models

Exposure to stressors in early postnatal life induces long-lasting modifications in brainfunction.Thisplasticity,an essential characteristic of the brain that enables adaptation to the environment, may also induce impairments in some psychophysiological functions, including learning and memory. Early life stress (ELS) has long-term effects on thehypothalamic-pituitary-adrenal axisresponse to stressors, and has been reported to lead toneuroinflammation,altered levelsof neurotrophic factors, modifications inneurogenesis andsynaptic plasticity,with changes in neurotransmitter systems and network functioning. In this review, we focus on early postnatal stress in animal models and their effects on learning and memory.Many studies have reported ELS-induced impairments in different types of memories, including spatial memory, fear memory, recognition (both for objects and social) memory, working memory and reversal learning. Studies are not always in agreement, however, no effects, or sometimes facilitation, being reported, depending on the nature and intensity of the early intervention, as well as the age when the outcome was evaluated and the sex of the animals. When considering processes occurring after consolidation, related with memory maintenance or modification, there are a very reduced number of reports. Future studies addressing the mechanisms underlying memory changes for ELS should shed some light on the understanding of the different effects induced by stressors of different types and intensities on cognitive functions.

Prior maternal separation stress alters the dendritic complexity of new hippocampal neurons and neuroinflammation in response to an inflammatory stressor in juvenile female rats

Stress during critical periods of neurodevelopment is associated with an increased risk of developing stress-related psychiatric disorders, which are more common in women than men. Hippocampal neurogenesis (the birth of new neurons) is vulnerable to maternal separation (MS) and inflammatory stressors, and emerging evidence suggests that hippocampal neurogenesis is more sensitive to stress in the ventral hippocampus (vHi) than in the dorsal hippocampus (dHi). Although research into the effects of MS stress on hippocampal neurogenesis is well documented in male rodents, the effect in females remains underexplored. Similarly, reports on the impact of inflammatory stressors on hippocampal neurogenesis in females are limited, especially when female bias in the prevalence of stress-related psychiatric disorders begins to emerge. Thus, in this study we investigated the effects of MS followed by an inflammatory stressor (lipopolysaccharide, LPS) in early adolescence on peripheral and hippocampal inflammatory responses and hippocampal neurogenesis in juvenile female rats. We show that MS enhanced an LPS-induced increase in the pro-inflammatory cytokine IL-1β in the vHi but not in the dHi. However, microglial activation was similar following LPS alone or MS alone in both hippocampal regions, while MS prior to LPS reduced microglial activation in both dHi and vHi. The production of new neurons was unaffected by MS and LPS. MS and LPS independently reduced the dendritic complexity of new neurons, and MS exacerbated LPS-induced reductions in the complexity of distal dendrites of new neurons in the vHi but not dHi. These data highlight that MS differentially primes the physiological response to LPS in the juvenile female rat hippocampus.

Influence of early life stress on depression: from the perspective of neuroendocrine to the participation of gut microbiota

Depression is the most common mental disorder and has become a heavy burden in modern society. Clinical studies have identified early life stress as one of the high-risk factors for increased susceptibility to depression. Alteration of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress is one of the key risk factors for depression susceptibility related to early life stress. Laboratory animal studies have demonstrated that maternal separation (MS) for extended periods elicits HPA axis changes. These changes persist into adulthood and resemble those present in depressed adult individuals, including hyperactivity of the HPA axis. In addition, there is growing evidence that inflammation plays an important role in depression susceptibility concerned with early life stress. Individuals that have experienced MS have higher levels of pro-inflammatory cytokines and are susceptible to depression. Recently, it has been found that the gut microbiota plays an important role in regulating behavior and is also associated with depression. The translocation of gut microbiota and the change of gut microbiota composition caused by early stress may be a reason. In this review, we discussed the mechanisms by which early life stress contributes to the development of depression in terms of these factors. These studies have facilitated a systematic understanding of the pathogenesis of depression related to early life stress and will provide new ideas for the prevention and treatment of depression.

Long term effects of early life stress on HPA circuit in rodent models

Adaptation to environmental challenges represents a critical process for survival, requiring the complex integration of information derived from both external cues and internal signals regarding current conditions and previous experiences. The Hypothalamic-pituitary-adrenal axis plays a central role in this process inducing the activation of a neuroendocrine signaling cascade that affects the delicate balance of activity and cross-talk between areas that are involved in sensorial, emotional, and cognitive processing such as the hippocampus, amygdala, Prefrontal Cortex, Ventral Tegmental Area, and dorsal raphe. Early life stress, especially early critical experiences with caregivers, influences the functional and structural organization of these areas, affects these processes in a long-lasting manner and may result in long-term maladaptive and psychopathological outcomes, depending on the complex interaction between genetic and environmental factors. This review summarizes the results of studies that have modeled this early postnatal stress in rodents during the first 2 postnatal weeks, focusing on the long-term effects on molecular and structural alteration in brain areas involved in Hypothalamic-pituitary-adrenal axis function. Moreover, a brief investigation of epigenetic mechanisms and specific genetic targets mediating the long-term effects of these early environmental manipulations and at the basis of differential neurobiological and behavioral effects during adulthood is provided.

Early life stress and brain plasticity: from molecular alterations to aberrant memory and behavior

Early life stress (ELS) is one of the most critical factors that could modify brain plasticity, memory and learning abilities, behavioral reactions, and emotional response in adulthood leading to development of different mental disorders. Prenatal and early postnatal periods appear to be the most sensitive periods of brain development in mammals, thereby action of various factors at these stages of brain development might result in neurodegeneration, memory impairment, and mood disorders at later periods of life. Deciphering the processes underlying aberrant neurogenesis, synaptogenesis, and cerebral angiogenesis as well as deeper understanding the effects of ELS on brain development will provide novel approaches to prevent or to cure psychiatric and neurological deficits caused by stressful conditions at the earliest stages of ontogenesis. Neuropeptide oxytocin serves as an amnesic, anti-stress, pro-angiogenic, and neurogenesis-controlling molecule contributing to dramatic changes in brain plasticity in ELS. In the current review, we summarize recent data on molecular mechanisms of ELS-driven changes in brain plasticity with the particular focus on oxytocin-mediated effects on neurogenesis and angiogenesis, memory establishment, and forgetting.

