Treadmill exercise after social isolation increases the levels of NGF, BDNF, and synapsin I to induce survival of neurons in the hippocampus, and improves depression-like behavior

Decoding serotonin: the molecular symphony behind depression

The serotonin (5-hydroxytryptamine) system represents a crucial neurotransmitter network that regulates mood, behavior, and cognitive functions, playing a significant role in the pathogenesis and progression of depression. Although this perspective faces significant challenges, the serotonin system continues to exert substantial modulatory effects on specific aspects of psychological functioning and actively contributes to multiple pathological processes in depression development. Therefore, this review systematically integrates interdisciplinary research advances regarding the relationship between the 5-hydroxytryptamine (5-HT) system and depression. By focusing on core biological processes including serotonin biosynthesis and metabolism, SERT gene regulatory networks, and protein molecular modifications, it aims to elucidate how 5-HT system dysregulation contributes to the development of depression, while providing novel research perspectives and therapeutic targets for innovative antidepressant drug development.

Effect of combined training in water on hippocampal neuronal Plasticity and memory function in healthy elderly rats

Purpose

The cyclic AMP response element-binding protein (CREB) and nerve growth factor (NGF) have been proposed as key modulators of brain health and are involved in synaptic plasticity. The study investigates how combined water-based training affects hippocampal neuron plasticity and memory function in old rats.

Methods

16 Wistar male rats 24-month-old were randomly divided into two groups: combined training (n = 8) and control (n = 8). Four sessions were performed per week for 10 weeks, and consisted of resistance and endurance training in water. The control group was placed in a water container during training for 30 minutes to be homogenized in terms of the stress conditions. The.NGF and CREB genes in the hippocampus were evaluated and the working memory was measured using real-time PCR and Y-maze tests. The SPSS 26 software was utilized in which independent t-tests were used to analyze the genes and the Mann-Whitney U test was used to analyze functional memory with a significant level of (P < 0.05).

Results

The combined training resulted in a significant rise in NGF and CREB gene expression in the hippocampus tissue of elderly rats compared to the control group (P < 0.05); however, there was no notable difference in the Y maze performance test between the two groups (P < 0.05).

Conclusions

These findings suggest that water-based combined training has beneficial effects on gene expression of NGF and CREB; however, it is necessary to conduct more studies to comprehend the effects of combined training on memory function.

Clostridium butyricum Alleviates DEHP Plasticizer-Induced Learning and Memory Impairment in Mice via Gut-Brain Axis

Di-(2-ethylhexyl) phthalate (DEHP) plasticizer, a well-known environmental and food pollutant, has neurotoxicity. However, it is unknown whether DEHP leads to learning and memory impairment through gut-brain axis and whether Clostridium butyricum can alleviate this impairment. Here, C57BL/6 mice were exposed to DEHP and treated with C. butyricum. Learning and memory abilities were evaluated through the Morris water maze. The levels of synaptic proteins, inflammatory cytokines, and 5-hydroxytryptamine (5-HT) were detected by immunohistochemistry or ELISA. Gut microbiota were analyzed through 16S rRNA sequencing. C. butyricum alleviated DEHP-induced learning and memory impairment and restored synaptic proteins. It significantly relieved DEHP-induced inflammation and recovered 5-HT levels. C. butyricum recovered the richness of the gut microbiota decreased by DEHP, with the Bifidobacterium genus increasing the most. Overall, C. butyricum alleviated DEHP-induced learning and memory impairment due to reduced inflammation and increased 5-HT secretion, which was partly attributed to the recovery of gut microbiota.

Modulatory Effect of Neurotrophic Factors on the TRPV1 Expression: Possible Mechanisms Involved in the Antiepileptic Effect of Exercise

Background: Epilepsy is one of the most important diseases of the central nervous system, for which has no definitive treatment. Neurotrophic factors increase the survival of nerve cells and improve the treatment of neurological diseases. Identifying factors that affect the increase of neurotrophins in the brain is an important goal for brain health and function. Objectives: This study aimed to investigate the effectiveness of exercise on neurotrophic factors by influencing the expression of vanilloid receptor type 1 (TRPV1). Methods: Convulsions were induced by injecting pentylenetetrazol (PTZ; 35 mg/kg) five hours after exercise. Animals were divided into five groups: sham (Sham), seizure (PTZ), exercise (EX), exercise with seizure induction (EX+PTZ), and exercise before seizure induction (EX-PTZ). The exercise was 30 minutes of forced running on a treadmill, five days a week for four weeks. Results: The average percentage of NGF cells in the exercise groups (EX), exercise with seizure induction (EX+PTZ), and exercise before seizure induction (EX-PTZ), and GDNF in the exercise group with seizure induction (EX+PTZ) had a significant increase compared to the seizure group (PTZ). Also, TRPV1 activity in exercise groups (EX), exercise with seizure induction (EX+PTZ), and exercise before seizure induction (EX-PTZ) showed a significant increase compared to the seizure group (PTZ). Conclusions: Our findings suggested the possible antiepileptic and antiepileptogenesis effects of exercise through activation of neurotrophic factors and TRPV1 modulation.

Effects of different physical activities on brain-derived neurotrophic factor: A systematic review and bayesian network meta-analysis

Background

Emerging evidence suggests that exercise is a simple and effective method for maintaining brain function.

Aims

This review evaluates the effects of five physical exercises, including aerobic training (AT), high-intensity interval training (HIIT), combined training (CT), resistance training (RT), and AT+RT, on the serum level of brain-derived neurotrophic factor (BDNF) in healthy and non-healthy populations.

Methods

We searched CNKI, PubMed, Embase, Scopus, Medline, Web of Science, and Cochrane Library databases to review randomized controlled studies on exercise interventions for BDNF. Quantitative merging analysis of the resulting data using Bayesian network meta-analysis.

Results

The screening and exclusion of the searched literature resulted in the inclusion of 39 randomized controlled trials containing 5 exercise interventions with a total of 2031 subjects. The AT, RT, AT+RT, HIIT, and CT groups (intervention groups) and the CG group (conventional control group) were assigned to 451, 236, 102, 84, 293, and 865 subjects, respectively. The Bayesian network meta-analysis ranked the effect of exercise on BDNF level improvement in healthy and non-healthy subjects as follows: RT > HIIT > CT > AT+RT > AT > CG. Better outcomes were observed in all five intervention groups than in the CG group, with RT having the most significant effect [MD = 3.11 (0.33, 5.76), p < 0.05].

Conclusions

RT at moderate intensity is recommended for children and older adults in the case of exercise tolerance and is effective in maintaining or modulating BDNF levels for promoting brain health.

Systematic Review Registration

https://inplasy.com, INPLASY202250164.

