Treadmill exercise improves behavioral outcomes and spatial learning memory through up-regulation of reelin signaling pathway in autistic rats

Anethole via increase in the gene expression of PI3K/AKT/mTOR mitigates the autistic-like behaviors induced by maternal separation stress in mice

Autism spectrum disorder (ASD) is a neurodegenerative disease with increasing incidence in the world. The maternal separation (MS) stress at early life with its own neuroendocrine and neurostructural changes can provide the basis for development of ASD. Previously it has been reported neuroprotective characteristics for anethole. The PI3K/AKT/mTOR signaling pathway has pivotal role in the function of central nervous system (CNS). This study aimed to evaluate the possible effects of anethole on the autistic-like behaviors in the maternally separated (MS) mice focusing on the potential role of the PI3K/AKT/mTOR pathway. Forty male Naval Medical Research Institute (NMRI) mice were assigned to five groups (n = 8) comprising a control group (treated with normal saline) and four groups subjected to MS and treated with normal saline and or anethole at doses of 31.25, 62.5 and 125 mg/kg, respectively. All gents were administrated via intraperitoneal (i.p.) route for 14 constant days. Behavioral tests were conducted, including the three-chamber test, shuttle box and resident-intruder test. The gene expression of the PI3K, AKT and mTOR assessed in the hippocampus by qRT-PCR. Findings indicated that MS is associated with autistic-like behaviors. Anethole increased the sociability and social preference indexes in the three-chamber test, increased duration of secondary latency in the shuttle box test and decreased aggressive behaviors in the resident-intruder test. Also, anethole increased the gene expression of PI3K, AKT and mTOR in the hippocampus of MS mice. We concluded that anethole through increase in the gene expression of PI3K/ AKT/mTOR mitigated autistic-like behaviors induced by MS in mice.

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.

Sex-related beneficial effects of exercise on cardiac function and rhythm in autistic rats

BACKGROUND

Cardiovascular diseases are prevalent in autistic patients. As exercise is useful in the treatment of medical conditions, this study aimed to identify the effect of low-intensity endurance exercise (LIEE) and moderate-intensity endurance exercise (MIEE) on cardiovascular events in autistic rats.

METHODS

Valproic acid (VPA) was administrated once on gestational day 12.5 to pregnant rats to produce autism-like symptoms in offspring. Thirty-day-old offspring were divided into 12 groups: Male-CTL, Male-VPA, Male-CTL + LIEE, Male-CTL + MIEE, Male-VPA + LIEE, Male-VPA + MIEE, Female-CTL, Female-VPA, Female-CTL + LIEE, Female-CTL + MIEE, Female-VPA + LIEE, and Female-VPA + MIEE. LIEE and MIEE were performed 5 days a week for 30 days. Twenty-four hours after the last exercise session, electrocardiogram and hemodynamic and cardiac function indices were recorded.

RESULTS

The results indicated that +dp/dt max and contractility index (CI) decreased in the Female-VPA group compared to the Female-CTL group. LIEE increased these parameters in the Female-VPA + LIEE group. However, MIEE normalized CI in the Male-VPA + MIEE compared to the Male-VPA group. Tau increased in the Female-VPA group compared to the Female-CTL group and it decreased in the Female-VPA + MIEE group compared to the Female-VPA group. LIEE and MIEE recovered the reduction of heart rate and the increase in P, R, and T amplitudes in Male-VPA group. LIEE and MIEE increased heart rate variability in the Male-VPA and Female-VPA groups.

CONCLUSIONS

The findings showed that LIEE and MIEE alleviated cardiac dysfunction and disturbances in heart rhythm in the autistic offspring. Exercise may be recommended as a routine program for autistic patients to prevent and treat the harmful cardiovascular consequences of autism.

Molecular mechanisms of exercise intervention in alleviating the symptoms of autism spectrum disorder: Targeting the structural alterations of synapse

Autism spectrum disorder (ASD) is a complex and heterogeneous neurodevelopmental disorder characterized by stereotyped behaviors, specific interests, and impaired social and communication skills. Synapses are fundamental structures for transmitting information between neurons. It has been reported that synaptic deficits, such as the increased or decreased density of synapses, may contribute to the onset of ASD, which affects the synaptic function and neuronal circuits. Therefore, targeting the recovery of the synaptic normal structure and function may be a promising therapeutic strategy to alleviate ASD symptoms. Exercise intervention has been shown to regulate the structural plasticity of synapses and improve ASD symptoms, but the underlying molecular mechanisms require further exploration. In this review, we highlight the characteristics of synaptic structural alterations in the context of ASD and the beneficial effects of an exercise intervention on improving ASD symptoms. Finally, we explore the possible molecular mechanisms of improving ASD symptoms through exercise intervention from the perspective of regulating synaptic structural plasticity, which contributes to further optimizing the related strategies of exercise intervention promoting ASD rehabilitation in future.

Implication of Hippocampal Neurogenesis in Autism Spectrum Disorder: Pathogenesis and Therapeutic Implications

Autism spectrum disorder (ASD) is a cluster of heterogeneous neurodevelopmental conditions with atypical social communication and repetitive sensory-motor behaviors. The formation of new neurons from neural precursors in the hippocampus has been unequivocally demonstrated in the dentate gyrus of rodents and non-human primates. Accumulating evidence sheds light on how the deficits in the hippocampal neurogenesis may underlie some of the abnormal behavioral phenotypes in ASD. In this review, we describe the current evidence concerning pre-clinical and clinical studies supporting the significant role of hippocampal neurogenesis in ASD pathogenesis, discuss the possibility of improving hippocampal neurogenesis as a new strategy for treating ASD, and highlight the prospect of emerging pro-neurogenic therapies for ASD.

Magnesium Potentiates the Vortioxetine’s Effects on Physical Performances and Biological Changes in Exercise-Induced Stress in Rats

Background and objectives: Vortioxetine (VRT) is a relatively new selective serotonin reuptake inhibitor (SSRI) antidepressant and serotonin receptor modulator, approved for the treatment of major depression and generalized anxiety disorder. Depression has been linked with psychomotor disengagement, oxidative stress burden and decreased blood levels of brain-derived neurotrophic factor (BDNF). In our study we performed the experimental investigation of VRT, magnesium and of their association on the rats’ endurance capacity, motor behavior and blood biological disturbances in rats subjected to forced exercise in treadmill test. Materials and Methods: The substances were administered orally for 14 consecutive days, as follows: group 1 (control): distilled water 0.3 mL/100 g body; group 2 (Mg): magnesium chloride 200 mg/kg body; group 3 (VRT): VRT 20 mg/kg body; group 4 (VRT+Mg): VRT 20 mg/kg body + magnesium chloride 200 mg/kg body. Magnesium was used as positive control substance with known effects in treadmill test. The consequences of VRT treatment on glucose, cortisol, BDNF and oxidative stress biomarkers (superoxide-dismutase, malondialdehyde, glutathione-peroxidase, lactate dehydrogenase) were also assessed. Results and conclusions: The use of VRT resulted in an improvement in motor capacity and an increase of the rats’ endurance to physical effort. The administration of VRT increased the serum BDNF levels and reduced the oxidative stress in rats subjected to physical effort. The association of magnesium potentiated the effects of VRT on physical performances, the antioxidant activity and the decreasing in serum stress markers in treadmill test in rats.