Changes in Hippocampal Plasticity in Depression and Therapeutic Approaches Influencing These Changes

Depression is a common neurological disease that seriously affects human health. There are many hypotheses about the pathogenesis of depression, and the most widely recognized and applied is the monoamine hypothesis. However, no hypothesis can fully explain the pathogenesis of depression. At present, the brain-derived neurotrophic factor (BDNF) and neurogenesis hypotheses have highlighted the important role of plasticity in depression. The plasticity of neurons and glial cells plays a vital role in the transmission and integration of signals in the central nervous system. Plasticity is the adaptive change in the nervous system in response to changes in external signals. The hippocampus is an important anatomical area associated with depression. Studies have shown that some antidepressants can treat depression by changing the plasticity of the hippocampus. Furthermore, caloric restriction has also been shown to affect antidepressant and hippocampal plasticity changes. In this review, we summarize the latest research, focusing on changes in the plasticity of hippocampal neurons and glial cells in depression and the role of BDNF in the changes in hippocampal plasticity in depression, as well as caloric restriction and mitochondrial plasticity. This review may contribute to the development of antidepressant drugs and elucidating the mechanism of depression.

Interplay between hormones and exercise on hippocampal plasticity across the lifespan

The hippocampus is a brain structure known to play a central role in cognitive function (namely learning and memory) as well as mood regulation and affective behaviors due in part to its ability to undergo structural and functional changes in response to intrinsic and extrinsic stimuli. While structural changes are achieved through modulation of hippocampal neurogenesis as well as alterations in dendritic morphology and spine remodeling, functional (i.e., synaptic) changes can be noted through the strengthening (i.e., long-term potentiation) or weakening (i.e., long-term depression) of the synapses. While age, hormone homeostasis, and levels of physical activity are some of the factors known to module these forms of hippocampal plasticity, the exact mechanisms through which these factors interact with each other at a given moment in time are not completely understood. It is well known that hormonal levels vary throughout the lifespan of an individual and it is also known that physical exercise can impact hormonal homeostasis. Thus, it is reasonable to speculate that hormone modulation might be one of the various mechanisms through which physical exercise differently impacts hippocampal plasticity throughout distinct periods of an individual's life. The present review summarizes the potential relationship between physical exercise and different types of hormones (namely sex, metabolic, and stress hormones) and how this relationship may mediate the effects of physical activity during three distinct life periods, adolescence, adulthood, and senescence. Overall, the vast majority of studies support a beneficial role of exercise in maintaining hippocampal hormonal levels and consequently, hippocampal plasticity, cognition, and mood regulation.

What and How Can Physical Activity Prevention Function on Parkinson's Disease?

Aim

This study was aimed at investigating the effects and molecular mechanisms of physical activity intervention on Parkinson's disease (PD) and providing theoretical guidance for the prevention and treatment of PD.

Methods

Four electronic databases up to December 2019 were searched (PubMed, Springer, Elsevier, and Wiley database), 176 articles were selected. Literature data were analyzed by the logic analysis method.

Results

(1) Risk factors of PD include dairy products, pesticides, traumatic brain injury, and obesity. Protective factors include alcohol, tobacco, coffee, black tea, and physical activity. (2) Physical activity can reduce the risk and improve symptoms of PD and the beneficial forms of physical activity, including running, dancing, traditional Chinese martial arts, yoga, and weight training. (3) Different forms of physical activity alleviate the symptoms of PD through different mechanisms, including reducing the accumulation of α-syn protein, inflammation, and oxidative stress, while enhancing BDNF activity, nerve regeneration, and mitochondrial function.

Conclusion

Physical activity has a positive impact on the prevention and treatment of PD. Illustrating the molecular mechanism of physical activity-induced protective effect on PD is an urgent need for improving the efficacy of PD therapy regimens in the future.

Shaping the adult brain with exercise during development: Emerging evidence and knowledge gaps

Exercise is known to produce a myriad of positive effects on the brain, including increased glia, neurons, blood vessels, white matter and dendritic complexity. Such effects are associated with enhanced cognition and stress resilience in humans and animal models. As such, exercise represents a positive experience with tremendous potential to influence brain development and shape an adult brain capable of responding to life's challenges. Although substantial evidence attests to the benefits of exercise for cognition in children and adolescents, the vast majority of existing studies examine acute effects. Nonetheless, there is emerging evidence indicating that exercise during development has positive cognitive and neural effects that last to adulthood. There is, therefore, a compelling need for studies designed to determine the extent to which plasticity driven by developmental exercise translates into enhanced brain health and function in adulthood and the underlying mechanisms. Such studies are particularly important given that modern Western society is increasingly characterized by sedentary behavior, and we know little about how this impacts the brain's developmental trajectory. This review synthesizes current literature and outlines significant knowledge gaps that must be filled in order to elucidate what exercise (or lack of exercise) during development contributes to the health and function of the adult brain.

Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus

Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.

