Spontaneous Wheel Running Research Articles

Spontaneous running wheel exercise during pregnancy prevents later neonatal-anoxia-induced somatic and neurodevelopmental alterations

IntroductionAbout 15–20 % of babies that suffer perinatal asphyxia die and around 25 % of the survivors exhibit permanent neural outcomes. Minimization of this global health problem has been warranted. This study investigated if the offspring of pregnant female rats allowed to spontaneously exercise on running wheels along a 11-day pregnancy period were protected for somatic and neurodevelopmental disturbs that usually follow neonatal anoxia. Methodsspontaneous exercise was applied to female rats which were housed in cages allowing free access to running wheels along a 11-day pregnancy period. Their offspring were submitted to anoxia 24–36 h after birth. Somatic and sensory-motor development of the pups were recorded until postnatal day 21 (P21). Myelin basic protein (MBP)-stained areas of sensory and motor cortices were measured at P21. Neuronal nuclei (NeuN)-immunopositive cells and synapsin-I levels in hippocampal formation were estimated at P21 and P75. Resultsgestational exercise and / or neonatal anoxia increased the weight and the size of the pups. In addition, gestational exercise accelerated somatic and sensory-motor development of the pups and protected them against neonatal-anoxia-induced delay in development. Further, neonatal anoxia reduced MBP stained area in the secondary motor cortex and decreased hippocampal neuronal estimates and synapsin-I levels at P21; gestational exercise prevented these effects. Therefore, spontaneous exercise along pregnancy is a valuable strategy to prevent neonatal-anoxia-induced disturbs in the offspring. Conclusionspontaneous gestational running wheel exercise protects against neonatal anoxia-induced disturbs in the offspring, including (1) physical and neurobehavioral developmental impairments, and (2) hippocampal and cortical changes. Thus, spontaneous exercise during pregnancy may represent a valuable strategy to prevent disturbs which usually follow neonatal anoxia.

Orexinergic neurons contribute to autonomic cardiovascular regulation for locomotor exercise.

While the hypothalamic orexinergic nervous system is established as having a pivotal role in the long-term regulation of various organismic functions, including wakefulness, metabolism and hypertensive states, whether this system contributes to the rapid autonomic cardiovascular regulation during physical activity remains elusive. This study aimed to elucidate the role of the orexinergic nervous system in transmitting volitional motor signals, i.e. central command, to drive somatomotor and sympathetic cardiovascular responses. We first found that this system is activated by voluntary locomotor exercise as evidenced by an increased expression of Fos, a marker of neural activation, in the orexinergic neurons of Sprague-Dawley rats engaged in spontaneous wheel running. Next, using transgenic Orexin-Cre rats for optogenetic manipulation of orexinergic neurons, we found that optogenetic excitation of orexinergic neurons caused sympathoexcitation on a subsecond timescale under anaesthesia. In freely moving conscious rats, this excitatory stimulation rapidly elicited exploration-like behaviours, predominantly locomotor activity, along with pressor and tachycardiac responses. Meanwhile, optogenetic inhibition of orexinergic neurons during spontaneous wheel running immediately suppressed locomotor activities and blood pressure elevation without affecting basal cardiovascular homeostasis. Taken together, these findings demonstrate the essential role of the orexinergic nervous system in the central circuitry that transmits central command signals for locomotor exercise. This study not only offers insights into the brain circuit mechanisms precisely regulating autonomic cardiovascular systems during voluntary exercise but also likely contributes to our understanding of brain mechanisms underlying abnormal cardiovascular adjustments to exercise in pathological conditions, such as hypertension. KEY POINTS: The hypothalamic orexinergic nervous system plays various roles in the long-term regulation of autonomic and endocrine functions, as well as motivated behaviours. We present a novel, rapid role of the orexinergic nervous system, revealing its significance as a crucial substrate in the brain circuit mechanisms that coordinate somatomotor and autonomic cardiovascular controls for locomotor exercise. Our data demonstrate that orexinergic neurons relay volitional motor signals, playing a necessary and sufficient role in the autonomic cardiovascular regulation required for locomotor exercise in rats. The findings contribute to our understanding of how the brain precisely regulates autonomic cardiovascular systems during voluntary exercise, providing insights into the central neural mechanisms that enhance physical performance moment-by-moment during exercise.

