The forced swim test as a model of depressive-like behavior

MCC950 ameliorates cognitive function by reducing white matter microstructure damage in rats after SAH

Neuroinflammation and white matter microstructure damage are important causes of cognitive impairment after subarachnoid hemorrhage (SAH). Nod-like receptor protein 3 (NLRP3) plays an important role in neuroinflammation after SAH and may be a potential therapeutic target for treatment of white matter microstructure injury. In this study, we observed whether MCC950, a specific inhibitor of the NLRP3 inflammasome, exerted a therapeutic effect after SAH. The SAH model was induced by endovascular perforation in SpragueDawley rats. MCC950 was injected intraperitoneally 1 h after SAH at a dose of 10 mg/kg. The results showed that MCC950 significantly attenuated white matter microstructure damage in some brain regions, and behavioral experiments confirmed that MCC950 ameliorated cognitive function in rats after SAH, which may provide a new method for the treatment of cognitive dysfunction in SAH patients.

Saffron carotenoids reversed the UCMS-induced depression and anxiety in rats: Behavioral and biochemical parameters, and hippocampal BDNF/ERK/CREB and NR2B signaling markers

BACKGROUND

Depression is a debilitating condition that affects the mind and the individual's body. The improving effects of saffron on depression and anxiety have long been discussed, with limited information about the molecular mechanism of action.

HYPOTHESIS/PURPOSE

Investigating the effect of saffron carotenoids, Crocin and Crocetin, on depression and anxiety in rats by emphasizing some signaling pathways involved.

STUDY DESIGN

Depression and anxiety were induced in rats via unpredictable chronic mild stress (UCMS). Then different rat groups were treated with Crocin, Crocetin, Fluoxetine, and vehicle. Behavioral tests were done before and after treatment.

METHODS

The serum Serotonin and Corticosterone and the expression of some hippocampal signaling proteins were studied. Furthermore, bioinformatics tools were used to predict the interactions of Crocin/ Crocetin with the Serotonin transporter and NMDA receptor subunit NR2B. Then, the patch-clamp was used to study the interaction of Crocetin with the NMDA receptor.

RESULTS

Various behavioral tests confirmed the induction of depression and the improvement of depression by these natural carotenoids. In addition, Crocin/ Crocetin significantly increased the decreased serum Serotonin and reduced the increased serum Corticosterone in the depressed groups. They also increased or caused a trend of increase in the CREB, ERK, BAD, BDNF, p11, and 5-HT1B expression in the hippocampus of the depressed groups. In addition, there were an increase or a trend in p-CREB/CREB, p-ERK1/2 /ERK1/2, and p-BAD/BAD ratios in the Crocin/ Crocetin treated depressed groups. However, the NR2B and FOXO3a expression showed a trend of decrease in depressed groups after treatment. The bioinformatics data indicated that Crocin/ Crocetin could bind to the Serotonin transporter (SLC6A4) and NR2B subunit of the NMDA receptor. Both carotenoids bind to the same site as Fluoxetine in the SLC6A4. However, they bound to different sites on the NR2B. So, Crocetin binds to NR2B at the same site as Ifenprodil. But Crocin bound to another site. The whole cell patch-clamp recording on the normal rat hippocampus revealed a significant decrease in the NMDA peak amplitude after Crocetin treatment, indicating its inhibitory effect on this receptor.

CONCLUSION

The antidepressant activities of Crocin/ Crocetin are possibly due to their effects on Serotonin and Corticosterone serum concentrations, NR2B expression, and the downstream signaling pathways. Furthermore, these natural carotenoids, like Fluoxetine, induced an increasing tendency in p11 and 5HT1B in depressed rats.

Chronic Pb Exposure Induces Anxiety and Depression-like Behaviors in Mice via Excitatory Neuronal Hyperexcitability in Ventral Hippocampal Dentate Gyrus

Lead (Pb) is a widespread neurotoxic pollutant. Pb exposure is associated with mood disorders, with no well-established neural mechanisms elucidated. In the present study, we aimed to investigate whether excitatory neurons in the dentate gyrus subregion of the ventral hippocampus (vDG) played a key role in Pb-induced anxiety and depression-like behaviors. C57BL/6 mice were exposed to 100 ppm Pb starting on day 1 of pregnancy until experiments were performed using the offspring. Behavioral studies suggested that chronic Pb exposure triggered anxiety and depression-like behaviors. A combination of electrophysiological, optogenetic, and immunohistochemistry experiments was conducted. Results showed that Pb exposure resulted in excitatory neuronal hyperexcitability in vDG and that the behavioral deficits caused by Pb exposure could be rescued by inhibition of excitatory neuronal activity. Moreover, it was found that the action potential (AP) threshold of excitatory neurons was decreased by electrophysiological recordings. Our study demonstrates a significant role for excitatory neurons in vDG in Pb-induced anxiety and depression-like behaviors in mice, which is likely a result of decreased AP threshold. These outcomes can serve as an important basis for understanding mechanisms of anxiety and depression under environmental Pb exposure and help in the design of therapeutic strategies.

Efficacy and Anti-Inflammatory Activity of Ashwagandha Sustained-Release Formulation on Depression and Anxiety Induced by Chronic Unpredictable Stress: in vivo and in vitro Studies

Background

Stress is the psychological, physiological, and behavioral response of an individual's body when they perceive a lack of equilibrium between the demands placed upon them and their ability to meet those demands. Adaptogens are herbs that help with stress management, and Ashwagandha is one such safe and effective adaptogen.

Objective

We evaluated the anti-neuroinflammatory potential of Ashwagandha sustained-release formulation (AshwaSR) by estimating the in vitro expression of pro-inflammatory cytokines, and its efficacy on anxiety and depression in an in vivo study.

Methods

Our in vitro study investigated the anti-inflammatory potential of AshwaSR by estimating the expression of tumour necrosis factor [TNF]-α and interleukin [IL]-1β levels in LPS-induced THP-1 human monocytes, and the antioxidant effects by its potential to inhibit the superoxide [SO] generation in PMA-induced HL-60 human monocytic cells. The in vivo study assessed the efficacy of AshwaSR on chronic unpredictable stress (CUS)-induced comorbid anxiety and depression in Sprague Dawley rats. Antidepressant and anxiolytic effects of AshwaSR were evaluated by open field test (OFT), elevated plus maze (EPM), forced swim test (FST), and Morris water maze (MWM) test.

Results

AshwaSR inhibited TNF-α, IL-1β and superoxide production in a dose-dependent manner in the in vitro study. The in vivo CUS model induced depression-like and anxiety-like behaviour. Treatments with AshwaSR and escitalopram showed improvement in the EPM and MWM models compared to the CUS-group.

Conclusion

In vitro study demonstrated that AshwaSR inhibits expressions of pro-inflammatory cytokines, IL-1β and TNF-α, and superoxide production. Further, the in vivo study confirmed its anxiolytic and stress-relieving effects in the CUS model that confirmed AshwaSR's potential in managing stress and stress-related symptoms.

SRSF10 regulates proliferation of neural progenitor cells and affects neurogenesis in developing mouse neocortex

Alternative pre-mRNA splicing plays critical roles in brain development. SRSF10 is a splicing factor highly expressed in central nervous system and plays important roles in maintaining normal brain functions. However, its role in neural development is unclear. In this study, by conditional depleting SRSF10 in neural progenitor cells (NPCs) in vivo and in vitro, we found that dysfunction of SRSF10 leads to developmental defects of the brain, which manifest as abnormal ventricle enlargement and cortical thinning anatomically, as well as decreased NPCs proliferation and weakened cortical neurogenesis histologically. Furthermore, we proved that the function of SRSF10 on NPCs proliferation involved the regulation of PI3K-AKT-mTOR-CCND2 pathway and the alternative splicing of Nasp, a gene encoding isoforms of cell cycle regulators. These findings highlight the necessity of SRSF10 in the formation of a structurally and functionally normal brain.

MPFC PV+ interneurons are involved in the antidepressant effects of running exercise but not fluoxetine therapy

Depression is a complex psychiatric disorder. Previous studies have shown that running exercise reverses depression-like behavior faster and more effectively than fluoxetine therapy. GABAergic interneurons, including the PV⁺ interneuron subtype, in the medial prefrontal cortex (MPFC) are involved in pathological changes of depression. It was unknown whether running exercise and fluoxetine therapy reverse depression-like behavior via GABAergic interneurons or the PV⁺ interneurons subtype in MPFC. To address this issue, we subjected mice with chronic unpredictable stress (CUS) to a 4-week running exercise or fluoxetine therapy. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that running exercise enriched GABAergic synaptic pathways in the MPFC of CUS-exposed mice. However, the number of PV⁺ interneurons but not the total number of GABAergic interneurons in the MPFC of mice exposed to CUS reversed by running exercise, not fluoxetine therapy. Running exercise increased the relative gene expression levels of the PV gene in the MPFC of CUS-exposed mice without altering other subtypes of GABAergic interneurons. Moreover, running exercise and fluoxetine therapy both significantly improved the length, area and volume of dendrites and the spine morphology of PV⁺ interneurons in the MPFC of mice exposed to CUS. However, running exercise but not fluoxetine therapy improved the dendritic complexity level of PV⁺ interneurons in the MPFC of mice exposed to CUS. In summary, the number and dendritic complexity level of PV⁺ interneurons may be important therapeutic targets for the mechanism by which running exercise reverses depression-like behavior faster and more effectively than fluoxetine therapy.