Exercise attenuates maternal separation-induced mood disorder-like behaviors by enhancing mitochondrial functions and neuroplasticity in the dorsal raphe

Loss of the mother-infant relationship during early childhood affects infant development and is known to increase the infant's vulnerability to neuropsychiatric disorders throughout life. Serotonin deficits and mitochondrial dysfunction in the dorsal raphe may underlie mood disorders such as anxiety and depression. Exercise is known to have a positive effect on brain function. In this study, we investigated the effect of exercise on mitochondrial function, apoptosis, and serotonin levels in the dorsal raphe as well as behavioral changes in cases of maternal separation. Exposure to the stress of maternal separation resulted in mitochondrial dysfunction in the dorsal raphe, including impaired Ca²⁺ homeostasis, an increase in reactive oxygen species such as H₂O₂, and a decrease in the O₂ respiration rate. Exposure to maternal separation stress also decreased tryptophan hydroxylase and 5-hydroxytryptamine positive cells and increased apoptosis, anxiety, and depression. The impairments in mitochondrial function, apoptosis, and serotonin in the dorsal raphe, as well as anxiety and depression, were all improved by exercise. Exercise might alter mitochondrial function, serotonin levels, and the rate of apoptosis in the dorsal raphe. Therefore, exercise might be an important non-pharmacological intervention for the prevention and treatment of the adverse effects of maternal separation.

Effects of treadmill exercise on the anxiety-like behavior through modulation of GSK3β/β-catenin signaling in the maternal separation rat pup

Maternal separation causes depression and anxiety. Exercise ameliorates maternal separation-induced depression. In this study, we investigated the effect of treadmill exercise on anxiety-like behavior in relation with glycogen synthase kinase 3 beta (GSK3β)/β-catenin pathway using maternal separation rat pups. For this study, elevated plus maze test, immunohistochemistry for serotonin (5-hydroxytryptamine, 5-HT), tryptophan hydroxylase (TPH), and western blot for total GSK3β (t-GSK3β), phosphorylated GSK3β (p-GSK3β), total β-catenin (t-β-catenin), and phosphorylated β-catenin (p-β-catenin) were conducted. The rat pups in the exercise groups were scheduled to run on a treadmill for 30 min once a day for 10 days, starting on postnatal day 21. For the rat pups in the fluoxetine-treated group, fluoxetine was orally administrated once a day for 10 consecutive days, starting on postnatal day 21. Anxiety-like behavior was appeared in the rat pups by maternal separation. Maternal separation suppressed 5-HT and TPH expression in the dorsal raphe. Maternal separation suppressed phosphorylation of GSK3β and increased phosphorylation of β-catenin in the hippocampus. However, treadmill exercise and fluoxetine treatment alleviated anxiety and increased 5-HT and TPH expression in the dorsal raphe. Treadmill exercise and fluoxetine treatment also enhanced GSK3β phosphorylation and suppressed β-catenin phosphorylation in the hippocampus. In this study, alleviating effect of treadmill exercise on maternal separation-induced anxiety appeared through enhancing 5-HT expression and GSK3β phosphorylation, and then inhibiting β-catenin phosphorylation. These results showed that treadmill exercise relieves anxiety through GSK3β/β-catenin pathway. Treadmill exercise showed similar ameliorating effect on anxiety-like behavior as fluoxetine.

Wnt signaling pathway is implicated in the alleviating effect of treadmill exercise on maternal separation-induced depression

Maternal separation in the developmental stage has a negative influence on brain development and causes depression. The extracellular ligand, Wnt, and its receptors play an important role in axis formation and neural development. Exercise inhibits apoptosis, increases cell proliferation, and exerts antidepressive effect. In this study, the effect of treadmill exercise on the maternal separation-induced depression was investigated in the aspect of Wnt signaling pathway. The maternal separation started on the postnatal day 14. The rat pups in the exercise groups were forced to run on a treadmill for 30 min once a day from postnatal day 21 to postnatal day 34. The rat pups in the maternal separation and fluoxetine-treated group were intraperitoneally injected with 5-mg/kg fluoxetine once a day from postnatal day 21 to postnatal day 34. Forced swimming test was performed to evaluate the depression level. Western blotting was performed for the expressions of Wnt signaling ligands, Wnt2 and Wnt3a, and Wnt signaling inhibitors, Dkk1, and sFRP3. Maternal separation showed depressive behaviors in the forced swimming test. Treadmill exercise alleviated depressive behaviors in the maternal separation rat pups. Expressions of Wnt2 and Wnt3a were decreased by maternal separation. Treadmill exercise alleviated maternal separation-induced reduction of Wnt2 and Wnt3a expressions. Expressions of Dkk1 and sFRP3 in the hippocampus were increased by maternal separation. Treadmill exercise alleviated maternal separation-induced reduction of Dkk1 and sFRP3 expressions. Our study demonstrated that treadmill exercise activates Wnt signaling pathway, and then exerted antidepressive effect.

Early life stress delays hippocampal development and diminishes the adult stem cell pool in mice

Early life stress predisposes to mental illness and behavioral dysfunction in adulthood, but the mechanisms underlying these persistent effects are poorly understood. Stress throughout life impairs the structure and function of the hippocampus, a brain system undergoing considerable development in early life. The long-term behavioral consequences of early life stress may therefore be due in part to interference with hippocampal development, in particular with assembly of the dentate gyrus (DG) region of the hippocampus. We investigated how early life stress produces long-term alterations in DG structure by examining DG assembly and the generation of a stable adult stem cell pool in routine housing and after stress induced by the limited bedding/nesting paradigm in mice. We found that early life stress leads to a more immature, proliferative DG than would be expected for the animal's age immediately after stress exposure, suggesting that early life stress delays DG development. Adult animals exposed to early life stress exhibited a reduction in the number of DG stem cells, but unchanged neurogenesis suggesting a depletion of the stem cell pool with compensation in the birth and survival of adult-born neurons. These results suggest a developmental mechanism by which early life stress can induce long-term changes in hippocampal function by interfering with DG assembly and ultimately diminishing the adult stem cell pool.

