rTMS Ameliorates Prenatal Stress-Induced Cognitive Deficits in Male-Offspring Rats Associated With BDNF/TrkB Signaling Pathway

Long-term voluntary running improves cognitive ability in developing mice by modulating the cholinergic system, antioxidant ability, and BDNF/PI3K/Akt/CREB pathway

Moderate physical exercise has positive effects on memory. The present study aimed to investigate the impact of long-term exercise on spatial memory in developing mice, as well as its association with the cholinergic system, antioxidant activities, apoptosis factor, and BDNF/PI3K/Akt/CREB pathway in the brain. In this study, Y maze and Novel object recognition (NOR) tests were employed to assess the impact of long-term voluntary exercise on memory. The cholinergic system, antioxidant activities, and apoptosis factors in the brain were quantified using Elisa. Additionally, western blot analysis was conducted to determine the expression of relevant proteins in the BDNF/PI3K/Akt/CREB pathway. The findings demonstrated that prolonged voluntary wheel running exercise enhanced memory in developing mice, concomitant with increased catalase (CAT) activity and decreased malondialdehyde (MDA) levels in the brain. Moreover, it could also increase the hippocampal acetylcholine (ACh) content and suppress the expression of neuronal apoptosis protein. Additionally, exercise also upregulated the expression of brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), phosphoinositide 3 kinases (PI3K), Akt, cAMP response element-binding protein (CREB), and phosphorylated cAMP response element-binding protein (p-CREB) in the hippocampus. These findings suggest that long-term voluntary wheel running exercise improves the spatial memory of developing mice by modulating the cholinergic system, antioxidant activities, apoptosis factors, and activating the BDNF/PI3K/Akt/CREB pathway.

Repetitive transcranial magnetic stimulation promotes motor function recovery in mice after spinal cord injury via regulation of the Cx43-autophagy loop

Spinal cord injury (SCI) is a severe condition with an extremely high disability rate. It is mainly manifested as the loss of motor, sensory and autonomic nerve functions below the injury site. High-frequency transcranial magnetic stimulation, a recently developed neuromodulation method, can increase motor function in mice with spinal cord injury. This study aimed to explore the possible mechanism by which transcranial magnetic stimulation (TMS) restores motor function after SCI. A complete T8 transection model of the spinal cord was established in mice, and the mice were treated daily with 15 Hz high-frequency transcranial magnetic stimulation. The BMS was used to evaluate the motor function of the mice after SCI. Western blotting and immunofluorescence were used to detect the expression of Connexin43 (CX43) and autophagy-related proteins in vivo and in vitro, and correlation analysis was performed to study the relationships among autophagy, CX43 and motor function recovery after SCI in mice. Western blotting was used to observe the effect of magnetic stimulation on the expression of mTOR pathway members. In the control group, the expression of CX43 was significantly decreased, and the expression of microtubule-associated protein 1 A/1b light chain 3 (LC3II) and P62 was significantly increased after 4 weeks of spinal cord transection. After high-frequency magnetic stimulation, the level of CX43 decreased, and the levels of LC3II and P62 increased in primary astrocytes. The BMS of the magnetic stimulation group was greater than that of the control group. High-frequency magnetic stimulation can inhibit the expression of CX43, which negatively regulates autophagic flux. HF-rTMS increased the expression levels of mTOR, p-mTOR and p-S6. Our experiments showed that rTMS can restore hindlimb motor function in mice after spinal cord injury via regulation of the Cx43-autophagy loop and activation of the mTOR signalling pathway.

Programmed cell death factor 4-mediated hippocampal synaptic plasticity is involved in early life stress and susceptibility to depression

Early life stress (ELS) increases the risk of depression later in life. Programmed cell death factor 4 (PDCD4), an apoptosis-related molecule, extensively participates in tumorigenesis and inflammatory diseases. However, its involvement in a person's susceptibility to ELS-related depression is unknown. To examine the effects and underlying mechanisms of PDCD4 on ELS vulnerability, we used a "two-hit" stress mouse model: an intraperitoneal injection of lipopolysaccharide (LPS) into neonatal mice was performed on postnatal days 7-9 (P7-P9) and inescapable foot shock (IFS) administration in adolescent was used as a later-life challenge. Our study shows that compared with mice that were only exposed to the LPS or IFS, the "two-hit" stress mice developed more severe depression/anxiety-like behaviors and social disability. We detected the levels of PDCD4 in the hippocampus of adolescent mice and found that they were significantly increased in "two-hit" stress mice. The results of immunohistochemical staining and Sholl analysis showed that the number of microglia in the hippocampus of "two-hit" stress mice significantly increased, with morphological changes, shortened branches, and decreased numbers. However, knocking down PDCD4 can prevent the number and morphological changes of microglia induced by ELS. In addition, we confirmed through the Golgi staining and immunohistochemical staining results that knocking down PDCD4 can ameliorate ELS-induced synaptic plasticity damage. Mechanically, the knockdown of PDCD4 exerts neuroprotective effects, possibly via the mediation of BDNF/AKT/CREB signaling. Combined, these results suggest that PDCD4 may play an important role in the ELS-induced susceptibility to depression and, thus, may become a therapeutic target for depressive disorders.