Effect of Broad-Spectrum Hemp Extract on Neurobehavioral Activity on the Immobilization Stress-Induced Model in Sprague Dawley Rats

Background

Broad-spectrum hemp extract is expected to be a promising new intervention for managing stress and anxiety. Research has shown that the cannabinoids found in Cannabis sativa, such as cannabidiol (CBD), tetrahydrocannabinol (THC), and cannabigerol (CBG), possess anxiolytic properties that can positively impact mood and stress.

Methods

In the current study, a broad-spectrum, nondetectable THC hemp extract with other minor cannabinoids (broad-spectrum hemp extract) was administered at 28 mg/kg·bw to evaluate its anxiolytic properties. This was performed using various behavioural models and biomarkers for oxidative stress. In addition, a 300 mg/kg·bw of Ashwagandha root extract was also incorporated to compare its effects on relieving stress and anxiety.

Results

The decreased levels of lipid peroxidation were measured in broad-spectrum hemp extract (36 nmol/ml), Ashwagandha (37 nmol/ml), and induction control (49 nmol/ml) treated groups of animals. The levels of 2-AG decreased in the broad-spectrum hemp extract (1.5 ng/ml), Ashwagandha (1.2 ng/ml), and induction control (2.3 ng/ml) treated groups of animals. The levels of FAAH decreased in broad-spectrum hemp extract (1.6 ng/ml), Ashwagandha (1.7 ng/ml), and induction control (1.9 ng/ml) treated groups of animals. The levels of catalase increased in broad-spectrum hemp extract (35 ng/ml), Ashwagandha (37 ng/ml), and induction control (17 ng/ml) treated groups of animals. Similarly, increased levels of glutathione were found in broad-spectrum hemp extract (30 ng/ml), Ashwagandha (27 ng/ml), and induction control (16 ng/ml) treated groups of animals.

Conclusion

Based on the results of this study, it can be concluded that broad-spectrum hemp extract inhibited the biomarkers for oxidative stress. Also, certain behavioural parameters showed improvements with respect to both the ingredient administered groups.

Early-life propofol exposure does not affect later-life GABAergic inhibition, seizure induction, or social behavior

The early developing brain is especially vulnerable to anesthesia, which can result in long lasting functional changes. We examined the effects of early-life propofol on adult excitatory-inhibitory balance and behavior. Postnatal day 7 male mice were exposed to propofol (250 mg/kg i.p.) and anesthesia was maintained for 2 h; control mice were given the same volume of isotonic saline and treated identically. The behavior and electrophysiology experiments were conducted when the mice were adults. We found that a 2-h neonatal propofol exposure did not significantly reduce paired pulse inhibition, alter the effect of muscimol (3 µM) to inhibit field excitatory postsynaptic potentials or alter the effect of bicuculline (100 µM) to increase the population spike in the CA1 region of hippocampal slices from adult mice. Neonatal propofol did not alter the evoked seizure response to pentylenetetrazol in adult mice. Neonatal propofol did not affect anxiety, as measured in the open field apparatus, depression-like behavior, as measured by the forced swim test, or social interactions with novel mice, in either the three-chamber or reciprocal social tests. These results were different from those with neonatal sevoflurane which demonstrated reduced adult GABAergic inhibition, increased seizure susceptibility and reduced social interaction. Even though sevoflurane and propofol both prominently enhance GABA inhibition, they have unique properties that alter the long-term effects of early-life exposure. These results indicate that clinical studies grouping several general anesthetic agents in a single group should be interpreted with great caution when examining long-term effects.

Potential Mechanisms of Imidacloprid-Induced Neurotoxicity in Adult Rats with Attempts on Protection Using Origanum majorana L. Oil/Extract: In Vivo and In Silico Studies

Imidacloprid (IMI) insecticide is rapidly metabolized in mammals and contributes to neurotoxicity via the blocking of nicotinic acetylcholine receptors, as in insects. Origanum majorana retains its great antioxidant potential in both fresh and dry forms. No data is available on the neuroprotective effect of this plant in laboratory animals. In this context, aerial parts of O. majorana were used to prepare the essential oil (OMO) and methanol extract (OME). The potential neuroprotective impact of both OMO and OME against IMI-induced neurotoxicity in rats was explored. Forty-two rats were divided into 6 groups, with 7 rats in each one. Rats were daily administered the oral treatments: normal saline, OMO, OME, IMI, IMI + OMO, and IMI + OME. Our results revealed the identification of 55 components in O. majorana essential oil, most belonging to the oxygenated and hydrocarbon monoterpenoid group. Moreover, 37 constituents were identified in the methanol extract, mostly phenolics. The potent neurotoxic effect of IMI on rats was confirmed by neurobehavioral and neuropathological alterations and a reduction of both acetylcholine esterase (AchE) activity and dopamine (DA), serotonin (5HT), and γ-aminobutyric acid (GABA) levels in the brain. Exposure of rats to IMI elevates the malondialdehyde (MDA) levels and reduces the antioxidant capacity. IMI could upregulate the transcription levels of nuclear factor-κB (NF-κB), interleukin-1 β (IL-1β), and tumor necrosis factor (TNF-α) genes and express strong caspase-3 and inducible nitric oxide synthase (iNOS) immunostaining in most examined brain areas. On the other hand, rats coadministered OMO or OME with IMI showed a marked improvement in all of the studied toxicological parameters. In conclusion, cotreatment of O. majorana extracts with IMI can protect against IMI neurotoxicity via their potent antioxidant, anti-inflammatory, and anti-apoptotic effects. Thus, we recommend a daily intake of O. majorana to protect against insecticide's oxidative stress-mediated neuroinflammatory stress and apoptosis. The molecular docking study of linalool, rosmarinic acid, γ-terpene, and terpene-4-ol justify the observed normalization of the elevated iNOS and TNF-α levels induced after exposure to IMI.

Functional magnetic resonance imaging study on anxiety and depression disorders induced by chronic restraint stress in rats

Persistent and negative stress stimulation is one of the most important factors leading to anxiety and depression in individuals, and it can negatively affect the normal function and structure of brain-related regions. However, the maladaptive changes of brain neural networks in anxiety and depression induced by chronic stress have not been explored in detail. In this study, we analyzed the changes in global information transfer efficiency, stress related blood oxygen level dependent (BOLD)- and diffusion tensor imaging (DTI)- signals and functional connectivity (FC) in rat models based on resting-state functional magnetic resonance imaging (rs-fMRI). The results showed that compared to control group, rats treated with chronic restraint stress (CRS) for 5 weeks had reconstructed the small-world network properties. In addition, CRS group had increased coherence and activity in bilateral Striatum (ST_R & L), but decreased coherence and activity in unilateral (left) Frontal Association Cortex (FrA_L) and unilateral (left) Medial Entorhinal Cortex (MEC_L). DTI analysis and correlation analysis confirmed the disrupted integrity of MEC_L and ST_R & L and their correlation to anxiety- and depressive-liked behaviors. Functional connectivity further showed these regions of interest (ROI) had decreased positive correlations with several brain areas, respectively. Our study comprehensively revealed the adaptive changes of brain neural networks induced by chronic stress and emphasized the abnormal activity and functional connectivity of ST_R & L and MEC_L in the pathological condition.

Solriamfetol improves chronic sleep fragmentation-induced increases in sleep propensity and ameliorates explicit memory in male mice

Obstructive sleep apnea (OSA) is a highly prevalent condition characterized by episodes of partial or complete breath cessation during sleep that induces sleep fragmentation (SF). One of the frequent manifestations of OSA is the presence of excessive daytime sleepiness (EDS) associated with cognitive deficits. Solriamfetol (SOL) and modafinil (MOD) are wake-promoting agents commonly prescribed to improve wakefulness in OSA patients with EDS. This study aimed to assess the effects of SOL and MOD in a murine model of OSA characterized by periodic SF. Male C57Bl/6J mice were exposed to either control sleep (SC) or SF (mimicking OSA) during the light period (06:00 h to 18:00 h) for 4 weeks, which consistently induces sustained excessive sleepiness during the dark phase. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg), or vehicle for 1 week while continuing exposures to SF or SC. Sleep/wake activity and sleep propensity were assessed during the dark phase. Novel Object Recognition test, Elevated-Plus Maze Test, and Forced Swim Test were performed before and after treatment. SOL or MOD decreased sleep propensity in SF, but only SOL induced improvements in explicit memory, while MOD exhibited increased anxiety behaviors. Chronic SF, a major hallmark of OSA, induces EDS in young adult mice that is mitigated by both SOL and MOD. SOL, but not MOD, significantly improves SF-induced cognitive deficits. Increased anxiety behaviors are apparent in MOD-treated mice. Further studies aiming to elucidate the beneficial cognitive effects of SOL are warranted.

