Suspension Test Research Articles

Ameliorative effect of α-tocopherol and tocotrienol-rich palm oil extract on menopause-associated mood disorder in ovariectomized mice

Menopause-associated mood disorder is characterized by emotional depression, anxiety, and stress, which accompany hypogonadism in women in the menopausal phase. The current treatment for menopause-associated mood disorder provides only symptomatic relief and is associated with many side effects. Supplementation with vitamin E has been shown to be effective in ameliorating anxiety and depression. However, the effects of vitamin E and its underlying mechanism in ameliorating menopause-associated mood disorders remain uncertain. This work evaluated the effects of α-tocopherol and tocotrienol-rich palm oil extract on depressive and anxiety-related phenotypes induced by estrogen deficiency through ovariectomy in mice. Our study revealed that ovariectomized mice exhibited alterations in behavior indicative of depressive- and anxiety-like behaviors. The serum corticosterone level, a glucocorticoid hormone associated with stress, was found to be elevated in ovariectomized mice as compared to the sham group. Oral administration of α-tocopherol (50 and 100 mg/kg) and tocotrienol-rich palm oil extract (100 and 200 mg/kg) for 14 days alleviated these behavioral changes, as observed in open field, social interaction, and tail suspension tests. However, treatment with tocotrienol-rich palm oil extract, but not α-tocopherol, modulated the depressive- and anxiety-like responses in ovariectomized mice subjected to chronic restraint stress. Both treatments suppressed the elevated serum corticosterone level. Our findings suggested that α-tocopherol and tocotrienol-rich palm oil extract alleviated menopause-associated mood disorder, at least in part, by modulating the hypothalamic-pituitary-adrenal (HPA) axis. The findings of this study can provide a new foundation for the treatment of menopause-associated depressive- and anxiety-like phenotypes, for the betterment of psychological wellbeing.

Efficacy of ginsenoside Rg1 on rodent models of depression: A systematic review and meta-analysis.

Depression is a prevalent psychiatric disease, and ginsenoside Rg1 is a bioactive compound extracted from the root of Panax ginseng C.A.Mey. To systematically investigate the effectiveness of Rg1 in rodent models of depression and provide evidence-based references for treating depression. Electronic searches for rodent studies were performed from inception to October 2022, e.g., PUBMED and EMBASE. Data extraction and quality evaluation were performed for the references, and meta-analysis was performed on the selected data using Review Manager 5.3.5. The outcomes were analyzed via a random-effect model and presented as mean difference (MD) with 95% confidence intervals (CIs). A total of 24 studies and 678 animals were included in this meta-analysis. Rg1 remarkably improved depressive-like symptoms of depressed rodents, including the sucrose preference test (25.08, 95% CI: 20.17-30.00, Z = 10.01, P < 0.00001), forced swimming test (MD = -37.69, 95% CI: (-45.18, -30.2); Z = 9.86, P < 0.00001), and the tail suspension test (MD = -22.93, seconds, 95% CI: (-38.49, -7.37); Z = 2.89, P = 0.004). The main antidepressant mechanism of Rg1 was concluded to be the neurotransmitter system, oxidant stress system, and inflammation. Conclusively, this study indicated the possible protective and therapeutic effects of Rg1 for treating depression via multiple mechanisms.

