Treadmill exercise inhibits traumatic brain injury-induced hippocampal apoptosis

Protective effects of physical exercise on MDMA-induced cognitive and mitochondrial impairment

Debate continues about the effect of 3, 4-methylenedioxymethamphetamine (MDMA) on cognitive and mitochondrial function through the CNS. It has been shown that physical exercise has an important protective effect on cellular damage and death. Therefore, we investigated the effect of physical exercise on MDMA-induced impairments of spatial learning and memory as well as MDMA effects on brain mitochondrial function in rats. Male wistar rats underwent short-term (2 weeks) or long-term (4 weeks) treadmill exercise. After completion of exercise duration, acquisition and retention of spatial memory were evaluated by Morris water maze (MWM) test. Rats were intraperitoneally (I.P) injected with MDMA (5, 10, and 15mg/kg) 30min before the first training trial in 4 training days of MWM. Different parameters of brain mitochondrial function were measured including the level of ROS production, mitochondrial membrane potential (MMP), mitochondrial swelling, mitochondrial outermembrane damage, the amount of cytochrome c release from the mitochondria, and ADP/ATP ratio. MDMA damaged the spatial learning and memory in a dose-dependent manner. Brain mitochondria isolated from the rats treated with MDMA showed significant increase in ROS formation, collapse of MMP, mitochondrial swelling, and outer membrane damage, cytochrome c release from the mitochondria, and finally increased ADP/ATP ratio. This study also found that physical exercise significantly decreased the MDMA-induced impairments of spatial learning and memory and also mitochondrial dysfunction. The results indicated that MDMA-induced neurotoxicity leads to brain mitochondrial dysfunction and subsequent oxidative stress is followed by cognitive impairments. However, physical exercise could reduce these deleterious effects of MDMA through protective effects on brain mitochondrial function.

Etifoxine improves sensorimotor deficits and reduces glial activation, neuronal degeneration, and neuroinflammation in a rat model of traumatic brain injury

Background

Traumatic brain injury (TBI) results in important neurological impairments which occur through a cascade of deleterious physiological events over time. There are currently no effective treatments to prevent these consequences. TBI is followed not only by an inflammatory response but also by a profound reorganization of the GABAergic system and a dysregulation of translocator protein 18 kDa (TSPO). Etifoxine is an anxiolytic compound that belongs to the benzoxazine family. It potentiates GABAergic neurotransmission, either through a positive allosteric effect or indirectly, involving the activation of TSPO that leads to an increase in neurosteroids synthesis. In several models of peripheral nerve injury, etifoxine has been demonstrated to display potent regenerative and anti-inflammatory properties and to promote functional recovery. Prior study also showed etifoxine efficacy in reducing brain edema in rats. In light of these positive results, we used a rat model of TBI to explore etifoxine treatment effects in a central nervous system injury, from functional outcomes to the underlying mechanisms.

Methods

Male Sprague-Dawley rats received contusion (n = 18) or sham (n = 19) injuries centered laterally to bregma over the left sensorimotor cortex. They were treated with etifoxine (50 mg/kg, i.p.) or its vehicle 30 min following injury and every day during 7 days. Rats underwent behavioral testing to assess sensorimotor function. In another experiment, injured rats (n = 10) or sham rats (n = 10) received etifoxine (EFX) (50 mg/kg, i.p.) or its vehicle 30 min post-surgery. Brains were then dissected for analysis of neuroinflammation markers, glial activation, and neuronal degeneration.

Results

Brain-injured rats exhibited significant sensorimotor function deficits compared to sham-injured rats in the bilateral tactile adhesive removal test, the beam walking test, and the limb-use asymmetry test. After 2 days of etifoxine treatment, behavioral impairments were significantly reduced. Etifoxine treatment reduced pro-inflammatory cytokines levels without affecting anti-inflammatory cytokines levels in injured rats, reduced macrophages and glial activation, and reduced neuronal degeneration.

Conclusions

Our results showed that post-injury treatment with etifoxine improved functional recovery and reduced neuroinflammation in a rat model of TBI. These findings suggest that etifoxine may have a therapeutic potential in the treatment of TBI.

Neuroprotective Effects of Bone Marrow Stromal Cell Transplantation in Combination With Treadmill Exercise Following Traumatic Brain Injury

Purpose:

Traumatic brain injury (TBI) causes cognitive impairments, motor deficits, and neuropsychiatric/behavioral deficits problems. Transplantation of bone marrow stromal cells (BMSCs) facilitates functional recovery from brain insults. Treadmill exercise increases neurogenesis and inhibits apoptosis. In this study, we investigated the effects of BMSC transplantation in combination with treadmill exercise on memory function, by evaluating its effect on neurogenesis and apoptosis in the hippocampus following TBI.

Methods:

TBI was induced using an electromagnetic-controlled cortical impact device. BMSCs were transplanted into both sides of traumatic scar region 1 week after TBI induction. One week after transplantation of BMSCs, the rats in the exercise groups were trained to run on a treadmill for 30 minutes once daily for 28 days. Step-down avoidance task and radial 8-arm maze test were conducted. Levels of 5-bromo-2ʹ-deoxyuridine and caspase-3 were evaluated using immunohistochemistry. Western blot was used to evaluate the expression of brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), total-extracellular signal-regulated kinase 1 and 2 (t-ERK1/2), phosphorylated-ERK1/2 (p-ERK1/2), Bcl-2, and Bax.