Desynchronization between Food Intake and Light Stimulations Induces Uterine Clock Quiescence in Female Mice

BackgroundDysmenorrhea is associated with breakfast skipping in young women, suggesting that fasting in the early active phase disrupts uterine functions. ObjectivesTo investigate the possible involvement of the uterine clock system in fasting-induced uterine dysfunction, we examined core clock gene expressions in the uterus using a 28-h interval-fed mouse model. MethodsYoung female mice (8 wk of age) were divided into 3 groups: group I (ad libitum feeding), group II (time-restricted feeding, initial 4 h of the active period every day), and group III (time-restricted feeding for 8 h with a 28-h cycle). Groups II and III have the same fasting interval of 20 h. After analyzing feeding and wheel running behaviors during 2 wk of dietary restriction, mice were sacrificed at 4-h intervals, and the expression profiles of clock genes in the uterus and liver were examined by qPCR. ResultsThe mice in group I took food mainly during the dark phase and those in group II during the initial 4 h of the dark phase, whereas those in group III delayed feeding time by 4 h per cycle. In all groups, spontaneous wheel running was observed during the dark phase. There was no difference in the quantity of feeding and the amount of running exercise among the 3 groups during the second week. The mRNA expressions of peripheral clock genes, Bmal1, Clock, Per1, Per2, Cry1, Nr1d1, and Dbp and a clock-controlled gene, Fabp1, in the uterus showed rhythmic oscillations with normal sequential expression cascade in groups I and II, whereas their expressions decreased and circadian cycles disappeared in group III. In contrast, liver core clock genes in group III showed clear circadian cycles. ConclusionsFluctuations in the timing of the first food intake impair the uterine clock oscillator system to reduce clock gene expressions and abolish their circadian rhythms.

Simultaneous assessment of spontaneous cage activity and voluntary wheel running in group-housed mice

Small animal models are frequently used to improve our understanding of the molecular and biological signaling pathways underlying the beneficial effects of physical activity and exercise. Unfortunately, when running wheels are employed, mice and rats are often kept single-housed to determine the individual running distance of each animal. However, social isolation can be stressful for rodents, and may alter an individual’s propensity for or response to exercise. For example, increased stress from single housing may significantly affect the results when investigating systemic metabolic responses to exercise. We have combined two already available and well-established systems, a radiotelemetry system and a running wheel, to determine spontaneous cage activity (SCA) as well as voluntary exercise (VE) levels of the individual animal in group-housed rodents. Further, we developed a simple software tool which allows monitoring and analyzing the data. Specifically, the radiotelemetry-system utilizes radio-frequency identification via a small, implanted chip to determine the location of each animal. Since, in addition to the animals’ position, also the location of the running wheel in the cage is known, the conclusion of which animal is exercising can be drawn. The developed software enables a fast and reliable assignment of the VE data to the individual animal and a simple analysis of the data collected. Hence, our combined method may be used to investigate the beneficial effects of physical activity, as well as the impact of therapeutic interventions on animal behavior in group-housed rodents.

Does Succinic Acid Treatment Improve Metabolic Health in a Murine Model of Early Aging?