Hippocampal PACAP signaling activation triggers a rapid antidepressant response

BackgroundThe development of ketamine-like rapid antidepressants holds promise for enhancing the therapeutic efficacy of depression, but the underlying cellular and molecular mechanisms remain unclear. Implicated in depression regulation, the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is investigated here to examine its role in mediating the rapid antidepressant response.MethodsThe onset of antidepressant response was assessed through depression-related behavioral paradigms. The signaling mechanism of PACAP in the hippocampal dentate gyrus (DG) was evaluated by utilizing site-directed gene knockdown, pharmacological interventions, or optogenetic manipulations. Overall, 446 mice were used for behavioral and molecular signaling testing. Mice were divided into control or experimental groups randomly in each experiment, and the experimental manipulations included: chronic paroxetine treatments (4, 9, 14 d) or a single treatment of ketamine; social defeat or lipopolysaccharides-injection induced depression models; different doses of PACAP (0.4, 2, 4 ng/site; microinjected into the hippocampal DG); pharmacological intra-DG interventions (CALM and PACAP6-38); intra-DG viral-mediated PACAP RNAi; and opotogenetics using channelrhodopsins 2 (ChR2) or endoplasmic natronomonas halorhodopsine 3.0 (eNpHR3.0). Behavioral paradigms included novelty suppressed feeding test, tail suspension test, forced swimming test, and sucrose preference test. Western blotting, ELISA, or quantitative real-time PCR (RT-PCR) analysis were used to detect the expressions of proteins/peptides or genes in the hippocampus.ResultsChronic administration of the slow-onset antidepressant paroxetine resulted in an increase in hippocampal PACAP expression, and intra-DG blockade of PACAP attenuated the onset of the antidepressant response. The levels of hippocampal PACAP expression were reduced in both two distinct depression animal models and intra-DG knockdown of PACAP induced depression-like behaviors. Conversely, a single infusion of PACAP into the DG region produced a rapid and sustained antidepressant response in both normal and chronically stressed mice. Optogenetic intra-DG excitation of PACAP-expressing neurons instantly elicited antidepressant responses, while optogenetic inhibition induced depression-like behaviors. The longer optogenetic excitation/inhibition elicited the more sustained antidepressant/depression-like responses. Intra-DG PACAP infusion immediately facilitated the signaling for rapid antidepressant response by inhibiting calcium/calmodulin-dependent protein kinase II (CaMKII)-eukaryotic elongation factor 2 (eEF2) and activating the mammalian target of rapamycin (mTOR). Pre-activation of CaMKII signaling within the DG blunted PACAP-induced rapid antidepressant response as well as eEF2-mTOR-brain-derived neurotrophic factor (BDNF) signaling. Finally, acute ketamine treatment upregulated hippocampal PACAP expression, whereas intra-DG blockade of PACAP signaling attenuated ketamine’s rapid antidepressant response.ConclusionsActivation of hippocampal PACAP signaling induces a rapid antidepressant response through the regulation of CaMKII inhibition-governed eEF2-mTOR-BDNF signaling.

Subchronic administration of scopolamine reverses UCMS-induced behavior in mice via eEF2 protein dephosphorylation

BackgroundThe cholinergic system has been increasingly linked to the pathophysiology of mood disorders such as depression, with the potential involvement of nicotinic and/or muscarinic receptors. Conventional antidepressants usually require weeks of daily dosing to achieve a full antidepressant response. In contrast, clinical studies have shown that scopolamine, a nonselective muscarinic acetylcholine receptor antagonist, can induce potent and rapid antidepressant effects, requiring only a few days of treatment. This study aimed to examine the suitability of the unpredictable chronic mild stress (UCMS) model of depression to reproduce the above scopolamine antidepressant activity patterns.MethodsRapid and sustained antidepressant-like effects were assessed by using the splash test, sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST) in animals undergoing the UCMS procedure and stress-naïve C57BL/6J mice. Western Blotting was used to measure tropomyosin receptor kinase B (TrkB), mammalian target of rapamycin (mTOR), eukaryotic elongation factor (eEF2) and postsynaptic density protein 95 (PSD95) levels.ResultsScopolamine induced antidepressant-like effects in a dose-dependent manner only after subchronic, but not single, administration in the UCMS model of depression in C57BL/6J mice without affecting locomotor activity. Specifically, scopolamine administered at a dose of 0.3 mg/kg for four consecutive days significantly reversed the UCMS-induced depressive-like behavior, such as apathy, anhedonia, and behavioral despair, while scopolamine, given at the same dose but only once, did not relieve the above symptoms. Scopolamine treatment was accompanied by eEF2 protein dephosphorylation and its subsequent reactivation in the prefrontal cortex (PFC).ConclusionSubchronic administration of scopolamine is needed to ameliorate UCMS-induced depressive-like behavior. The suggested mechanism of scopolamine action covers eEF2 protein activity in the PFC.