Chronic fluoxetine treatment in socially-isolated rats modulates the prefrontal cortex synaptoproteome

Exposure to chronic social isolation (CSIS) and synapse dysfunction have been implicated in the etiology of major depressive disorder (MDD). Fluoxetine (Flx) has been widely used to treat MDD, but its mechanisms of action remain elusive. We employed comparative synaptoproteomics to investigate the changes in the levels of proteins and molecular signaling pathways in prefrontal cortical samples of adult male Wistar rats exposed to CSIS, a rat model of depression, and CSIS rats treated with chronic Flx and controls, using liquid chromatography coupled to tandem mass spectrometry. Flx-treated control rats showed a decreased level of proteins involved in vesicle-mediated transport, and a predominantly increased level of exocytosis-associated proteins. CSIS significantly reduced the level of proteins involved in the ATP metabolic process, clathrin-dependent endocytosis, and proteolysis. Flx treatment in CSIS rats stimulated synaptic vesicle trafficking by increasing the regulation of exo/endocytosis-associated proteins, proteins involved in synaptic plasticity including neurogenesis, Cox5a, mitochondria-associated proteins involved in oxidative phosphorylation, and ion transport proteins (Slc8a2, Atp1b2). Flx treatment resulted in an increased synaptic vesicle dynamic, plasticity and mitochondrial functionality, and a suppression of CSIS-induced impairment of these processes. BIOLOGICAL SIGNIFICANCE: Identifying biomarkers of MDD and treatment response is the goal of many studies. Contemporary studies have shown that many molecular alterations associated with the pathophysiology of MDD reside within the synapse. As part of this research, a growing importance is the use of proteomics, as monitoring the changes in protein levels enables the identification of (possible) biochemical pathways and processes of importance for the development of depressive-like behavior and the efficacy of antidepressant treatments. We profiled proteomic changes representative of the development of CSIS-induced depressive-like behavior and the antidepressant effects of Flx. Our study has identified synaptosomal proteins and altered molecular pathways that may be potential markers of prefrontal cortical synaptic dysfunction associated with depressive-like behavior, and further clarified the mechanisms of depressive-like behavior and mode of action of Flx. Our findings indicate potential PFC synaptic targets for antidepressant treatment.

Antidepressant and Anxiolytic Potentials of the Chewing Stick, Salvadora persica

Materials and Methods

Salvadora persica stem bark was extracted with two different solvents, i.e., ethyl acetate and water, and preliminary phytochemical screening was performed. Two behavioral models were used: an elevated plus maze test (EPM) and the light and dark model test for anxiolytic parameters, and a forced swim test (FST) for antidepressant effects. Healthy mice weighing 18-40 gms were treated orally in four groups (n = 6), i.e., negative control treated with normal saline and positive control with 1 mg/kg diazepam (EPM) and 30 mg/kg fluoxetine (FST), and the test groups were treated with 500 mg/kg of aqueous and ethyl acetate Sp extract. The number of entries and duration spent in the open arm for 5 minutes were the parameters for evaluating the anxiolytic activity (EPM). Duration of immobility was measured for 5 min in the FST model.

Results

In EPM, both the Sp extracts significantly (p < 0.005) increased the number of entries and the time spent in the open arms and was much similar to those of diazepam. Similarly, these extracts and fluoxetine significantly (p < 0.005) decreased the immobility time in FST.

Conclusion

The results suggest the therapeutic potential of Salvadora persica an alternative in the management of comorbid anxiety and depression.

Activation of CREB-BDNF Pathway in Pyramidal Neurons in the Hippocampus Improves the Neurological Outcome of Mice with Ischemic Stroke

Cerebral ischemia is characterized by several pathological reaction evolving over time. Hyperactivation of glutamatergic neurons is the main factor leading to excitotoxicity which potentiates oxidative stress and triggers the mechanisms of neural apoptosis after cerebral ischemia. However, it is unclear whether glutamate in the ventral hippocampal Cornus Ammonis 1 (vCA1) acts a part in neurological deficits, pain perception, anxiety, and depression induced by ischemic stroke. We investigated the effects of chemogenetic inhibition or activation of vCA1 pyramidal neurons which are mainly glutamatergic neurons on sequelae induced by cerebral ischemia. Our results revealed that inhibition of vCA1 pyramidal neurons by chemogenetics alleviated neurological deficits, pain perception, anxiety, and depression caused by cerebral ischemia in mice, but activation of vCA1 pyramidal neurons had limited effects. Moreover, we found that stroke was accompanied by decreased levels of cAMP-response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in vCA1, which are modulated by glutamate. In this study, overexpression of CREB protein in pyramidal neurons in vCA1 by AAV virus significantly upregulated the content of BDNF and ameliorated the dysfunction induced by ischemic stroke. Our results demonstrated activation of the CREB-BDNF pathway in vCA1 pyramidal neurons significantly improved neurological deficits, pain perception, anxiety, and depression induced by ischemic stroke.

Increased BDNF and hippocampal dendritic spine density are associated with the rapid antidepressant-like effect of iron-citalopram and iron-imipramine combinations in mice

Iron supplementation previously demonstrated antidepressant-like effects in post-partum rats. The present study evaluates the possible synergistic antidepressant effect of sub-therapeutic dose of iron co-administered with citalopram or imipramine in female Institute of Cancer Research mice. Depression-like symptoms were induced in the forced swim (FST), tail suspension (TST), and open space swim (OSST) tests while open field test (OFT) was used to assess locomotor activity. Mice (n=8) received iron (0.8- 7.2 mg/kg), citalopram (3-30 mg/kg), imipramine (3-30 mg/kg), desferrioxamine (50 mg/kg) or saline in the single treatment phase of each model and subsequently a sub-therapeutic dose of iron co-administered with citalopram or imipramine. Assessment of serum BDNF and dendritic spine density was done using ELISA and Golgi staining techniques respectively. Iron, citalopram and imipramine, unlike desferrioxamine, reduced immobility score in the TST, FST and OSST without affecting locomotor activity, suggesting antidepressant-like effect. Sub-therapeutic dose of iron in combination with citalopram or imipramine further enhanced the antidepressant-like effect, producing a more rapid effect when compared to the iron, citalopram or imipramine alone. Iron, citalopram and imipramine or their combinations increased serum BDNF concentration, hippocampal neuronal count and dendritic spine densities. Our study provides experimental evidence that iron has antidepressant-like effect and sub-therapeutic dose of iron combined with citalopram or imipramine produces more rapid antidepressant-like effect. We further show that iron alone or its combination with citalopram or imipramine attenuates the neuronal loss associated with depressive conditions, increases dendritic spines density and BDNF levels. These finding suggest iron-induced neuronal plasticity in the mice brain.

Long-lasting and sex-dependent effects of late lactational maternal deprivation on socioemotional behaviors in adult mice

The lactation period is an important period for individual development and a sensitive period for the behavioral phenotypes and plasticity of individual offspring. Early life experiences (e.g., maternal deprivation (MD) and neglect) have significant long-lasting and dual effects on individual stress reactivities during adulthood. Theoretically, stress inoculation can improve the adaptive capacity of the body, but overstress can lead to dysfunction when adaptive mechanisms fail.To date, the potential effects of late lactational MD on the socioemotional behaviors of mouse offspring during adulthood are still not fully understood. In the present study, mice were subjected to early deprivation by individually separating pups from their dam for 0 min, 15 min, and 3 h per day from PND 13-25. The social dominance test (SDT), social interaction test (SI), open field test (OFT), and forced swim test (FST) were carried out during adulthood. The results showed that the social dominance of male mice in the 15 min/d MD group significantly increased, especially in low-rank mice. In the 3 h/d MD group, the social dominance of female mice was decreased, especially in the lower-rank mice. The anxiolytic and antidepressant-like effects of the 15 min/d MD group were significantly increased in male mice. Our study provides direct evidence that MD during late lactation period results in long-lasting effects on social dominance as well as on anxiety and depression phenotypes in a sex-dependent manner.

Effects of the Recurrent and Different Doses of Ketamine Exposure on Anxiety-like Behaviors and Locomotor Activity in Juvenile Rats

BACKGROUND

Ketamine is a widely used anesthetic agent. Although the potential adverse effects of ketamine use in juvenile age are uncertain, certain studies reported that children exposed to recurrent anesthesia could face an increased risk of neurodevelopmental deficits in motor function and behavioral risks. We aimed to investigate the long-term effects of repeated exposure to various ketamine doses on anxious behavior and locomotor activity in juvenile rats.

OBJECTIVE

We aimed to investigate the long-term effects of repeated exposure to various ketamine doses on anxious behavior and locomotor activity in juvenile rats.

METHODS

Thirty-two Wistar Albino juvenile male rats were randomized into 5 mg/kg, 20 mg/kg, and 50 mg/kg ketamine (KET) and saline (Group C) Groups and KET was administered for 3 consecutive days at 3-hour intervals in 3 doses. Ten days after the last KET dose, behavioral parameters were analyzed with an open field test (OFT), elevated plus maze (EPM), and light-dark box (LDB). Satistical analysis was conducted with Kruskall-Wallis test followed by Dunn's Multiple Comparison Test.

RESULTS

Unsupported rearing behavior decreased in 50 mg/kg KET Groups when compared to Group C. Incorrect transition time, total grooming time, and transfer latency time increased significantly in the 50 mg/kg KET Group when compared to Group C.

CONCLUSION

These results suggested that 50 mg/kg KET led to anxiety-like behavior and destroyed memory and spatial navigation. Ketamine doses were associated with late effects of ketamine on anxiety- like behavior in juvenile rats. Further studies are needed to determine the mechanisms that play a role in the different effects of ketamine doses on anxiety and memory.