Results:

TBI deteriorated memory function, suppressed neurogenesis, and accelerated apoptosis in the hippocampus. Treadmill exercise and BMSC transplantation independently improved memory function by increasing neurogenesis with suppression of apoptosis through the BDNF-ERK pathway in the TBI-induced rats. Combination of BMSC transplantation with treadmill exercise showed additional enhancement of neurogenesis and suppression of apoptosis in the hippocampus.

Conclusions:

The present study shows that treadmill exercise may aid the therapeutic effect of BMSC transplantation on TBI in rats.

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.

The Impact of Previous Physical Training on Redox Signaling after Traumatic Brain Injury in Rats: A Behavioral and Neurochemical Approach

Throughout the world, traumatic brain injury (TBI) is one of the major causes of disability, which can include deficits in motor function and memory, as well as acquired epilepsy. Although some studies have shown the beneficial effects of physical exercise after TBI, the prophylactic effects are poorly understood. In the current study, we demonstrated that TBI induced by fluid percussion injury (FPI) in adult male Wistar rats caused early motor impairment (24 h), learning deficit (15 days), spontaneous epileptiform events (SEE), and hilar cell loss in the hippocampus (35 days) after TBI. The hippocampal alterations in the redox status, which were characterized by dichlorofluorescein diacetate oxidation and superoxide dismutase (SOD) activity inhibition, led to the impairment of protein function (Na(+), K(+)-adenosine triphosphatase [ATPase] activity inhibition) and glutamate uptake inhibition 24 h after neuronal injury. The molecular adaptations elicited by previous swim training protected against the glutamate uptake inhibition, oxidative stress, and inhibition of selected targets for free radicals (e.g., Na(+), K(+)-ATPase) 24 h after neuronal injury. Our data indicate that this protocol of exercise protected against FPI-induced motor impairment, learning deficits, and SEE. In addition, the enhancement of the hippocampal phosphorylated nuclear factor erythroid 2-related factor (P-Nrf2)/Nrf2, heat shock protein 70, and brain-derived neurotrophic factor immune content in the trained injured rats suggests that protein expression modulation associated with an antioxidant defense elicited by previous physical exercise can prevent toxicity induced by TBI, which is characterized by cell loss in the dentate gyrus hilus at 35 days after TBI. Therefore, this report suggests that previous physical exercise can decrease lesion progression in this model of brain damage.

Delayed restraint procedure enhances cognitive recovery of spatial function after fimbria-fornix transection

PURPOSE

To i) evaluate the effect of a restraint procedure (7 days, 2 h/day) on place learning after fimbria-fornix transection (FF), ii) investigate effects of early vs. late administration of restraint, and iii) establish effects of the restraint procedure on expression of brain derived neurotrophic factor (BDNF) in prefrontal cortex and hippocampus.

METHODS

Fifty rats subjected to FF or sham surgery and divided into groups exposed to restraint immediately (early restraint) or 21 days (late restraint) after surgery were trained to acquire an allocentric place learning task. In parallel, 29 animals were subjected to FF or sham surgery and an identical restraint procedure in order to measure concentrations of BDNF and corticosterone.

RESULTS

The performance of the sham operated rats was positively affected by the late restraint. In FF-lesioned animals, the late restraint significantly improved task performance compared to the lesioned group with no restraint, while the early restraint was associated with a negative impact on task acquisition. Biochemical analysis after restraint procedure revealed a lesion-induced upregulation of BDNF in FF animals.

CONCLUSIONS

The improved task performance of lesioned animals suggests a therapeutic effect of this manipulation, independent of BDNF. This effect is sensitive to the temporal administration of treatment.

The Effects of Exercise on Cognitive Recovery after Acquired Brain Injury in Animal Models: A Systematic Review

The objective of the present paper is to review the current status of exercise as a tool to promote cognitive rehabilitation after acquired brain injury (ABI) in animal model-based research. Searches were conducted on the PubMed, Scopus, and psycINFO databases in February 2014. Search strings used were: exercise (and) animal model (or) rodent (or) rat (and) traumatic brain injury (or) cerebral ischemia (or) brain irradiation. Studies were selected if they were (1) in English, (2) used adult animals subjected to acquired brain injury, (3) used exercise as an intervention tool after inflicted injury, (4) used exercise paradigms demanding movement of all extremities, (5) had exercise intervention effects that could be distinguished from other potential intervention effects, and (6) contained at least one measure of cognitive and/or emotional function. Out of 2308 hits, 22 publications fulfilled the criteria. The studies were examined relative to cognitive effects associated with three themes: exercise type (forced or voluntary), timing of exercise (early or late), and dose-related factors (intensity, duration, etc.). The studies indicate that exercise in many cases can promote cognitive recovery after brain injury. However, the optimal parameters to ensure cognitive rehabilitation efficacy still elude us, due to considerable methodological variations between studies.

Exercise Regulation of Cognitive Function and Neuroplasticity in the Healthy and Diseased Brain

Regular exercise broadly enhances physical and mental health throughout the lifespan. Animal models have provided us with the tools to gain a better understanding of the underlying biochemical, physiological, and morphological mechanisms through which exercise exerts its beneficial cognitive effects. One brain region in particular, the hippocampus, is especially responsive to exercise. It is critically involved in learning and memory and is one of two regions in the mammalian brain that continues to generate new neurons throughout life. Exercise prevents the decline of the hippocampus from aging and ameliorates many neurodegenerative diseases, in part by increasing adult hippocampal neurogenesis but also by activating a multitude of molecular mechanisms that promote brain health. In this chapter, we first describe some rodent models used to study effects of exercise on the brain. Then we review the rodent work focusing on the mechanisms behind which exercise improves cognition and brain health in both the normal and the diseased brain, with emphasis on the hippocampus.