Aging is associated with a decline in metabolic health, specifically increased body weight, adiposity, mitochondrial dysfunction, and impaired insulin-stimulated glucose transport contributing to greater incidence of type II diabetes, even in early aging. Previously, we have documented that succinic acid (SA) improves mitochondrial function likely through increased mitochondrial biogenesis; however, the effects of SA on age-related metabolic health are unknown. Therefore, we sought to determine the effect of SA treatment on metabolic health in an early aging mouse model. Methods Metabolic health was measured in 43 mice (24 young (YG) vehicle, 19 aged (16 months); aged mice were randomized to vehicle (n=8) or succinic acid (n=11, 0.75 mg/ml in drinking water), respectively). After 6 weeks of treatment, insulin, glucose, and pyruvate tolerance tests were completed, and physical activity (PA), via spontaneous wheel running, was assessed for both the young and aged mice. Body weight (BW), epididymal white adipose tissue (EWAT) and heart mass measurements were obtained to assess possible effects on obesity, adiposity, and heart health. Results The aged mice had significantly increased BW (YG 27 ± 4 vs. Aged 38 ± 3g), heart weight (YG 0.13 ± 0.01 vs. Aged 0.17 ± 0.01 g), and EWAT mass (YG 0.51 ± 0.08 vs. Aged 1.4 ± 0.38 g) (all, p<0.05). Aged also had reduced pyruvate tolerance (YG 25470 ± 1206 vs. Aged 31883 ± 4348 area under the curve, AUC, p<0.05), though glucose (YG 47119 ± 3460 vs. Aged 43979 ± 8750 AUC) and insulin tolerance (YG 15425 ± 4364 vs. Aged 14928 ± 1762 AUC) were not affected by age (both, p>0.05). PA tended to be ~50% lower in the aged (YG 8778 ± 5774 vs. Aged 4132±1523 rev) mice, while aged mice treated with SA increased PA by 48% (6118 ± 2203 rev). SA treatment had no effect on BW (Aged 37.8 ± 2.7 vs. Aged-SA 37.7 ± 3.2 g), EWAT mass (Aged 1.4 ± 0.4 vs. Aged-SA 1.3 ± 0.4g), nor heart mass (Aged 0.17 ± 0.01 vs. Aged-SA 0.19 ± 0.04g) (all, p>0.05). Despite no significant age difference in glucose tolerance, SA treatment seemed to reduce the AUC in the aged animals (Aged 43979 ± 8750 vs. Age-SA 37181 ± 5383 AUC, p= 0.11); however, no such effect for SA was found with insulin or pyruvate tolerance. Conclusion In a murine model of early aging, despite elevated body weight, adiposity, and heart weight, we found no age-associated impact on glucose or insulin tolerance, though the impaired pyruvate tolerance is suggestive of greater gluconeogenesis in this model of early aging. Treatment with SA had no significant effect on body weight or adiposity, but we did find tendencies for improved glucose tolerance and physical activity. Further work is needed to determine if treatment with succinic acid, an FDA-approved compound, might improve metabolic health with aging.

Effects of lifelong spontaneous exercise on the M1/M2 macrophage polarization ratio and gene expression in adipose tissue of super-aged mice.

In the adipose tissue (AT), an increase in the M1 macrophage (M1Ø)/M2 macrophage (M2Ø) polarization ratio can be a risk factor enhancing the inflammatory response during aging, as well as increasing the risk of chronic disease, thereby reducing lifespan, or at least reducing "healthy" lifespan. The purpose of this study was to analyze and compare the AT M1Ø/M2Ø polarization ratio at the final lifespan stage in aged and control animals performing lifelong spontaneous wheel running. Based on flow cytometric analysis, the AT ratio of macrophages revealed M2Ø polarization following lifelong spontaneous exercise (LSE) regardless of age. However, for Icam1 and Tnf, the qPCR analysis showed no difference in gene expressions in young mice; Arg1 expression was higher in Young-EXE (exercising) than in Young-CON (control) mice (p<.0001). In Old-EXE, Icam1 (p<.0001) and Tnf (p<.0001) expression were lower than in Old-CON; for Arg1, gene expression in Old-EXE was higher than in Old-CON (p<.0001). LSE prevents deterioration of physical fitness owing to aging, maintaining high M2Ø polarization levels in the AT. Additionally, LSE does not downregulate Icam1 and Tnf in the AT but appears to suppress the increased M1Ø polarization ratio attributed to aging by upregulating Arg1.

Impact of long-lasting spontaneous physical activity on bone morphogenetic protein 4 in the heart and tibia in murine model of heart failure.