Bibliometric analysis of research trends of physical activity intervention for autism spectrum disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social impairment, restricted interests, and repetitive stereotyped behaviors. At present, its pathogenesis has not been fully understood. Various methods are used for clinical treatment and intervention, among which physical activity (PA) intervention also has an obvious effect. This study has used bibliometric methods and visual analysis methods to analyze 885 studies of PA intervention in ASD from 2003 to 2022 in the Web of Science (WoS) database in order to provide theoretical support for the follow-up research on the effect of PA with ASD. The main findings of this study are as follows. First, the literature on PA interventions in ASD research showed a growing trend. The leading institution in this field is the University of Delaware, forming a core group of authors represented by authors such as Sean Healy and Carol Curtin et al. Second, the research focus of this research area mainly includes PA interventions for children and adolescents with ASD. PA can improve symptoms such as stereotyped behaviors and motor function in patients with ASD as well as can reduce childhood obesity rates and improve quality of life. Third, skill, youth, prevalence, and meta-analysis systematic reviews were found. It is the long-term concern and focus of researchers. In conclusion, the current research is only a short-term analysis, and it is not possible to verify the long-term effect; thus, future data analysis should evaluate and explore the long-term effects of PA interventions on ASD including cohort and longitudinal study types focused on the rehabilitation of patients with ASD. Moreover, testing the sustainability of benefits for children with ASD and constructing a multidimensional exercise integrated intervention model are the main directions for future research in this field.

Swimming Training Mitigates Neurological Impairment of Intracerebral Haemorrhage in Mice via the Serine-Threonine Kinase/Glycogen Synthase Kinase 3β Signalling Pathway

Swimming training (ST) can mitigate functional disorders in neurological diseases, but the effect and mechanism of ST in improving the neurological function of intracerebral haemorrhage (ICH) have not been reported. Our study aimed to explore the protective effect of early ST on ICH mice and its relationship with the serine-threonine kinase (Akt)/glycogen synthase kinase 3β (GSK3β) pathway. Our findings showed that the ICH model mice had poor behavioural manifestations in the Y maze test and open field test compared to the ST group and sham group. The modified neurological severity score was increased in the ICH mice, and 7 days of ST intervention significantly attenuated the neurological deficits. The ratios of myo-inositol/creatine, lactate/creatine and glutamate/creatine were decreased, and the ratios of N-acetylaspartate/creatine and choline/creatine were increased in the ICH mice with ST intervention. ST intervention decreased the expression of Iba1 and GFAP. Seven days of ST significantly increased the expression of p-Akt/Akt compared to that in the ICH mice. Furthermore, the Akt kinase inhibitor GSK690693 exacerbated neurological impairment, increased the expression of Iba1, GFAP and Bax/Bcl-2, and reversed the anti-apoptotic effects and anti-glia activation of ST, which was associated with the inhibition of p-Akt/Akt and p-GSK3β/GSK3β expression. These results indicated that the protective role of ST in ICH was mediated via the Akt/GSK3β pathway. In conclusion, ST displayed neuroprotection by inhibiting apoptosis and glial activation in ICH mice by activating the Akt/GSK3β signalling pathway.

Sex Differences in Spatial Learning and Memory in Valproic Acid Rat Model of Autism: Possible Beneficial Role of Exercise Interventions

In the current study, we first tried to determine sex differences in spatial learning and memory in the valproic acid (VPA) rat model of autism. Second, the effects of interval training (IT) and continuous training (CT) exercises were examined in male and female offsprings. To induce autism-like animal model, the pregnant rats were injected 500 mg/kg NaVPA (intraperitoneal) at the embryonic day 12.5. IT and CT aerobic exercises were started at postnatal day 56. Then, on postnatal days 84–89, a Morris water maze (MWM) test was conducted on the separate groups of offsprings. Aerobic training was performed on a rodent treadmill with 0% slope for 8 weeks, 5 days/week, and 50 min/day. Unlike control animals, VPA-exposed female offspring had a better performance than VPA-exposed male offspring in MWM acquisition. In the case of MWM reference memory, we did not observe a sex difference between VPA-exposed male and VPA-exposed female offspring. Both IT and CT exercises in both control and VPA-exposed male rats significantly improved MWM acquisition. Moreover, both IT and CT exercises significantly improved MWM acquisition in control female rats. In addition, IT exercise (but not CT) significantly improved MWM acquisition in VPA-exposed female offsprings. Both IT and CT exercises in VPA-exposed that male and female offsprings improved the MWM reference memory. In conclusion, our observation demonstrated that prenatal exposure to VPA affects the spatial learning and memory in a sex dependent manner. We have shown that both IT and CT exercises are able to improve cognitive function in healthy and autistic rat offsprings.

Targeting PI3K-AKT/mTOR signaling in the prevention of autism

PI3K-AKT/mTOR signaling pathway represents an essential signaling mechanism for mammalian enzyme-related receptors in transducing signals or biological processes such as cell development, differentiation, cell survival, protein synthesis, and metabolism. Upregulation of the PI3K-AKT/mTOR signaling pathway involves many human brain abnormalities, including autism and other neurological dysfunctions. Autism is a neurodevelopmental disorder associated with behavior and psychiatric illness. This research-based review discusses the functional relationship between the neuropathogenic factors associated with PI3K-AKT/mTOR signaling pathway. Ultimately causes autism-like conditions associated with genetic alterations, neuronal apoptosis, mitochondrial dysfunction, and neuroinflammation. Therefore, inhibition of the PI3K-AKT/mTOR signaling pathway may have an effective therapeutic value for autism treatment. The current review also summarizes the involvement of PI3K-AKT/mTOR signaling pathway inhibitors in the treatment of autism and other neurodegenerative disorders.

Progressive increase in the complexity and translatability of rodent testing to assess space-radiation induced cognitive impairment

Ground-based rodent models have established that space radiation doses (approximately those that astronauts will be exposed to on a mission to Mars) significantly impair performance in a wide range of cognitive tasks. Over the last 40 years there has been a progressive increase in both the complexity and the translatability (to humans) of the cognitive tasks investigated. This review outlines technical and conceptual advances in space radiation rodent testing approaches, along with the advances in analytical approaches, that will make data from ground based studies more amenable to probabilistic risk analysis. While great progress has been made in determining the impact of space radiation on many advanced cognitive processes, challenges remain that need to be addressed prior to commencing deep space missions. A summary of on-going attempts to address existing knowledge gaps and the critical role that rodent studies will have in establishing the impact of space radiation on even more complex (human) cognitive tasks are presented and discussed.