Understanding How Physical Exercise Improves Alzheimer’s Disease: Cholinergic and Monoaminergic Systems

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, characterized by the accumulation of proteinaceous aggregates and neurofibrillary lesions composed of β-amyloid (Aβ) peptide and hyperphosphorylated microtubule-associated protein tau, respectively. It has long been known that dysregulation of cholinergic and monoaminergic (i.e., dopaminergic, serotoninergic, and noradrenergic) systems is involved in the pathogenesis of AD. Abnormalities in neuronal activity, neurotransmitter signaling input, and receptor function exaggerate Aβ deposition and tau hyperphosphorylation. Maintenance of normal neurotransmission is essential to halt AD progression. Most neurotransmitters and neurotransmitter-related drugs modulate the pathology of AD and improve cognitive function through G protein-coupled receptors (GPCRs). Exercise therapies provide an important alternative or adjunctive intervention for AD. Cumulative evidence indicates that exercise can prevent multiple pathological features found in AD and improve cognitive function through delaying the degeneration of cholinergic and monoaminergic neurons; increasing levels of acetylcholine, norepinephrine, serotonin, and dopamine; and modulating the activity of certain neurotransmitter-related GPCRs. Emerging insights into the mechanistic links among exercise, the neurotransmitter system, and AD highlight the potential of this intervention as a therapeutic approach for AD.

Physical Exercise and Health: A Focus on Its Protective Role in Neurodegenerative Diseases

Scientific evidence has demonstrated the power of physical exercise in the prevention and treatment of numerous chronic and/or age-related diseases, such as musculoskeletal, metabolic, and cardiovascular disorders. In addition, regular exercise is known to play a key role in the context of neurodegenerative diseases, as it helps to reduce the risk of their onset and counteracts their progression. However, the underlying molecular mechanisms have not yet been fully elucidated. In this regard, neurotrophins, such as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), glia cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4), have been suggested as key mediators of brain health benefits, as they are involved in neurogenesis, neuronal survival, and synaptic plasticity. The production of these neurotrophic factors, known to be increased by physical exercise, is downregulated in neurodegenerative disorders, suggesting their fundamental importance in maintaining brain health. However, the mechanism by which physical exercise promotes the production of neurotrophins remains to be understood, posing limits on their use for the development of potential therapeutic strategies for the treatment of neurodegenerative diseases. In this literature review, we analyzed the most recent evidence regarding the relationship between physical exercise, neurotrophins, and brain health, providing an overview of their involvement in the onset and progression of neurodegeneration.

Depresssion, anxiety and other cognitive consequences of social isolation: Drug and non-drug treatments

OBJECTIVE

During the COVID-19 pandemic, quarantine and staying at home is advised. The social relationship between people has become deficient, and human social isolation (SI) has become the consequence of this situation. It was shown that SI has made changes in hippocampal neuroplasticity, which will lead to poor cognitive function and behavioural abnormalities. There is a connection between SI, learning, and memory impairments. In addition, anxiety-like behaviour and increased aggressive mood in long-term isolation have been revealed during the COVID-19 outbreak.

METHODS

Term searches was done in Google Scholar, Scopus, ScienceDirect, Web of Science and PubMed databases as well as hand searching in key resource journals from 1979 to 2020.

RESULTS

Studies have shown that some drug administrations may positively affect or even prevent social isolation consequences in animal models. These drug treatments have included opioid drugs, anti-depressants, Antioxidants, and herbal medications. In addition to drug interventions, there are non-drug treatments that include an enriched environment, regular exercise, and music.

CONCLUSION

This manuscript aims to review improved cognitive impairments induced by SI during COVID-19.

Treadmill exercise sex-dependently alters susceptibility to depression-like behaviour, cytokines and BDNF in the hippocampus and prefrontal cortex of rats with sporadic Alzheimer-like disease

Alzheimer's disease (AD) is associated with increased depression-related behaviours. Previous studies have reported a greater risk of AD and depression in women. In recent years, we and others have provided evidence that exercise during life could be used as a therapeutic strategy for stress-related disorders such as depression. The main goal of the current study was to determine whether treadmill exercise during life can reduce depression-related behaviours in male and female Wistar rats with sporadic Alzheimer-like disease (ALD). Animals were subjected to treadmill exercise eight weeks before and four weeks after ALD induction by streptozocin (STZ). We measured body weight, food intake, and depression-related symptoms in rats using five behavioural tests. We measured brain-derived-neurotrophic factor (BDNF), tumour-necrosis factor (TNF)-α, and interleukin (IL)-10 levels in the hippocampus and prefrontal cortex of animals. Our findings showed that exercise but not ALD induction decreased body weight and food intake in male and female rats. ALD induction increased depression-related symptoms and hippocampal TNF-α in male and female rats. Besides, treadmill exercise alone decreased depression-related behaviours and increased hippocampal BDNF in females but not males. We also found that treadmill exercise decreased depression-related behaviours and TNF-α in the hippocampus and prefrontal cortex, and increased IL-10 in the prefrontal cortex and BDNF in the hippocampus of female ALD-induced rats. However, treadmill exercise only reduced anhedonia-like behaviour and hippocampal TNF-α in male ALD-induced rats. Overall, the evidence from this study suggests that treadmill exercise alters depression-related behaviours, brain BDNF and cytokines in a sex-dependant manner in rats with sporadic Alzheimer-like disease.

An updated reappraisal of synapsins: structure, function and role in neurological and psychiatric disorders

Synapsins (Syns) are phosphoproteins strongly involved in neuronal development and neurotransmitter release. Three distinct genes SYN1, SYN2 and SYN3, with elevated evolutionary conservation, have been described to encode for Synapsin I, Synapsin II and Synapsin III, respectively. Syns display a series of common features, but also exhibit distinctive localization, expression pattern, post-translational modifications (PTM). These characteristics enable their interaction with other synaptic proteins, membranes and cytoskeletal components, which is essential for the proper execution of their multiple functions in neuronal cells. These include the control of synapse formation and growth, neuron maturation and renewal, as well as synaptic vesicle mobilization, docking, fusion, recycling. Perturbations in the balanced expression of Syns, alterations of their PTM, mutations and polymorphisms of their encoding genes induce severe dysregulations in brain networks functions leading to the onset of psychiatric or neurological disorders. This review presents what we have learned since the discovery of Syn I in 1977, providing the state of the art on Syns structure, function, physiology and involvement in central nervous system disorders.