Bone morphogenetic protein 4 (BMP4) plays an important role in bone remodeling and in heart failure pathogenesis. The aim of this study was to evaluate the effect of spontaneous physical activity on the expression of BMP4 in the heart and tibia of the transgenic (Tgαq*44) mice, representing a model of chronic heart failure. Tgαq*44 and wild‐type FVB mice (WT) were randomly assigned either to sedentary or to trained groups undergoing 8 weeks of spontaneous wheel running. The BMP4 protein expression in heart and tibiae was evaluated using Western immunoblotting and the phosphorus and calcium in the tibiae was assessed using the X‐ray microanalysis. BMP4 content in the hearts of the Tgαq*44‐sedentary mice was by ~490% higher than in the WT‐sedentary mice, whereas in tibiae the BMP4 content of the Tgαq*44‐sedentary mice was similar to that in the WT‐sedentary animals. Tgαq*44 mice revealed by ~28% poorer spontaneous physical activity than the WT mice. No effect of performed physical activity on the BMP4 content in the hearts of either in the Tgαq*44 or WT mice was observed. However, 8‐week spontaneous wheel running resulted in a decrease in the BMP4 expression in tibiae (by ~43%) in the group of Tgαq*44 mice only, with no changes in their bone phosphorus and calcium contents. We have concluded that prolonged period of spontaneous physical exercise does not increase the risk of the progression of the BMP4‐mediated pathological cardiac hypertrophy and does not affect bone mineral status in the chronic heart failure mice.

Spontaneous running wheel improves neuroprotection efficacy of ischemic postconditioning in mice following ischemia/reperfusion injury

Ischemic postconditioning (IP) has been shown to provide protection for ischemia/reperfusion (IR) injury, but its efficacy is limited. In this study we hypothesized that spontaneous running wheel (RW) could improve neuroprotection efficacy of IP for IR. We established mouse models of IR and showed that compared to Sham group, IR group had obvious brain infract and neurological dysfunction. In IR+IP group, brain infract and neurological dysfunction improved compared to IR group. However, in IR+IP+RW group brain infract and neurological dysfunction improved much better. TUNEL assay showed that IP but not RW significantly reduced the number of apoptotic cells after IR. However, the number of apoptotic cells was significantly reduced in RW+IP group. In addition, the levels of pro-apoptotic factors increased in IR group but significantly reduced in IR+IP+RW group, while the levels of antiapoptotic factors decreased in IR group but significantly increased in IR+IP+RW group. Moreover, in IR+IP+RW group, MDA level was further decreased and SOD level was further increased compared to IR+IP group. Finally, both PI3K inhibitor and STAT3 inhibitor significantly worsened brain infract and neurological dysfunction and promoted apoptosis in IR mice. In conclusion, RW combined with IP reduces brain infract and neurological dysfunction in mice after IR, and this is associated with enhanced anti-apoptotic and anti-oxidant benefits via the activation of PI3K and STAT3 pathways.

Effect of chronic stress on running wheel activity in mice.

Acute and chronic stress have been reported to have differing effects on physical activity in rodents, but no study has examined a chronic stress protocol that incorporates stressors often experienced by rodents throughout a day. To examine this, the effects of the Unpredictable Chronic Mild Stress (UCMS) protocol on voluntary running wheel activity at multiple time points, and/or in response to acute removal of chronic stress was determined. Twenty male Balb/c mice were given access and accustomed to running wheels for 4 weeks, after which they were randomized into 2 groups; exercise (EX, n = 10) and exercise with chronic stress using a modified UCMS protocol for 7 hours/day (8:00 a.m.-3:00p.m.), 5 days/week for 8 weeks (EXS, n = 10). All mice were given access to running wheels from approximately 3:30 p.m. to 7:30 a.m. during the weekday, however during weekends mice had full-time access to running wheels (a time period of no stress for the EXS group). Daily wheel running distance and time were recorded. The average running distance, running time, and work each weekday was significantly lower in EXS compared to EX mice, however, the largest effect was seen during week one. Voluntary wheel running deceased in all mice with increasing age; the pattern of decline appeared to be similar between groups. During the weekend (when no stress was applied), EXS maintained higher distance compared to EX, as well as higher daily distance, time, and work compared to their weekday values. These results indicate that mild chronic stress reduces total spontaneous wheel running in mice during the first week of the daily stress induction and maintains this reduced level for up to 8 consecutive weeks. However, following five days of UCMS, voluntary running wheel activity rebounds within 2–3 days.