Repetitive transcranial magnetic stimulation impacts the executive function of patients with vascular cognitive impairment: a systematic review and meta-analysis

Objective

Executive dysfunction is a core symptom of vascular cognitive impairment (VCI), which seriously affects patients' prognosis. This paper aims to investigate the effectiveness of rTMS on executive function in VCI.

Methods

The databases selected for this study included Pubmed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, China Science and Technology Journal Database (VIP), and China Biology Medicine Disc (CBM). The screening times were conducted from the time of library construction until August 23, 2023. The inclusion criteria for this meta-analysis were randomized controlled trials (RCTs) on rTMS for VCI, which include executive function scores. The primary metrics were executive subscale scores of the Cognitive Comprehensive Scale and total scores of the Executive Specificity Scale. The secondary metrics were subscale scores of the Executive Specificity Scale. The quality of each eligible study was assessed using the Cochrane Risk of Bias tool. Meta-analysis and bias analysis were performed using Stata (version 16.0) and RevMan (version 5.3).

Results

A total of 20 high-quality clinical RCTs with 1,049 samples were included in this paper. The findings from the primary outcomes revealed that within the rTMS group, there were significantly higher scores observed for the executive sub-item on the cognitive composite scale (SMD = 0.93, 95% CI = 0.77-1.08, p < 0.00001, I 2 = 14%) and the total score on the executive specific scale (SMD = 0.69, 95% CI = 0.44-0.94, p < 0.00001, I 2 = 0%) compared to the control group. As for the secondary outcome measures, as shown by the Trail Making Test-A (time) (MD = -35.75, 95% CI = -68.37 to -3.12, p = 0.03, I 2 = 55%), the Stroop-C card (time) (SMD = -0.46, 95% CI = -0.86 to -0.06, p = 0.02, I 2 = 0%) and the Stroop-C card (correct number) (SMD = 0.49, 95% CI = 0.04-0.94, p = 0.03, I 2 = 0%), the experimental group shorts time and enhances accuracy of executive task in comparison to the control group. Subgroup analysis of the main outcome demonstrated that intermittent theta burst stimulation (iTBS), higher frequency, lower intensity, longer duration, and combined comprehensive therapy exhibited superior efficacy.

Conclusion

rTMS is effective in the treatment of the executive function of VCI. The present study has some limitations, so multi-center, large-sample, objective indicators and parameters are needed to further explore in the future.Systematic review registration:https://www.crd.york.ac.uk/prospero/, CRD42023459669.

Repetitive transcranial magnetic stimulation ameliorates cognitive deficits in mice with radiation-induced brain injury by attenuating microglial pyroptosis and promoting neurogenesis via BDNF pathway

BACKGROUND

Radiation-induced brain injury (RIBI) is a common and severe complication during radiotherapy for head and neck tumor. Repetitive transcranial magnetic stimulation (rTMS) is a novel and non-invasive method of brain stimulation, which has been applied in various neurological diseases. rTMS has been proved to be effective for treatment of RIBI, while its mechanisms have not been well understood.

METHODS

RIBI mouse model was established by cranial irradiation, K252a was daily injected intraperitoneally to block BDNF pathway. Immunofluorescence staining, immunohistochemistry and western blotting were performed to examine the microglial pyroptosis and hippocampal neurogenesis. Behavioral tests were used to assess the cognitive function and emotionality of mice. Golgi staining was applied to observe the structure of dendritic spine in hippocampus.

RESULTS

rTMS significantly promoted hippocampal neurogenesis and mitigated neuroinflammation, with ameliorating pyroptosis in microglia, as well as downregulation of the protein expression level of NLRP3 inflammasome and key pyroptosis factor Gasdermin D (GSDMD). BDNF signaling pathway might be involved in it. After blocking BDNF pathway by K252a, a specific BDNF pathway inhibitor, the neuroprotective effect of rTMS was markedly reversed. Evaluated by behavioral tests, the cognitive dysfunction and anxiety-like behavior were found aggravated with the comparison of mice in rTMS intervention group. Moreover, the level of hippocampal neurogenesis was found to be attenuated, the pyroptosis of microglia as well as the levels of GSDMD, NLRP3 inflammasome and IL-1β were upregulated.

CONCLUSION

Our study indicated that rTMS notably ameliorated RIBI-induced cognitive disorders, by mitigating pyroptosis in microglia and promoting hippocampal neurogenesis via mediating BDNF pathway.