Endurance exercise-induced expression of autophagy-related protein coincides with anabolic expression and neurogenesis in the hippocampus of the mouse brain

Autophagy and neurogenesis play a pivotal role in maintaining cellular homeostasis of neurons in the brain. Endurance exercise (EXE) serves as a potent regulator of both autophagy and neurogenesis in the hippocampus of the brain; however, the underlying molecular mechanisms of the dual expression remains unclear. Thus, we examined the signaling pathways of EXE-induced autophagy and neurogenesis-associated protein expression in the hippocampus. C57BL/6 male mice (10 weeks old) were randomly divided into two groups: control group (n = 10) and EXE group (EXE, n = 10). Our results showed that EXE increased expression of autophagy-related protein [LC3 II, BECLIN1, autophagy-related 7 (ATG7), p62, LAMP2, CATHEPSIN L and transcription factor EB] in the presence of anabolic signaling expression (AKT-mammalian target of rapamycin-ribosomal S6 kinase). Intriguingly, long-term EXE-mediated neurogenesis in the hippocampus was observed despite the downregulated expressions of canonical neurotrophic factors (e.g. brain-derived neurotrophic factor, glial cell line-derived neurotrophic factors and nerve growth factor); instead, upregulation of neuregulin-1 (NRG1)-mediated signaling cascades (e.g. NRG1-extracellular signal-regulated kinase-ribosomal s6 kinase-cyclic adenosine mono-phosphate response element-binding protein) were associated with EXE-induced hippocampal neurogenesis and synaptic plasticity. Our data, for the first time, show that EXE-mediated expression of autophagy-related protein coincides with anabolic expression and that NRG1 is involved in EXE-mediated neurogenesis and synaptic plasticity. Taken together, this study provides a novel mechanism of hippocampal autophagy and neurogenesis, which may provide potential insight into developing therapeutic neuroprotective strategies.

Hippocampal PGC-1α-mediated positive effects on parvalbumin interneurons are required for the antidepressant effects of running exercise

Running exercise was shown to have a positive effect on depressive-like symptoms in many studies, but the underlying mechanism of running exercise in the treatment of depression has not been determined. Parvalbumin-positive interneurons (PV⁺ interneurons), a main subtype of GABA neurons, were shown to be decreased in the brain during the depression. PGC-1α, a molecule that is strongly related to running exercise, was shown to regulate PV⁺ interneurons. In the present study, we found that running exercise increased the expression of PGC-1α in the hippocampus of depressed mice. Adult male mice with PGC-1α gene silencing in the hippocampus ran on a treadmill for 4 weeks. Then, depression-like behavior was evaluated by the behavioral tests, and the PV⁺ interneurons in the hippocampus were investigated. We found that running exercise could not improve depressive-like symptoms or increase the gene expression of PV because of the lack of PGC-1α in the hippocampus. Moreover, a lack of PGC-1α in the hippocampus decreased the number and activity of PV⁺ interneurons in the CA3 subfield of the hippocampus, and running exercise could not reverse the pathological changes because of the lack of PGC-1α. The present study demonstrated that running exercise regulates PV⁺ interneurons through PGC-1α in the hippocampus of mice to reverse depressive-like behaviors. These data indicated that hippocampal PGC-1α-mediated positive effects on parvalbumin interneurons are required for the antidepressant actions of running exercise. Our results will help elucidate the antidepressant mechanism of running exercise and identify new targets for antidepressant treatment.

The positive effects of running exercise on hippocampal astrocytes in a rat model of depression

Running exercise has been shown to alleviate depressive symptoms, but the mechanism of its antidepressant effect is still unclear. Astrocytes are the predominant cell type in the brain and perform key functions vital to central nervous system (CNS) physiology. Mounting evidence suggests that changes in astrocyte number in the hippocampus are closely associated with depression. However, the effects of running exercise on astrocytes in the hippocampus of depression have not been investigated. Here, adult male rats were subjected to chronic unpredictable stress (CUS) for 5 weeks followed by treadmill running for 6 weeks. The sucrose preference test (SPT) was used to assess anhedonia of rats. Then, immunohistochemistry and modern stereological methods were used to precisely quantify the total number of glial fibrillary acidic protein (GFAP)⁺ astrocytes in each hippocampal subregion, and immunofluorescence was used to quantify the density of bromodeoxyuridine (BrdU)⁺ and GFAP⁺ cells in each hippocampal subregion. We found that running exercise alleviated CUS-induced deficit in sucrose preference and hippocampal volume decline, and that CUS intervention significantly reduced the number of GFAP⁺ cells and the density of BrdU⁺/GFAP⁺ cells in the hippocampal CA1 region and dentate gyrus (DG), while 6 weeks of running exercise reversed these decreases. These results further confirmed that running exercise alleviates depressive symptoms and protects hippocampal astrocytes in depressed rats. These findings suggested that the positive effects of running exercise on astrocytes and the generation of new astrocytes in the hippocampus might be important structural bases for the antidepressant effects of running exercise.

Neuroprotective Benefits of Exercise and MitoQ on Memory Function, Mitochondrial Dynamics, Oxidative Stress, and Neuroinflammation in D-Galactose-Induced Aging Rats

Exercise and antioxidants have health benefits that improve cognitive impairment and may act synergistically. In this study, we examined the effects of treadmill exercise (TE) and mitochondria-targeted antioxidant mitoquinone (MitoQ), individually or combined, on learning and memory, mitochondrial dynamics, NADPH oxidase activity, and neuroinflammation and antioxidant activity in the hippocampus of D-galactose-induced aging rats. TE alone and TE combined with MitoQ in aging rats reduced mitochondrial fission factors (Drp1, Fis1) and increased mitochondrial fusion factors (Mfn1, Mfn2, Opa1). These groups also exhibited improved NADPH oxidase activity and antioxidant activity (SOD-2, catalase). TE or MitoQ alone decreased neuroinflammatory response (COX-2, TNF-α), but the suppression was greater with their combination. In addition, aging-increased neuroinflammation in the dentate gyrus was decreased in TE but not MitoQ treatment. Learning and memory tests showed that, contrarily, MitoQ alone demonstrated some similar effects to TE but not a definitive improvement. In conclusion, this study demonstrated that MitoQ exerted some positive effects on aging when used as an isolated treatment, but TE had a more effective role on cognitive impairment, oxidative stress, inflammation, and mitochondria dysfunction. Our findings suggest that the combination of TE and MitoQ exerted no synergistic effects and indicated regular exercise should be the first priority in neuroprotection of age-related cognitive decline.

Ganoderic Acid A-Mediated Modulation of Microglial Polarization is Involved in Depressive-Like Behaviors and Neuroinflammation in a Rat Model of Post-Stroke Depression

BACKGROUND

Post-stroke depression (PSD) is a common complication after stroke. Ganoderic acid A (GAA), one of the main bioactive Ganoderma triterpenoids, exerts preventive and therapeutic effects in many diseases. However, the function of GAA in PSD has not been well studied.