Dexmedetomidine Ameliorates Sleep Deprivation-Induced Depressive Behaviors in Mice

PURPOSE

Sleep deprivation induces depressive symptoms. Dexmedetomidine is a α2-adrenoreceptor agonist and this drug possesses sedative, anxiolytic, analgesic, and anesthetic-sparing effect. In this study, the action of dexmedetomidine on sleep deprivation-induced depressive behaviors was investigated using mice.

METHODS

For the inducing of sleep deprivation, the mice were placed inside a water cage containing 15 platforms and filled with water up to 1 cm below the platform surface for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (0.5, 1, and 2 μg/kg) was intraperitoneally treated into the mice, one time per a day during 6 days. Then, forced swimming test and tail suspension test were conducted. Immunohistochemistry for tyrosine hydroxylase (TH), 5-hydroxytryptamine (5-HT; serotonin), tryptophan hydroxylase (TPH) and western blot for D1 dopamine receptor were also performed.

RESULTS

Sleep deprivation increased the immobility latency in the forced swimming test and tail suspension test. The expressions of TPH, 5-HT, and D1 dopamine receptor were decreased, whereas, TH expression was increased by sleep deprivation. Dexmedetomidine decreased the immobility latency and increased the expressions of TPH, 5-HT, and D1 dopamine receptor, whereas, HT expression was decreased by dexmedetomidine treatment.

CONCLUSION

In our results, dexmedetomidine alleviated sleep deprivation-induced depressive behaviors by increasing 5-HT synthesis and by decreasing dopamine production with up-regulation of D1 dopamine receptor.

Ablation of proliferating neural stem cells during early life is sufficient to reduce adult hippocampal neurogenesis

Environmental exposures during early life, but not during adolescence or adulthood, lead to persistent reductions in neurogenesis in the adult hippocampal dentate gyrus (DG). The mechanisms by which early life exposures lead to long-term deficits in neurogenesis remain unclear. Here, we investigated whether targeted ablation of dividing neural stem cells during early life is sufficient to produce long-term decreases in DG neurogenesis. Having previously found that the stem cell lineage is resistant to long-term effects of transient ablation of dividing stem cells during adolescence or adulthood (Kirshenbaum, Lieberman, Briner, Leonardo, & Dranovsky, ), we used a similar pharmacogenetic approach to target dividing neural stem cells for elimination during early life periods sensitive to environmental insults. We then assessed the Nestin stem cell lineage in adulthood. We found that the adult neural stem cell reservoir was depleted following ablation during the first postnatal week, when stem cells were highly proliferative, but not during the third postnatal week, when stem cells were more quiescent. Remarkably, ablating proliferating stem cells during either the first or third postnatal week led to reduced adult neurogenesis out of proportion to the changes in the stem cell pool, indicating a disruption of the stem cell function or niche following stem cell ablation in early life. These results highlight the first three postnatal weeks as a series of sensitive periods during which elimination of dividing stem cells leads to lasting alterations in adult DG neurogenesis and stem cell function. These findings contribute to our understanding of the relationship between DG development and adult neurogenesis, as well as suggest a possible mechanism by which early life experiences may lead to lasting deficits in adult hippocampal neurogenesis.

Regular exercise and creatine supplementation prevent chronic mild stress-induced decrease in hippocampal neurogenesis via Wnt/GSK3β/β-catenin pathway

PURPOSE

Chronic stress can lead to mood-related psychomotor behaviors such as despair. Decreased hippocampal neurogenesis has been observed in patients with depression and in animal models of depression. Exercise enhances the population of the new born cells in the dentate gyrus (DG). A few studies have demonstrated that creatine has antidepressant effects in humans. However, the mechanism underpinning these effects is poorly understood. Therefore, we examined whether regular exercise and/or creatine was closely associated with the activity of the Wnt/GSK3β/β-catenin pathway in the hippocampal DG.

METHODS

Mice were subjected to 4 weeks of chronic mild stress starting a week prior to the start of a 4-week protocol of treadmill running and creatine supplementation. Tail suspension (TST) and forced swimming tests (FST) were carried out 2 days after the final treadmill running session. Immunohistochemical and western blot analyses were conducted to evaluate hippocampal neurogenesis, GSK3β activity, and nuclear β-catenin protein levels in the DG. Furthermore, Wnt signaling antagonism in the DG using stereotaxic injection was performed.

RESULTS

Chronic mild stress-induced increase in immobility in the TST and FST were restored by treadmill running and/or creatine supplementation. The number of Ki-67+ and doublecortin (DCX)+ cells were decreased by chronic stress, and this decline was reversed by the exercise and supplement regimen, along with the changes in GSK3β activity and nuclear β-catenin protein levels in the DG. Local antagonism of DG Wnt signaling caused an increase in immobility even 5 days after injection with C59.

CONCLUSION

Regular exercise combined with creatine supplementation had a greater effect on hippocampal neurogenesis via the Wnt/GSK3β/β-catenin pathway activation compared with each treatment in chronic mild stress-induced behavioral depression.

Exercise Ameliorates Motor Deficits and Improves Dopaminergic Functions in the Rat Hemi-Parkinson's Model

To determine the influences of exercise on motor deficits and dopaminergic transmission in a hemiparkinson animal model, we measured the effects of exercise on the ambulatory system by estimating spatio-temporal parameters during walking, striatal dopamine (DA) release and reuptake and synaptic plasticity in the corticostriatal pathway after unilateral 6-OHDA lesions. 6-OHDA lesioned hemiparkinsonian rats were exercised on a fixed speed treadmill for 30 minutes per day. Controls received the same lesion but no exercise. Animals were subsequently analyzed for behavior including gait analysis, rotarod performance and apomorphine induced rotation. Subsequently, in vitro striatal dopamine release was analyzed by using FSCV and activity-dependent plasticity in the corticostriatal pathway was measured in each group. Our data indicated that exercise could improve motor walking speed and increase the apomorphine-induced rotation threshold. Exercise also ameliorated spatiotemporal impairments in gait in PD animals. Exercise increased the parameters of synaptic plasticity formation in the corticostriatal pathway of PD animals as well as the dynamics of dopamine transmission in PD animals. Fixed speed treadmill training 30 minutes per day could ameliorate spatial-temporal gait impairment, improve walking speed, dopamine transmission as well as corticostriatal synaptic plasticity in the unilateral 6-OHDA lesioned rat model.