Dopamine D3 receptor status modulates sexual dimorphism in voluntary wheel running behavior in mice

Sexual dimorphism has been described in various aspects of physiological and pathophysiological processes involving dopaminergic signaling. This might account for the different disease characteristics in men and women in e.g. Parkinson’s disease or ADHD. A better understanding might contribute to the future individualization of therapy.We examined spontaneous wheel running activity of male and female mice, homo- and heterozygote for dopamine D3 receptor deficiency (D3R −/− and D3R+/−), and compared them to wild type controls. We found higher wheel running activity in female mice than in their male littermates. D3−/− mice, irrespective of sex, were also hyperactive compared to both D3+/− and wild type animals. Hyperactivity of D3−/− female mice was pronounced during the first days of wheel running but then decreased while their male counterparts continued to be hyperactive. Physical activity was menstrual cycle-dependent. Activity fluctuations were also seen in D3 receptor knockout mice and are therefore presumably independent of D3 receptor activation.Our data underscore the complex interaction of dopaminergic signaling and gonadal hormones that leads to specific running behavior. Furthermore, we detected sex- and D3 receptor status-specific reactions during novel exposure to the running wheel. These findings suggest the need for adapting dopaminergic therapies to individual factors such as sex or even menstrual cycle to optimize therapeutic success.

Adaptation to a blood pressure telemetry system revealed by measures of activity, agility and operant learning in mice

IntroductionImplantable telemetry enables continuous monitoring of physiological functions in freely moving animals and can greatly complement pharmacological research. Despite its miniaturization, a sensor/transmitter constitutes 5% or more of a mouse's bodyweight. The aim of the present study was to evaluate whether factors related to the presence of a probe/transmitter influence the ambulatory activity, strength, agility, or operant, motivated behaviors of this small rodent. MethodsAdult male mice (C57BL/6N, 22–25g, 9–10weeks; implanted n=26, intact n=45) were evaluated during week-long tests, conducted three and eight weeks after surgical implantation of the PA-C10 blood pressure probe. An open field test, grip force measurement, Rotarod test were performed, followed by 7-day continuous monitoring of spontaneous wheel running activity and positively reinforced operant conditioning in an automated data collection system. ResultsAn implanted blood pressure transmitter did not affect behavior of mice in the open field test, on the Rotarod or their grip force, compared to unoperated controls. Voluntary wheel running distance was reduced three, but not eight weeks after implantation. Three weeks after the surgery, performance in the positively reinforced operant conditioning in operated mice was slightly decreased compared to intact animals, while retention and acquisition of a 2nd, reversal-learning task eight weeks after the surgery were unaffected. DiscussionWe conclude that an implantable transmitter may have detectable effects in the first few weeks following implantation on some elements of mouse behavior. With sufficient recovery, mice perform comparably to unoperated controls in tests of strength, endurance, agility and learned operant behavior.

A microstructural analysis distinguishes motor and motivational influences over voluntary running in animals chronically exposed to methylmercury and nimodipine

Adult-onset methylmercury (MeHg) exposure produces sensorimotor impairment and related changes in behavior. The present study investigated MeHg effects on the microstructure of spontaneous wheel running in adult BALB/c mice chronically exposed to 0ppm or 15ppm MeHg via daily drinking water. To test the hypothesis that MeHg neurotoxicity is related to impaired calcium homeostasis, MeHg-exposed mice received 0, 20, or 200ppm of the L-type calcium-channel blocker nimodipine in their daily chow diet. To examine MeHg-related changes in the microstructure of running, we partitioned spontaneous wheel running into activity epochs using a change-point algorithm and derived estimates of the within-bout response rate (primarily a motor-function measure), the duration of pausing between bouts (primarily a motivation measure), and the length of response bouts (a hybrid measure) from those epochs. Mice also performed regular rotarod sessions, providing a second measure of motor coordination. MeHg impaired rotarod performance and nimodipine dose-dependently mitigated that effect. MeHg decreased the distance run and within-bout running rate, especially during the final weeks of exposure and nimodipine attenuated and delayed that impairment. The interbout interval was only slightly but significantly affected by MeHg with no evidence of decline at the end of exposure and no influence of nimodipine. Despite the presence of impaired running, there was no evidence of fatigue through the course of long, three-hour sessions. These findings suggest that the microstructure of behavior provides sensitive and interpretable measures of MeHg effects, support the utility of bout analysis for separating motor and motivational effects of drug and toxicant exposure, and show selective neuroprotection by nimodipine.