Exercise Intervention in Treatment of Neuropsychological Diseases: A Review

Faced with a constant inundation of information and increasing pressures brought by the continuous development of modern civilization, people are increasingly faced with mental health challenges that are only now being actively researched. Mental illness is caused by brain dysfunction due to internal and external pathogenic factors that destroy the integrity of the human brain and alter its function. Regular participation in physical exercise can stimulate the cerebral cortex and simultaneously increase the supply of oxygen and nutrients, helping to preserve or restore normal functioning of the nervous system. In conjunction with other systems of the body, the nervous system constitutes the neuro-humoral regulation system responsible for maintaining the stable state of the human body. This paper is a systematic review of studies investigating the effects of exercise intervention on several common neuropsychological diseases, including depression, anxiety disorder, autism, and attention-deficit/hyperactivity disorder. Furthermore, we discuss possible physiological mechanisms underlying exercise-induced benefits and study limitations that must be addressed by future research. In many cases, drug therapy is ineffective and brings unwanted side effects. Based on the literature, we conclude that exercise intervention plays a positive role and that certain standards must be established in the field to make physical activity consistently effective.

Oxytocin Differentiated Effects According to the Administration Route in a Prenatal Valproic Acid-Induced Rat Model of Autism

Background and objectives: The hormone oxytocin (OXT) has already been reported in both human and animal studies for its promising therapeutic potential in autism spectrum disorder (ASD), but the comparative effectiveness of various administration routes, whether central or peripheral has been insufficiently studied. In the present study, we examined the effects of intranasal (IN) vs. intraperitoneal (IP) oxytocin in a valproic-acid (VPA) autistic rat model, focusing on cognitive and mood behavioral disturbances, gastrointestinal transit and central oxidative stress status. Materials and Methods: VPA prenatally-exposed rats (500 mg/kg; age 90 days) in small groups of 5 (n = 20 total) were given OXT by IP injection (10 mg/kg) for 8 days consecutively or by an adapted IN pipetting protocol (12 IU/kg, 20 μL/day) for 4 consecutive days. Behavioral tests were performed during the last three days of OXT treatment, and OXT was administrated 20 minutes before each behavioral testing for each rat. Biochemical determination of oxidative stress markers in the temporal area included superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA). A brief quantitative assessment of fecal discharge over a period of 24 hours was performed at the end of the OXT treatment to determine differences in intestinal transit. Results: OXT improved behavioral and oxidative stress status in both routes of administration, but IN treatment had significantly better outcome in improving short-term memory, alleviating depressive manifestations and mitigating lipid peroxidation in the temporal lobes. Significant correlations were also found between behavioral parameters and oxidative stress status in rats after OXT administration. The quantitative evaluation of the gastrointestinal (GI) transit indicated lower fecal pellet counts in the VPA group and homogenous average values for the control and both OXT treated groups. Conclusions: The data from the present study suggest OXT IN administration to be more efficient than IP injections in alleviating autistic cognitive and mood dysfunctions in a VPA-induced rat model. OXT effects on the cognitive and mood behavior of autistic rats may be associated with its effects on oxidative stress. Additionally, present results provide preliminary evidence that OXT may have a balancing effect on gastrointestinal motility.

Impact of exercise on hippocampal neurogenesis in hyperglycemic diabetes

Hyperglycemic diabetes is a chronic metabolic disorder characterized by high level of plasma glucose. Numerous studies have shown that hy-perglycemic diabetes leads to brain dysfunction including cognitive im-pairment and emotional disorders. This study evaluated the impact of exercise on brain dysfunction, hippocampal neurogenesis, and cogni-tive impairment in hyperglycemic diabetes. The present study suggests that exercise improves hyperglycemic control and prevents decline of cognition through increasing hippocampal neurogenesis. Understanding the mechanism of exercise for hippocampal neurogenesis can lead to the development of therapeutic strategies for metabolic disorders.

Effects of Maternal Physical Exercise on Global DNA Methylation and Hippocampal Plasticity of Rat Male Offspring

Intrauterine exposure to exercise is beneficial to cognition of the offspring. Although it is advisable to start practicing physical exercise during pregnancy, it is probable that practitioners or sedentary women keep their previous habits during gestation. This study was designed to evaluate the effects of maternal aerobic exercise initiated before and maintained during gestation, or performed in these isolated periods, on cognition and plasticity in the hippocampus of offspring. Groups of male pups were categorized by the exposure of their mothers to: treadmill off (sedentary, SS), pregestational exercise (ES), gestational exercise (SE) or combined protocols (EE). Between postnatal day 20 (P20) and P23 the offspring received one daily 5-bromo-2'-deoxiuridine (BrdU) injection and, from P47 to P51, were evaluated by the Morris water maze task. At P53, hippocampal global DNA methylation, survival of progenitor cells (BrdU), Brain-derived Neurotrophic Factor (BDNF) and reelin levels were measured. The offspring from ES, SE and EE mothers demonstrated improved spatial learning compared to SS, but hippocampal DNA methylation was significantly modified only in the offspring from ES mothers. The offspring from ES and SE mothers presented higher number of BrdU+ and reelin+ hippocampal cells than EE and SS. No differences were observed in the BDNF levels among the groups. The maternal pregestational and gestational isolated exercise protocols showed similar effects for offspring plasticity and spatial cognitive ability, while the combined protocol simply improved their spatial learning. Interestingly, only pregestational exercise was able to induce plasticity in the offspring hippocampus associated with modulation of global DNA methylation.

Exercise, spinogenesis and cognitive functions

Exercise training improves mental and cognitive functions by enhancing neurogenesis and neuroprotection. Recent studies suggest the facilitation of spinogenesis across different brain regions including hippocampus and cerebral cortex by physical activity. In this article we will summarize major findings for exercise effects on synaptogenesis and spinogenesis, in order to provide mechanisms for exercise intervention of both psychiatric diseases and neurodegenerative disorders. We will also revisit major findings for molecular mechanism governing exercise-related spinogenesis, and will discuss the screening for novel factors, or exerkines, whose levels are correlated with endurance training and affect neural plasticity. We believe that further studies focusing on the molecular mechanism of exercise-mediate spinogenesis should benefit the optimization of exercise therapy in clinics and the evaluation of treatment efficiency using specific biomarkers.