Treadmill exercise activates PI3K/Akt signaling pathway leading to GSK-3β inhibition in the social isolated rat pups

Social isolation is known to precipitate depression-like symptoms in rodents and has emerged as a dependable paradigm to screen the behavioral and neurobiological changes observed in humans. In the present study, the undying mechanisms of treadmill exercise on social isolation-induced depression was evaluated. The rat pups in the social isolation groups were housed individually. The social isolation procedures started on the postnatal day 14. The rat pups in the exercise groups were forced to run on treadmill for 30 min once a day from postnatal day 21 to postnatal day 34. The expression of phosphoinositide 3 kinase (PI3K), tyrosine kinase B (Akt), and glycogen synthase kinase 3β (GSK-3β) in the hippocampus were determined by using western blot analysis. The ratio phosphorylated PI3K (p-PI3K)/PI3K and phosphorylated Akt (p-Akt)/Akt were decreased and the ratio of phosphorylated-GSK-3 (p-GSK-3β)/GSK-3β was increased by social isolation. Treadmill exercise increased the ratio p-PI3K/PI3K and p-Akt/Akt and suppressed the ratio of p-GSK-3β/GSK-3β in the hippocampus of social isolated rat pups. Treadmill exercise activates PI3K/Akt signaling pathway leading to GSK-3β inhibition in social isolated rats. These results suggested that treadmill exercise may improve depressive symptoms via activation of PI3K/Akt signaling pathway.

Role of exercise on molecular mechanisms in the regulation of antidepressant effects

Regular exercise reduces depressive-like behavior activation. In this study, we look for exact roles of exercise on molecular and neuronal mechanisms for antidepressant action by studying the hippocampal neuroplasticity and proliferation. Increased hippocampal neurogenesis with exercise has potential significance for depression. Exercise promotes brain health in the molecular levels in the hippocampus and also affects behavior in a similar way to chronic antidepressant treatment. Wingless (Wnt) and frizzled signaling system plays an important role in cell proliferation, growth, and differentiation during development. Our results demonstrate complicated, differential effects of antidepressants on Wnt signaling system, and assume a role for selected signaling molecules in the neurogenic activity of antidepressant care. Our review suggests that exercise may preserve brain function by increasing neurogenesis through activating Wnt signaling pathway in the psychiatric disorders, such as depression.

Treadmill exercise ameliorates social isolation-induced depression through neuronal generation in rat pups

Social isolation is known to induce emotional and behavioral changes in animals and humans. The effect of treadmill exercise on depression was investigated using social isolated rat pups. The rat pups in the social isolation groups were housed individually. The rat pups in the exercise groups were forced to run on treadmill for 30 min once a day from postnatal day 21 to postnatal day 34. In order to evaluate depression state of rat pups, forced swimming test was performed. Newly generated cells in the hippocampal dentate gyrus were determined by 5-bromo-2′-deoxyuridine (BrdU) immunohistochemistry. We examined the expression of 5-hydroxytryptamine (5-HT) and tryptophan hydroxylase (TPH) in the dorsal raphe using immunofluorescence. The expression of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) was detected by Western blot analysis. The present results demonstrated that social isolation increased resting time and decreased mobility time. Expression of 5-HT and TPH in the dorsal raphe and expression of BDNF and TrkB in the hippocampus were decreased by social isolation. The number of BrdU-positive cells in the hippocampal dentate gyrus was suppressed by social isolation. Treadmill exercise decreased resting time and increased mobility in the social isolated rat pups. Expression of 5-HT, TPH, BDNF, and TrkB was increased by treadmill exercise. The present results suggested that treadmill exercise may ameliorates social isolation-induced depression through increasing neuronal generation.

Age-dependent differences of treadmill exercise on spatial learning ability between young- and adult-age rats

The effect of exercise, which increases hippocampal neurogenesis and improves memory function, is well documented, however, differences in the effect of exercise on young children and adults are not yet known. In the present study, age-dependent differences of treadmill exercise on spatial learning ability between young- and adult-age rats were investigated. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 6 weeks. Radial 8-arm maze test was conducted for the determination of spatial learning ability. Cell proliferation in the hippocampal dentate gyrus was determined by 5-bromo-2′-deoxyuridine immunohistochemistry. Western blot for brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) was performed. In the present study, the number of errors in the young-age rats was effectively decreased by treadmill exercise. Hippocampal neurogenesis was more active in the young-age rats than in the adult-age rats. BDNF and TrkB expression in the hippocampus was greater in the adult-age rats than in the young-age rats. The results of this study showed that adults have excellent spatial learning abilities than children, but the improvement of exercise-induced spatial learning ability through neurogenesis is better in children.