Omega-3 fatty acids prevent nicotine withdrawal-induced exacerbation of anxiety and depression by affecting oxidative stress balance, inflammatory response, BDNF and serotonin metabolism in rats

Adolescents are known to be more vulnerable than adults to the adverse effects of nicotine dependence. In the present study, we aimed to investigate whether adolescent nicotine exposure, followed by a period of abstinence, could affect the anxiety- and depressive-like behaviors in rats. For this purpose, behavioral assessments were carried out using open field test, elevated plus maze and forced swimming test in male rats received chronic nicotine intake during adolescence followed by a period of abstinence in adulthood, compared to their control counterparts. In addition, O3 pre-treatment was done at three different doses to reveal whether it could prevent nicotine withdrawal effects. Then, animals were euthanized and the cortical concentrations of oxidative stress markers, inflammatory indices, brain-derived neurotrophic factor, serotonin and the enzymatic activity of monoamine oxidase-A were measured. Results indicated that nicotine withdrawal exacerbates the behavioral signs of anxiety through alteration of the brain oxidative stress balance, inflammatory response and serotonin metabolism. Moreover, we found that omega 3 pre-treatment significantly prevents the nicotine withdrawal-induced complications by restoration of changes in the mentioned biochemical indices. Moreover, the improving effects of O3 fatty acids were found to be dose-dependent in all experiments. Taken together, we would like to suggest the O3 fatty acids supplementation as a safe, inexpensive and effective strategy for prevention or amelioration of detrimental effects induced by nicotine withdrawal at cellular and behavioral levels.

Role of Bifidobacterium spp. intake in improving depressive mood and well-being and its link to kynurenine blood level: an interventional study

OBJECTIVES

Evidence for the contribution of the brain-gut-microbiota axis to the depression pathophysiology is increasing nowadays. Disturbed gut microbiota equilibrium along with bad dietary habits both lead to kynurenine pathway abnormalities contributing to the depression pathophysiology. In this respect, many studies are found but the interventional clinical trials are limited. The present interventional study aims to evaluate the impact of Bifidobacterium spp. supplementation together with improving dietary intake on depressive mood and well-being and their correlation with kynurenine blood level in adult Egyptian healthy volunteers.

METHODS

A number of 98 healthy female volunteers with a mean age of 46.96 ± 1.82 years were selected and enrolled in this study. They were given yogurt enriched with Bifidobacterium spp. daily for eight weeks. Clinical examination as well as questionnaires for the evaluation of psychological well-being and depression were done at base line and after eight weeks of intervention. Fasting blood samples and stool samples were collected from all subjects at baseline and eight weeks after the intervention for the investigation of serum kynurenine concentration, blood hemoglobin, serum transaminases (ALT & AST) serum urea and creatinine as well as fecal Bifidobacterium count.

RESULTS

Data revealed that both depression and well-being showed highly significant improvement combined with significant drop in kynurenine blood level after intervention. Also, a significant rise in fecal Bifidobacterium count and a significant improvement in hemoglobin level and activity of liver enzymes were recorded. After intervention, a significant negative correlation was recorded between depression and fecal Bifidobacterium count as well as between serum kynurenine level, and well-being.

CONCLUSION

Bifidobacterium spp. supplementation combined with improvement in dietary intake resulted in improvement of depressive mood and well-being and reduced kynurenine blood level.

Blueberry Extract Modulates Brain Enzymes Activities and Reduces Neuroinflammation: Promising Effect on Lipopolysaccharide-Induced Depressive-Like Behavior

Major depressive disorder (MDD) is one of the most common neuropsychiatric disorders with high rates of prevalence and mortality. MDD is pathophysiologically complex, and treatment options are limited. Blueberries are rich in polyphenols and have neuroprotective potential. The aim of this study was to investigate the effects of blueberry extract on neuroinflammatory and neuroplasticity parameters, as well as Na⁺/K⁺-ATPase, monoamine oxidase-A (MAO-A), and acetylcholinesterase (AChE) activities in the cerebral cortex and hippocampus of mice subject to lipopolysaccharide (LPS)-induced depressive-like behavior. We also analyzed the interaction between anthocyanins and indoleamine 2 3-dioxygenase (IDO). Male Swiss mice (60-day-old) received vehicle, fluoxetine (20 mg/kg), or blueberry extract (100 or 200 mg/kg) intragastrically for 7 days before intraperitoneal LPS (0.83 mg/kg) injection. Twenty-four hours after LPS administration, the mice were subjected to behavioral tests. Both fluoxetine and blueberry extract (200 mg/kg) decreased the immobility time in the forced swim test, without affecting locomotor activity. Fluoxetine attenuated the decrease of Na⁺/K⁺-ATPase in the cerebral cortex, while blueberry extract promoted this same effect in the hippocampus. Additionally, fluoxetine and blueberry extract attenuated the decrease in the activity of MAO-A in the hippocampus. Blueberry extract (200 mg/kg) also prevented LPS-induced increase in AChE activity in the hippocampus as well as LPS upregulation of relative mRNA expression of tumor necrosis factor alpha, interleukin (IL)-1β, and IL-10 in the cerebral cortex. Molecular docking analysis revealed binding sites for malvidin 3-galactoside (- 7.8 kcal/mol) and malvidin 3-glucoside (- 7.9 kcal/mol) residues with IDO. Taken together, these results indicate that blueberry extract improved depression-like behavior and attenuated the neurochemical and molecular changes in the brains of mice challenged with LPS.

Inflammatory Immune Process and Depression-like Behavior in Hypothyroid Rats: A [18F] DPA-714 Micro Positron Emission Tomography Study

Hypothyroidism is closely related to mental disorders, mainly depression, through an as-yet-unknown mechanism. The cerebral inflammatory immune process has been implied to play a pivotal role in the onset of affective symptoms in several conditions. In order to gain insight into the mechanism underlying the depressive behaviors in hypothyroid rats, brain microglial activation was evaluated using micro positron emission tomography imaging with a translocator protein (TSPO) radioligand. Hypothyroidism was induced in adult male Wistar rats by administration of 0.05% propylthiouracil in drinking water for five weeks. Open field, forced swimming and tail suspension tests were employed to evaluate the depressive behavior in hypothyroid rats, and the relationship between the behavioral changes and brain microglial activation was evaluated using [18F] DPA-714 micro positron emission tomography imaging. The open field test revealed significantly reduced first-minute activity and rearing behavior in the hypothyroid group, as well as significantly increased immobility in the forced swimming test and the tail suspension test. Hypothyroidism induced significantly increased microglial activation in the hippocampus. The radioligand uptake in the hippocampus correlated negatively with first-minute activity in the open field test (p < 0.05), and the radioligand uptake in the hippocampus correlated positively with changes in the immobility time in the forced swimming test and the tail suspension test (p < 0.05). Immunohistochemistry also confirmed the activation of microglia and inflammatory bodies in hypothyroid rats. The results indicate that hypothyroidism can induce depressive behavior in adult Wistar rats, microglial activation in the hippocampus plays an important role in the depressive behavior in hypothyroid rats and the inflammatory immune mechanism may underlie the behavioral abnormalities in thyroid dysfunction. Furthermore, the findings in the present study suggest there might be a common mechanism underlying depressive behavior in adult-onset hypothyroidism and depression.

Impact of nonalcoholic fatty liver disease-related metabolic state on depression

Nonalcoholic fatty liver disease (NAFLD), also recently referred as metabolic (dysfunction)-associated fatty liver disease (MAFLD), is characterized by hepatocyte steatosis in the setting of metabolic risk conditions and in the absence of an underlying precursor, for instance alcohol consumption, hepatotropic viruses and hepatotoxic drugs. A possible association between NAFLD and depression has been proposed, owing to intersecting pathophysiological pathways. This narrative review aimed to summarize the current evidence that illustrate the potential pathophysiological and clinical linkage between NAFLD-related metabolic state and depression. Prefrontal cortex lesions are suggested to be a consequence of liver steatosis-associated systematic hyperinflammatory state, a phenomenon also occurring in depression. In addition, depressive symptoms are present in neurotransmitter imbalances. These abnormalities seem to be correlated with NAFLD/MAFLD, in terms of insulin resistance (IR), ammonia and gut dysbiosis' impact on serotonin, dopamine, noradrenaline levels and gamma aminobutyric acid receptors. Furthermore, reduced levels of nesfatin-1 and copine-6-associated BDNF (brain-derived neurotrophic factor) levels have been considered as a probable link between NAFLD and depression. Regarding NAFLD-related gut dysbiosis, it stimulates mediators including lipopolysaccharides, short-chain fatty acids and bile acids, which play significant role in depression. Finally, western diet and IR, which are mainstay components of NAFLD/MAFLD, are, also, substantiated to affect neurotransmitters in hippocampus and produce neurotoxic lipids that contribute to neurologic dysfunction, and thus trigger emotional disturbances, mainly depressive symptoms.