Antidepressant advantage of Chaihushugan san in female mice: A novel signaling mechanism in hippocampus

Ethnopharmacological relevancyChaihushugan san (CSS), a classic formula for soothing the liver and relieving depression, has been identified to produce rapid antidepressant-like effects in female mice. However, the gender predominance and underlying mechanisms of CSS's antidepressant remain unclear. Aim of the studyIn this study, we focused on unraveling the gender predominance of CSS in antidepressant and the specific neuronal mechanisms that mediate this predominance. Methods and materialsTail suspension test (TST), forced swimming test (FST) and sucrose preference test (SPT) were used to evaluate depressive phenotypes or antidepressant-like effects of CSS in female and male chronic unpredictable mild stress (CUMS) mice model. RNA-sequencing was used to screen specific target for CSS antidepressant gender dominance. RT-PCR and elisa were used to detect the expressions of specific molecule, hormones, and inflammatory factors in the hippocampus. hippocampal viral overactivation and pharmacological blockade were used to detect the correlation between CSS antidepressant gender dominance and related targets. ResultsIn the present study, both female and male mice displayed depressive phenotypes including significant increasing immobility time in TST and reducing sucrose preference ratio in SPT after exposing CUMS for 3 weeks. However, acute administration of CSS (2, 4 g/kg) improved the depressive phenotypes only in female mice or not male mice at 2 h later. Moreover, the expressions of TC2N were increased only in female mice after exposing CUMS for 3 weeks, which were also reversed by CSS after a single administration 2 h later, but no alterations in male mice. The hippocampal expressions of estrogen receptor β (Erβ), pro-inflammatory factors (IL-1β and TNF-α) and anti-inflammatory factors (IL-10, TGF-β and IL-1Rα) were all abnormal in female CUMS mice model, which were all normalized by CSS. Furthermore, overactivation of hippocampal TC2N by AAV-TC2N+/+ blocked the antidepressant-like effects of CSS and the up-regulation of hippocampal Erβ in female mice. However, inhibition of Erβ blunted the antidepressant-like effects of CSS and CSS's suppression of pro-inflammatory factors (IL-1β and TNF-α), which had no any effect on hippocampal TC2N and anti-inflammatory factors (IL-10 and TGF-β). ConclusionsThe study revealed that CSS had antidepressant superiority in female mice depending on inhibiting hippocampal TC2N and then activating Erβ, further inhibiting the release of pro-inflammatory factors to produce antidepressant effects, which provided a basis for the guidance of CSS in clinical application, new ideas and targets for the development of drugs for depression with gender differences.

Protracted opioid withdrawal behaviors are reduced by nitric oxide inhibition in mice

Following opioid cessation, patients with opioid use disorder experience physical and psychological withdrawal symptoms. Prolonged negative affect, including anxiety and heightened stress reactivity, continues after physical withdrawal symptoms subside, contributing to the high relapse rates. The nitric oxide system plays a role in synaptic plasticity downstream of the mu opioid receptor pathway, and nitric oxide synthase inhibitors attenuate physical opioid withdrawal signs. We hypothesized that N(gamma)-nitro-l-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, would reduce negative affect after protracted opioid withdrawal. Therefore, we first modeled withdrawal in male and female mice using 5 days of morphine injections followed by behavioral tests after one week of forced abstinence from morphine. One week of morphine withdrawal caused altered responses to tests of affective behavior in both male and female mice. There were, however, both subtle and significant sex differences among many of the behavioral measures of negative affect. Males and females had differences in immobility during the tail suspension test during morphine withdrawal, while only females had altered grooming in the sucrose splash test. Forced l-NAME in the animals’ drinking water during withdrawal attenuated all physical and affective measures of withdrawal in males and females but there were subtle differences. Together, these results suggest that the nitric oxide system may be a target to ameliorate the different behavioral manifestations of negative affect in males and females.

Antidepressant Effect and Mechanism of Picea mariana Essential Oil on Reserpine-Induced Depression Model Mice.

The disturbance of brain biochemical substances serves as a primary cause and aggravating factor of depression. This study aimed to investigate the principal components of Picea mariana and its effect on reserpine-induced depression mice,w ith its relationship with brain central transmitters and related proteins. The main constituents of P. mariana essential oil (PMEO) were analyzed by GC-MS spectrometry. The quiescent time in the tail suspension test (TST) and forced swim test (FST), along with the weight change of the mice was detected. The number of normal neurons was quantified through Nissl staining. Immunohistochemistry was employed to determine the levels of 5HT-1A and 5HT-2A in the brain. Western blotting was utilized to detect 5HT-2A, CRF and TrkB protein levels. RT-qPCR was used to detect the mRNA levels of 5HT-1A, 5HT-2A, TrkB, CRF, and BDNF. The main active ingredients of PMEOs were (-) -bornyl acetate (44.95%), γ-Terpinene (14.17%), and β-Pinene (10.12%). PMEOs effectively improved the retardation and weight loss due to anorexia in depression-like mice. This improvement was associated with an increase in the number of normal neurons. After administering different doses of PMEOs, the levels of 5HT-1A, 5HT-2A, CRF, and TrkB were found to be increased in brain tissue. RT-qPCR revealed that the mRNA levels of CRF, 5HT-1A, and 5HT-2A were generally upregulated, whereas TrkB and BDNF were downregulated. PMEO can effectively alleviate depression induced by reserpine, which may be attributed to its regulation of 5HT-1A, 5HT-2A, CRF and TrkB protein expression, thus reducing brain nerve injury.