METHODS

PSD model was established via stimulating rats with chronic unpredictable mild stress stimulations (CUMS) after middle cerebral artery occlusion (MCAO). Rats were treated with GAA before CUMS. Depressive-like behaviors were investigated by body weight alteration, open field test (OFT), and sucrose preference test (SPT). Neuronal damage was evaluated by hematoxylin and eosin (HE) staining and Western blotting. Inflammation was detected by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Microglial polarization was analyzed via qRT-PCR and Western blotting. The extracellular signal-regulated kinase (ERK)/cAMP-response element-binding protein (CREB) pathway was analyzed by Western blotting, and inactivated by the inhibitor PD98059 (PD).

RESULTS

GAA attenuated PSD-induced depressive-like behaviors in rats. GAA mitigated PSD-induced neuronal damage and reduced BDNF and NGF levels in the cerebral hippocampus. GAA weakened PSD-induced inflammatory response in the cerebral hippocampus. GAA prevented pro-inflammatory (M1) polarization and promoted anti-inflammatory (M2) polarization, as indicated by decreased iNOS and CD86 levels and increased Arg-1 and CD206 levels. GAA restored the PSD-induced inactivation of the ERK/CREB pathway. GAA regulated M1/M2 microglial polarization by activating the ERK/CREB pathway.

CONCLUSION

GAA alleviated the depressive-like behaviors and brain inflammation in PSD rats, indicating its potential for PSD therapy.

p-Cresol Sulfate Caused Behavior Disorders and Neurodegeneration in Mice with Unilateral Nephrectomy Involving Oxidative Stress and Neuroinflammation

Protein-bound uremic toxins, such as p-cresol sulfate (PCS), can be accumulated with declined renal function and aging and is closely linked with central nervous system (CNS) diseases. In the periphery, PCS has effects on oxidative stress and inflammation. Since oxidative stress and inflammation have substantial roles in the pathogenesis of neurological disorders, the CNS effects of PCS were investigated in unilateral nephrectomized C57/BL/6 mice. Unlike intact mice, unilateral nephrectomized mice showed increased circulating levels of PCS after exogenous administration. Upon PCS exposure, the unilateral nephrectomized mice developed depression-like, anxiety-like, and cognitive impairment behaviors with brain PCS accumulation in comparison with the nephrectomy-only group. In the prefrontal cortical tissues, neuronal cell survival and neurogenesis were impaired along with increased apoptosis, oxidative stress, and neuroinflammation. Circulating brain-derived neurotrophic factors (BDNF) and serotonin were decreased in association with increased corticosterone and repressor element-1 silencing transcription factor (REST), regulators involved in neurological disorders. On the contrary, these PCS-induced changes were alleviated by uremic toxin absorbent AST-120. Taken together, PCS administration in mice with nephrectomy contributed to neurological disorders with increased oxidative stress and neuroinflammation, which were alleviated by PCS chelation. It is suggested that PCS may be a therapeutic target for chronic kidney disease-associated CNS diseases.

Swimming exercise ameliorates mood disorder and memory impairment by enhancing neurogenesis, serotonin expression, and inhibiting apoptosis in social isolation rats during adolescence

Social isolation during adolescence is associated with anxiety, depres-sion, and memory impairment. Exercise has been reported as a positive effect on brain function, especially hippocampus. The present study ex-amined the effect of swimming exercise on apoptosis, cell proliferation, and serotonin expression in social isolation rats during adolescence stage. Social isolation started at postnatal day 21 and continued for 6 weeks. The rats in the swimming group were forced to swim for 60 min once daily during 6 days per week for 6 consecutive weeks. The rats in the social isolation during adolescence showed anxiety, depression, short-term memory impairment. Social isolation facilitated apoptosis and inhibited cell proliferation and differentiation. Social isolation sup-pressed expression of serotonin, brain-derived neurotrophic factor, and tyrosine kinase B. Swimming exercise alleviated anxiety, depression, short-term impairment. Swimming exercise suppressed apoptosis, en-hanced neurogenesis, and increased serotonin expression. In our study, swimming exercise ameliorates mood disorder and memory impairment by enhancing neurogenesis and serotonin expression and inhibiting apoptosis in social isolation.

Exercise enhances the effectiveness of vitamin D therapy in rats with Alzheimer's disease: emphasis on oxidative stress and inflammation

Alzheimer's disease (AD) is characterized by gradual loss of memory and cognitive functions which can affect anyone. Authors declared that there is a link between vitamin D and brain function. It has been proven that vitamin D plays an important role in improving AD cognitive functions. Researchers have found that exercise has many beneficial effects on humans. In addition to cardioprotection, it has been demonstrated that exercise provides an effective improvement in different brain functions. So in our study, we aimed to evaluate the effect of each of vitamin D and/ or exercise on AD and if they could be used as a potential line for treating AD. This study was conducted on fifty female white albino rats divided equally into 5 groups: control group, Alzheimer group induced by Lipopolysaccharide, Alzheimer group treated with vitamin D, Alzheimer group treated with exercise and Alzheimer group treated with both vitamin D and exercise. The following parameters were assessed in rat brain tissues: acetylcholine esterase (AChE) activity, levels of amyloid β 42 and tau proteins, dopamine brain neurotransmitter, BDNF and NGF by ELISA. Serum levels of IL-6 and IL-10 were assessed by ELISA. MDA, GSH and vitamin D levels were also estimated in addition to cognitive function tests and histopathological examination of rat brain tissues. In Alzheimer group, there was a significant increase in the proinflammatory cytokine IL-6, the lipid peroxidation marker MDA, amyloid β and tau proteins^, levels. In addition to a significant increase in time consumed in T-maze test. Alzheimer group also showed a significant decrease in the anti-inflammatory cytokine IL-10, the anti-oxidative stress biomarker GSH, the neurotransmitters AChE and dopamine, and the growth factors BDNF and NGF as well as serum vitamin D levels. Treatment with either vitamin D or exercise significantly improved cognitive dysfunction and the histopathological picture of the brains of Alzheimer's rats with the best results in combined vitamin D and exercise treated group. The treated groups, especially combined vitamin D and exercise group, showed a significant decrease in IL-6, MDA, amyloid β and tau proteins levels, but on the other hand they showed a significant increase in IL-10, GSH, AChE, dopamine, BDNF and NGF. These data suggest that combined vitamin D and exercise could be considered as a potential and effective line for treating AD.