Combination of treadmill exercise with bone marrow stromal cells transplantation activates protein synthesis-related molecules in soleus muscle of the spinal cord injured rats

The present study investigated whether treadmill exercise with bone marrow stromal cells (BMSCs) transplantation increase expression level of protein synthesis-related molecules in the soleus muscle after spinal cord injury (SCI). The spinal cord contusion injury was performed at the T9-10 level using the impactor (10 g×25 mm). BMSCs were cultured from femur and tibia of 4-week-old rats and then transplanted directly into the lesion 1-week post injury. The rats in exercise group were walking on treadmill device for 6 days per a week during 6 weeks. Prepared soleus muscles were used for examining mechanisms of protein synthesis after SCI. Myostatin induction level was increased by SCI, but BMSCs engrafting after SCI decreased compared to SCI group. Combination of treadmill exercise with BMSCs showed more potent decrement on myostatin expression. Protein kinase B (Akt) and mammalian target of rapamycin (mTOR) levels were significantly increased in SCI and BMSCs transplantation group compared to SCI group. Combination of treadmill exercise with BMSCs further facilitated expression levels of Akt and mTOR. Insulin-like growth factor-I (IGF-I) and phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) induction levels were more increased in SCI and BMSC transplantation group compared to SCI group. Combination of treadmill exercise with BMSCs further increased expression levels of IGF-I and p-CREB, although statistical significance was not appeared. Combining treadmill exercise with BMSCs transplantation might accelerate protein synthesis and hypertrophy in the soleus muscle after SCI through activation of IGF-I/mTOR signaling pathway.

Treadmill Exercise Alleviates Circadian Rhythm Disruption-Induced Memory Deficits by Activation of Glucocorticoid Receptor and Brain-Derived Neurotrophic Factor-Dependent Pathway

Purpose

Circadian rhythm affects learning process, memory consolidation, and long-term memory. In this study, the alleviating effect of exercise on circadian rhythm disruption-induced memory deficits was investigated.

Methods

BMAL1 knockdown transgenic mice (BMAL1 TG) were used as the BMAL1-TG group and the BMAL1-TG with treadmill exercise group. Female C57BL/6J mice of the same age were used as the wildtype group and the wildtype with treadmill exercise group. The mice in the treadmill exercise groups performed running on a motorized treadmill under the dark-dark conditions for 8 weeks. Short-term memory, nonspatial object memory, and spatial learning memory were determined using stepdown avoidance test, novel object-recognition test, and radial 8-arm maze test. Immunohistochemistry for doublecortin and 5-bromo-2’-deoxyuridine was conducted for the determination of hippocampal neurogenesis. Using the western blot analysis, we determined the expressions of glucocorticoid receptor (GR) and factors related to the neurogenesis and memory consolidation, such as brain-derived neurotrophic factor, tyrosine kinase B, p44/42 mitogen-activated protein kinase, cyclic AMP-responsive element binding protein, phosphatidylinositol 3-kinase, protein kinas B, protein kinase C alpha, early-growth-response gene 1.

Results

Circadian rhythm disruption impaired memory function through inhibiting the expressions of GR and the factors related to neurogenesis and memory consolidation. Treadmill exercise improved memory function via enhancing the expressions of GR and above-mentioned factors.

Conclusions

Treadmill exercise acts as the zeitgeber that improves memory function under the circadian rhythm disrupted conditions.

On the Run for Hippocampal Plasticity

Accumulating research in rodents and humans indicates that exercise benefits brain function and may prevent or delay onset of neurodegenerative conditions. In particular, exercise modifies the structure and function of the hippocampus, a brain area important for learning and memory. This review addresses the central and peripheral mechanisms underlying the beneficial effects of exercise on the hippocampus. We focus on running-induced changes in adult hippocampal neurogenesis, neural circuitry, neurotrophins, synaptic plasticity, neurotransmitters, and vasculature. The role of peripheral factors in hippocampal plasticity is also highlighted. We discuss recent evidence that systemic factors released from peripheral organs such as muscle (myokines), liver (hepatokines), and adipose tissue (adipokines) during exercise contribute to hippocampal neurotrophin and neurogenesis levels, and memory function. A comprehensive understanding of the body-brain axis is needed to elucidate how exercise improves hippocampal plasticity and cognition.

Modulation of sphingosine 1-phosphate (S1P) attenuates spatial learning and memory impairments in the valproic acid rat model of autism

RATIONALE

Autism spectrum disorders (ASD) are a set of pervasive neurodevelopmental disorders that manifest in early childhood, and it is growing up to be a major cause of disability in children. However, the etiology and treatment of ASD are not well understood. In our previous study, we found that serum levels of sphingosine 1-phosphate (S1P) were increased significantly in children with autism, indicating that S1P levels may be involved in ASD.

OBJECTIVE

The objective of this study was to identify a link between increased levels of S1P and neurobehavioral changes in autism.

METHODS

We utilized a valproic acid (VPA) -induced rat model of autism to evaluate the levels of S1P and the expression of sphingosine kinase (SphK), a key enzyme for S1P production, in serum and hippocampal tissue. Furthermore, we assessed cognitive functional changes and histopathological and neurochemical alterations in VPA-exposed rats after SphK blockade to explore the possible link between increased levels of S1P and neurobehavioral changes in autism.

RESULTS

We found that SphK2 and S1P are upregulated in hippocampal tissue from VPA-exposed rats, while pharmacological inhibition of SphK reduced S1P levels, attenuated spatial learning and memory impairments, increased the expression of phosphorylated CaMKII and CREB and autophagy-related proteins, inhibited cytochrome c release, decreased the expression of apoptosis related proteins, and protected against neuronal loss in the hippocampus.

CONCLUSION

We have demonstrated that an increased level of SphK2/S1P is involved in the spatial learning and memory impairments of autism, and this signaling pathway represents a novel therapeutic target and direction for future studies.

Environmental enrichment and exercise are better than social enrichment to reduce memory deficits in amyloid beta neurotoxicity

Recently, nongenetic animal models to study the onset and development of Alzheimer's disease (AD) have appeared, such as the intrahippocampal infusion of peptides present in Alzheimer amyloid plaques [i.e., amyloid-β (Aβ)]. Nonpharmacological approaches to AD treatment also have been advanced recently, which involve combinations of behavioral interventions whose specific effects are often difficult to determine. Here we isolate the neuroprotective effects of three of these interventions-environmental enrichment (EE), anaerobic physical exercise (AnPE), and social enrichment (SE)-on Aβ-induced oxidative stress and on impairments in learning and memory induced by Aβ. Wistar rats were submitted to 8 wk of EE, AnPE, or SE, followed by Aβ infusion in the dorsal hippocampus. Short-term memory (STM) and long-term memory (LTM) of object recognition (OR) and social recognition (SR) were evaluated. Biochemical assays determined hippocampal oxidative status: reactive oxygen species, lipid peroxidation by thiobarbituric acid reactive substance (TBARS) test, and total antioxidant capacity by ferric reducing/antioxidant power (FRAP), as well as acetylcholinesterase activity. Aβ infusion resulted in memory deficits and hippocampal oxidative damage. EE and AnPE prevented all memory deficits (STM and LTM of OR and SR) and lipid peroxidation (i.e., TBARS). SE prevented only the SR memory deficits and the decrease of total antioxidant capacity decrease (i.e., FRAP). Traditionally, findings obtained with EE protocols do not allow discrimination of the roles of the three individual factors involved. Here we demonstrate that EE and physical exercise have better neuroprotective effects than SE in memory deficits related to Aβ neurotoxicity in the AD model tested.