Along the microbiota-gut-brain axis: Use of plant polysaccharides to improve mental disorders

With the development of gut microbiota-specific interventions for mental disorders, the interactions between plant polysaccharides and microbiota in the intestinal and their consequent effects are becoming increasingly important. In this review, we discussed the role of plant polysaccharides in improving various mental disorders via the microbiota-gut-brain axis. The chemical and structural characteristics and metabolites of these plant polysaccharides were summarised. Plant polysaccharides and their metabolites have great potential for reshaping gut microbiota profiles through gut microbiota-dependent fermentation. Along the microbiota-gut-brain axis, the consequent pharmacological processes that lead to the elimination of the symptoms of mental disorders include 1) regulation of the central monoamine neurotransmitters, amino acid transmitters and cholinergic signalling system; 2) alleviation of central and peripheral inflammation mainly through the NLRP3/NF-κB-related signalling pathway; 3) inhibition of neuronal apoptosis; and 4) enhancement of antioxidant activities. According to this review, monosaccharide glucose and structure -4-α-Glcp-(1→ are the most potent compositions of the most reported plant polysaccharides. However, the causal structure-activity relationship remains to be extensively explored. Moreover, mechanistic elucidation, safety verification, and additional rigorous human studies are expected to advance plant polysaccharide-based product development targeting the microbiota-gut-brain axis for people with mental disorders.

Repetitive transcranial magnetic stimulation and fluoxetine attenuate astroglial activation and benefit behaviours in a chronic unpredictable mild stress mouse model of depression

Objectives: Repetitive transcranial magnetic stimulation (rTMS) has been considered as an effective antidepressant treatment; however, the mechanism of its antidepressant effect is still unclear. Fluoxetine, a selective serotonin reuptake inhibitor antidepressant, may be neuroprotective. The objective of the present study was to evaluate the effect and underlying possible neuroprotective mechanism of rTMS and fluoxetine on abnormal behaviours in a depressive mouse model induced by chronic unpredictable mild stress (CUMS).Methods: After 28 days of CUMS exposure, mice were chronically treated with rTMS (10 Hz for 5 s per train, total 20 trains per day) and (or) fluoxetine (5 mg/kg/day, intraperitoneally) for 28 days targeting on the frontal cortex. After the behavioural tests, the protein expressions of glial fibrillary acidic protein (GFAP), brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) were measured by immunohistochemistry and (or) Western Blot.Results: The results showed rTMS and (or) fluoxetine attenuated the locomotion decrease, anxiety and depressive like behaviours in the CUMS-exposed mice.Conclusion: Our results suggest that both rTMS and fluoxetine could benefit the CUMS-induced abnormal behaviours including depressive-like behaviours, and the beneficial effects of rTMS as well as fluoxetine on depression might be partly related to their neuroprotective effect on attenuating astroglial activation and BDNF decrease.

The study of therapeutic efficacy and mechanisms of Schisandra chinensis and Evodia rutaecarpa combined treatment in a rat model of Alzheimer's disease

Schisandra chinensis and Evodia rutaecarpa are traditional Chinese herbs used to treat neurodegenerative diseases. This study investigates the combined effects of SC and ER on learning and memory in an Alzheimer's disease rat model and their underlying mechanisms.

Methods

High-performance liquid chromatography was employed to analyze the primary active constituents of Schisandra and Evodia. The effects of the combined treatment of Schisandra and Evodia on learning and memory in an Alzheimer's disease rat model were evaluated through Morris water maze and Hematoxylin-Eosin staining experiments. Immunohistochemical analysis was conducted to investigate the impact of S-E on Aβ1-42 and P-tau proteins. Western blotting and real-time quantitative polymerase chain reaction were utilized to quantify the expression of pivotal proteins and genes within the BDNF/TRKB/CREB and GSK-3β/Tau pathways.

Results

The treatment group exhibited significant neuroprotective effects, ameliorating learning and memory impairments in the Alzheimer's disease rat model. The treatment regimen modulated the activity of the BDNF/TRKB/CREB and GSK-3β/Tau pathways by influencing the expression of relevant genes, thereby reducing the generation of Aβ1-42 and P-Tau proteins and inhibiting the deposition of senile plaques. Furthermore, among the three treatment groups, the combined treatment demonstrated notably superior therapeutic effects on Alzheimer's disease compared to the single-drug treatment groups.