Voluntary Exercise Preconditioning Activates Multiple Antiapoptotic Mechanisms and Improves Neurological Recovery after Experimental Traumatic Brain Injury

Physical activity can attenuate neuronal loss, reduce neuroinflammation, and facilitate recovery after brain injury. However, little is known about the mechanisms of exercise-induced neuroprotection after traumatic brain injury (TBI) or its modulation of post-traumatic neuronal cell death. Voluntary exercise, using a running wheel, was conducted for 4 weeks immediately preceding (preconditioning) moderate-level controlled cortical impact (CCI), a well-established experimental TBI model in mice. Compared to nonexercised controls, exercise preconditioning (pre-exercise) improved recovery of sensorimotor performance in the beam walk task, as well as cognitive/affective functions in the Morris water maze, novel object recognition, and tail-suspension tests. Further, pre-exercise reduced lesion size, attenuated neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex. In addition, exercise preconditioning activated the brain-derived neurotrophic factor pathway before trauma and amplified the injury-dependent increase in heat shock protein 70 expression, thus attenuating key apoptotic pathways. The latter include reduction in CCI-induced up-regulation of proapoptotic B-cell lymphoma 2 (Bcl-2)-homology 3-only Bcl-2 family molecules (Bid, Puma), decreased mitochondria permeabilization with attenuated release of cytochrome c and apoptosis-inducing factor (AIF), reduced AIF translocation to the nucleus, and attenuated caspase activation. Given these neuroprotective actions, voluntary physical exercise may serve to limit the consequences of TBI.

Neuroprotective roles of pituitary adenylate cyclase-activating polypeptide in neurodegenerative diseases

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic bioactive peptide that was first isolated from an ovine hypothalamus in 1989. PACAP belongs to the secretin/glucagon/vasoactive intestinal polypeptide (VIP) superfamily. PACAP is widely distributed in the central and peripheral nervous systems and acts as a neurotransmitter, neuromodulator, and neurotrophic factor via three major receptors (PAC1, VPAC1, and VPAC2). Recent studies have shown a neuroprotective role of PACAP using in vitro and in vivo models. In this review, we briefly summarize the current findings on the neurotrophic and neuroprotective effects of PACAP in different brain injury models, such as cerebral ischemia, Parkinson’s disease (PD), and Alzheimer’s disease (AD). This review will provide information for the future development of therapeutic strategies in treatment of these neurodegenerative diseases. [BMB Reports 2014; 47(7): 369-375]

Aerobic exercise alleviates ischemia-induced memory impairment by enhancing cell proliferation and suppressing neuronal apoptosis in hippocampus

PURPOSE

Neurogenic lower urinary tract dysfunction (NLUTD) is a possible consequence of several neurological disorders. NLUTD may produce debilitating symptoms and serious complications, such as chronic renal failure, and recurrent urinary tract infections. Many animal studies of NLUTD symptoms have focused on animal models of cerebral ischemia. In the present study, we investigated the effects of treadmill exercise on memory function and its relation to cell proliferation and apoptosis in the hippocampus, following transient global ischemia in gerbils.

METHODS

To induce transient global ischemia in gerbil, both common carotid arteries were occluded for 5 minutes. Gerbils in the exercise groups were forced to run on a treadmill exercise for 30 minutes once a day for 2 weeks. Step-down avoidance task and Y maze task were performed. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-staining, immunohistochemistry for 5-bromo-2'-deoxyridine, doublecortin, caspase-3, and Western blot for brain-derived neurotrophic factor (BDNF), Bax, Bcl-2, cytochrome c, caspase-3 were conducted.

RESULTS

Ischemia caused memory impairment with an increase of cell proliferation, BDNF expression, and apoptosis in the hippocampus. Treadmill exercise improved memory function with further increase of cell proliferation and BDNF expression and a decrease of apoptosis.

CONCLUSIONS

The animal model that we have developed and our assessment of the relation between exercise and brain function can be useful tools for future investigations of NLUTD symptoms associated with stroke, particularly ischemic stroke. The present study suggests that treadmill exercise promoted the recovery of brain function after cerebral ischemia.

Anti-Apoptotic Signal Transduction Mechanism of Electroacupuncture in Acute Spinal Cord Injury