Running exercise protects oligodendrocytes in the medial prefrontal cortex in chronic unpredictable stress rat model

Previous postmortem and animal studies have shown decreases in the prefrontal cortex (PFC) volume and the number of glial cells in the PFC of depression. Running exercise has been shown to alleviate depressive symptoms. However, the effects of running exercise on the medial prefrontal cortex (mPFC) volume and oligodendrocytes in the mPFC of depressed patients and animals have not been investigated. To address these issues, adult male rats were subjected to chronic unpredictable stress (CUS) for 5 weeks, followed by treadmill running for 6 weeks. Then, the mPFC volume and the mPFC oligodendrocytes were investigated using stereology, immunohistochemistry, immunofluorescence and western blotting. Using a CUS paradigm that allowed for the analysis of anhedonia, we found that running exercise alleviated the deficits in sucrose preference, as well as the decrease in the mPFC volume. Meanwhile, we found that running exercise significantly increased the number of CNPase⁺ oligodendrocytes and Olig2⁺ oligodendrocytes, reduced the ratio between Olig2⁺/NG2⁺ oligodendrocytes and Olig2⁺ oligodendrocytes and increased myelin basic protein (MBP), CNPase and Olig2 protein expression in the mPFC of the CUS rat model. However, running exercise did not change NG2⁺ oligodendrocyte number in the mPFC in these rats. These results indicated that running exercise promoted the differentiation of oligodendrocytes and myelin-forming ability in the mPFC in the context of depression. These findings suggest that the beneficial effects of running exercise on mPFC volume and oligodendrocytes in mPFC might be an important structural basis for the antidepressant effects of running exercise.

A New Technique for Research on Wound Healing through Extraction of Mandibular Lower Incisors in Wistar Rats

Objective The aim of this study was to explain a new technique for research on wound healing through extraction of mandibular lower incisors in Wistar rats.

Materials and Methods Fifty Wistar rats were used from studies using the experimental animal to investigate the effects of wound healing drugs on alveolar bone. The mandibular incisors of the Wistar rats were extracted using a special modified bein and special pulling pliers under general anesthesia. The tooth socket after extraction was closed using a 5.0 suture nylon needle.

Results The results of this technique used in this extraction showed 2% incisor tooth fracture and 3% bleeding, and that all fractured teeth could be removed properly, and bleeding could be stopped after suturing.

Conclusion The new techniques we use can be useful for research on mucosal and alveolar bone healing, specifically finding new types of drugs to accelerate wound healing after alveolar bone post extraction.

Methanol stem bark extract of Adansonia digitata ameliorates chronic unpredictable mild stress-induced depression-like behavior: Involvement of the HPA axis, BDNF, and stress biomarkers pathways

Background Adansonia digitata L. (Malvaceae) is used locally in the management of depressive illnesses, and its antidepressant-like effect has been previously reported. The present study was aimed at determining the effect of the methanol extract of the stem bark of A. digitata (MEAD) on chronic unpredictable mild stress (CUMS) and the possible mechanism responsible for its antidepressant activity. Methods Acute toxicity of MEAD was determined using the OECD guideline 420. The CUMS model was used to induce depression, and behavioral tests such as sucrose preference test (SPT), open field test (OFT), novel-object recognition test (NORT), and tail suspension test (TST) were carried out in mice. The concentrations of plasma cortisol and brain-derived neurotrophic factor (BDNF) protein in the brain were assessed using enzyme-linked immunosorbent assay kits. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were assessed using colorimetric methods. Results The LD50 was established to be ≥5000 mg/kg. On CUMS-induced depression, MEAD significantly (p ≤ 0.05) and dose dependently reversed the weight loss, increased the line-crossing activity in OFT, increased sucrose consumption in SPT, decreased the duration of immobility in TST, and increased the novelty exploration time in NORT. The MEAD extract significantly (p ≤ 0.05) and dose dependently increased the levels of BDNF, decreased the levels of plasma cortisol, increased the levels of total SOD activity, and decreased the levels of plasma MDA. Conclusion Our findings show that MEAD ameliorates CUMS-induced depressive-like behavior and its effect is possibly mediated via the neuroendocrine, neurotrophic, and oxidative stress pathways.

Tactile Stimulation on Adulthood Modifies the HPA Axis, Neurotrophic Factors, and GFAP Signaling Reverting Depression-Like Behavior in Female Rats

Depression is a common psychiatric disease which pharmacological treatment relieves symptoms, but still far from ideal. Tactile stimulation (TS) has shown beneficial influences in neuropsychiatric disorders, but the mechanism of action is not clear. Here, we evaluated the TS influence when applied on adult female rats previously exposed to a reserpine-induced depression-like animal model. Immediately after reserpine model (1 mg/kg/mL, 1×/day, for 3 days), female Wistar rats were submitted to TS (15 min, 3×/day, for 8 days) or not (unhandled). Imipramine (10 mg/kg/mL) was used as positive control. After behavioral assessments, animals were euthanized to collect plasma and prefrontal cortex (PFC). Behavioral observations in the forced swimming test, splash test, and sucrose preference confirmed the reserpine-induced depression-like behavior, which was reversed by TS. Our findings showed that reserpine increased plasma levels of adrenocorticotropic hormone and corticosterone, decreased brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B, and increased proBDNF immunoreactivity in the PFC, which were also reversed by TS. Moreover, TS reestablished glial fibrillary acidic protein and glucocorticoid receptor levels, decreased by reserpine in PFC, while glial cell line-derived neurotrophic factor was increased by TS per se. Our outcomes are showing that TS applied in adulthood exerts a beneficial influence in depression-like behaviors, modulating the HPA axis and regulating neurotrophic factors more effectively than imipramine. Based on this, our proposal is that TS, in the long term, could be considered a new therapeutic strategy for neuropsychiatric disorders improvement in adult life, which may represent an interesting contribution to conventional pharmacological treatment.

Influence of Quadrato Motor Training on Salivary proNGF and proBDNF

Previous studies demonstrated exercise-induced modulation of neurotrophins, such as Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF). Yet, no study that we are aware of has examined their change as a function of different training paradigms. In addition, the understanding of the possible training-induced relationship between NGF and BDNF change is still lacking. Consequently, in the current study we examined the effect of a Walking Training (WT) and of Quadrato Motor Training (QMT) on NGF and BDNF precursors (proNGF and proBDNF). QMT is a specifically structured sensorimotor training that involves sequences of movements based on verbal commands, that was previously reported to improve spatial cognition, reflectivity, creativity as well as emotion regulation and general self-efficacy. In addition, QMT was reported to induce electrophysiological and morphological changes, suggesting stimulation of neuroplasticity processes. In two previous independent studies we reported QMT-induced changes in the salivary proNGF and proBDNF levels. Our present results demonstrate that following 12 weeks of daily QMT practice, proNGF level increases while proBDNF showed no significant change. More importantly, while no correlation between the two neurotrophins prior to training was detectable, there was a significant correlation between change in proNGF and proBDNF levels. Taken together the current results suggest that the two neurotrophins undergo a complex modulation, likely related to the different pathways by which they are produced and regulated. Since variations of these neurotrophins have been previously linked to depression, stress and anxiety, the current study may have practical implications and aid in understanding the possible physiological mechanisms that mediate improved well-being, and the dynamic change of neurotrophins as a result of training.