Spatial learning and neurogenesis: Effects of cessation of wheel running and survival of novel neurons by engagement in cognitive tasks

Physical exercise stimulates cell proliferation in the adult dentate gyrus and facilitates acquisition and/or retention of hippocampal-dependent tasks. It is established that regular physical exercise improves cognitive performance. However, it is unclear for how long these benefits last after its interruption. Independent groups of rats received both free access to either unlocked (EXE Treatment) or locked (No-EXE Treatment) running wheels for 7 days, and daily injections of bromodeoxyuridine (BrdU) in the last 3 days. After a time delay period of either 1, 3, or 6 weeks without training, the animals were tested in the Morris water maze (MWM) either in a working memory task dependent on hippocampal function (MWM-HD) or in a visible platform searching task, independent on hippocampal function (MWM-NH). Data confirmed that exposure of rats to 7 days of spontaneous wheel running increases cell proliferation and neurogenesis. In contrast, neurogenesis was not accompanied by significant improvements of performance in the working memory version of the MWM. Longer time delays between the end of exercise and the beginning of cognitive training in the MWM resulted in lower cell survival; that is, the number of novel surviving mature neurons was decreased when this delay was 6 weeks as compared with when it was 1 week. In addition, data showed that while exposure to the MWM-HD working memory task substantially increased survival of novel neurons, exposure to the MWM-NH task did not, thus indicating that survival of novel dentate gyrus neurons depends on the engagement of this brain region in performance of cognitive tasks. © 2015 Wiley Periodicals, Inc.

MiR21 is Associated with the Cognitive Improvement Following Voluntary Running Wheel Exercise in TBI Mice.

Recent evidences revealed that the alteration of microRNAs (miRNAs) might be associated with neuroplasticity induced by voluntary running wheel (RW) exercise in mice suffered from traumatic brain injury (TBI). In the present study, we explored the possible role of miR21 involved in the cognitive improvement following voluntary RW in TBI mice. Firstly, in situ hybridization and quantitative real-time PCR (qRT-PCR) were employed to determine the hippocampal expression and location of miR21 in TBI mice with or without spontaneous RW. Either miR21-mimics/plenti-miR21 or miR21-agomir/miR21-sponge was employed to regulate the miR21 expression in vivo and in vitro. Acquisition of spatial learning and memory retention was assessed by Morris Water Maze (MWM) test. Golgi stain was also performed to evaluate the alteration of hippocampal dendrite. Our finding confirmed that the elevated miR21 level in hippocampal post-TBI was significantly reduced by spontaneous RW. Overexpression of miR21 in TBI mice with spontaneous RW induced deteriorations in spatial learning and memory retention by significant decreases in the somata size and branch points of the hippocampus neurons. In vitro transduction with miR21 also reduced the neurite extension and the area of cultured hippocampal neuron. However, miR21 down-regulation reversed these effects. The present data strongly suggest that miR21 is an important molecule that has been involved in neuroprotection induced by voluntary RW exercise post-TBI.

Metabolomic analysis of long-term spontaneous exercise in mice suggests increased lipolysis and altered glucose metabolism when animals are at rest.

Exercise has been associated with several beneficial effects and is one of the major modulators of metabolism. The working muscle produces and releases substances during exercise that mediate the adaptation of the muscle but also improve the metabolic flexibility of the complete organism, leading to adjustable substrate utilization. Metabolomic studies on physical exercise are scarce and most of them have been focused on the effects of intense exercise in professional sportsmen. The aim of our study was to determine plasma metabolomic adaptations in mice after a long-term spontaneous exercise intervention study (18 mo). The metabolic changes induced by long-term spontaneous exercise were sufficient to achieve complete discrimination between groups in the principal component analysis scores plot. We identified plasma indicators of an increase in lipolysis (elevated unsaturated fatty acids and glycerol), a decrease in glucose and insulin plasma levels and in heart glucose consumption (by PET), and altered glucose metabolism (decreased alanine and lactate) in the wheel running group. Collectively these data are compatible with an increase in skeletal muscle insulin sensitivity in the active mice. We also found an increase in amino acids involved in catecholamine synthesis (tyrosine and phenylalanine), in the skeletal muscle pool of creatine phosphate and taurine, and changes in phospholipid metabolism (phosphocholine and choline in lipids) between the sedentary and the active mice. In conclusion, long-term spontaneous wheel running induces significant plasma and tissue (heart) metabolic responses that remain even when the animal is at rest.