Different ratios of Schisandra chinensis and Evodia rutaecarpa combination for treating Alzheimer's disease

Schisandra chinensis and Evodia rutaecarpa are traditional Chinese herbs that have been used for many years to treat neurodegenerative diseases. In Chinese medicine, multiple herbs are often used in combination to enhance their efficacy, and different combination ratios can produce different therapeutic effects, thus flexibly responding to the needs of various patients. This study aimed to investigate the effects of different ratios of Schisandra and Evodia herbs on learning and memory impairment in rats with Alzheimer's disease (AD) and their specific mechanisms of action. Morris water maze and hematoxylin and eosin (HE) staining experiments were performed to evaluate the effects of different ratios of Schisandra-Evodia on learning memory in AD model rats. Immunohistochemical experiments were performed to investigate the effects of Schisandra-Evodia on the Aβ1-42 and P-Tau proteins, and protein immunoblotting (WB) was performed to determine the expression of key proteins in two pathways, BDNF/TrkB/CREB and GSK-3β/Tau. Our experimental results show that all Schisandra-Evodia groups showed significant neuroprotective effects, improved learning memory impairment, and reduced levels of Aβ1-42 and P-Tau proteins in AD model rats. Schisandra-Evodia upregulated BDNF, P-TrkB/TrkB, and P-CREB/CREB protein expression and downregulated GSK-3β and P-Tau/Tau protein expression. Among the different Schisandra-Evodia ratio groups, the 2:1 group showed the strongest therapeutic effect on AD. Our research results indicate that Schisandra-Evodia can reduce Aβ1-42 and P-Tau protein content by modulating the activity of two pathways, BDNF/TrkB/CREB and GSK-3β/Tau, thus improving neuronal cell damage and cognitive deficits caused by AD. In addition, we found that a Schisandra-Evodia ratio of 2:1 had the most profound therapeutic effect on AD.

Beta-caryophyllene mitigates the cognitive impairment caused by repeated exposure to aspartame in rats: Putative role of BDNF-TrKB signaling pathway and acetylcholinesterase activity

Aspartame (ASP) is a common sweetener, but studies show it can harm the nervous system, causing learning and memory deficits. β-caryophyllene (BCP), a natural compound found in foods, including bread, coffee, alcoholic beverages, and spices, has already described as a neuroprotector agent. Remarkably, ASP and BCP are commonly consumed, including in the same meal. Therefore, considering that (a) the BCP displays plenty of beneficial effects; (b) the ASP toxicity; and (c) that they can be consumed in the same meal, this study sought to investigate if the BCP would mitigate the memory impairment induced by ASP in rats and investigate the involvement of the brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrKB) signaling pathway and acetylcholinesterase (AChE) activity. Young male Wistar rats received ASP (75 mg/kg; i.g.) and/or BCP (100 mg/kg; i.p.) once daily, for 14 days. At the end of the treatment, the animals were evaluated in the open field and object recognition tests. The cerebral cortex and hippocampus samples were collected for biochemical and molecular analyses. Results showed that the BCP effectively protected against the cognitive damage caused by ASP in short and long-term memories. In addition, BCP mitigated the increase in AChE activity caused by ASP. Molecular insights revealed augmented BDNF and TrKB levels in the hippocampus of rats treated with BCP, indicating greater activation of this pathway. In conclusion, BCP protected against ASP-induced memory impairment. AChE activity and the BDNF/TrkB signaling pathway seem to be potential targets of BCP modulatory role in this study.

Sex-Dependent Effect of Chronic Piromelatine Treatment on Prenatal Stress-Induced Memory Deficits in Rats

Prenatal stress impairs cognitive function in rats, while Piromelatine treatment corrects memory decline in male rats with chronic mild stress. In the present study, we aimed to evaluate the effect of chronic treatment with the melatonin analogue Piromelatine on the associative and spatial hippocampus-dependent memory of male and female offspring with a history of prenatal stress (PNS). We report that male and female young adult offspring with PNS treated with a vehicle had reduced memory responses in an object recognition test (ORT). However, the cognitive performance in the radial arm maze test (RAM) was worsened only in the male offspring. The 32-day treatment with Piromelatine (20 mg/kg, i.p.) of male and female offspring with PNS attenuated the impaired responses in the ORT task. Furthermore, the melatonin analogue corrected the disturbed spatial memory in the male offspring. While the ratio of phosphorylated and nonphosphorylated adenosine monophosphate response element binding protein (pCREB/CREB) was reduced in the two sexes with PNS and treated with a vehicle, the melatonin analogue elevated the ratio of these signaling molecules in the hippocampus of the male rats only. Our results suggest that Piromelatine exerts a beneficial effect on PNS-induced spatial memory impairment in a sex-dependent manner that might be mediated via the pCREB/CREB pathway.

Altered cognition and anxiety in adolescent offspring whose mothers underwent different-pattern maternal sleep deprivation, and cognition link to hippocampal expressions of Bdnf and Syt-1

Background

Inadequate sleep during pregnancy negatively affects the neural development of offspring. Previous studies have focused on the continuous sleep deprivation (CSD) paradigm, but the sleep pattern during late pregnancy is usually fragmented.

Objective

To compare the effects of CSD and fragmented sleep deprivation (FSD) in late pregnancy on emotion, cognition, and expression of synaptic plasticity-related proteins in offspring mice.