Pathophysiological and neurobehavioral characteristics of a propionic acid-mediated autism-like rat model

Autism spectrum disorder (ASD) is induced by complex hereditary and environmental factors. However, the mechanisms of ASD development are poorly understood. The purpose of this study was to identify standard indicators of this condition by comparing clinical, pathophysiological, and neurobehavioral features in an autism-like animal model. A total of 22 male Sprague-Dawley rats were randomly divided into control and 500 mg/kg propionic acid (PPA)-treated groups. Rats were subjected to behavioral tests, gene expression analyses, and histological analyses to detect pathophysiological and neurobehavioral alterations. Exploratory activity and non-aggressive behavior were significantly reduced in PPA-treated rats, whereas enhanced aggressive behavior during adjacent interactions was observed on day 14 after PPA administration. To evaluate gene expression after PPA administration, we analyzed hippocampal tissue using reverse transcription PCR. Glial fibrillary acidic protein was augmented in the PPA-treated group on day 14 after appearance of ASD-like behaviors by PPA administration, whereas octamer-binding transcription factor 4 expression was significantly decreased in the PPA-treated group. Histological evaluation revealed significantly reduced diameter and layer thickness of granule cells in PPA-treated rats compared with control rats. We conclude that PPA administration induced abnormal neural cell organization, which may have led to autism-like neurobehaviors, including increased aggressive behavior, reduced exploratory activity, and isolative and passive behaviors.

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.

Beneficial effect of interventional exercise on autistic Fragile X syndrome

[Purpose] The purpose of the present review is to discuss recent published articles in the understanding of efficacy of interventional exercise on autistic Fragile X syndrome (FXS) with special emphasis on its significance in clinical application in patients. [Methods] This review article was identified scientifically and/or clinically relevant articles from PubMed that directly/indirectly met the inclusion criteria. [Results] Mutation of fragile X mental retardation 1 (fmr1) gene on the X chromosome is related with loss of fragile X mental retardation protein (FMRP) that affecting physiological and behavioral abnormalities. Autistic FXS individuals exhibit disturbed sleep and altered circadian behavior. Although the underlying molecular mechanisms are not been fully explored, interventional exercise in autistic FXS has been clinically used for the treatment of physiological and behavioral abnormalities as well as psychiatric disorder in autistic FXS. [Conclusion] This review describes beneficial efficacy of interventional exercise and its controversy in patients with autistic FXS. This review also provides interventional strategies for clinicians and scientists that the way of neurophysiological approaches according to the level of physical and behavioral abnormalities.

Genetic architecture for human aggression: A study of gene-phenotype relationship in OMIM

Genetic studies of human aggression have mainly focused on known candidate genes and pathways regulating serotonin and dopamine signaling and hormonal functions. These studies have taught us much about the genetics of human aggression, but no genetic locus has yet achieved genome-significance. We here present a review based on a paradoxical hypothesis that studies of rare, functional genetic variations can lead to a better understanding of the molecular mechanisms underlying complex multifactorial disorders such as aggression. We examined all aggression phenotypes catalogued in Online Mendelian Inheritance in Man (OMIM), an Online Catalog of Human Genes and Genetic Disorders. We identified 95 human disorders that have documented aggressive symptoms in at least one individual with a well-defined genetic variant. Altogether, we retrieved 86 causal genes. Although most of these genes had not been implicated in human aggression by previous studies, the most significantly enriched canonical pathways had been previously implicated in aggression (e.g., serotonin and dopamine signaling). Our findings provide strong evidence to support the causal role of these pathways in the pathogenesis of aggression. In addition, the novel genes and pathways we identified suggest additional mechanisms underlying the origins of human aggression. Genome-wide association studies with very large samples will be needed to determine if common variants in these genes are risk factors for aggression. © 2015 Wiley Periodicals, Inc.

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.

Epicatechin Plus Treadmill Exercise are Neuroprotective Against Moderate-stage Amyloid Precursor Protein/Presenilin 1 Mice

Background:

Epidemiological evidence suggests that exercise and dietary polyphenols are beneficial in reducing Alzheimer's disease (AD) risk.

Materials and Methods:

In the present study, 8 months old amyloid precursor protein/presenilin 1 (APP/PS1) mice (a moderate pathology phase) were given the green tea catechin (-)-epicatechin delivered orally in the drinking water (50 mg/kg daily), along with treadmill exercise for 4 months, in order to investigate whether the combination can ameliorate the cognitive loss and delay the progression of AD in APP/PS1 transgenic (Tg) mice.

Results:

At termination, untreated-Tg mice showed elevated soluble amyloid-β (Aβ_1–40) and Aβ_1–42 levels and deficits in spatial learning and memory, compared with their wild-type littermates. The combined intervention protected against cognitive deficits in the Morris water maze, lowered soluble Aβ_1–40 and Aβ_1–42 levels in the hippocampus as well as reducing brain oxidative stress. In addition, brain-derived neurotrophic factor proteins wee elevated and Akt/GSK-3/cAMP response element-binding protein signaling was activated in the combination group.

Conclusions:

Dietary polyphenol plus exercise may exert beneficial effects on brain health and slow the progression of moderate- or mid-stages of AD.

SUMMARY

Amyloid precursor protein/presenilin 1 transgenic mice showed elevated soluble amyloid-β (Aβ_1–40) and Aβ_1–42 levels and deficits in spatial learning and memory, compared with their wild-type littermates

Oral administration of epicatechin, combined with treadmill exercise for 4 months, could protect against cognitive deficits, and lowered soluble Aβ_1–40 and Aβ_1–42 levels as well as reducing brain oxidative stress

Brain-derived neurotrophic factor proteins were elevated, and Akt/GSK-3/cAMP response element binding protein signaling was activated in the combination group

Dietary polyphenol plus exercise might exert beneficial effects on brain health and slow the progression of moderate- or mid-stages of Alzheimer's disease.