Spinal cord injury (SCI) can be caused by a variety of pathogenic factors. In China, acupuncture is widely used to treat SCI. We previously found that acupuncture can reduce apoptosis and promote repair after SCI. However, the antiapoptotic mechanisms by which acupuncture exerts its effects on SCI remain unclear. Our aim was to investigate the role of the PI3K/Akt and extracellular signal-regulated kinases (ERK)1/2 signalling pathways in acupuncture treatment of acute SCI. Eighty pure-bred New Zealand rabbits were randomly divided into the following five groups (n=16 per group): control; model; elongated needle electroacupuncture (EA); EA+LY294002; and EA+PD98059. We established a spinal cord contusion model of SCI in all experimental groups except controls, in which only a laminectomy was performed. After SCI, three of the groups received EA once daily for 3 days. One hour before SCI, the two drug groups received LY294002 (Akt inhibitor; 10 μg, 20 μL) or PD98059 (ERK inhibitor; 3 μg, 20 μL) via intrathecal injection. At 48 h after SCI, animals were killed and spinal cord tissue samples were collected for transferase dUTP nick end labelling (TUNEL) assays, immunohistochemistry and western blot assays. EA significantly increased p-Akt and p-ERK1/2 expression, reduced cytochrome c and caspase-3 expression and inhibited neuronal apoptosis in the injured spinal cord segment. The opposite effects were seen after using Akt and ERK inhibitors. Acupuncture promotes the repair of SCI, possibly by activation of the PI3K/Akt and ERK1/2 signalling pathways and by inhibition of the mitochondrial apoptotic pathway.

Improved cognitive performance following aerobic exercise training in people with traumatic brain injury

OBJECTIVE

To examine cognitive function in individuals with traumatic brain injury (TBI) prior to and after participation in an aerobic exercise training program.

DESIGN

Pre-post intervention study.

SETTING

Medical research center.

PARTICIPANTS

Volunteer sample of individuals (N=7) (age, 33.3±7.9y) with chronic nonpenetrating TBI (injury severity: 3=mild, 4=moderate; time since most current injury: 4.0±5.5y) who were ambulatory.

INTERVENTION

Twelve weeks of supervised vigorous aerobic exercise training performed 3 times a week for 30 minutes on a treadmill.

MAIN OUTCOME MEASURES

Cognitive function was assessed using the Trail Making Test Part A (TMT-A), Trail Making Test Part B (TMT-B), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Sleep quality and depression were measured with the Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory, version 2 (BDI-II). Indices of cardiorespiratory fitness were used to examine the relation between improvements in cognitive function and cardiorespiratory fitness.

RESULTS

After training, improvements in cognitive function were observed with greater scores on the TMT-A (10.3±6.8; P=.007), TMT-B (9.6±7.0; P=.011), and RBANS total scale (13.3±9.3; P=.009). No changes were observed in measures of the PSQI and BDI-II. The magnitude of cognitive improvements was also strongly related to the gains in cardiorespiratory fitness.

CONCLUSIONS

These findings suggest that vigorous aerobic exercise training may improve specific aspects of cognitive function in individuals with TBI and cardiorespiratory fitness gains may be a determinant of these improvements.

Postnatal treadmill exercise alleviates short-term memory impairment by enhancing cell proliferation and suppressing apoptosis in the hippocampus of rat pups born to diabetic rats

During pregnancy, diabetes mellitus exerts detrimental effects on the development of the fetus, especially the central nervous system. In the current study, we evaluated the effects of postnatal treadmill exercise on short-term memory in relation with cell proliferation and apoptosis in the hippocampus of rat pups born to streptozotocin (STZ)-induced diabetic maternal rats. Adult female rats were mated with male rats for 24 h. Two weeks after mating, the pregnant female rats were divided into two groups: control group and STZ injection group. The pregnant rats in the STZ injection group were administered 40 mg/kg of STZ intraperitoneally. After birth, the rat pups were divided into the following four groups: control group, control with postnatal exercise group, maternal STZ-injection group, and maternal STZ-injection with postnatal exercise group. The rat pups in the postnatal exercise groups were made to run on a treadmill for 30 min once a day, 5 times per week for 2 weeks beginning 4 weeks after birth. The rat pups born to diabetic rats were shown to have short-term memory impairment with suppressed cell proliferation and increased apoptosis in the hippocampal dentate gyrus. Postnatal treadmill exercise alleviated short-term memory impairment by increased cell proliferation and suppressed apoptosis in the rat pups born to diabetic rats. These findings indicate that postnatal treadmill exercise may be used as a valuable strategy to ameliorate neurodevelopmental problems in children born to diabetics.

Treadmill exercise inhibits hippocampal apoptosis through enhancing N-methyl-D-aspartate receptor expression in the MK-801-induced schizophrenic mice

Schizophrenia is a severe mental disorder characterized by abnormal mental functioning and disruptive behaviors. Abnormal expression of N-methyl-D-aspartate (NMDA) receptor, one of the glutamate receptor subtypes, has also been suggested to contribute to the symptoms of schizophrenia. The effect of treadmill exercise on schizophrenia-induced apoptosis in relation with NMDA receptor has not been evaluated. In the present study, we investigated the effect of treadmill exercise on neuronal apoptosis in the hippocampus using MK-801-induced schizophrenic mice. MK-801 was intraperitoneally injected once a day for 2 weeks. The mice in the exercise groups were forced to run on a treadmill exercise for 60 min, once a day for 2 weeks. In the present results, repeated injection of the NMDA receptor antagonist MK-801 reduced expression of NMDA receptor in hippocampal CA2-3 regions. MK-801 injection increased casapse-3 expression and enhanced cytochrome c release in the hippocampus. The ratio of Bax to Bcl-2 was higher in the MK-801-induced schizophrenia mice than the normal mice. In contrast, treadmill exercise enhanced NMDA receptor expression, suppressed caspae-3 activation and cytochrome c release, and inhibited the ratio of Bax to Bcl-2. Based on present finding, we concluded that NMDA receptor hypofunctioning induced neuronal apoptosis in MK-801-induced schizophrenic mice. Treadmill exercise suppressed neuronal apoptosis through enhancing NMDA receptor expression in schizophrenic mice.