Serum amyloid P component (SAP) modulates antidepressant effects through promoting membrane insertion of the serotonin transporter

Serum amyloid P component (SAP) is a universal constituent of human amyloid deposits including those in Alzheimer's disease. SAP has been observed to be elevated in patients with depression, and higher SAP levels are associated with better response to the antidepressant escitalopram. The mechanisms underlying these clinical observations remain unclear. We examined the effect of SAP on serotonin transporter (SERT) expression and localization using Western blot, confocal microscopy, and positron emission tomography with the radioligand [11C]DASB. We also investigated the effect of SAP on treatment response to escitalopram in mice with the forced swim test (FST), a classical behaviour paradigm to assess antidepressant effects. SAP reduced [11C]DASB binding as an index of SERT levels, consistent with Western blots showing decreased total SAP protein because of increased protein degradation. In conjunction with the global decrease in SERT levels, SAP also promotes VAMP-2 mediated SERT membrane insertion. SAP levels are correlated with behavioural despair and SSRI treatment response in mice with FST. In MDD patients, the SAP and membrane SERT levels are correlated with response to SSRI treatment. SAP has complex effects on SERT levels and localization, thereby modulating the effect of SSRIs, which could partially explain clinical variability in antidepressant treatment response. These results add to our understanding of the mechanism for antidepressant drug action, and with further work could be of clinical utility.

Neurexins in serotonergic neurons regulate neuronal survival, serotonin transmission, and complex mouse behaviors

Extensive serotonin (5-hydroxytryptamine, 5-HT) innervation throughout the brain corroborates 5-HT's modulatory role in numerous cognitive activities. Volume transmission is the major mode for 5-HT transmission but mechanisms underlying 5-HT signaling are still largely unknown. Abnormal brain 5-HT levels and function have been implicated in autism spectrum disorder (ASD). Neurexin (Nrxn) genes encode presynaptic cell adhesion molecules important for the regulation of synaptic neurotransmitter release, notably glutamatergic and GABAergic transmission. Mutations in Nrxn genes are associated with neurodevelopmental disorders including ASD. However, the role of Nrxn genes in the 5-HT system is poorly understood. Here, we generated a mouse model with all three Nrxn genes disrupted specifically in 5-HT neurons to study how Nrxns affect 5-HT transmission. Loss of Nrxns in 5-HT neurons reduced the number of serotonin neurons in the early postnatal stage, impaired 5-HT release, and decreased 5-HT release sites and serotonin transporter expression. Furthermore, 5-HT neuron-specific Nrxn knockout reduced sociability and increased depressive-like behavior. Our results highlight functional roles for Nrxns in 5-HT neurotransmission, 5-HT neuron survival, and the execution of complex behaviors.

Inflammation and Treatment-Resistant Depression from Clinical to Animal Study: A Possible Link?

The aim of this study was to investigate the relationship between treatment-resistant depression (TRD) and inflammation in humans and experimental models. For the human study, a retrospective cohort study was conducted with 206 participants; half were on antidepressants for major depressive disorder. The patients were divided into healthy and depressed groups. Inflammation was assessed based on the values of the main inflammatory biomarkers (CRP, WBC and ESR). For the animal experiments, 35 adult male Wistar rats were assigned to stressed and non-stressed groups. Inflammation and stress were induced using lipopolysaccharide and chronic unpredictable mild stress. A 10 mg/kg intraperitoneal injection of fluoxetine (FLX), a known antidepressant, was simultaneously administered daily for 4 weeks. Behavioral tests were performed. The plasma levels of inflammatory and stress biomarkers were measured and were significantly higher in the stressed and non-responsive groups in both studies. This study provides evidence of the link between inflammation and TRD. We further observed a possible link via the Phosphorylated Janus Kinase 2 and Phosphorylated Signal Transducer and Activator of Transcription 3 (P-JAK2/P-STAT3) signaling pathway and found that chronic stress and high inflammation hinder the antidepressant effects of FLX. Thus, non-response to antidepressants could be mitigated by treating inflammation to improve the antidepressant effect in patients with TRD.

A novel aged mouse model of recurrent intracerebral hemorrhage in the bilateral striatum

The current animal models of stroke primarily model a single intracerebral hemorrhage (ICH) attack, and there is a lack of a reliable model of recurrent ICH. In this study, we established 16-month-old C57BL/6 male mouse models of ICH by injecting collagenase VII-S into the left striatum. Twenty-one days later, we injected collagenase VII-S into the right striatum to simulate recurrent ICH. Our results showed that mice subjected to bilateral striatal hemorrhage had poorer neurological function at the early stage of hemorrhage, delayed recovery in locomotor function, motor coordination, and movement speed, and more obvious emotional and cognitive dysfunction than mice subjected to unilateral striatal hemorrhage. These findings indicate that mouse models of bilateral striatal hemorrhage can well simulate clinically common recurrent ICH. These models should be used as a novel tool for investigating the pathogenesis and treatment targets of recurrent ICH.

Polypyrimidine tract binding protein knockdown reverses depression-like behaviors and cognition impairment in mice with lesioned cholinergic neurons

Background and objectives

Depression is a common comorbidity of dementia and may be a risk factor for dementia. Accumulating evidence has suggested that the cholinergic system plays a central role in dementia and depression, and the loss of cholinergic neurons is associated with memory decline in aging and Alzheimer's patients. A specific loss of cholinergic neurons in the horizontal limb of the diagonal band of Broca (HDB) is correlated with depression and dysfunction of cognition in mice. In this study, we examined the potential regenerative mechanisms of knockdown the RNA-binding protein polypyrimidine tract binding protein (PTB) in reversing depression-like behaviors and cognition impairment in mice with lesioned cholinergic neurons.

Methods

We lesioned cholinergic neurons in mice induced by injection of 192 IgG-saporin into HDB; then, we injected either antisense oligonucleotides or adeno-associated virus-shRNA (GFAP promoter) into the injured area of HDB to deplete PTB followed by a broad range of methodologies including behavioral examinations, Western blot, RT-qPCR and immunofluorescence.

Results

We found that the conversion of astrocytes to newborn neurons by using antisense oligonucleotides on PTB in vitro, and depletion of PTB using either antisense oligonucleotides or adeno-associated virus-shRNA into the injured area of HDB could specifically transform astrocytes into cholinergic neurons. Meanwhile, knockdown of PTB by both approaches could relieve the depression-like behaviors shown by sucrose preference, forced swimming or tail-suspension tests, and alleviate cognitive impairment such as fear conditioning and novel object recognition in mice with lesioned cholinergic neurons.

Conclusion

These findings suggest that supplementing cholinergic neurons after PTB knockdown may be a promising therapeutic strategy to revert depression-like behaviors and cognitive impairment.

Carnosic Acid Mitigates Depression-Like Behavior in Ovariectomized Mice via Activation of Nrf2/HO-1 Pathway

The peri- and post-menopausal periods have been described as the "window of vulnerability" for the development of depressive symptoms that impair women activities and quality of life. The etiopathogenesis of these symptoms is multifactorial and may confer resistance to traditional antidepressants. Attention is now directed toward phytochemicals for their pleiotropic functions and safer profiles. This study investigated the possible perturbation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways as an underlying mechanism of post-ovariectomy depression and highlighted the potential benefits of carnosic acid (CA) on the associated behavioral, biochemical, and histopathological alterations. Female Balb/c mice were randomly assigned to be sham-operated or ovariectomized (OVX). After 3 weeks, OVX mice received either a vehicle, CA (20 mg/kg/day), or tin protoporphyrin IX (SnPP-IX; a heme oxygenase-1 (HO-1) inhibitor; 50 μmol/kg/day) for 3 weeks. Our findings revealed that OVX mice had depressive but not anxiety-like behavior. Suppressed Nrf2 and its downstream signaling, and augmented proinflammatory markers were observed in both the hippocampus and prefrontal cortex. CA treatment alleviated depressive behavior, induced the expression of Nrf2, HO-1, thioredoxin-1, and brain-derived neurotrophic factor, and enhanced serotonin levels. CA also suppressed oxidative stress, reduced TNF-α, IL-1β, and iNOS mRNA expression, and ameliorated OVX-induced histopathological changes. SnPP-IX aggravated post-OVX behavioral, neurobiochemical, and histological deteriorations, and reduced CA-protective effects. In conclusion, Nrf2/HO-1 signaling suppression and the associated proinflammatory state are key mechanisms in post-OVX depression. CA exerts multifaceted neuroprotection in OVX mice and represents a promising candidate for clinical evaluation as an antidepressant.

Augmented impulsive behavior in febrile seizure-induced mice

Febrile seizure (FS) is one of the most prevalent etiological events in childhood affecting 2-5% of children from 3 months to 5 years old. Debates on whether neurodevelopmental consequences rise in later life following a febrile seizure or not are still ongoing however there is limited evidence of its effect, especially in a laboratory setting. Moreover, the comparative study using both male and female animal models is sparse. To examine the effect of FS on the behavioral features of mice, both sexes of ICR mice were induced with hyperthermic seizures through exposure to an infrared heat lamp. The mice were divided into two groups, one receiving a single febrile seizure at postnatal day 11 (P11) and one receiving three FS at P11, P13, and P15. Starting at P30 the FS-induced mice were subjected to a series of behavioral tests. Mice with seizures showed no locomotor and motor coordination deficits, repetitive, and depressive-like behavior. However, the FS-induced mice showed impulsive-like behavior in both elevated plus maze and cliff avoidance tests, which is more prominent in male mice. A greater number of mice displayed impaired CAT in both males and females in the three-time FS-induced group compared to the single induction group. These results demonstrate that after induction of FS, male mice have a higher susceptibility to consequences of febrile seizure than female mice and recurrent febrile seizure has a higher chance of subsequent disorders associated with decreased anxiety and increased impulsivity. We confirmed the dysregulated expression of impulsivity-related genes such as 5-HT1A and tryptophan hydroxylase 2 from the prefrontal cortices of FS-induced mice implying that the 5-HT system would be one of the mechanisms underlying the increased impulsivity after FS. Taken together, these findings are useful in unveiling future discoveries about the effect of childhood febrile seizure and the mechanism behind it.