Treadmill exercise ameliorates depressive symptoms through increasing serotonin expression in postpartum depression rats

Postpartum depression (PPD) is defined as the depressive symptoms that occur from the moment of delivery until 12 months after delivery. PPD symptoms are closely associated with reduced activity of the serotonergic system. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in the pathogenesis of depression. Tryptophan hydroxylase (TPH) catalyzes the rate-limiting step of 5-HT biosynthesis in the serotonergic neurons. Exercise exerts anti-depressive effect on depression patients as well as on animal models of depression. In the present study, the effect of treadmill exercise on PPD was investigated using rats. For this study, open field test for activity and forced swimming test for depressive symptoms, and immunohistochemistry for 5-HT and TPH were conducted. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 2 weeks. Activity in the open field test was decreased in the postpartum rats, however, performing treadmill running increased activity in the postpartum rats. The climbing time was decreased and the immobility time was increased in the postpartum rats. Treadmill exercise increased climbing time and suppressed immobility time in the postpartum rats. 5-HT and TPH expressions in the dorsal raphe were suppressed in the postpartum rats, and treadmill exercise enhanced 5-HT and TPH expressions in the postpartum rats. Treadmill exercise ameliorated the PPD very effectively by enhancing serotonin level.

Treadmill exercise improves depression-like symptoms by enhancing serotonergic function through upregulation of 5-HT1A expression in the olfactory bulbectomized rats

The olfactory bulbectomy (OBX) is a well-known method inducing animal model of depression. Depression is associated with dysfunction of serotonin (5-hydroxytryptamine, 5-HT) system. In the present study, antidepressive effect of treadmill exercise was investigated using olfactory bulbectomized rats. After bilateral bulbectomy, the rats in the treadmill exercise groups were subjected to run on a treadmill for 30 min once a day during 28 days. Increased immobility time and decreased fast time in the forced swim test were observed in the olfactory bulbectomized rats. Sucrose preference in the sucrose preference test was decreased and activity in the open field test was also increased in the olfactory bulbectomized rats. Treadmill exercise decreased immobility time and activity and increased fast time and sucrose preference in the olfactory bulbectomized rats. Expressions of 5-HT and tryptophan hydroxylase (TPH) in the dorsal raphe of rats were suppressed by OBX and treadmill exercise increased the expressions of 5-HT and TPH in the olfactory bulbectomized rats. Serotonin receptor type 1A (5-HT1A) expression in the dorsal raphe was reduced by OBX and treadmill exercise increased 5-HT1A expression in the olfactory bulbectomized rats. In the present study, treadmill exercise ameliorated OBX-induced depressive symptoms. The antidepressive effect of treadmill exercise might be ascribed to the enhancement of serotonergic function through upregulation of 5-HT1A expression in the dorsal raphe.

Treadmill Exercise Improves Memory Function Depending on Circadian Rhythm Changes in Mice

Purpose

Exercise enhances memory function by increasing neurogenesis in the hippocampus, and circadian rhythms modulate synaptic plasticity in the hippocampus. The circadian rhythm-dependent effects of treadmill exercise on memory function in relation with neurogenesis were investigated using mice.

Methods

The step-down avoidance test was used to evaluate short-term memory, the 8-arm maze test was used to test spatial learning ability, and 5-bromo-2’-deoxyuridine immunofluorescence was used to assess neurogenesis. Western blotting was also performed to assess levels of synaptic plasticity-associated proteins, such as brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element-binding protein, early growth response protein 1, postsynaptic density protein 95, and growth-associated protein 43. The mice in the treadmill exercise at zeitgeber 1 group started exercising 1 hour after sunrise, the mice in the treadmill exercise at zeitgeber 6 group started exercising 6 hours after sunrise, and the mice in the treadmill exercise at zeitgeber 13 group started exercising 1 hour after sunset. The mice in the exercise groups were forced to run on a motorized treadmill for 30 minutes once a day for 7 weeks.

Results

Treadmill exercise improved short-term memory and spatial learning ability, and increased hippocampal neurogenesis and the expression of synaptic plasticity-associated proteins. These effects of treadmill exercise were stronger in mice that exercised during the day or in the evening than in mice that exercised at dawn.

Conclusions

Treadmill exercise improved memory function by increasing neurogenesis and the expression of synaptic plasticity-associated proteins. These results suggest that the memory-enhancing effect of treadmill exercise may depend on circadian rhythm changes.

Role of exercise on the brain

The functions of adult hippocampal neurogenesis have been extensively investigated during the past decade. Numerous studies have shown that adult neurogenesis may play an important role in the hippocampal-dependent learning and memory. This study evaluated the influence of exercise on hippocampal neurogenesis, neural plasticity, neurotrophic factors, and cognition. Areas of research focused on enhancing effect of exercise for adult hippocampal neurogenesis and protective role of exercise against brain diseases. The present study suggests that exercise improves brain functions and prevents decline of cognition across the lifespan. Understanding of neurobiological mechanisms of exercise on brain functions may lead to the development of novel therapeutic strategy for neurodegenerative disorders.

Music application alleviates short-term memory impairments through increasing cell proliferation in the hippocampus of valproic acid-induced autistic rat pups

Autism is a neurodevelopmental disorder and this disorder shows impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive patterns of behaviors and interests. The effect of music on short-term memory in the view of cell proliferation in the hippocampus was evaluated using valproic acid-induced autistic rat pups. Animal model of autism was made by subcutaneous injection of 400-mg/kg valproic acid into the rat pups on the postnatal day 14. The rat pups in the music-applied groups were exposed to the 65-dB comfortable classic music for 1 hr once a day, starting postnatal day 15 and continued until postnatal day 28. In the present results, short-term memory was deteriorated by autism induction. The numbers of 5-bromo-2'-deoxyridine (BrdU)-positive, Ki-67-positive, and doublecortin (DCX)-positive cells in the hippocampal dentate gyrus were decreased by autism induction. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions in the hippocampus were also suppressed in the autistic rat pups. Music application alleviated short-term memory deficits with enhancing the numbers of BrdU-positive, Ki-67-positive, and DCX-positive cells in the autistic rat pups. Music application also enhanced BDNF and TrkB expressions in the autistic rat pups. The present study show that application of music enhanced hippocampal cell proliferation and alleviated short-term memory impairment through stimulating BDNF-TrkB signaling in the autistic rat pups. Music can be suggested as the therapeutic strategy to overcome the autism-induced memory deficits.