Betaine improves METH-induced depressive-like behavior and cognitive impairment by alleviating neuroinflammation via NLRP3 inflammasome inhibition

Methamphetamine abuse has been associated with central nervous system damage, contributing to the development of neuropsychiatric disorders such as depressive-like behavior and cognitive impairment. With the escalating prevalence of METH abuse, there is a pressing need to explore effective therapeutic interventions. Thus, the objective of this research was to investigate whether betaine can protect against depressive-like behavior and cognitive impairment induced by METH. Following intraperitoneal injections of METH in mice, varying doses of betaine were administered. Subsequently, the behavioral responses of mice and the impact of betaine intervention on METH-induced neural damage, synaptic plasticity, microglial activation, and NLRP3 inflammatory pathway activation were assessed. Administration 30 mg/kg and 100 mg/kg of betaine ameliorated METH-induced depressive-like behaviors in the open field test, tail suspension test, forced swimming test, and sucrose preference test and cognitive impairment in the novel object recognition test and Barnes maze test. Moreover, betaine exerted protective effects against METH-induced neural damage and reversed the reduced synaptic plasticity, including the decline in dendritic spine density, as well as alterations in the expression of hippocampal PSD95 and Synapsin-1. Additionally, betaine treatment suppressed hippocampal microglial activation induced by METH. Likewise, it also inhibited the activation of the hippocampal NLRP3 inflammasome pathway and reduced IL-1β and TNF-α release. These results collectively suggest that betaine's significant role in mitigating depressive-like behavior and cognitive impairment resulting from METH abuse, presenting potential applications in the prevention and treatment of substance addiction.

New polycyclic polyprenylated acylphloroglucinols with antidepressant activities from Hypericum perforatum L.

Six new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperidiones A-F (1–6), were obtained from Hypericum perforatum L. Their structures were characterized via extensive spectroscopic analyses, the circular dichroism data of the in situ formed [Mo2(OCOCH3)4] complexes, the nuclear magnetic resonance calculation with DP4 + probability analysis, and the calculated electronic circular dichroism (ECD) spectra. Compounds 1–6 are bicyclic polyprenylated acylphloroglucinols with a major bicyclo[3.3.1]nonane-2,4,9-trione skeleton. Notably, compound 1 is a rare PPAP with a hydroperoxy group, and a plausible biosynthetic pathway for 1 was proposed. Compounds 4 and 6 exhibited significant neuroprotective effects under 10 μM against corticosterone (CORT)-injured SH-SY5Y cells. Furthermore, compound 4 demonstrated a noteworthy antidepressant effect at the dose of 5 mg/kg in the tail suspension test (TST) of mice, which was equivalent to 5 mg/kg of fluoxetine. And it potentially exerted an antidepressant effect through the hypothalamic–pituitary–adrenal (HPA) axis.

Sex Influences Genetic Susceptibility to Depression-Like Behaviors in Chronic Unpredictable Mild Stress-Exposed Wistar Rats.