Abbreviations used: AD: Alzheimer's disease, Tg: APP/PS1 transgenic, BDNF: Brain-derived neurotrophic factor, Aβ: Amyloid-β, APP: Amyloid precursor protein, PS1: Presenilin 1, nTg: Wild-type littermates, IACUC: Institutional Animal Care and Use Committee, GSSG: Glutathione oxidized form, GSH: Glutathione reductase, SOD: Superoxide dismutase, CAT: Catalase, LPO: Lipoperoxidation, CREB: cAMP response element binding protein.

Can Exercise Make You Smarter, Happier, and Have More Neurons? A Hormetic Perspective

Exercise can make you smarter, happier and have more neurons depending on the dose (intensity) of the training program. It is well recognized that exercise protocols induce both positive and negative effects depending on the intensity of the exercise, among other key factors, a process described as a hormetic-like biphasic dose-response. However, no evidences have been reported till very recently about the biphasic response of some of the potential mediators of the exercise-induced actions. This hypothesis and theory will focus on the adult hippocampal neurogenesis (AHN) as a putative physical substrate for hormesis responses to exercise in the context of exercise-induced actions on cognition and mood, and on the molecular pathways which might potentially be mediating these actions.

Alpha1-Adrenoceptor Antagonists Improve Memory by Activating N-methyl-D-Aspartate-Induced Ion Currents in the Rat Hippocampus

PURPOSE

Alpha1 (α1)-adrenoceptor antagonists are widely used to treat lower urinary tract symptoms. These drugs not only act on peripheral tissues, but also cross the blood-brain barrier and affect the central nervous system. Therefore, α1-adrenoceptor antagonists may enhance brain functions. In the present study, we investigated the effects of tamsulosin, an α1-adrenoceptor antagonist, on short-term memory, as well as spatial learning and memory, in rats.

METHODS

The step-down avoidance test was used to evaluate short-term memory, and an eight-arm radial maze test was used to evaluate spatial learning and memory. TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling) staining was performed in order to evaluate the effect of tamsulosin on apoptosis in the hippocampal dentate gyrus. Patch clamp recordings were used to evaluate the effect of tamsulosin on ionotropic glutamate receptors, such as N-methyl-D-aspartate (NMDA), amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and kainate receptors, in hippocampal CA1 neurons.

RESULTS

Tamsulosin treatment improved short-term memory, as well as spatial learning and memory, without altering apoptosis. The amplitudes of NMDA-induced ion currents were dose-dependently increased by tamsulosin. However, the amplitudes of AMPA- and kainate-induced ion currents were not affected by tamsulosin.

CONCLUSIONS

Tamsulosin enhanced memory function by activating NMDA receptor-mediated ion currents in the hippocampus without initiating apoptosis. The present study suggests the possibility of using tamsulosin to enhance memory under normal conditions, in addition to its use in treating overactive bladder.

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.

Treadmill exercise improves short-term memory by enhancing hippocampal cell proliferation in quinolinic acid-induced Huntington's disease rats

Huntington’s disease (HD) is an inherited genetic disorder, characterized by cognitive dysfunction and abnormal body movements called chorea. Quinolinic acid (QA) is an endogenous metabolite of tryptophan in the kynurenine pathway. QA-induced alterations are similar to the symptoms of HD patients. Physical exercise has beneficial effects on the brain functions. Exercise increases production of neurotrophic factors in the brain and improves learning ability and memory function. In the present study, we investigated the effects of treadmill exercise short-term memory on QA-induced HD rats in relation with cell proliferation. For the induction of Huntington’s animal model, 2 μL of 100 nmol QA was intrastriatal injected into the rats. The rats in the treadmill exercise groups were forced to run on a treadmill for 30 min once a day, five times a week for 2 weeks. Step-down avoidance test was conducted for the determination of short-term memory. Cell proliferation in the hippocampal dentate gyrus was determined by 5-bromo-2′-deoxyuridine (BrdU) and doublecortin (DCX) immunohistochemistry. Western blot for brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) were performed. In the present results, treadmill exercise alleviated QA-induced short-term memory impairment in HD rats. Treadmill exercise increased cell proliferation in the hippocampal dentate gyrus through enhancing BDNF expression in the HD rats. These results revealed that treadmill exercise is effective for the symptom improvement in the HD patients.

Connectivity in Autism: A Review of MRI Connectivity Studies

Autism spectrum disorder (ASD) affects 1 in 50 children between the ages of 6 and 17 years. The etiology of ASD is not precisely known. ASD is an umbrella term, which includes both low- (IQ < 70) and high-functioning (IQ > 70) individuals. A better understanding of the disorder and how it manifests in individual subjects can lead to more effective intervention plans to fulfill the individual's treatment needs.Magnetic resonance imaging (MRI) is a non-invasive investigational tool that can be used to study the ways in which the brain develops or deviates from the typical developmental trajectory. MRI offers insights into the structure, function, and metabolism of the brain. In this article, we review published studies on brain connectivity changes in ASD using either resting state functional MRI or diffusion tensor imaging.The general findings of decreases in white matter integrity and in long-range neural coherence are well known in the ASD literature. Nevertheless, the detailed localization of these findings remains uncertain, and few studies link these changes in connectivity with the behavioral phenotype of the disorder. With the help of data sharing and large-scale analytic efforts, however, the field is advancing toward several convergent themes, including the reduced functional coherence of long-range intra-hemispheric cortico-cortical default mode circuitry, impaired inter-hemispheric regulation, and an associated, perhaps compensatory, increase in local and short-range cortico-subcortical coherence.

Dietary-induced obesity disrupts trace fear conditioning and decreases hippocampal reelin expression

Both obesity and over-consumption of palatable high fat/high sugar "cafeteria" diets in rats has been shown to induce cognitive deficits in executive function, attention and spatial memory. Adult male Sprague-Dawley rats were fed a diet that supplemented standard lab chow with a range of palatable foods eaten by people for 8 weeks, or regular lab chow. Memory was assessed using a trace fear conditioning procedure, whereby a conditioned stimulus (CS) is presented for 10s and then 30s after its termination a foot shock (US) is delivered. We assessed freezing to the CS (flashing light) in a neutral context, and freezing in the context associated with footshock. A dissociation was observed between levels of freezing in the context and to the CS associated with footshock. Cafeteria diet fed rats froze less than control chow fed rats in the context associated with footshock (P<0.01), indicating that encoding of a hippocampus-dependent context representation was impaired in these rats. Conversely, cafeteria diet fed rats froze more (P<0.05) to the CS than chow fed rats, suggesting that when hippocampal function was compromised the cue was the best predictor of footshock, as contextual information was not encoded. Dorsal hippocampal mRNA expression of inflammatory and neuroplasticity markers was analysed at the end of the experiment, 10 weeks of diet. Of these, mRNA expression of reelin, which is known to be important in long term potentiation and neuronal plasticity, was significantly reduced in cafeteria diet fed rats (P=0.003). This implicates reductions in hippocampal plasticity in the contextual fear memory deficits seen in the cafeteria diet fed rats.