Spontaneous running wheel improves cognitive functions of mouse associated with miRNA expressional alteration in hippocampus following traumatic brain injury.

Traumatic brain injury (TBI) is an insult to the brain that results in impairments of cognitive and physical functioning. Both of human research and animal studies demonstrate that spontaneous exercise can facilitate neuronal plasticity and improve cognitive function in normal or TBI rodent models. However, the possible mechanisms underlying are still not well known. We postulated that spontaneous running wheel (RW) altered microRNA (miRNA) expressions in hippocampus of mice following TBI, which might be associated with the improvement in cognitive functions. In the present study, acquisition of spatial learning and memory retention was assessed by using the Morris water maze (MWM) test on days 15 post RW exercise. Then, microarray analyses in miRNA files were employed, and the expressional changes of miRNAs in the hippocampus of mice were detected. The results showed that spontaneous RW exercise (i) recovered the hippocampus-related cognitive deficits induced by TBI, (ii) altered hippocampal expressions of miRNAs in both of sham and TBI mice, and (iii) miR-21 or miR-34a was associated with the recovery process. The present results indicated that an epigenetic mechanism might be involved in voluntary exercise-induced cognitive improvement of mice that suffered from TBI.

Abstract 18310: Therapeutic Use of Encapsulated Genetically Engineered Mesenchymal Stem Cells for Vascular Regeneration

Background: We have previously shown that encapsulation of mesenchymal stem cells (MSCs) in alginate improves cell retention and efficacy of stem cell therapies in the hind limb model of vascular insufficiency. Erythropoietin (EPO), a hematopoietic cytokine, is also known as an angiogenic factor. The purpose of this study is to evaluate the efficacy of encapsulated, gene transfected MSCs as therapeutic strategy for enhancing collateral formation in hind limb ischemia model by using EPO transfected MSCs (MSC-EPO). Methods and Results: MSCs and MSCs-EPO were encapsulated into alginate microcapsules. Hind limb ischemia was induced by ligating and excising both the super facial femoral artery and vein in the left leg. The mice were implanted with either empty capsules, encapsulated 1 X 10 6 MSCs (MSC group), encapsulated 0.9 X 10 6 MSCs + 0.1 X 10 6 MSCs-EPO (low EPO group), or encapsulated 0.5 X 10 6 of MSC + 0.5 X 10 6 of MSCs-EPO (high EPO group). Blood analysis was performed on post-operative day (POD) 14 and 28 and histological evaluation with immunohistochemistry was performed on POD 14 (n=4/group). To evaluate the functional recovery, a spontaneous running wheel test was performed between POD 14 to POD 21. On POD 14, there was no significant change in hematocrit in 4 groups. On POD 28, the hematocrit in the high EPO group was significantly increased (57.2±4.6%) Histological evaluation revealed that the density of collateral vessels was increased in both the low and high EPO groups. (0.7±0.04, 0.84±005, 0.98±0.05 and 1.06±0.06 respectively) Although the high EPO group had a much higher density of collateral vessels, the running distance was significantly reduced to two third of the other groups.(6507±208.3, 6223±294.0, 6067±510.5 and 3952±322.1m/day, respectively) Conclusion: The use of alginate encapsulation of MSCs is a viable strategy for site directed gene therapy. Our data show that EPO can be effectively delivered resulting in an improvement in collateral vessel formation. However, chronic over-expression of EPO may cause adverse effects likley as a result of increased blood viscosity.