Differential expression of genes in the subgranular zone and granular cell layer of the hippocampus after running

[Purpose]

Despite numerous studies, the mechanisms underlying the effects of exercise on brain function are not yet fully understood. Adult hippocampal neurogenesis is one of the most well-known effects of exercise on the brain, but its physiological roles during exercise are still ambiguous, mostly due to the difference in the structure and composition of each part of the hippocampus.

[Methods]

In this study, we analyzed exercise-induced changes in gene expression in the subgranular zone (SGZ) and granular cell layer (GCL) of the hippocampus.

[Results]

Surprisingly, only about 10% of changes were common to both areas. Tollip expression, which is altered in the SGZ and in Engrailed-2 mutant mice following exercise, did not change in the GCL. Tollip levels were not changed in the whole hippocampus after two weeks of treadmill exercise, but immunofluorescence analysis showed that Tollip and Ki-67 co-localize in the hippocampal dentate gyrus . Through siRNA knockdown experiments, we found that levels of DCX and cellular survival rates were decreased in Tollip-deficient Neuro2A cells.

[Conclusion]

Taken together, these results suggest a role for Tollip in mediating the beneficial effects of exercise, probably affecting cellular health in the SGZ of the hippocampus.

Orexin/hypocretin receptor modulation of anxiolytic and antidepressive responses during social stress and decision-making: Potential for therapy

Hypothalmic orexin/hypocretin (Orx) neurons in the lateral and dorsomedial perifornical region (LH-DMH/PeF) innervate broadly throughout the brain, and receive similar inputs. This wide distribution, as well as two Orx peptides (Orx_A and Orx_B) and two Orx receptors (Orx₁ and Orx₂) allow for functionally related but distinctive behavioral outcomes, that include arousal, sleep-wake regulation, food seeking, metabolism, feeding, reward, addiction, and learning. These are all motivational functions, and tie the orexin systems to anxiety and depression as well. We present evidence, that for affective behavior, Orx₁ and Orx₂ receptors appear to have opposing functions. The majority of research on anxiety- and depression-related outcomes has focused on Orx₁ receptors, which appear to have primarily anxiogenic and pro-depressive actions. Although there is significant research suggesting contrary findings, the primary potential for pharmacotherapies linked to the Orx₁ receptor is via antagonists to block anxious and depressive behavior. Dual orexin receptor antagonists have been approved for treatment of sleep disorders, and are likely candidates for adaptation for affect disorder treatments. However, we present evidence here that demonstrates the Orx₂ receptors are anxiolytic and antidepressive. Using a new experimental pre-clinical model of anxious and depressive behavior stimulated by social stress and decision-making that produces two stable behavioral phenotypes, Escape/Resilient and Stay/Susceptible, we tested the effects of intracerebroventricular injections of Orx₂ agonist and antagonist drugs. Over ten behavioral measures, we have demonstrated that Orx₂ agonists promote resilience, as well as anxiolytic and antidepressive behavior. In contrast, Orx₂ antagonists or knockdown kindle anxious and pro-depressive behavior plus increase susceptibility. The results suggest that the Orx₂ receptor may be a useful target for pharmacotherapies to treat anxiety and depression.

Protective Effects of Liu Wei Di Huang Wan on the Liver, Orbitofrontal Cortex Nissl Bodies, and Neurites in MSG+PH-Induced Liver Regeneration Rat Model

Introduction. To examine the protective effects of Liu Wei Di Huang Wan formula (LWDH) on liver and orbitofrontal cortex (OFC) injuries in monosodium glutamate (MSG) and partial hepatectomy (PH) rat model. Methods. Neonatal Wistar rats were given MSG or saline on postnatal days 2, 4, 6, 8, and 10. The rats were caged into five groups and treated accordingly at six weeks old as follows: Saline group, Saline+PH group, MSG group, MSG+PH group, and LWDH group (MSG+PH+LWDH). The PH was performed during week 8 by excision of the left and median hepatic lobes (occupying about 68% of whole liver).On day 8 after the PH, the rats were subjected to an inner OFT before being sacrificed. The liver and OFC were stained using H&E, ORO, or Nissl staining. The expression of neurotrophic factors (β-NGF, BDNF) was examined in the OFC lysates by ELISA. Serum levels of cytokines (IL-1β, VEGF) were examined using the Bio-Plex suspension array. Results. LWDH increased the total distance traveled by the animals (p<0.05), and LWDH improved the integrity of the Nissl bodies in the OFC (mean area of the Nissl bodies, p<0.01; mean diameter, p<0.05; mean density, p<0.05; and IOD, p<0.01). There were less white area in the liver (p>0.05) and decreased hepatic steatosis (p<0.01) in LWDH group. LWDH administration decreased the expression of serum levels of IL-1β (p>0.05), while it increased VEGF (p>0.05) expression. LWDH administration increased the expression of BDNF (p>0.05) and β-NGF (p>0.05) in the OFC, all as compared to the MSG+PH group. Conclusion. LWDH partly protected the animals from depressive-like behaviors in the MSG+PH-induced liver regeneration neonatal rat model. LWDH alleviated hepatic injury and steatosis and, furthermore, protected the Nissl body integrity and the growth of neurites.

Treadmill exercise alleviated prenatal buprenorphine exposure-induced depression in rats

Mounting evidence suggests that physical exercise shows health benefits in a range of diseases, including psychiatric disorders. Perinatal opioid exposure produces neurobehavioral abnormality, which includes depression symptoms, in patients and their offspring following chronic use of buprenorphine, a mixed agonist/antagonist with a high affinity to opioid receptors, for pain control. Previously, we demonstrated that prenatal buprenorphine exposure in pregnant Sprague-Dawley rats starting from gestation day 7 and lasting for 14 days caused the development of depression-like phenotypes in pups at postnatal day 21. Using the same prenatal buprenorphine exposure model, we further demonstrated that a 4-week course of moderate treadmill exercise conducted on pups starting from postnatal day 22 improved depression-like neurobehaviors. Prenatal buprenorphine exposure-induced neurobehavioral changes were accompanied by reductions of neuronal survival, neural stem cell-associated genes, plasma level of brain-derived neurotrophic factor (BDNF) and serotonin, phosphorylated tropomyosin-related kinase receptor type B (TrkB), phosphorylated extracellular signal-regulated kinase (ERK), PKA activity, phosphorylated cAMP response element-binding protein (CREB), and CREB DNA binding activity, as well as elevation of repressor element-1 silencing transcription factor (REST), oxidative stress, and inflammatory responses. Those changes in parameters of plasma and brain were improved by treadmill exercise. In conclusion, the findings of the current study suggest that a non-pharmacological option, i.e., moderate treadmill exercise, alleviated the development of depression-like neurobehaviors by resolving the oxidative and inflammatory burden as well as by enhancing neurochemical and neuroendocrine signaling.