The Oil Formulation Derived from Moringa Oleifera Seeds Ameliorates Behavioral Abnormalities in Water-immersion Restraint Stress Mouse Model

Purpose

Repeated stress events are well known to be associated with the onset of behavioral abnormalities including depression, anxiety and memory impairment. In spite of the traditional uses of Moringa oleifera (MO), no experimental evidence for its use against chronic stress exists. Here, we investigated whether seed oil from MO (MOO) could improve behavior abnormalities of chronic stress mice induced by water-immersion restraint stress (WIRS) and the underlying mechanism.

Methods

BALB/C male mice at 12 weeks of age were exposed to chronic WIRS for two weeks and divided in to four groups: normal group, WIRS group, WIRS+MOO1 group (treated with MOO at the dose of 1 mL/kg BW), and WIRS+MOO2 group (treated with MOO 2 mL/kg BW). The MOO treatment was given orally for 23 days. On day 24, we checked the behavior parameters, the plasma level of cortisol, acetylcholinesterase (AChE) activity in hippocampus, mRNA expression level of brain-derived neurotrophic factor (BDNF) and oxidative stress parameters in brain tissues. In addition, we also checked the histopathological features of the gastric mucosa wall.

Results

Administration of MOO ameliorated anxiety-like, depression-like and memory impairment phenotypes in the WIRS mouse model although the plasma cortisol concentrations were comparable among the groups. Of note, MOO both in two doses could suppress the AChE activity in hippocampus tissue and ameliorated the MDA level in prefrontal cortex tissue in mice exposed to WIRS. Although only WIRS+MOO2 group could increase the mRNA expression of BDNF, the histopathological gastric mucosa wall features were improved in all MOO groups.

Conclusion

Taken together, these finding suggested that MOO may have a neuroprotective effect in the mouse model of WIRS as evidenced by improving the abnormal behaviors through enhancing mRNA expression level of BDNF, inhibited AChE activity, and prevented the increase of MDA level in the brain.

Inhibition of Microglial NLRP3 with MCC950 Attenuates Microglial Morphology and NLRP3/Caspase-1/IL-1β Signaling In Stress-induced Mice

Major depressive disorder is characterized by the deficiencies of monoamine neurotransmitters, neurotrophic factors and persistent neuroinflammation. Microglial activation has been associated with neuroinflammation-related mental diseases, accompanied by NLR family pyrin domain containing 3 (NLRP3) inflammasome. Here, we investigated the effect of NLRP3 inhibition by its small molecular inhibitor MCC950 on inflammatory activity and depressive-like mice induced by chronic unpredictable mild stress (CUMS), followed by the behavioral tests including sucrose preference test and forced swimming test. NLRP3/caspase-1/IL-1β signaling and microglial morphology in the prefrontal cortex were measured. The results showed that CUMS caused a decrease in sucrose preference and an increase in immobility time, which were reversed by NLRP3 inhibitor MCC950. In addition, NLRP3 inhibition decreased the number of microglia and changed the activated state of microglia to a resting state by morphology 3D reconstruction. Moreover, NLRP3 inhibition inactivated NLRP3/caspase-1/IL-1β signaling in the prefrontal cortex. The results from immunofluorescence demonstrated that NLRP3 and IL-1β expression was decreased in microglia in response to MCC950 treatment. Accordingly, proinflammatory cytokines were also decreased by NLRP3 inhibition. In conclusion, this study demonstrates that microglial NLRP3 inhibition prevents stress-induced neuroinflammation in the prefrontal cortex and suggests that microglial NLRP3 could be one of the potential therapeutic targets for depression treatment.

Inflammation triggered by the NLRP3 inflammasome is a critical driver of diabetic bladder dysfunction

Diabetes is a rapidly expanding epidemic projected to affect as many as 1 in 3 Americans by 2050. This disease is characterized by devastating complications brought about high glucose and metabolic derangement. The most common of these complications is diabetic bladder dysfunction (DBD) and estimates suggest that 50-80% of patients experience this disorder. Unfortunately, the Epidemiology of Diabetes Interventions and Complications Study suggests that strict glucose control does not decrease ones risk for incontinence, although it does decrease the risk of other complications such as retinopathy, nephropathy and neuropathy. Thus, there is a significant unmet need to better understand DBD in order to develop targeted therapies to alleviate patient suffering. Recently, the research community has come to understand that diabetes produces a systemic state of low-level inflammation known as meta-inflammation and attention has focused on a role for the sterile inflammation-inducing structure known as the NLRP3 inflammasome. In this review, we will examine the evidence that NLRP3 plays a central role in inducing DBD and driving its progression towards an underactive phenotype.

Effect of aflatoxin B1 exposure on the progression of depressive-like behavior in rats

While it is well documented that aflatoxin B1 (AFB1); one of the most toxic food contaminants is linked to the development of depression. However, the mechanism on how it affects the gut and brain health leading to depressive-like behavior remains unclear. This study was conducted to determine the effect of AFB1 on the progression of depressive-like behavior. Thirty-two (n = 32) male Sprague Dawley rats were randomly allocated into four groups: control, low-dose (5 μg AFB1/kg), high-dose (25 μg AFB1/kg) and positive control group; exposed on chronic unpredictable mild stress (CUMS). After 4 weeks of exposure, sucrose preference test (SPT) and force swim test (FST) were used to measure behavioral despair. Fecal samples were selectively cultured to profile the bacteria. Body weight and relative organs weights were compared among groups. AFB1 and CUMS caused reduction in body weight and food intake as well as increased relative weight of adrenal glands, liver, and brain. Rats in AFB1 and CUMS groups had suppressed sucrose preference and prolonged immobility time in FST, wherein this could indicate anhedonia. Besides, fecal count of Lactobacillus spp. was significantly low following AFB1 exposure, with increasing count of Bifidobacterium spp, in comparison to the control. Indeed, further biochemical analysis and metagenomic approach are warranted to explore the underlying mechanisms on the role of gut microbiota dysbiosis and dysregulation of gut-brain axis due to AFB1 neurotoxicity on the progression of depressive-like behavior.

Neuromodulatory roles of PIPER GUINEENSE and honey against Lead-Induced neurotoxicity in social interactive behaviors and motor activities in rat models

Background

Piper guineense and honey contain antioxidative, anti-inflammatory, and antimicrobial properties that can help restore neuronal and other cell damage. To investigate the neuromodulatory roles of p. guineense and honey against lead toxicity on the hippocampus and cerebellum, impairing social behaviors and motor activities.

Methodology

Thirty Wistar rats were separated into six groups of five rats each, marked with dye. Group A served as control; B was untreated lead; C was a medium dose of the extract (50 mg/kg) and honey (1000 mg/kg); D was a high dose of the extract (80 mg/kg) and honey (1500 mg/kg); E received extract (80 mg/kg), and F received honey (1500 mg/kg). All groups received 110 mg/kg of lead orally, except the control. Social interaction, antidepressant effects, and motor activities were studied using a sociability chamber (SC), Forced Swim Test (FST), and String methods. A blood sample was used to evaluate glutathione peroxidase (GPx) and glutathione oxide transaminase (GOT), while the lipid level was estimated using cerebellar homogenate. Neuronal damage, vacuolation, necrosis, cell degeneration, and alterations in both hippocampus and cerebellum marked untreated group, with decreased GPx and GOT activities followed by impaired motor activities, social behavior, memory, and motivation. Using SCT, group B spent significantly lesser time (47.60 ± 47.60) with stranger 1 compared to A (138.20 ± 34.05), while group C spent considerably more time with stranger 1 (86.80 ± 30.32) than group B at P ≥ 0.05. The treatment increased the enzyme level and restored histoarchitecture (Figures 1-12), improving motor activities, social behavior, memory, motivation, and social affiliation (Tables 3, 4, 2, and 6). The extract and honey may be helpful as neuromodulators in lead toxicity in a dose-dependent manner.

In Vivo Antidepressant-Like Effect Assessment of Two Aloysia Species in Mice and LCMS Chemical Characterization of Ethanol Extract

Medicinal plants belonging to the Verbenaceae family demonstrated antidepressant effects in preclinical studies. Depression is one of the largest contributors to the global health burden of all countries. Plants from the Aloysia genus are traditionally used for affective disorders, and some of them have proven anxiolytic and antidepressant activity. The aim of this work was to evaluate the antidepressant effect of the ethanolic extract of Aloysia gratissima var. gratissima (Agg) and Aloysia virgata var. platyphylla (Avp) in mice. A tail suspension test (TST) and forced swimming test (FST) were conducted after three doses in a period of 24 h and after 7 days of treatment. Imipramine was used as an antidepressant drug. The main results demonstrated that Agg extract reduced the immobility time in mice treated orally for 7 consecutive days when compared to the control group (reduced by about 77%, imipramine 70%). Animals treated with three doses of Avp in a 24-h period had reduced immobility time in the FST (60%), and after 7 days of treatment the reduction was greater (Avp 50, 100, and 200 about 85%; Avp 400, 96.5%; p < 0.0001, imipramine, 77%). LCMS analysis showed the presence of verbascoside, hoffmaniaketone, and hoffmaniaketone acetate in both, A. virgata var. platyphylla and A. gratissima var gratissima. The flavonoids nepetin and 6-hydroxyluteolin were also found in Agg. Both tested extracts demonstrated promising antidepressant-like activity in mice.