Influence of mild traumatic brain injury during pediatric stage on short-term memory and hippocampal apoptosis in adult rats

Traumatic brain injury (TBI) is a leading cause of neurological deficit in the brain, which induces short- and long-term brain damage, cognitive impairment with/without structural alteration, motor deficits, emotional problems, and death both in children and adults. In the present study, we evaluated whether mild TBI in childhood causes persisting memory impairment until adulthood. Moreover, we investigated the influence of mild TBI on memory impairment in relation with hippocampal apoptosis. For this, step-down avoidance task, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and immunohistochemistry for caspase-3 were performed. Male Sprague-Dawley rats were used in the experiments. The animals were randomly divided into two groups: sham-operation group and TBI-induction group. The mild TBI model was created with an electromagnetic contusion device activated at a velocity of 3.0 m/sec. The results showed that mild TBI during the pediatric stage significantly decreased memory retention. The numbers of TUNEL-positive and caspase-3-positive cells were increased in the TBI-induction group compared to those in the sham-operation group. Defective memory retention and apoptosis sustained up to the adult stage. The present results shows that mild TBI induces long-lasting cognitive impairment from pediatric to adult stages in rats through the high level of apoptosis. The finding of this study suggests that children with mild TBI may need intensive treatments for the reduction of long-lasting cognitive impairment by secondary neuronal damage.

Multimodal treatment of distal sensorimotor polyneuropathy in diabetic patients: a randomized clinical trial

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of the application of analyzing treadmill, muscle strengthening, and balance training compared with a standard care intervention in patients with diabetic neuropathy.

METHODS

Twenty-seven patients, 63% female (mean ± standard deviations age, 72 ±9 years), with diabetic neuropathy randomly assigned to receive a multimodal manual treatment approach including analyzing treadmill with feedback focused, isokinetic dynamometric muscle strengthening, and balance retraining on dynamic balance platform or a standard care intervention for activities targeted to improve endurance, manual exercises of muscle strengthening, stretching exercises, gait, and balance exercises (5 weekly over 4 weeks). This study was designed as a double-blind, randomized clinical trial. Measures were assessed at pretreatment, 4 weeks posttreatment, and 2-month follow-up.

RESULTS

No important baseline differences were observed between groups. At the end of the treatment period, the experimental group showed a significant increase in gait endurance in a 6-minute walk test, 65.6 m (F[2.0] = 9.636; P = .001). In addition, the 6-minute walk test increased after the intervention, and an even greater difference was found at follow-up (P = .005) for the standard care group. The Functional Independence Measure in both groups increased (P < .01) and continued until the follow-up in the standard care group (P = .003).

CONCLUSIONS

The results suggest that the experimental rehabilitation program showed positive effects on the gait endurance after 4 weeks of treatment, whereas it did not produce significant improvements of the gait speed. Both the treatments produced significant improvement of functionalities of the patient.

Treadmill exercise ameliorates symptoms of attention deficit/hyperactivity disorder through reducing Purkinje cell loss and astrocytic reaction in spontaneous hypertensive rats

Attention deficit/hyperactivity disorder (ADHD) is a neurobehavioral disorder of cognition. We investigated the effects of treadmill exercise on Purkinje cell and astrocytic reaction in the cerebellum of the ADHD rat. Adult male spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKYR) weighing 210± 10 g were used. The animals were randomly divided into four groups (n= 15): control group, ADHD group, ADHD and methylphenidate (MPH)-treated group, ADHD and treadmill exercise group. The rats in the MPH-treated group as a positive control received 1 mg/kg MPH orally once a day for 28 consecutive days. The rats in the treadmill exercise group were made to run on a treadmill for 30 min once a day for 28 days. Motor coordination and balance were determined by vertical pole test. Immunohistochemistry for the expression of calbindinD-28 and glial fibrillary acidic protein (GFAP) in the cerebellar vermis and Western blot for GFAP, Bax, and Bcl-2 were conducted. In the present results, ADHD significantly decreased balance and the number of calbindin-positive cells, while GFAP expression and Bax/Bcl-2 ratio in the cerebellum were significantly increased in the ADHD group compared to the control group (P< 0.05, respectively). In contrast, treadmill exercise and MPH alleviated the ADHD-induced the decrease of balance and the number of calbindine-positive cells, and the increase of GFAP expression and Bax/Bcl-2 ratio in the cerebellum (P< 0.05, respectively). Therefore, the present results suggested that treadmill exercise might exert ameliorating effect on ADHD through reduction of Purkinje cell loss and astrocytic reaction in the cerebellum.