Long-term voluntary exercise prevents post-weaning social isolation-induced cognitive impairment in rats

This study aimed to determine the effect of exercise on locomotion, anxiety-related behavior, learning, and memory in socially isolated post-weaning rats, as well as the correlation between exercise and the concentration of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the hippocampus. Rats were randomly assigned to three groups: the control group; the social isolation group; the social isolation plus exercise (SIE) group. Social isolation conditions, with or without exercise were maintained for 90d, and then multiple behavioral tests, including the open-field test, elevated plus maze test, and Morris water maze (MWM) test were administered. Following behavioral assessment, hippocampal tissue samples were obtained for measurement of BDNF and NGF. There wasn't a significant difference in locomotor activity between the groups (P>0.05). Anxiety scores were higher in the socially isolated group (P<0.05) than in the SIE group (P<0.05). According to the probe trial session of the MWM test results, exercise training improved platform crossings' number in the socially isolated rats (P<0.05). Exercise training ameliorated social isolation-induced reduction in hippocampal BDNF and NGF content (P<0.05). These findings suggest that exercise training improves cognitive functions via increasing hippocampal BDNF and NGF concentrations in socially isolated post-weaning rats.

Hippocampal BDNF in physiological conditions and social isolation

Exposure of an organism to chronic psychosocial stress may affect brain-derived neurotrophic factor (BDNF) expression that has been implicated in the etiology of psychiatric disorders, such as depression. Given that depression in humans has been linked with social stress, the chronic social stress paradigms for modeling psychiatric disorders in animals have thus been developed. Chronic social isolation in animal models generally causes changes in hypothalamic-pituitary-adrenal axis functioning, associated with anxiety- and depressive-like behaviors. Also, this chronic stress causes downregulation of BDNF protein and mRNA in the hippocampus, a stress-sensitive brain region closely related to the pathophysiology of depression. In this review, we discuss the current knowledge regarding the structure, function, intracellular signaling, inter-individual differences and epigenetic regulation of BDNF in both physiological conditions and depression and changes in corticosterone levels, as a marker of stress response. Since BDNF levels are age dependent in humans and rodents, this review will also highlight the effects of adolescent and adult chronic social isolation models of both genders on the BDNF expression.

Exercise increases mTOR signaling in brain regions involved in cognition and emotional behavior

Exercise can enhance learning and memory and produce resistance against stress-related psychiatric disorders such as depression and anxiety. In rats, these beneficial effects of exercise occur regardless of exercise controllability: both voluntary and forced wheel running produce stress-protective effects. The mechanisms underlying these beneficial effects of exercise remain unknown. The mammalian target of rapamycin (mTOR) is a translation regulator important for cell growth, proliferation, and survival. mTOR has been implicated in enhancing learning and memory as well as antidepressant effects. Moreover, mTOR is sensitive to exercise signals such as metabolic factors. The effects of exercise on mTOR signaling, however, remain unknown. The goal of the present study was to test the hypothesis that exercise, regardless of controllability, increases levels of phosphorylated mTOR (p-mTOR) in brain regions important for learning and emotional behavior. Rats were exposed to 6 weeks of either sedentary (locked wheel), voluntary, or forced wheel running conditions. At 6 weeks, rats were sacrificed during peak running and levels of p-mTOR were measured using immunohistochemistry. Overall, both voluntary and forced exercise increased p-mTOR-positive neurons in the medial prefrontal cortex, striatum, hippocampus, hypothalamus, and amygdala compared to locked wheel controls. Exercise, regardless of controllability, also increased numbers of p-mTOR-positive glia in the striatum, hippocampus, and amygdala. For both neurons and glia, the largest increase in p-mTOR positive cells was observed after voluntary running, with forced exercise causing a more modest increase. Interestingly, voluntary exercise preferentially increased p-mTOR in astrocytes (GFAP+), while forced running increased p-mTOR in microglia (CD11+) in the inferior dentate gyrus. Results suggest that mTOR signaling is sensitive to exercise, but subtle differences exist depending on exercise controllability. Increases in mTOR signaling could contribute to the beneficial effects of exercise on cognitive function and mental health.

Type 2 Deiodinase Disruption in Astrocytes Results in Anxiety-Depressive-Like Behavior in Male Mice

Millions of levothyroxine-treated hypothyroid patients complain of impaired cognition despite normal TSH serum levels. This could reflect abnormalities in the type 2 deiodinase (D2)-mediated T4-to-T3 conversion, given their much greater dependence on the D2 pathway for T3 production. T3 normally reaches the brain directly from the circulation or is produced locally by D2 in astrocytes. Here we report that mice with astrocyte-specific Dio2 inactivation (Astro-D2KO) have normal serum T3 but exhibit anxiety-depression-like behavior as found in open field and elevated plus maze studies and when tested for depression using the tail-suspension and the forced-swimming tests. Remarkably, 4 weeks of daily treadmill exercise sessions eliminated this phenotype. Microarray gene expression profiling of the Astro-D2KO hippocampi identified an enrichment of three gene sets related to inflammation and impoverishment of three gene sets related to mitochondrial function and response to oxidative stress. Despite normal neurogenesis, the Astro-D2KO hippocampi exhibited decreased expression of four of six known to be positively regulated genes by T3, ie, Mbp (∼43%), Mag (∼34%), Hr (∼49%), and Aldh1a1 (∼61%) and increased expression of 3 of 12 genes negatively regulated by T3, ie, Dgkg (∼17%), Syce2 (∼26%), and Col6a1 (∼3-fold) by quantitative real-time PCR. Notably, in Astro-D2KO animals, there was also a reduction in mRNA levels of genes known to be affected in classical animal models of depression, ie, Bdnf (∼18%), Ntf3 (∼43%), Nmdar (∼26%), and GR (∼20%), which were also normalized by daily exercise sessions. These findings suggest that defects in Dio2 expression in the brain could result in mood and behavioral disorders.

The Antidepressant Effect of Angelica sinensis Extracts on Chronic Unpredictable Mild Stress-Induced Depression Is Mediated via the Upregulation of the BDNF Signaling Pathway in Rats

Angelica sinensis (AS), a traditional Chinese herbal medicine, has pharmaceutical effects on menstrual illness, cerebrovascular diseases, cardiovascular diseases, and cognitive impairments. However, until recently, few studies had explored its antidepressant effect. The current study attempts to investigate the effect of AS extracts on chronic unpredictable mild stress- (CUMS-) induced depression in rats. Male SD rats were exposed to a CUMS-inducing procedure for 5 weeks, resulting in rodent depressive behaviors that included reduced sucrose consumption and lessened sucrose preference ratios in sucrose preference test, prolonged immobility times and decreased struggling time in force swim test, and decreased locomotor activity in open field test. Moreover, the expression of brain derived neurotrophic factor (BDNF) and the phosphorylation of cAMP-response element binding protein (CREB) and extracellular signal-regulated protein kinase (ERK 1/2) were markedly decreased in the hippocampus in depressed rats. However, chronically treating the depressed rats with AS (1 g/kg) normalized their depression-related behaviors and molecular profiles. In conclusion, in the present study, we show that AS extracts exerted antidepressant effects that were mediated by the BDNF signaling pathway: in AS-treated depressed rats, the expression of the BDNF protein and the phosphorylation of its downstream targets (ERK 1/2, CREB) were upregulated in the hippocampus.