Swimming exercise enhances the hippocampal antioxidant status of female Wistar rats

OBJECTIVES

Moderate exercise is known to have health benefits, while both sedentarism and strenuous exercise have pro-oxidant effects. In this study, we assessed the effect of moderate exercise on the antioxidant homeostasis of rats' hippocampi.

METHODS

Female Wistar rats were submitted to a 30-minute swimming protocol on 5 days a week, for 4 weeks. Control rats were immersed in water and carefully dried. Production of hippocampal reactive species, activity of antioxidant enzymes, and glutathione levels in these animals were determined up to 30 days after completion of the 4-week protocol.

RESULTS

Production of reactive species and hippocampal glutathione levels were increased 1 day after completion of the 4-week protocol, and returned to control levels after 7 days. Antioxidant enzyme activities were increased both 1 day (catalase) and 7 days (superoxide dismutase and glutathione peroxidase) after completion of the protocol. Thirty days after completion of the protocol, none of the antioxidant parameters evaluated differed from those of controls.

DISCUSSION

Our results reinforce the benefits of aerobic exercise, which include positive modulation of antioxidant homeostasis in the hippocampi. The effects of exercise are not permanent; rather, an exercise regimen must be continued in order to maintain the neurometabolic adaptations.

Inhibitory Effects of Isoquinoline Alkaloid Berberine on Ischemia-Induced Apoptosis via Activation of Phosphoinositide 3-Kinase/Protein Kinase B Signaling Pathway

Purpose

Berberine is a type of isoquinoline alkaloid that has been used to treat various diseases. A neuroprotective effect of berberine against cerebral ischemia has been reported; however, the effects of berberine on apoptosis in relation to reactive astrogliosis and microglia activation under ischemic conditions have not yet been fully evaluated. In the present study, we investigated the effects of berberine on global ischemia-induced apoptosis, and focused on the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in the hippocampus using gerbils.

Methods

Gerbils received berberine orally once a day for 14 consecutive days, starting one day after surgery. In this study, a step-down avoidance task was used to assess short-term memory. Furthermore, we employed the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay to evaluate DNA fragmentation, immunohistochemistry to investigate glial fibriallary acidic protein, CD11b, and caspase-3, and western blot to assess PI3K, Akt, Bax, Bcl-2, and cytochrome c.

Results

Our results revealed that berberine treatment alleviated ischemia-induced short-term memory impairment. Treatment with berbeine also attenuated ischemia-induced apoptosis and inhibited reactive astrogliosis and microglia activation. Furthermore, berberine enhanced phospho-PI3K and phospho-Akt expression in the hippocampus of ischemic gerbils.

Conclusions

Berberine exerted a neuroprotective effect against ischemic insult by inhibiting neuronal apoptosis via activation of the PI3K/Akt signaling pathway. The antiapoptotic effect of berberine was achieved through inhibition of reactive astrogliosis and microglia activation. Berberine may therefore serve as a therapeutic agent for stroke-induced neurourological problems.

Pre-ischemic treadmill training alleviates brain damage via GLT-1-mediated signal pathway after ischemic stroke in rats

Physical exercise could play a neuroprotective role in both human and animals. However, the involved signal pathways underlying the neuroprotective effect are still not well established. This study was to investigate the possible signal pathways involved in the neuroprotection of pre-ischemic treadmill training after ischemic stroke. Seventy-two SD rats were randomly assigned into three groups (n=24/group): sham surgery group, middle cerebral artery occlusion (MCAO) group and MCAO with exercise group. Following three weeks of treadmill training exercise, ischemic stroke was induced by occluding the middle cerebral artery (MCA) in rat for 2 h, followed by reperfusion. Twenty-four hours after MCAO/reperfusion, 12 rats in each group were evaluated for neurological deficit scores and then sacrificed to measure the infarct volume (n=6) and cerebral edema (n=6). Six rats in each group were sacrificed to measure the expression level of glutamate transporter-1 (GLT-1), protein kinase C-α (PKC-α), Akt, and phosphatidylinositol 3 kinase (PI3K) (n=6). Two hundred and eighty minutes (4.67 h) after occlusion, six rats in each group were decapitated to detect the mRNA expression level of metabotropic glutamate receptor 5 (mGluR5) and N-methyl-D-aspartate receptor subunit type 2B (NR2B) (n=6).The results demonstrated that pre-ischemic treadmill training exercise reduced brain infarct volume, cerebral edema and neurological deficits, also decreased the over expression of PKC-α and increased the expression level of GLT-1, Akt and PI3K after ischemic stroke (p<0.05). The over-expression of mGluR5 and NR2B mRNA was also inhibited by pre-ischemic exercise (p<0.05). In summary, exercise preconditioning ameliorated brain damage after ischemic stroke, which might be involved in two signal pathways: PKC-α-GLT-1-Glutamate and PI3K/Akt-GLT-1-Glutamate.

Treadmill exercise alleviates impairment of spatial learning ability through enhancing cell proliferation in the streptozotocin-induced Alzheimer's disease rats

Alzheimer’s disease is the most common cause of dementia. This disease is a progressive and irreversible brain disorder accompanied with severe learning and memory impairment. Exercise increases cognitive ability, attenuates motor deficits, increases new neuron formation, and ameliorates neurological impairments in several neurodegenerative diseases. This study investigated the effects of treadmill exercise on spatial learning ability in relation with cell proliferation in the hippocampus. The rat model of Alzheimer’s disease was induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) using a stereotaxic instrument. The rats in the exercise groups were forced to run on a treadmill for once 30 min daily for 28 consecutive days starting at 3 days after the ICV injection of STZ. Radial 8-arm maze test was conducted for the spatial learning ability. New neuron formation in the hippocampus was detected by 5-bromo-2’-deoxyuridine (BrdU) immunohistochemistry. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions were examined by western blot analysis. The present results show that ICV injection of STZ impaired spatial learning ability. Decreased cell proliferation with decrement of BDNF and TrkB expressions in the hippocampus were observed in the STZ-induced Alzheimer’s disease rats. However, treadmill exercise alleviated deficits of spatial learning ability. Treadmill exercise enhanced cell proliferation and increased BDNF and TrkB expressions in the rats with ICV injection of STZ. The present study suggests that treadmill exercise can be a useful strategy for treating memory impairment induced by several neurodegenerative diseases.