Treadmill exercise reduces spinal cord injury-induced apoptosis by activating the PI3K/Akt pathway in rats

Apoptosis occurring secondary to spinal cord injury (SCI) causes further neural damage and functional loss. In this study, a rat model was used to investigate the effect of treadmill exercise on SCI-induced apoptosis and expression of neurotrophic factors. To produce SCI, a contusion injury (10 g × 25 mm) was applied subsequent to laminectomy at the T9–T10 level. Following SCI, treadmill exercise was performed for six weeks. Hindlimb motor function was evaluated with a grid-walking test. The expression of neurotrophic factors and the level of apoptosis at the site of SCI were determined by western blotting. SCI reduced hindlimb motor function and suppressed expression of neurotrophin (NT)-3 and insulin-like growth factor (IGF)-1. Expression of phosphatidylinositol 3-kinase (PI3K), the ratio of phosphorylated Akt to Akt (pAkt/Akt) and the ratio of B-cell lymphoma 2 (Bcl-2) to Bax (Bcl-2/Bax) were decreased, and cleaved caspase-3 expression was increased by SCI. Treadmill exercise enhanced hindlimb motor function and increased expression of nerve growth factor (NGF), NT-3 and IGF-1 in the SCI rats. Treadmill exercise increased PI3K expression, the pAkt/Akt and the Bcl-2/Bax ratios, and suppressed cleaved caspase-3 expression in the injured spinal cord. This study demonstrated that treadmill exercise promotes the recovery of motor function by suppressing apoptosis in the injured spinal cord. The beneficial effect of exercise may be attributed to the increase in expression of neurotrophic factors via activation of the PI3K/Akt pathway.

The effect of different intensities of treadmill exercise on cognitive function deficit following a severe controlled cortical impact in rats

Exercise has been proposed for the treatment of traumatic brain injury (TBI). However, the proper intensity of exercise in the early phase following a severe TBI is largely unknown. To compare two different treadmill exercise intensities on the cognitive function following a severe TBI in its early phase, rats experienced a controlled cortical impact (CCI) and were forced to treadmill exercise for 14 days. The results revealed that the rats in the low intensity exercise group had a shorter latency to locate a platform and a significantly better improvement in spatial memory in the Morris water maze (MWM) compared to the control group (p < 0.05). The high intensity exercise group showed a longer latency and a mild improvement in spatial memory compared to the control group rats in the MWM; however, this difference was not statistically significant (p > 0.05). The brain-derived neurotrophic factor (BDNF) and p-CREB protein levels in the contralateral hippocampus were increased significantly in the low intensity exercise group. Our results suggest that 2 weeks of low intensity of treadmill exercise is beneficial for improving cognitive function and increasing hippocampal BDNF expression after a severe TBI in its early phase.

Exogenous administration of PACAP alleviates traumatic brain injury in rats through a mechanism involving the TLR4/MyD88/NF-κB pathway

Pituitary adenylate cyclase-activating polypeptide (PACAP) is effective in reducing axonal damage associated with traumatic brain injury (TBI), and has immunomodulatory properties. Toll-like receptor 4 (TLR4) is an important mediator of the innate immune response. It significantly contributes to neuroinflammation induced by brain injury. However, it remains unknown whether exogenous PACAP can modulate TBI through the TLR4/adapter protein myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway. In this study, we investigated the potential neuroprotective mechanisms of PACAP pretreatment in a weight-drop model of TBI. PACAP38 was microinjected intracerebroventricularly before TBI. Brain samples were extracted from the pericontusional area in the cortex and hippocampus. We found that TBI induced significant upregulation of TLR4, with peak expression occurring 24 h post-trauma, and that pretreatment with PACAP significantly improved motor and cognitive dysfunction, attenuated neuronal apoptosis, and decreased brain edema. Pretreatment with PACAP inhibited upregulation of TLR4 and its downstream signaling molecules MyD88, p-IκB, and NF-κB, and suppressed increases in the levels of the downstream inflammatory agents interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), in the brain tissue around the injured cortex and in the hippocampus. Administration of PACAP both in vitro and in vivo attenuated the ability of the TLR4 agonist lipopolysaccharide (LPS) to increase TLR4 protein levels. Therefore, PACAP exerts a neuroprotective effect in this rat model of TBI, by inhibiting a secondary inflammatory response mediated by the TLR4/MyD88/NF-κB signaling pathway in microglia and neurons, thereby reducing neuronal death and improving the outcome following TBI.

Long-term consequences of developmental alcohol exposure on brain structure and function: therapeutic benefits of physical activity

Developmental alcohol exposure both early in life and during adolescence can have a devastating impact on normal brain structure and functioning, leading to behavioral and cognitive impairments that persist throughout the lifespan. This review discusses human work as well as animal models used to investigate the effect of alcohol exposure at various time points during development, as well as specific behavioral and neuroanatomical deficits caused by alcohol exposure. Further, cellular and molecular mediators contributing to these alcohol-induced changes are examined, such as neurotrophic factors and apoptotic markers. Next, this review seeks to support the use of aerobic exercise as a potential therapeutic intervention for alcohol-related impairments. To date, few interventions, behavioral or pharmacological, have been proven effective in mitigating some alcohol-related deficits. Exercise is a simple therapy that can be used across species and also across socioeconomic status. It has a profoundly positive influence on many measures of learning and neuroplasticity; in particular, those measures damaged by alcohol exposure. This review discusses current evidence that exercise may mitigate damage caused by developmental alcohol exposure and is a promising therapeutic target for future research and intervention strategies.