Delayed Formation of Neonatal Reflexes and of Locomotor Skills Is Associated with Poor Maternal Behavior in OXYS Rats Prone to Alzheimer's Disease-like Pathology

Postnatal brain development is characterized by high plasticity with critical windows of opportunity where any intervention may positively or adversely influence postnatal growth and lead to long-lasting consequences later in life. Poor maternal care is among these interventions. Here, we found that senescence-accelerated OXYS rats prone to an Alzheimer's disease-like pathology are characterized by more passive maternal behavior and insufficient care for pups as compared to control (Wistar) rats. OXYS pups demonstrated a delay in physical development (of auricle detachment, of emergence of pelage and incisors, of eye opening, and of vaginal opening in females) and late manifestation of reflexes and locomotor skills. All observed behavioral abnormalities are connected either with poor coordination of limbs' movements or with a decrease in motivation and development of depression-like behavior. It is possible that their manifestations can be promoted by the features of maternal behavior of OXYS rats. Overall, these early-life events may have long-lasting consequences and contribute to neurodegeneration and development of the Alzheimer's disease-like pathology later in life.

Atranorin, a Secondary Metabolite of Lichens, Exhibited Anxiolytic/Antidepressant Activity in Wistar Rats

Atranorin (ATR) is one of lichens' many known secondary metabolites. Most current studies have investigated the various effects of ATR in vitro and only sporadically in vivo. The latest data indicate that ATR may have anxiolytic/antidepressive effects. This study aimed to analyze the potential of ATR in a depression-like state in male Wistar rats. Pregnant females were stressed by restricting their mobility in the final week of pregnancy three times a day for 45 min each, for three following days. After birth, progeny aged 60 days was stressed repeatedly. The male progeny was divided into three groups as follows: CTR group as a healthy control (n = 10), DEP group as a progeny of restricted mothers (n = 10), and ATR group as a progeny of restricted mothers, treated daily for one month with ATR (n = 10; 10 mg/kg of body weight, p.o.). Our results show that ATR acts as an antioxidant and markedly changes animal behavior. Concomitantly, hippocampal neurogenesis increases in the hilus and subgranular zone, together with the number of NeuN mature neurons in the hilus and CA1 regions. Our results indicate a potential antidepressant/anxiolytic effect of ATR. However, further studies in this area are needed.

Explicit memory, anxiety and depressive like behavior in mice exposed to chronic intermittent hypoxia, sleep fragmentation, or both during the daylight period

Obstructive sleep apnea (OSA) is a chronic and highly prevalent condition characterized by chronic intermittent hypoxia (IH) and sleep fragmentation (SF), and can lead to a vast array of end-organ morbidities, particularly affecting cardiovascular, metabolic and neurobehavioral functioning. OSA can induce cognitive and behavioral and mood deficits.

Male C57Bl/6J 8-week-old mice were housed in custom-designed cages with a silent motorized mechanical sweeper traversing the cage floor at 2-min intervals (SF) during daylight for four weeks. Sleep control (SC) consisted of keeping sweeper immobile. IH consisted of cycling FiO₂ 21% 90 seconds-6.3% 90s or room air (RA; FiO₂ 21%) for sixteen weeks and combined SF-IH was conducted for nine weeks. Open field novel object recognition (NOR) testing, elevated-plus maze test (EPMT), and forced swimming test (FST) were performed.

SF induced cognitive NOR performance impairments in mice along with reduced anxiety behaviors while IH induced deficits in NOR performance, but increased anxiety behaviors. SF-IH induced impaired performance in NOR test of similar magnitude to IH or SF alone. Combined SF-IH exposures did not affect anxiety behaviors.

Thus, both SF an IH altered cognitive function while imposing opposite effects on anxiety behaviors. SF-IH did not magnify the detrimental effects of isolated SF or IH and canceled out the effects on anxiety. Based on these findings, the underlying pathophysiologic processes underlying IH and SF adverse effects on cognitive function appear to differ, while those affecting anxiety counteract each other.

The Efficacy of N-Acetyl-Cysteine (NAC) Supplementation in FST Model for Screening Antidepressants

Introduction

The model for screening antidepressant-like activity in pre-clinical drug studies include, rat forced swimming test (FST). The reports on N-acetylcysteine (NAC) as an antioxidant supplement in stress related disorder is well documented. This study was aimed at potential antidepressant mechanism of N-Acetyl Cysteine (NAC), a glutamate precursor on FST animal model for screening antidepressant drugs using fluoxetine, a selective serotonin reuptake inhibitors (SSRIs) as standard antidepressant drug.

Methods

Thirty adult male Wistar rats used for this study were randomly divided into six groups each with five (n=5) rats. The control group (A) received 1 ml of normal saline daily, group B served as the FST model, group C received 200mg/kg/day of NAC, group D received 20mg/kg/day of fluoxetine, group E the FST model treated with 200mg/kg/day of NAC, and F is the FST model treated with 20mg/kg/day of fluoxetine. Drugs were given orally. The effects of NAC on brain weights, the FST paradigms, sucrose preference test (SPT) for anhedonia were assessed and data analyzed using ANOVA where Tukey post-hoc test for statistical significance was set at (p < 0.05). The brains fixed in 4% paraformaldehyde, were processed and the paraffin embedded tissue were serially sectioned at 5 μm thick to be stained using Haematoxylin and Eosin (H and E) stain, immuno-histochemistry for synaptophysin (p38) and astrocytes (GFAP) activities in the prefrontal cortex (PFC).

Results

Findings showed that NAC prevented FST-induced anxiety-like behaviors demonstrated by an increased SPT (that alleviates anhedonia), mobility time, and reduced immobility time. NAC caused an increase in brain weights and prevented FST-induced neurodegeneration, the proliferation of reactive astrocytes, and diminished synaptophysin immunoreactivity in the PFC similar to that seen in fluoxetine a standard anti-depressant drug.

Conclusion

NAC treatment significantly exhibits its neuroprotective mechanism via inhibiting the proliferation of reactive astrocytes, which protects neurons and synapses from oxidative tissue damage induced by FST, hence an increase in synaptophysin activity that culminates in increased neural activity, increased SPT, and reduced immobility time.

Construction and evaluation of an alcohol vapor chamber system

An increasing number of studies demonstrated that alcohol vapor chamber is an effective way to model physical signs of alcohol use disorders. Although researchers are developing different vapor chambers to study chronic alcohol exposure model worldwide, few studies build and modify their own vapor chambers in China. Here, we designed and established an alcohol vapor chamber system for small animals. We described a paradigm showing how to control and monitor alcohol concentration in whole system. The vapor chamber system with several advantages including accommodating up to ten standard mouse cages. Furthermore, the system was tested by evaluating the blood alcohol concentration and neuron injury in mice. Importantly, the alcohol withdrawal after vapor exposure caused motor coordination impairment, anxiolytic- and depression-like behavior. Finally, the N-methyl-D-aspartate receptor (NMDAR)-mediated glutamatergic transmissions in the medial prefrontal cortex was changed after alcohol vapor exposure-induced behaviors. The frequency and amplitude of spontaneous excitatory postsynaptic currents between control and alcohol groups were not different, suggesting that alcohol exposure-induced behaviors are associated with the change in NMDAR response. Taken together, the new alcohol vapor chamber system was constructed, which would help to research the relationship between the stable alcohol exposure and withdrawal behaviors and to study chronic alcohol exposure-induced disorders in China.

Activation of Somatostatin-Expressing Neurons in the Lateral Septum Improves Stress-Induced Depressive-like Behaviors in Mice

Depression is a debilitating mood disorder with highly heterogeneous pathogenesis. The limbic system is well-linked to depression. As an important node in the limbic system, the lateral septum (LS) can modulate multiple affective and motivational behaviors. However, the role of LS in depression remains unclear. By using c-Fos expression mapping, we first screened and showed activation of the LS in various depression-related behavioral tests, including the forced swim test (FST), tail suspension test (TST), and sucrose preference test. In the LS, more than 10% of the activated neurons were somatostatin-expressing (SST) neurons. We next developed a microendoscopic calcium imaging method in freely moving mice and revealed that LS^SST neural activity increased during mobility in the TST but not open field test. We hypothesize that LS^SST neuronal activity is linked to stress and depression. In two mouse models of depression, repeated lipopolysaccharide (LPS) injection and chronic restraint stress (CRS), we showed that LS neuronal activation was suppressed. To examine whether the re-activation of LS^SST neurons can be therapeutically beneficial, we optogenetically activated LS^SST neurons and produced antidepressant-like effects in LPS-injected mice by increasing TST motility. Moreover, chemogenetic activation of LS^SST neurons increased FST struggling in the CRS-exposed mice. Together, these results provide the first evidence of a role for LS^SST neurons in regulating depressive-like behaviors in mice and identify them as a potential therapeutic target for neuromodulation-based intervention in depression.