Dysregulation of the IGF-I/PI3K/AKT/mTOR signaling pathway in autism spectrum disorders

The IGF-I/PI3K/AKT/mTOR signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, motility, survival, metabolism and protein synthesis. Insulin-like growth factor-I (IGF-I) is synthesized in the liver and fibroblasts, and its biological actions are mediated by the IGF-I receptor (IGF-IR). The binding of IGF-I to IGF-IR leads to the activation of phosphatidylinositol 3-kinase (PI3K). Activated PI3K stimulates the production of phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] and phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3]. The PH domain of AKT (protein kinase B, PKB) (v-AKT murine thymoma viral oncogene homolog) binds to PI(4,5)P2 and PI(3,4,5)P3, followed by phosphorylation of the Thr308 and Ser473 regulatory sites. Tuberous sclerosis complex 1 (TSC1) and TSC2 are upstream regulators of mammalian target of rapamycin (mTOR) and downstream effectors of the PI3K/AKT signaling pathway. The activation of AKT suppresses the TSC1/TSC2 heterodimer, which is an upstream regulator of mTOR. Dysregulated IGF-I/PI3K/AKT/mTOR signaling has been shown to be associated with autism spectrum disorders (ASDs). In this review, we discuss the emerging evidence for a functional relationship between the IGF-I/PI3K/AKT/mTOR pathway and ASDs, as well as a possible role of this signaling pathway in the diagnosis and treatment of ASDs.

Treadmill exercise improves short-term memory by enhancing neurogenesis in amyloid beta-induced Alzheimer disease rats

Alzheimer's disease is one of the most devastating neurodegenerative disorders, and this disease is characterized by severe memory impairment and decline of cognition. Hippocampal neurons are vulnerable to injury induced by Alzheimer's disease. Physical exercise is known to promote cell survival and functional recovery after brain injuries. In the present study, we investigated the effects of treadmill exercise on short-term memory in relation with neurogenesis in the rats with amyloid β25-35 (Aβ25-35)-induced Alzheimer's disease. The rat model of Alzheimer's disease was induced by the intracerebroventricular (ICV) injection of Aβ25-35, using a stereotaxic instrument. The rats in the exercise group were forced to run on a treadmill for 30 min once daily for 4 consecutive weeks, starting 2 days after Aβ25-35 injection. Presently, short-term memory was deteriorated and apical dendritic length in the hippocampus was shortened in the hippocampus by Aβ25-35 injection. In contrast, treadmill exercise alleviated memory impairment and increased apical dendritic length in the Aβ25-35-injected rats. Neurogenesis and brain-derived neurotorphic factor (BDNF) and tyrosine kinase B (trkB) in the hippocampal dentate gyrus were decreased by Aβ25-35 injection. Treadmill exercise increased neurogenesis and expressions of BDNF and trkB expressions. The present study shows that treadmill exercise may provide therapeutic value for the alleviating symptoms of Alzheimer's disease.

Treadmill exercise enhances NMDA receptor expression in schizophrenia mice

Schizophrenia is a serious psychiatric disorder with several symptoms including cognitive dysfunction. Although the causes of schizophrenia are still unclear, there is a strong suspicion that the abnormality in N-methyl-D-aspartate (NMDA) receptor may contribute to schizophrenia symptoms. In the present study, the effect of treadmill exercise on the NMDA receptor expression was evaluated using MK-801-induced schizophrenia mice. Immunohistochemistry for expressions of NMDA receptor tyrosine hydroxylase (TH) was conducted. Western blot for brain-derived neurotrophic factor (BDNF) was also performed. In the present results, the mice in the MK-801-treated group displayed reduced NMDA receptor expression. Enhanced TH expression and suppressed BDNF expression were also observed in the MK-801-treated mice. Treadmill exercise improved NMDA receptor expression in the MK-801-induced schizophrenia mice. Treadmill exercise also suppressed TH expression and enhanced BDNF expression in the MK-801-induced schizophrenia mice. The present study showed that down-regulation of NMDA receptor demonstrated schizophrenia-like parameters, meanwhile treadmill running improved schizophrenia-related parameters through enhancing NMDA receptor expression.

Treadmill exercise alleviates prenatal noise stress-induced impairment of spatial learning ability through enhancing hippocampal neurogenesis in rat pups

Stress alters brain cell properties and then disturbs cognitive processes, such as learning and memory. In this study, we investigated the effect of postnatal treadmill exercise on hippocampal neurogenesis and spatial learning ability of rat pups following prenatal noise stress. The impact of exercise intensity (mild-intensity exercise vs heavy-intensity exercise) was also compared. The pregnant rats in the stress-applied group were exposed to a 95 dB supersonic machine sound for 1 h once a day from the 15th day after mating until delivery. After birth, the rat pups in the exercise groups were made to run on a treadmill for 30 min once a day for 7 consecutive days, starting 4 weeks after birth. The spatial learning ability was tested using radial-arm maze task and hippocampal neurogenesis was determined by 5-bromo-2′-deoxyuridine (BrdU) immunohistochemistry. The rat pups born from the stress-applied maternal rats spent more time for the seeking of water and showed higher number of error in the radial-arm maze task compared to the control group. These rat pups showed suppressed neurogenesis in the hippocampus. In contrast, the rat pups performed postnatal treadmill exercise saved time for seeking of water and showed lower number of error compared to the stress-applied group. Postnatal treadmill exercise also enhanced neurogenesis in the hippocampus. The mild-intensity exercise showed more potent impact compared to the heavy-intensity exercise. The present results reveal that postnatal treadmill exercise lessens prenatal stress-induced deterioration of brain function in offspring.

Treadmill exercise ameliorates impairment of spatial learning ability through enhancing dopamine expression in hypoxic ischemia brain injury in neonatal rats

Substantia nigra and striatum are vulnerable to hypoxic ischemia brain injury. Physical exercise promotes cell survival and functional recovery after brain injury. However, the effects of treadmill exercise on nigro-striatal dopaminergic neuronal loss induced by hypoxic ischemia brain injury in neonatal stage are largely unknown. We determined the effects of treadmill exercise on survival of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum after hypoxic ischemia brain injury. On postnatal 7 day, left common carotid artery of the neonatal rats ligated for two hours and the neonatal rats were exposed to hypoxia conditions for one hour. The rat pups in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 12 weeks, starting 22 days after induction of hypoxic ischemia brain injury. Spatial learning ability in rat pups was determined by Morris water maze test after last treadmill exercise. The viability of dopamine neurons in the substantia nigra and dopamine fibers in the striatum were analyzed using immunohistochemistry. In this study, hypoxic ischemia injury caused loss of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum. Induction of hypoxic ischemia deteriorated spatial learning ability. Treadmill exercise ameliorated nigro-striatal dopaminergic neuronal loss, resulting in the improvement of spatial learning ability. The present study suggests the possibility that treadmill exercise in early adolescent period may provide a useful strategy for the recovery after neonatal hypoxic ischemia brain injury.