A Bidirectional Relationship between Executive Function and Health Behavior: Evidence, Implications, and Future Directions

Physically active lifestyles and other health-enhancing behaviors play an important role in preserving executive function into old age. Conversely, emerging research suggests that executive functions facilitate participation in a broad range of healthy behaviors including physical activity and reduced fatty food, tobacco, and alcohol consumption. They do this by supporting the volition, planning, performance monitoring, and inhibition necessary to enact intentions and override urges to engage in health damaging behavior. Here, we focus firstly on evidence suggesting that health-enhancing behaviors can induce improvements in executive function. We then switch our focus to findings linking executive function to the consistent performance of health-promoting behaviors and the avoidance of health risk behaviors. We suggest that executive function, health behavior, and disease processes are interdependent. In particular, we argue that a positive feedback loop may exist whereby health behavior-induced changes in executive function foster subsequent health-enhancing behaviors, which in turn help sustain efficient executive functions and good health. We conclude by outlining the implications of this reciprocal relationship for intervention strategies, the design of research studies, and the study of healthy aging.

Central monoaminergic systems are a site of convergence of signals conveying the experience of exercise to brain circuits involved in cognition and emotional behavior

Physical activity can enhance cognitive function and increase resistance against deleterious effects of stress on mental health. Enhanced cognitive function and stress resistance produced by exercise are conserved among vertebrates, suggesting that ubiquitous mechanisms may underlie beneficial effects of exercise. In the current review, we summarize the beneficial effects of exercise on cognitive function and stress resistance and discuss central and peripheral signaling factors that may be critical for conferring the effects of physical activity to brain circuits involved in cognitive function and stress. Additionally, it is suggested that norepinephrine and serotonin, highly conserved monoamines that are sensitive to exercise and able to modulate behavior in multiple species, could represent a convergence between peripheral and central exercise signals that mediate the beneficial effects of exercise. Finally, we offer the novel hypothesis that thermoregulation during exercise could contribute to the emotional effects of exercise by activating a subset of temperature-sensitive serotonergic neurons in the dorsal raphe nucleus that convey anxiolytic and stress-protective signals to forebrain regions. Throughout the review, we discuss limitations to current approaches and offer strategies for future research in exercise neuroscience.

Maternal alterations in the proteome of the medial prefrontal cortex in rat

Proteomic differences between rat dams and control mothers deprived of their pups immediately after delivery were investigated in the medial prefrontal cortex (mPFC). A 2-D DIGE minimal dye technique combined with LC-MS/MS identified 32 different proteins that showed significant changes in expression in the mPFC, of which, 25 were upregulated and 7 were downregulated in dams. The identity of one significantly increased protein, the small heat-shock protein alpha-crystallin B chain (Cryab), was confirmed via Western blot analysis. Alpha-crystallin B chain was distributed in scattered cells in the mPFC, as demonstrated by immunohistochemistry. Furthermore, it was found to be localized in parvalbumin-containing neurons using double labeling. The elevation of its mRNA level in rat dams was also demonstrated via RT-PCR. The functional classification of the altered proteins was conducted using the UniProt and Gene Ontology protein databases. The identified proteins predominantly participate in synaptic transport and plasticity, neuron development, oxidative stress and apoptosis, and cytoskeleton organization. A common regulator and target analysis of these proteins determined using the Elsevier Pathway Studio Platform suggests that protein level changes associated with pup nursing are driven by growth factors and cytokines, while the MAP kinase pathway was identified as a common target. A high proportion of the proteins that were found to be altered in the mPFC are associated with depression.

BIOLOGICAL SIGNIFICANCE

The behavior and emotional state of females change robustly when they become mothers. The brain, which governs these changes, may also undergo molecular alterations in mothers. As no proteomics approaches have been applied regarding maternal changes in the brain, we addressed this issue in the mPFC as this brain area is the uppermost cortical center of maternal control and the associated mood changes. The high number of protein-level alterations found between mothers taking care of their litter and those without pups indicates that pup nursing is associated with cortical protein-level changes. Alterations in proteins participating in synaptic transport, plasticity and neuron development suggest neuroplastic changes in the maternal brain. In turn, the relatively high number of altered proteins in the mPFC associated with depression suggests that the physiological effects of the protein-level alterations in the maternal mPFC could promote the incidence of postpartum depression. Cryab, a protein confirmed to be increased during maternal behaviors, was selectively found in parvalbumin cells, which, as fast-spiking interneurons, are associated with depression. The function of Cryab should be further investigated to establish whether it can be used to identify drug targets for future drug development.

Neuroprotective Effects of Voluntary Exercise in an Inherited Retinal Degeneration Mouse Model

PURPOSE

Our previous investigations showed that involuntary treadmill exercise is neuroprotective in a light-induced retinal degeneration mouse model, and it may act through activation of tropomyosin-related kinase B (TrkB) receptors. This study investigated whether voluntary running wheel exercise can be neuroprotective in an inheritable model of the retinal degenerative disease retinitis pigmentosa (RP), rd10 mice.

METHODS

Breeding pairs of rd10 and C57BL/6J mice were given free-spinning (active) or locked (inactive) running wheels. Pups were weaned into separate cages with their parents' respective wheel types, and visual function was tested with ERG and a virtual optokinetic system at 4, 5, and 6 weeks of age. Offspring were killed at 6 weeks of age and retinal cross-sections were prepared for photoreceptor nuclei counting. Additionally, separate cohorts of active and inactive rd10 pups were injected daily for 14 days after eye opening with a selective TrkB receptor antagonist (ANA-12) or vehicle solution and assessed as described above.

RESULTS

Mice in the rd10 active group exhibited significant preservation of visual acuity, cone nuclei, and total photoreceptor nuclei number. Injection with ANA-12 precluded the preservation of visual acuity and photoreceptor nuclei number in rd10 mice.

CONCLUSIONS

Voluntary running partially protected against the retinal degeneration and vision loss that otherwise occurs in the rd10 mouse model of RP. This protection was prevented by injection of ANA-12, suggesting that TrkB activation mediates exercise's preservation of the retina. Exercise may serve as an effective, clinically translational intervention against retinal degeneration.