Methylphenidate prevents high-fat diet (HFD)-induced learning/memory impairment in juvenile mice

The prevalence of childhood obesity has risen dramatically and coincident with this upsurge is a growth in adverse childhood psychological conditions including impulsivity, depression, anxiety and attention deficit/hyperactive disorder (ADHD). Due to confounds that exist when determining causality of childhood behavioral perturbations, controversy remains as to whether overnutrition and/or childhood obesity is important. Therefore, we examined juvenile mice to determine if biobehaviors were impacted by a short-term feeding (1-3wks) of a high-fat diet (HFD). After 1wk of a HFD feeding, mouse burrowing and spontaneous wheel running were increased while mouse exploration of the open quadrants of a zero maze, perfect alternations in a Y-maze and recognition of a novel object were impaired. Examination of mouse cortex, hippocampus and hypothalamus for dopamine and its metabolites demonstrated increased homovanillic acid (HVA) concentrations in the hippocampus and cortex that were associated with decreased cortical BDNF gene expression. In contrast, pro-inflammatory cytokine gene transcripts and serum IL-1α, IL-1β, TNF-α and IL-6 were unaffected by the short-term HFD feeding. Administration to mice of the psychostimulant methylphenidate prevented HFD-dependent impairment of learning/memory. HFD learning/memory impairment was not inhibited by the anti-depressants desipramine or reboxetine nor was it blocked in IDO or IL-1R1 knockout mice. In sum, a HFD rapidly impacts dopamine metabolism in the brain appearing to trigger anxiety-like behaviors and learning/memory impairments prior to the onset of weight gain and/or pre-diabetes. Thus, overnutrition due to fats may be central to childhood psychological perturbations such as anxiety and ADHD.

Spontaneous Wheel Running Exercise Induces Brain Recovery via Neurotrophin-3 Expression Following Experimental Traumatic Brain Injury in Rats

[Purpose] The aim of the present study was to investigate the expression of neurotrophin-3 (NT-3) after applying spontaneous wheel running exercises (SWR) after experimental traumatic brain injury (TBI). [Subjects and Methods] Thirty male Sprague-Dawley rats were divided into 3 groups; 20 rats were subjected to controlled cortical impact for TBI, and then, animals were randomly collected from the SWR group and subjected to wheel running exercise for 3 weeks. Ten rats were not subjected to any injury or running exercise to compare with the effect of TBI and SWR. Immunohistochemistry, Western blotting, skilled ladder rung walking test, and 2,3,5-triphenyltetrazolium chloride staining analysis for the evaluation of NT-3 expression were used to assess brain damage and recovery. [Results] The TBI-induced decrease in NT-3 expression was recovered by wheel running exercise. Moreover, decreased ischemic volume and progressive neurobehavioral outcome were observed in the SWR group. [Conclusion] Spontaneous running exercise promotes brain recovery and motor function through an increase in expression of NT-3.

Efecto del ejercicio físico sobre las alteraciones cognitivas y el estrés oxidativo en un modelo transgénico APP/PSN1 para la enfermedad de Alzheimer

IntroductionThe beneficial effects of physical exercise, in both the treatment and the prevention of several diseases, have been extensively demonstrated. The most common dementia, Alzheimer′s disease (AD), is a disorder in which exercise induces significant improvement at pathophysiopathological and cognitive levels. In the present work, we studied the relationship between physical exercise, oxidative stress, and cognition in the double transgenic mice model (2×Tg) for AD, APP/PSN1. This model is mainly based on the cerebral deposition of amyloid β plaques. Material and methodsEighteen ten-month-old mice were divided into four experimental groups: exercised 2×Tg (2×Tg-E) (n=5), rested 2×Tg (2×Tg-R) (n=5), exercised controls (control-E) (n=4) and rested controls (control-R) (n=4). We trained the animals for twelve weeks with a combination of forced exercise (treadmill running three days/week) and spontaneous wheel running. The animals were evaluated with physical and cognitive tests before and after the training period. We analyzed systemic and cortical oxidative damage and the induction of antioxidant enzymes. ResultsThe 2×Tg-R mice showed a decrease in their grip strength and VO2max as they grew older which was prevented by training. The 2×Tg-E group showed better memory than the 2×Tg-R animals. All the trained groups demonstrated greater exploratory capacity and less anxiety than the sedentary animals. Systemic oxidative damage was slightly decreased in the 2×Tg, although we found no difference in the lipoperoxidation and in the induction of the antioxidant defense in cortex between groups. ConclusionsPhysical exercise leads to improvements in the grip strength, VO2max, cognition, and memory in 2×Tg mice. These improvements are not significantly related to changes in the antioxidant defenses or a reduction in the oxidative damage brought about by exercise.