Methods

Pregnant CD-1 mice were either subjected to 3/6 h of CSD/FSD during gestation days 15-21, while those in the control group were left untreated. After delivery, the offspring were divided into five groups, i.e., control (CON), short or long CSD (CSD3h, CSD6h), and short or long FSD (FSD3h, FSD6h). When the offspring were 2 months old, the anxiety-like behavior level was tested using the open field (OF) and elevated plus maze (EPM) test, and spatial learning and memory were evaluated using the Morris water maze (MWM) test. The expression of hippocampal of brain-derived neurotrophic factor (Bdnf) and synaptotagmin-1 (Syt-1) was determined using RT-PCR and western blotting.

Results

The CSD6h, FSD3h, and FSD6h had longer latency, fewer center times in the OF test, less open arms time and fewer numbers of entries in the open arms of the EPM, longer learning distance swam and lower memory percentage of distance swam in the target quadrant in the MWM test, and decreased BDNF and increased Syt-1 mRNA and protein levels in the hippocampus. Compared to the CSD6h, the FSD3h and FSD6h had longer distance swam, a lower percentage of distance swam in the target quadrant, decreased BDNF, and increased Syt-1 mRNA and protein levels in the hippocampus.

Conclusion

The results suggested that maternal sleep deprivation during late pregnancy impairs emotion and cognition in offspring, and FSD worsened the cognitive performance to a higher extent than CSD. The observed cognitive impairment could be associated with the expression of altered hippocampal of Bdnf and Syt-1 genes.

Sex differences in the vulnerability of the hippocampus to prenatal stress

Distressing events during pregnancy that engage activity of the body's endocrine stress response have been linked with later life cognitive deficits in offspring and associated with developmental changes in cognitive-controlling neural regions. Interestingly, prenatal stress (PS)-induced alterations have shown some sex specificity. Here, we review the literature of animal studies examining sex-specific effect of physical PS on the function and structure of the hippocampus as hippocampal impairments likely underlie PS-associated deficits in learning and memory. Furthermore, the connectivity between the hypothalamic-pituitary-adrenal (HPA) axis and the hippocampus as well as the heavy presence of glucocorticoid receptors (GRs) in the hippocampus suggests this structure plays an important role in modulation of activity within stress circuitry in a sex-specific pattern. We hope that better understanding of sex-specific, PS-related hippocampal impairment will assist in uncovering the molecular mechanisms behind sex-based risk factors in PS populations across development, and perhaps contribute to greater precision in management of cognitive disturbances in this vulnerable population.

Effects of Repetitive Transcranial Magnetic Stimulation on Gait and Postural Control Ability of Patients with Executive Dysfunction after Stroke

Objective: To assess the effects of repetitive transcranial magnetic stimulation (rTMS) on the gait and postural control ability of patients with executive dysfunction (ED) after stroke. Methods: A total of 18 patients with ED after stroke were randomly assigned into two groups, including an experimental group and a sham group. Patients in both groups received routine rehabilitation therapy, and patients in the experimental group underwent rTMS on the left dorsolateral prefrontal cortex (DLPFC) for 2 weeks (5 HZ, 80%MT, 1200 pulses). In the sham group, patients experienced sham stimulation treatment, in which the coil was placed vertically with the head. Before and after treatment, patients in both groups were subjected to Montreal cognitive assessment (MoCA) scoring, Fugl−Meyer assessment of lower extremity (L-FMA), Stroop color-word test (SCWT), gait analysis, foot plantar pressure test, 10-m walking test (10MWT), Berg balance scale (BBS), and timed up and go test (TUGT). In the SCWT, it was attempted to record the time of each card (SCWT-T), the correct number (SCWT-C), Stroop interference effect-time (SIE-T), and SIE correct count (SIE-C). The TUGT was categorized into four stages: getting up (GT), walking straight (WT), turning around (TT), and sitting down (ST), in which the total time of TUGT was calculated. Results: After two weeks of treatment, the evaluation indexes were improved in the two groups, some of which were statistically significant. In the experimental group, SCWT-T, SIE-T, SIE-C, GT, WT, TT, ST, and TUGT were significantly improved after treatment (p < 0.05). SCWT-C, L-FMA score, 10MWT, GT, WT, stride length, step width, foot plantar pressure, pressure center curve, and activities of daily living were not statistically different from those before treatment (p > 0.05). After treatment, SCWT-T, SIE-C, SIE-T, BBS score, TT, and ST in the experimental group were significantly shorter than those before treatment, with statistical differences (p < 0.05). Compared with the sham group, SCWT-C, L-FMA score, 10MWT, GT, WT, TUGT, stride length, step width, foot plantar pressure, pressure center curve, and motor skills were not significantly improved (p > 0.05). Conclusion: It was revealed that post-stroke rTMS treatment of patients with ED could improve executive function, improve postural control function, and reduce the risk of falling. In addition, rTMS of DLPFC could be a therapeutic target for improving postural control ability and reducing the risk of falling.