Early postinjury exercise reverses memory deficits and retards the progression of closed-head injury in mice

Closed-head injury (CHI) usually involves both physical damage of neurons and neuroinflammation. Although exercise promotes neuronal repair and suppresses neuroinflammation, CHI patients currently often remain resting during the post-traumatic period. This study aimed to investigate whether and how postinjury exercise benefited the brain structure and function in mice after CHI. Closed-head injury immediately caused an elevated neurological severity score, with rapid loss of object recognition memory, followed by progressive location-dependent brain damage (neuronal loss and activation of microglia in the cortex and hippocampus). An early exercise protocol at moderate intensity (starting 2 days postimpact and lasting for 7 or 14 days) effectively restored the object recognition memory and prevented the progressive neuronal loss and activation of microglia. However, if the exercise started 9 days postimpact, it was unable to recover recognition memory deficits. In parallel, early exercise intervention drastically promoted neurite regeneration, while late exercise intervention was much less effective. We also tested the possible involvement of brain-derived neurotrophic factor (BDNF) and mitogen-activated protein kinase phosphatase-1 (MKP-1) in the exercise-induced beneficial effects. Exercise gradually restored the impact-abolished hippocampal expression of BDNF and MPK-1, while oral administration of triptolide (a synthesis inhibitor of MKP-1 and an antagonist of nuclear factor-B) before each bout of exercise blocked the restorative effects of exercise on MKP-1 and recognition memory, as well as the exercise-induced retardation of neuronal loss. Although triptolide treatment alone inhibited activation of microglia and maintained neuronal numbers, it did not recover the injury-hampered recognition memory. Overall, moderate exercise shortly after CHI reversed the deficits in recognition memory and prevented the progression of brain injury.

Treadmill and wheel exercise alleviate lipopolysaccharide-induced short-term memory impairment by enhancing neuronal maturation in rats

Lipopolysaccharide (LPS) is an endotoxin derived from Gram‑negative bacteria, which induces brain inflammation. LPS‑induced brain inflammation deteriorates hippocampus‑dependent cognitive deficits. In the present study, we investigated the effects of forced treadmill exercise and voluntary wheel exercise on short‑term memory in relation to neuronal maturation in LPS‑induced brain inflammation of rats. Brain inflammation in rats was induced by an injection of LPS into the cerebral ventricle. Short‑term memory was evaluated using a step‑down avoidance task. Cell proliferation in the hippocampal dentate gyrus was determined by 5‑bromo‑2'‑deoxyuridine (BrdU), a marker of new cells, immunohistochemistry. Western blot analysis for the determination of doublecortin (DCX), a marker of immature neurons and neuronal nuclear antigen (NeuN), a marker of mature neurons, was performed. In the present study, LPS‑induced brain inflammation impaired short‑term memory by increasing DCX expression and suppressing NeuN expression. These results suggest that LPS‑induced brain inflammation disturbs neuronal maturation. The number of BrdU‑positive cells in the hippocampal dentate gyrus was increased by LPS injection. This increase in the number of BrdU‑positive cells can be ascribed to the increase in the number of of immature neurons following LPS injection. On the other hand, forced treadmill exercise and voluntary wheel exercise improved brain inflammation‑induced short‑term memory impairment by suppressing DCX expression and increasing NeuN expression, enhancing neuronal maturation. Forced treadmill exercise and voluntary wheel exercise showed similar efficacy. From these results, it can be inferred that forced treadmill exercise and voluntary wheel exercise may improve memory function deteriorated by brain inflammation.

Treadmill exercise ameliorates dopaminergic neuronal loss through suppressing microglial activation in Parkinson's disease mice

AIMS

Parkinson's disease is a debilitating neurodegenerative disorder characterized by the gradual loss of dopaminergic neurons. We investigated the effects of treadmill exercise on dopaminergic neuronal loss and microglial activation using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/P)-induced Parkinson's disease mice.

MAIN METHODS

Parkinson's disease was induced in mice by injection of MPTP/P. The mice in the exercise groups were put on a treadmill to run for 30min/day, five times per week for four weeks. Motor balance and coordination was measured using rota-rod test. Expressions of inducible nitric oxide synthase (iNOS) and phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated NH(2)-terminal kinase (p-JNK), phosphorylated p-38 (p-p38), CD200, and CD200 receptor were determined by western blotting. Expressions of tyrosine hydroxylase (TH) and CD11b were evaluated by immunohistochemistry.

KEY FINDINGS

Parkinson's disease mice displayed poor motor balance and coordination with loss of nigrostriatal dopaminergic neurons. iNOS expression was enhanced via up-regulation of phosphorylated mitogen-activated protein kinases (p-MAPKs) signaling, such as p-ERK, p-JNK, and p-p-38 in the Parkinson's disease mice. Microglial activation was also observed in the Parkinson's disease mice, showing increased CD11b expression with suppressed CD200 and CD200 receptor expressions. Treadmill exercise prevented the loss of nigrostriatal dopaminergic neurons, and ameliorated the motor balance and coordination dysfunction in the Parkinson's disease mice. Treadmill exercise suppressed iNOS expression via down-regulation of MAPKs and also inhibited microglial activation in the Parkinson's disease mice.

SIGNIFICANCE

Treadmill exercise prevented dopaminergic neuronal loss by inhibiting brain inflammation through suppression of microglial activation in the Parkinson's disease mice.

Changes in spatial memory and BDNF expression to simultaneous dietary restriction and forced exercise

Previous literature suggests that learning and memory formation can be influenced by diet and exercise. In the current study, we investigated the combined effects of forced swimming exercise (FSE) and every other day fasting (EODF) on spatial memory formation and on the levels of brain-derived neurotrophic factor (BDNF) in the hippocampus of Wistar male rats. The radial arm water maze (RAWM) paradigm was used to assess changes in learning and memory formation, whereas ELISA assay was used to measure BDNF protein levels. The FSE and/or EODF were simultaneously instituted for 6 weeks. Results show that FSE improved learning, short-term as well as long-term memory formation, and significantly increased BDNF protein in the hippocampus (p<0.05). However, EODF had no effect on either spatial learning and memory formation or the levels of hippocamapal BDNF protein (p>0.05). In addition, EODF did not modulate beneficial effect of swimming exercise on cognitive function (p>0.05). Thus exercise enhanced, while EODF did not affect spatial learning and memory formation.