Postnatal Treadmill Exercise Alleviates Prenatal Stress-Induced Anxiety in Offspring Rats by Enhancing Cell Proliferation Through 5-Hydroxytryptamine 1A Receptor Activation

Purpose:

Stress during pregnancy is a risk factor for the development of anxiety-related disorders in offspring later in life. The effects of treadmill exercise on anxiety-like behaviors and hippocampal cell proliferation were investigated using rats exposed to prenatal stress.

Methods:

Exposure of pregnant rats to a hunting dog in an enclosed room was used to induce stress. Anxiety-like behaviors of offspring were evaluated using the elevated plus maze test. Immunohistochemistry for the detection of 5-bromo-2ʹ- deoxyuridine and doublecortin (DCX) in the hippocampal dentate gyrus and 5-hydroxytryptamine 1A receptors (5-HT_1A) in the dorsal raphe was conducted. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) levels in the hippocampus were evaluated by western blot analysis.

Results:

Offspring of maternal rats exposed to stress during pregnancy showed anxiety-like behaviors. Offspring also showed reduced expression of BDNF, TrkB, and DCX in the dentate gyrus, decreased cell proliferation in the hippocampus, and reduced 5-HT_1A expression in the dorsal raphe. Postnatal treadmill exercise by offspring, but not maternal exercise during pregnancy, enhanced cell proliferation and expression of these proteins.

Conclusions:

Postnatal treadmill exercise ameliorated anxiety-like behaviors in offspring of stressed pregnant rats, and the alleviating effect of exercise on these behaviors is hypothesized to result from enhancement of cell proliferation through 5-HT_1A activation in offspring rats.

Effects of maternal hypothyroidism during pregnancy on learning, memory and hippocampal BDNF in rat pups: Beneficial effects of exercise

Hypothyroidism during early development leads to numerous morphological, biochemical and functional changes in developing brain. In this study, we investigated the effects of voluntary and treadmill exercise on learning, memory and hippocampal BDNF levels in both hypothyroid male and female rat pups. To induce hypothyroidism in the mothers, 6-propyl-2-thiouracil (PTU) was added to their drinking water (100mg/L) from their embryonic day 6 to their postnatal day (PND) 21. For 14days, from PNDs 31 to 44, the rat pups were trained with one of the two different exercise protocols, namely the mild treadmill exercise and the voluntary wheel exercise. On PNDs 45-52, a water maze was used for testing their learning and memory ability. The rats were sacrificed one day later and their BDNF levels were then measured in the hippocampus. The findings of the present study indicate that hypothyroidism during the fetal period and the early postnatal period is associated with the impairment of spatial learning and memory and reduced hippocampal BDNF levels in both male and female rat offspring. Both the short-term treadmill exercise and the voluntary wheel exercise performed during the postnatal period reverse the behavioral and neurochemical deficits induced by developmental thyroid hormone insufficiency in both male and female rat offspring. The findings of this study thus demonstrate a marked reversibility of both behavioral and neurochemical disorders induced by developmental thyroid hormone insufficiency through the performance of exercise.

Effects of Moderate Aerobic Exercise on Cognitive Abilities and Redox State Biomarkers in Older Adults

We used a moderate aerobic exercise program for 24 weeks to measure the positive impact of physical activity on oxidative stress and inflammatory markers and its association with cognitive performance in healthy older adults. A total of 100 healthy subjects (65–95 Yrs) were randomly classified into two groups: control group (n = 50) and exercise group (n = 50). Cognitive functioning, physical activity score, MDA, 8-OHdG, TAC, and hs-CRP were assessed using LOTCA battery, prevalidated PA questionnaire, and immunoassay techniques. LOTCA 7-set scores of cognitive performance showed a significant correlation with physical activity status and the regulation of both oxidative stress free radicals and inflammatory markers in all older subjects following 24 weeks of moderate exercise. Physically active persons showed a higher cognitive performance along with reduction in the levels of MDA, 8-OHdG, and hs-CRP and increase in TAC activity compared with sedentary participants. Cognitive performance correlated positively with the increase in TAC activity and physical fitness scores and negatively with MDA, 8-OHdG, and hs-CRP, respectively. There was a significant improvement in motor praxis, vasomotor organization, thinking operations, and attention and concentration among older adults. In conclusion, moderate aerobic training for 24 weeks has a positive significant effect in improving cognitive functions via modulating redox and inflammatory status of older adults.

Effects of treadmill exercise on hippocampal neurogenesis in an MPTP /probenecid-induced Parkinson's disease mouse model

[Purpose] This study aimed to investigate the effect of treadmill exercise on non-motor function, specifically long-term memory, in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid-induced Parkinson’s disease mouse model. [Methods] A mouse model of Parkinson’s disease was developed by injecting 20 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 250 mg/kg of probenecid (P). We divided in into four groups: probenecid group, probenecid-exercise group, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid group, and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid-exercise group. Mice in the exercise groups ran on treadmill for 30 min/day, five times per week for 4 weeks. [Results] Latency in the passive avoidance test increased in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid-exercise group compared with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid group. In addition, the number of 5-bromo-2-deoxyuridine/NeuN-positive cells and 5-bromo-2-deoxyuridine/doublecortin-positive cells in the hippocampal dentate gyrus was higher in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid-exercise group than that in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid group. These changes were associated with the expression of brain-derived neurotrophic factor in the hippocampus. [Conclusion] Our results suggest that treadmill exercise may improve long-term memory in Parkinson’s disease mice by facilitating neurogenesis via increased expression of neurotrophic factors.