High-frequency repetitive transcranial magnetic stimulation improves spatial episodic learning and memory performance by regulating brain plasticity in healthy rats

Background

Repetitive transcranial magnetic stimulation (rTMS) is an effective way to stimulate changes in structural and functional plasticity, which is a part of learning and memory. However, to our knowledge, rTMS-induced specific activity and neural plasticity in different brain regions that affect cognition are not fully understood; nor are its mechanisms. Therefore, we aimed to investigate rTMS-induced cognition-related neural plasticity changes and their mechanisms in different brain regions.

Methods

A total of 30 healthy adult rats were randomly divided into the control group and the rTMS group (n = 15 rats per group). The rats in the control and the rTMS group received either 4 weeks of sham or high-frequency rTMS (HF-rTMS) over the prefrontal cortex (PFC). Cognitive function was detected by Morris water maze. Functional imaging was acquired by resting-state functional magnetic resonance imaging (rs-fMRI) before and after rTMS. The protein expressions of BDNF, TrkB, p-Akt, Akt, NR1, NR2A, and NR2B in the PFC, hippocampus, and primary motor cortex (M1) were detected by Western blot following rTMS.

Results

After 4 weeks of rTMS, the cognitive ability of healthy rats who underwent rTMS showed a small but significant behavioral improvement in spatial episodic learning and memory performance. Compared with the pre-rTMS or the control group, rats in the rTMS group showed increased regional homogeneity (ReHo) in multiple brain regions in the interoceptive/default mode network (DMN) and cortico-striatal-thalamic network, specifically the bilateral PFC, bilateral hippocampus, and the left M1. Western blot analyses showed that rTMS led to a significant increase in the expressions of N-methyl-D-aspartic acid (NMDA) receptors, including NR1, NR2A, and NR2B in the PFC, hippocampus, and M1, as well as an upregulation of BDNF, TrkB, and p-Akt in these three brain regions. In addition, the expression of NR1 in these three brain regions correlated with rTMS-induced cognitive improvement.

Conclusion

Overall, these data suggested that HF-rTMS can enhance cognitive performance through modulation of NMDA receptor-dependent brain plasticity.

Contribution of hippocampal BDNF/CREB signaling pathway and gut microbiota to emotional behavior impairment induced by chronic unpredictable mild stress during pregnancy in rats offspring

Background

Numerous studies have shown that exposure to prenatal maternal stress (PMS) is associated with various psychopathological outcomes of offspring. The accumulating evidence linking bacteria in the gut and neurons in the brain (the microbiota-gut-brain axis) has been aconsensus; however, there is a lack of research on the involvement mechanism of gut microbiota in the regulation of the BDNF/CREB signaling pathway in the hippocampus of prenatally stressed offspring.

Methods

Pregnant rats were subjected to chronic unpredictable mild stress (CUMS) to establish the prenatal maternal stress model. The body weight was measured and the behavioral changes were recorded. Offspring were tested to determine emotional state using sucrose preference test (SPT), open-field test (OFT) and suspended tail test (STT). Gut microbiota was evaluated by sequencing the microbial 16S rRNA V3-V4 region, and the interactive analysis of bacterial community structure and diversity was carried out. The expression of hippocampal BDNF, TrkB and CREB mRNA and proteins were respectively measured using RT-PCR and Western blotting.

Results

Prenatal maternal stress increased maternal plasma corticosterone levels, slowed maternal weight gain and caused depression-like behaviors (all P < 0.05). In offspring, prenatal maternal stress increased plasma corticosterone levels (P < 0.05) and emotional behavior changes (depression-like state) were observed (P < 0.05). The species abundance, diversity and composition of the offspring's gut microbiota changed after the maternal stress during pregnancy (P < 0.05). Compared with the control group's offspring, the species abundance of Lactobacillaceae was dropped, while the abundance of the Muribaculaceae species abundance was risen. Concurrent, changes in the hippocampal structure of the offspring and decreases in expression of BDNF/CREB signaling were noted (P < 0.05).

Conclusions

Prenatal maternal stress leads to high corticosterone status and abnormal emotion behavior of offspring, which may be associated with the abnormal BDNF/CREB signaling in hippocampus of offspring caused by the change of gut microbiota composition.