Coupling hippocampal neurogenesis to brain pH through proneurogenic small molecules that regulate proton sensing G protein-coupled receptors

Acidosis, a critical aspect of central nervous system (CNS) pathophysiology and a metabolic corollary of the hypoxic stem cell niche, could be an expedient trigger for hippocampal neurogenesis and brain repair. We recently tracked the function of our isoxazole stem cell-modulator small molecules (Isx) through a chemical biology-target discovery strategy to GPR68, a proton (pH) sensing G protein-coupled receptor with no known function in brain. Isx and GPR68 coregulated neuronal target genes such as Bex1 (brain-enriched X-linked protein-1) in hippocampal neural progenitors (HCN cells), which further amplified GPR68 signaling by producing metabolic acid in response to Isx. To evaluate this proneurogenic small molecule/proton signaling circuit in vivo, we explored GPR68 and BEX1 expression in brain and probed brain function with Isx. We localized proton-sensing GPR68 to radial processes of hippocampal type 1 neural stem cells (NSCs) and, conversely, localized BEX1 to neurons. At the transcriptome level, Isx demonstrated unrivaled proneurogenic activity in primary hippocampal NSC cultures. In vivo, Isx pharmacologically targeted type 1 NSCs, promoting neurogenesis in young mice, depleting the progenitor pool without adversely affecting hippocampal learning and memory function. After traumatic brain injury, cerebral cortical astrocytes abundantly expressed GPR68, suggesting an additional role for proton-GPCR signaling in reactive astrogliosis. Thus, probing a novel proneurogenic synthetic small molecule's mechanism-of-action, candidate target, and pharmacological activity, we identified a new GPR68 regulatory pathway for integrating neural stem and astroglial cell functions with brain pH.

Moderate traumatic brain injury triggers rapid necrotic death of immature neurons in the hippocampus

Traumatic brain injury (TBI) causes cell death predominantly in the cerebral cortex, but there is additional secondary cell death in the hippocampus. We previously found that most of the dying cells in the mouse hippocampus are newborn immature granular neurons in a mouse model of lateral controlled cortical impact (CCI) injury with a moderate level of impact. It is not known how long this selective cell death in the hippocampal dentate gyrus lasts, and how it is induced. Using Fluoro-Jade B and immunohistochemistry, we show that most of the neuron death in the hippocampus occurs within 24 hours after TBI and that cell death continues at low level for at least another 2 weeks in this lateral CCI model. Most of the dying immature granular neurons did not exhibit morphologic characteristics of apoptosis, and only a small subpopulation of the dying cells was positive for apoptotic markers. In contrast, most of the dying cells coexpressed the receptor-interacting protein 1, a marker of necrosis, suggesting that immature neurons mainly died of necrosis. These results indicate that moderate TBI mainly triggers rapid necrotic death of immature neurons in the hippocampus in a mouse CCI model.

Physical exercise ameliorates deficits induced by traumatic brain injury

The extent and depth of traumatic brain injury (TBI) remains a major determining factor together with the type of structural insult and its location, whether mild, moderate or severe, as well as the distribution and magnitude of inflammation and loss of cerebrovascular integrity, and the eventual efficacy of intervention. The influence of exercise intervention in TBI is multiple, ranging from anti-apoptotic effects to the augmentation of neuroplasticity. Physical exercise diminishes cerebral inflammation by elevating factors and agents involved in immunomodulatory function, and buttresses glial cell, cerebrovascular, and blood-brain barrier intactness. It provides unique non-pharmacologic intervention that incorporate different physical activity regimes, whether dynamic or static, endurance or resistance. Physical training regimes ought necessarily to be adapted to the specific demands of diagnosis, type and degree of injury and prognosis for individuals who have suffered TBI.

Potentials of endogenous neural stem cells in cortical repair

In the last few decades great thrust has been put in the area of regenerative neurobiology research to combat brain injuries and neurodegenerative diseases. The recent discovery of neurogenic niches in the adult brain has led researchers to study how to mobilize these cells to orchestrate an endogenous repair mechanism. The brain can minimize injury-induced damage by means of an immediate glial response and by initiating repair mechanisms that involve the generation and mobilization of new neurons to the site of injury where they can integrate into the existing circuit. This review highlights the current status of research in this field. Here, we discuss the changes that take place in the neurogenic milieu following injury. We will focus, in particular, on the cellular and molecular controls that lead to increased proliferation in the Sub ventricular Zone (SVZ) as well as neurogenesis. We will also concentrate on how these cellular and molecular mechanisms influence the migration of new cells to the affected area and their differentiation into neuronal/glial lineage that initiate the repair mechanism. Next, we will discuss some of the different factors that limit/retard the repair process and highlight future lines of research that can help to overcome these limitations. A clear understanding of the underlying molecular mechanisms and physiological changes following brain damage and the subsequent endogenous repair should help us develop better strategies to repair damaged brains.