Physical exercise prevents short and long-term deficits on aversive and recognition memory and attenuates brain oxidative damage induced by maternal deprivation

It is known from previous research that physical exercise prevents long-term memory deficits induced by maternal deprivation in rats. But we could not assume similar effects of physical exercise on short-term memory, as short- and long-term memories are known to result from some different memory consolidation processes. Here we demonstrated that, in addition to long-term memory deficit, the short-term memory deficit resultant from maternal deprivation in object recognition and aversive memory tasks is also prevented by physical exercise. Additionally, one of the mechanisms by which the physical exercise influences the memory processes involves its effects attenuating the oxidative damage in the maternal deprived rats' hippocampus and prefrontal cortex.

Treadmill exercise enhances spatial learning ability through suppressing hippocampal apoptosis in Huntington's disease rats

Huntington’s disease is a chronic neurodegenerative disorder inherited in an autosomal dominant fashion, and characterized as involuntary movement. Quinolinic acid has been used to produce an animal model of Huntington’s disease. In the present study, the effect of treadmill exercise on spatial-learning ability and motor coordination focusing on the apoptosis in the hippocampus was investigated using quinolinic acid-induced Huntington’s disease rats. Huntington’s disease was induced by unilateral intrastriatal injection of quinolinic acid (2 μL of 100 nmol) using stereotaxic instrument. The rats in the treadmill exercise groups were subjected to run on a treadmill for 30 min once a day during 14 days. Spatial learning ability and motor coordination were determined by radial 8-arm maze test and rota-rod test. Immunohistochemistry for caspase-3 and western blot for Bax and Bcl-2 were also conducted for the detection of apoptosis. In the present results, spatial learning ability and motor coordination were deteriorated by intrastriatal injection of quinolinic acid. In contrast, treadmill exercise exerted ameliorating effect on quinolinic acid-induced deterioration of spatial learning ability and motor coordination. Bcl-2 expression in the hippocampus was de-creased and expressions of casepase-3 and Bax in the hippocampus were increased in the quinolinic acid-induced Huntington’s disease rats. Treadmill exercise increased Bcl-2 expression and decreased expressions of casepase-3 and Bax in the Huntington’s disease rats. The present results showed that treadmill exercise might ameliorate quinolinic acid-induced loss of spatial learning ability and motor coordination by suppressing apoptosis in the hippocampus.

Stress-Induced Depression Is Alleviated by Aerobic Exercise Through Up-Regulation of 5-Hydroxytryptamine 1A Receptors in Rats

PURPOSE

Stress is associated with depression, which induces many psychiatric disorders. Serotonin, also known as 5-hydroxy-tryptamine (5-HT), acts as a biochemical messenger and regulator in the brain. It also mediates several important physiological functions. Depression is closely associated with an overactive bladder. In the present study, we investigated the effect of treadmill exercise on stress-induced depression while focusing on the expression of 5-HT 1A (5-H1A) receptors in the dorsal raphe.

METHODS

Stress was induced by applying a 0.2-mA electric foot shock to rats. Each set of electric foot shocks comprised a 6-second shock duration that was repeated 10 times with a 30-second interval. Three sets of electric foot shocks were applied each day for 7 days. For the confirmation of depressive state, a forced swimming test was performed. To visualize the expression of 5-HT and tryptophan hydroxylase (TPH), immunohistochemistry for 5-HT and TPH in the dorsal raphe was performed. Expression of 5-H1A receptors was determined by western blot analysis.

RESULTS

A depressive state was induced by stress, and treadmill exercise alleviated the depression symptoms in the stress-induced rats. Expressions of 5-HT, TPH, and HT 1A in the dorsal raphe were reduced by the induction of stress. Treadmill exercise increased 5-HT, TPH, and HT 1A expressions in the stress-induced rats.

CONCLUSIONS

Treadmill exercise enhanced 5-HT synthesis through the up-regulation of 5-HT1A receptors, and improved the stress-induced depression. In the present study, treadmill exercise improved depression symptoms by enhancing 5-HT1A receptor expression. The present results suggest that treadmill exercise might be helpful for the alleviation of overactive bladder and improve sexual function.

Postnatal treadmill exercise attenuates prenatal stress-induced apoptosis through enhancing serotonin expression in aged-offspring rats

Maternal stress during pregnancy affects negative impact on health of offspring. In the present study, we compared the effects of maternal treadmill exercise and offspring treadmill exercise on prenatal stress-induced apoptosis and serotonin expression in offspring. Stress to the pregnant rats was induced by exposure of maternal rats to the hunting dog in an enclosed room. Exposure time was 10 min, three times per day, with a 1-h interval between exposures. This regimen was maintained from the seventh day of gestation until delivery. The pregnant rats in the exercise group were forced to run on a motorized tread-mill for 30 min once a day, started 7 days after pregnancy until delivery. The offspring in the exercise group were forced to run on a motorized treadmill for 30 min once a day, started 4 weeks after birth for 4 weeks. In the present results, offspring exposed to prenatal stress exhibited lower Bcl-2 level and higher Bax level in the hippocampus, lower 5-hydroxytryptamine (5-HT) and tryptophan hydroxylase (TPH) expression in the dorsal raphe, and higher c-Fos expression in the locus coeruleus compared to age-matched control rats. Treadmill exercise of offspring suppressed Bax expression and enhanced Bcl-2 expression in the hippocampus, increased 5-HT and TPH expression in the dorsal raphe, and enhanced c-Fos expression in the locus coeruleus of offspring. Tread-mill exercise of offspring suppressed prenatal stress-induced apoptosis and normalized prenatal stress-induced alterations in serotonin synthesis and neuronal activation. However maternal treadmill exercise during pregnancy exerted no significant effect on offspring.