Neuronal Nitric Oxide Synthase Regulates Depression-like Behaviors in Shortening-Induced Obese Mice

Shortening is mainly derived from the partial hydrogenation of palm oil and widely used in fast food. Food processed with shortening contains high levels of industrial trans fatty acids. Studies have shown that there is a correlation between industrial trans fatty acids, obesity, and depression. However, the regulatory effect of neuronal nitric oxide synthase (nNOS) on depression in obese patients is still unknown. The purpose of this study was to explore mood changes in obese mice fed a high shortening diet, and to determine the regulatory effect of nNOS on depressive-like behaviors in obese mice. We used a high shortening diet-induced obesity mouse model to systematically assess the metabolic response, behavioral changes, prefrontal and hippocampal nNOS protein levels, and the effect of nNOS inhibitors (7-nitroindole) on depression-like behavior in obese mice. Interestingly, obese mice on a 9-week high-shortening diet developed short-term spatial working memory impairment and anxiety-like behavior, and obesity may be a risk factor for cognitive impairment and mood disorders. In animals fed a high shortening diet for 12 weeks, obese mice developed depression-like behavior and had significantly elevated levels of nNOS protein expression in the hippocampus and prefrontal lobe. Administration of the nNOS inhibitor 7-nitroindole could improve depression-like behaviors in obese mice, further suggesting that inhibition of nNOS is helpful for depression associated with obesity.

Boosting Neurogenesis in the Adult Hippocampus Using Antidepressants and Mesenchymal Stem Cells

The hippocampus is one of the few privileged regions (neural stem cell niche) of the brain, where neural stem cells differentiate into new neurons throughout adulthood. However, dysregulation of hippocampal neurogenesis with aging, injury, depression and neurodegenerative disease leads to debilitating cognitive impacts. These debilitating symptoms deteriorate the quality of life in the afflicted individuals. Impaired hippocampal neurogenesis is especially difficult to rescue with increasing age and neurodegeneration. However, the potential to boost endogenous Wnt signaling by influencing pathway modulators such as receptors, agonists, and antagonists through drug and cell therapy-based interventions offers hope. Restoration and augmentation of hampered Wnt signaling to facilitate increased hippocampal neurogenesis would serve as an endogenous repair mechanism and contribute to hippocampal structural and functional plasticity. This review focuses on the possible interaction between neurogenesis and Wnt signaling under the control of antidepressants and mesenchymal stem cells (MSCs) to overcome debilitating symptoms caused by age, diseases, or environmental factors such as stress. It will also address some current limitations hindering the direct extrapolation of research from animal models to human application, and the technical challenges associated with the MSCs and their cellular products as potential therapeutic solutions.

Cognitive Deficits Found in a Pro-inflammatory State are Independent of ERK1/2 Signaling in the Murine Brain Hippocampus Treated with Shiga Toxin 2 from Enterohemorrhagic Escherichia coli

Shiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS), and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. The purpose of this work is to elucidate the signaling pathways that may activate the inflammatory processes triggered by Stx2, which produces cognitive alterations at the level of the hippocampus. Results demonstrate that Stx2 produced depression-like behavior, pro-inflammatory cytokine release, and NF-kB activation independent of the ERK1/2 signaling pathway, while co-administration of Stx2 and LPS reduced memory index. On the other hand, LPS activated NF-kB dependent on ERK1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.

Does a Single Exposure to General Anesthesia Have a Cumulative Effect on the Developing Brain after Mild Perinatal Asphyxia?

Background: General anesthesia (GA) in pediatric patients represents a clinical routine. Factors such as increased birth age and maternal chronic conditions cause more infants to experience hypoxic-ischemic encephalopathy, an additional risk for anesthesia. Aim: This study evaluates the effect of one sevoflurane-induced GA episode on the immature brain previously exposed to perinatal asphyxia (PA). Methods: Postnatal day 6 (PND6) Wistar rats were exposed to a 90-min episode of normoxia/PA and at PND15 to a 120-min episode of normoxia/GA. Four groups were analyzed: Control (C), PA, GA, and PA-GA. Post-exposures, fifteen pups/group were sacrificed and the hippocampi were isolated to assess S-100B and IL-1B protein levels, using ELISA. At maturity, the behavior was assessed by: forced swimming test (FST), and novel object recognition test. Results: Hippocampal S-100B level was increased in PA, GA, and PA-GA groups, while IL-1B was increased in PA, but decreased in PA-GA. The immobility time was increased in PA and PA-GA, in FST. Conclusions: Both PA and GA contribute to glial activation, however with no cumulative effect. Moreover, PA reduces the rats’ mobility, irrespective of GA exposure, while memory evaluated by the novel object recognition test was not influenced.

Colitis-associated intestinal microbiota regulates brain glycine and host behavior in mice

Inflammatory bowel diseases (IBD) are chronic and relapsing inflammatory disorders of the gastrointestinal tract with complex etiology and no strategies for complete cure. IBD are often complicated by mental disorders like anxiety and depression, indicating substantial shifts in the microbiota gut-brain axis. However, the mechanisms connecting IBD to mental diseases are still under debate. Here we use Muc2 knockout mouse model of chronic colitis to uncouple the effects of the intestinal microbiota on host behavior from chronic inflammation in the gut. Muc2 knockout male mice exhibit high exploratory activity, reduced anxiety-related behaviors, impaired sensorimotor gating, and altered social preference towards males and females. Microbial transfer to wild-type mice via littermate co-housing shows that colitis-associated microbiota rather than inflammation per se defines behavioral features in Muc2 colitis model. Metagenomic profiling and combination of antibiotic treatments revealed that bacterial species Akkermansia muciniphila is associated with the behavioral phenotype in mutants, and that its intestinal abundance correlates with social preference towards males. Metabolomic analysis together with pharmacological inhibition of Gly and NMDA receptors helped us to determine that brain glycine is responsible for the behavioral phenotype in Muc2 mice. Blood and brain metabolic profiles suggest that microbiota-dependent changes in choline metabolism might be involved in regulation of central glycine neurotransmission. Taken together, our data demonstrates that colitis-associated microbiota controls anxiety, sensorimotor gating and social behavior via metabolic regulation of the brain glycinergic system, providing new venues to combat neurological complications of IBD.

Acute stress induces severe neural inflammation and overactivation of glucocorticoid signaling in interleukin-18-deficient mice

Interleukin-18 (IL18) is an inflammatory cytokine that is related to psychiatric disorders such as depression and cognitive impairment. We previously found that IL18 deficiency may cause hippocampal impairment, resulting in depression-like behavioral changes. However, the potential role of IL18 in stressful conditions remains uncertain. In the present study, we examined the effect of IL18 on neural inflammation and stress tolerance during acute stress. Littermate Il18^+/+ and Il18^-/- mice were exposed to a single restraint stress for 6 h, and all assessments were performed 18 h after the mice were released from the restraint. In Il18^-/- mice exposed to acute stress, the immobility times in both the forced swim test and tail suspension test were decreased, although no difference was observed in Il18^+/+ mice. Il1β, Il6, and Tnfα expression levels in the hippocampus of stressed Il18^-/- mice were significantly higher than those in the other groups. Moreover, the numbers of astrocytes and microglia, including those in the active form, were also increased compared with those in other groups. Regarding the molecular mechanism, the HSF5 and TTR genes were specifically expressed in stressed Il18^-/- mice. As a potential treatment, intracerebral administration of IL18 to Il18^-/- mice resulted in partial recovery of changes in behavioral assessments. Our results revealed that IL18-deficient mice were more sensitive and had a longer response to acute stress than that in normal mice. In addition, neural inflammation and augmentation of glucocorticoid signals caused by stress were more intense and remained longer in Il18^-/- mice, resulting in behavioral changes. In conclusion, IL18 might be an indispensable factor that modulates the stress response and maintains balance between neural inflammation and glucocorticoid signaling.

Voluntary wheel-running activities ameliorate depressive-like behaviors in mouse dry eye models

Recent clinical studies indicate that dry eye is closely associated with psychiatric disorders such as depression and anxiety. Here, we investigated whether two types of mouse dry eye models showed depressive-like behavior in forced swim and sucrose preference tests, and whether voluntary wheel-running helped ameliorate depressive states. To reproduce the dry eye models, the exorbital lacrimal glands (ELG) or exorbital and intraorbital lacrimal glands (ELG+ILG) were bilaterally excised from male C57BL/6J mice. Tear volume was persistently reduced in both models, but the ELG+ILG excision mice exhibited more severe corneal damage than the ELG excision mice. In the forced swim and sucrose preference tests, the gland excision mice showed longer immobility and shorter climbing times, and lower sucrose preference than sham-operated mice, respectively, which appeared earlier in the ELG+ILG excision mice. Wheel-running activities were significantly lower in the ELG+ILG excision mice, but not in the ELG excision mice. After short-period wheel-running, the longer immobility times and the shorter climbing times in the forced swim completely disappeared in both models. Our results suggest that dry eyes might directly cause a depressive disorder that depends on the severity and duration of the ocular surface damage, and that voluntary motor activity could help recovery from a depressive state induced by dry eye.