Hydroxytyrosol alleviates oxidative stress and neuroinflammation and enhances hippocampal neurotrophic signaling to improve stress-induced depressive behaviors in mice

Hydroxytyrosol (HT), the main phenolic compound in olives and olive products, has antioxidative, anti-inflammatory, neuroprotective, and other physiological functions. The effects of HT on depression are unclear. The aim of this study was to explore the effects of HT on chronic unpredictable mild stress (CUMS) induced depressive-like behaviors. Mice were exposed to CUMS for 9 weeks and then treated with HT beginning in the second week and continuing for 7 weeks. Behavioral, biochemical, and molecular tests were conducted at the end of the experiment. The sucrose preference was significantly decreased in the CUMS group versus the healthy control group. Also, immobility times in forced swimming and tail suspension tests were increased in CUMS-induced mice, but treatment with HT significantly reversed this change. HT ameliorated oxidative stress in CUMS-exposed mice by enhancing superoxide dismutase activity and reducing reactive oxygen species and malondialdehyde levels in the hippocampus. HT administration significantly suppressed microglia activation and inhibited the expression of tumor necrosis factor alpha and interleukin 1 beta in the hippocampus versus the untreated group. The expression level of glial fibrillary acidic protein (GFAP) and the number of GFAP-immunoreactive astrocytes in the hippocampus were significantly augmented by HT. Furthermore, HT treatment increased the expression of hippocampal brain-derived neurotrophic factor (BDNF), phosphorylated tropomyosin receptor kinase B (p-TrkB), and phosphorylated c-AMP response element binding protein (p-CREB) compared with the untreated CUMS group. Overall, HT improved CUMS-induced depressive-like behaviors in mice by alleviating oxidative stress and neuroinflammation and by enhancing the BDNF/TrkB/CREB signaling pathway.

Notoginsenoside R1 Improves Cerebral Ischemia/Reperfusion Injury by Promoting Neurogenesis via the BDNF/Akt/CREB Pathway

Notoginsenoside R1 (R1), a major component isolated from P. notoginseng, is a phytoestrogen that exerts many neuroprotective effects in a rat model of ischemic stroke. However, its long-term effects on neurogenesis and neurological restoration after ischemic stroke have not been investigated. The aim of this study was to evaluate the effects of R1 on neurogenesis and long-term functional recovery after ischemic stroke. We used male Sprague-Dawley rats subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). R1 was administered by intraperitoneal (i.p.) injection immediately postischemia. We showed that R1 significantly decreased infarct volume and neuronal loss, restored neurological function, and stimulated neurogenesis and oligodendrogenesis in rats subjected to MCAO/R. More importantly, R1 promoted neuronal proliferation in PC12 cells in vitro. The proneurogenic effects of R1 were associated with the activation of Akt/cAMP responsive element-binding protein, as shown by the R1-induced increase in brain-derived neurotrophic factor (BDNF) expression, and with the activation of neurological function, which was partially eliminated by selective inhibitors of BDNF and PI3K. We demonstrated that R1 is a promising compound that exerts neuroprotective and proneurogenic effects, possibly via the activation of BDNF/Akt/CREB signaling. These findings offer insight into exploring new mechanisms in long-term functional recovery after R1 treatment of ischemic stroke.

Application of expert system and LSTM in extracting index of synaptic plasticity

The indexes of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), can usually be measured by evaluating the slope and/or magnitude of field excitatory postsynaptic potentials (fEPSPs). So far, the process depends on manually labeling the linear portion of fEPSPs one by one, which is not only a subjective procedure but also a time-consuming job. In the present study, a novel approach has been developed in order to objectively and effectively evaluate the index of synaptic plasticity. Firstly, we introduced an expert system applying symbolic rules to discard the contaminated waveform in an interpretable way, and further generate supervisory signals for subsequent seq 2seq model based on neural networks. For the propose of enhancing the system generalization ability to deal with the contaminated data of fEPSPs, we employed long short-term memory (LSTM) networks. Finally, the comparison was performed between the automatically labeling system and manually labeling system. These results show that the expert system achieves an accuracy of 96.22% on Type-I labels, and the LSTM supervised by the expert system obtains an accuracy of 96.73% on Type-II labels. Compared to the manually labeling system, the hybrids system is able to measure the index of synaptic plasticity more objectively and efficiently. The new system can reach the level of the human expert ability, and accurately produce the index of synaptic plasticity in a fast way.

Fetal alcohol and maternal stress modify the expression of proteins controlling postnatal development of the male rat hippocampus

Background: Developing brains can partially get over prenatal alcohol exposure-related detrimental conditions by activating some mechanisms involved in survival. Objectives: This study aimed to shed light on the molecular correlates of compensatory mechanisms by examining temporal profiles in the expression of proteins controlling postnatal development in the rat hippocampus prenatally exposed to intubation stress/ethanol. Methods: Male pups were randomly assigned to age subgroups (n = 21/age) which were sacrificed on postnatal day (PD)1, PD10, PD30, and PD60. Ethanol (6 g/kg/day) were intragastrically intubated to the dams throughout 7-21 gestation days. The expression of neurogenesis and angiogenesis markers, extracellular matrix proteins, and growth-promoting ligands were examined by western blot. Results: The most rapid increase in the index of neuronal maturation was noted between PD10-PD30 (p < .05). Prenatal stress caused a decrease of neurogenesis markers at birth and an increase of their expressions at PD10 and PD30 to reach control levels (p < .001). The impact of fetal-alcohol was observed as a decrease in the expression of synaptic plasticity protein versican at birth (p < .001), an increase in the synaptic repulsion protein ephrin-B2 at PD10 (p < .001), and a decrease in the maturation of BDNF at PD30 (p < .001) with a decrease in the mature neuron markers at PD30 (p < .001) and PD60 (p = .005) which were compensated with upregulation of angiogenesis and increasing brevican expression, a neuronal maturation protein (p < .001). Conclusion: These data provide in vivo evidence for the potential therapeutic factors related to neurogenesis, angiogenesis, and neurite remodeling which may tolerate the alcohol/stress dependent teratogenicity in the developing hippocampus.

Over-expressed MST1 impaired spatial memory via disturbing neural oscillation patterns in mice

The activated mammalian Ste20-like serine/threonine kinases 1 (MST1) was found in the central nervous system diseases, such as cerebral ischemia, stroke and ALS, which were related with cognitions. The aim of this study was to examine the effect of elevated MST1 on memory functions in C57BL/6J mice. We also explored the underlying mechanism about the pattern alteration of neural oscillations, closely associated with cognitive dysfunctions, at different physiological rhythms, which were related to a wide range of basic and higher-level cognitive activities. A mouse model of the adeno-associated virus (AAV)-mediated overexpression of MST1 was established. The behavioral experiments showed that spatial memory was significantly damaged in MST1 mice. The distribution of either theta or gamma power was clearly disturbed in MST1 animals. Moreover, the synchronization in both theta and gamma rhythms, and theta-gamma cross-frequency coupling were significantly weakened in MST1 mice. In addition, the expressions of GABAA receptor, GAD67 and parvalbumin (PV) were obviously increased in MST1 mice. Meanwhile, blocking MST1 activity could inhibit the activation of FOXO3a and YAP. The above data suggest that MST1-overexpression may induce memory impairments via disturbing the patterns of neural activities, which is possibly associated with the abnormal GABAergic expression level.

Angelica polysaccharide ameliorates memory impairment in Alzheimer's disease rat through activating BDNF/TrkB/CREB pathway

This study aimed to investigate the effect of Angelica sinensis polysaccharides (ASP) on Alzheimer’s disease (AD) and its underlying mechanisms. In our study, we build the AD model by injecting Aβ25–35. Morris water maze (MWM) was applied to investigate learning and memory. Moreover, neurotransmitters, free radical, and inflammatory factors were also measured. Pathological change and neuronal death in hippocampus CA1, CA3, and DG region were detected by HE staining and Nissl staining. The neuronal apoptosis was detected by TUNEL. The expressions of caspase-3, Bcl-2 and Bax were measured by immunohistochemistry and Western blot. The expressions of BDNF, TrkB, p-Akt, Akt, p-CREB, and CREB were measured by Western blot. Our results showed that ASP could ameliorate spatial learning and memory deficiency in AD rats. ASP decreased AchE level and increased the levels of Ach and chAT in AD rats. ASP could increase the activity of SOD and CAT, decrease MDA activity, and inhibit the expression levels of inflammatory factors and neurons apoptosis in AD rats. Pathological change of hippocampus CA1, CA3, and DG region was ameliorated by ASP. In addition, the effects of ASP were reversed by K252a (TrkB inhibitor). Our study demonstrated that ASP could ameliorate memory impairment in AD rat through activating BDNF/TrkB/CREB pathway.

Impact statement

The present study demonstrated that ASP could ameliorate memory impairment through regulation of the balance of neurotransmitters, free radical metabolism, inflammation, and neurons apoptosis. Moreover, the mechanism of ASP on memory impairment may be related to BDNF/TrkB/CREB pathway in AD. Our research provides an innovatively regulatory mechanism about the ASP in AD rat and points a new way to the treatment of AD.

Transcriptional and epigenetic changes of brain derived neurotrophic factor following prenatal stress: A systematic review of animal studies

Gestational period plays critical role in neuropsychological development. One of the genes that undergoes changes by prenatal stress (PNS) exposure, is the gene coding brain derived neurotrophic factor (BDNF). Studies have reported different patterns of change following PNS in BDNF, which emphasizes the complexity of the issue. In this review, systematic search of PubMed, Scopus, Web of Science and Cochrane CENTRAL databases was performed. Primary searches resulted in 2132 studies and finally 43 studies were found to meet the inclusion criteria. Transcriptional and epigenetic changes of BDNF gene in the brain were recorded. Decreased or unchanged BDNF total mRNA and BDNF mature protein, with hypermethylation of the coding exons were the most reported changes. However, stress paradigm, gender of the fetus and the day of sacrifice were found to significantly affect the results. Hippocampus and prefrontal cortex are the most vulnerable regions. They can show long lasting and persistent transcriptional and epigenetics changes of BDNF gene following PNS. Further studies evaluating the importance of these findings in humans are essential.