Depression is one of the most common mood disorders among psychiatric diseases. It affects about 10% of the adult population. However, its etiopathogenesis remains poorly understood. Exploring the dynamics of stress-susceptibility and resilience will help in understanding the molecular and biological mechanisms underlying the etiopathogenesis of depression. This study aimed to determine the differences and/or similarities in factors responsible for susceptibility to depression-like behaviors in male and female Wistar rats subjected to chronic unpredictable mild stress (CUMS). Sixty Wistar rats (30 male and 30 female) weighing between 120 and 150g were used for this study. The rats were divided into two sub-groups: control (10) and test (20) groups. Rats in the test groups were subjected to CUMS. Depression-like behaviors were assessed using light-dark box, sucrose preference, and tail suspension tests. Rats that showed depression-like behaviors following the behavioral tests (CUMS-susceptible group) were sacrificed, and their hippocampi were excised. Genomic deoxyribonucleic acid (gDNA) was purified from the hippocampal samples. Purified gDNA was subjected to whole genome sequencing (WGS). Base-calling of sequence reads from raw sequencing signal (FAST5) files was carried out, and variants were called from alignment BAM files. The corresponding VCF files generated from the variant calling experiment were filtered. Genes were identified, their impacts estimated, and variants annotated. Functional enrichment analysis was then carried out. Approximately 41% of the male and 49% of the female rats subjected to CUMS showed significant (p < 0.05) depression-like behaviors following assessment on behavioral tests. WGS of the hippocampal DNA revealed 289,839 single nucleotide polymorphisms variant types, 7002 insertions, and 34,459 deletions in males, and 1,570,186 single nucleotide polymorphisms variant types, 109,860 insertions, and 597,241 deletions in female Wistar rats. Three genes with high-impact variants were identified in male and 22 in female Wistar rats, respectively. In conclusion, female Wistar rats are more susceptible to depression-like behaviors after exposure to CUMS than males. They also have more gene variants (especially high-impact variants) than male Wistar rats.

The involvement of Slc7a11/xCT related iron accumulation on acupuncture intervention in 6-OHDA-induced Parkinson rat

BackgroundAcupuncture plays a critical role for the treatment of patients with Parkinson's disease (PD), which is characterized by ferroptosis of dopaminergic neurons. It has been found that acupuncture can reduce iron accumulation. However, the mechanism of acupuncture therapy against PD by inhibiting ferroptosis remains unclear. ObjectiveTo investigate the potential mechanism of acupuncture on alleviating ferroptosis in 6-OHDA-induced PD rats. MethodsMale Sprague-Dawley rats were randomly divided into sham group, acupuncture group, and PD model group, with the PD model induced by 6-OHDA. The motor function of the rats was tested by the rotation test and suspension test, respectively. Immunohistochemistry and iron staining were performed to analyze nerve damage, and the effect of acupuncture on the accumulation of iron in the substantia nigra (SN). RNA-seq analysis in the SN of rats were performed to discover ferroptosis-related genes. Differentially expressed genes (DEGs) resulted from the acupuncture treatment were identified and were used for Gene Ontology (GO) function, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. A protein–protein interaction (PPI) network was constructed, and alternative splicing (AS) analysis of the transcriptome was performed. Western blot was used to detect the protein level change of Slc7a11/xCT. ResultsRotation test and suspension test indicated a positive effect of acupuncture on body weight gain and limb function. Perl's iron staining and ELISA test detected 6-OHDA induced iron accumulation in the SN and nerve damage, which was mitigated by acupuncture treatment. Acupuncture treatment brought about the differential expression of a total of 1088 genes in the SN of rats. GO and KEGG enrichment revealed that such DEGs were mainly associated with several key biological process (BP), cellular component (CC) and molecular function (MF) terms. These terms included collagen fibril organization, extracellular matrix organization, collagen trimer, extracellular matrix components, chemokine receptor binding and cargo receptor activity, etc. Additionally, the DEGs were found to be involved in pathways such as complement and coagulation. The PPI network of DEGs suggested a critical role of Slc7a11, which was further supported by an up-regulated Slc7a11/xCT protein level in the substantia nigra (SN) tissue of rats treated with acupuncture compared to their PD model counterparts (P = 0.045). ConclusionAcupuncture may prevent ferroptosis through Slc7a11/xCT as one of the targets in 6-OHDA-induced PD model and thereby could be promising for PD treatment.

Examination of the Effect of Dimethyl Trisulfide in Acute Stress Mouse Model with the Potential Involvement of the TRPA1 Ion Channel.

Polysulfides are endogenously produced in mammals and generally associated with protective functions. Our aim was to investigate the effect of dimethyl trisulfide (DMTS) in a mouse model of acute stress. DMTS activates transient receptor potential ankyrin 1 (TRPA1) channels and leads to neuropeptide release, potentially that of substance P (SP). We hypothesize that DMTS might inhibit the degrading enzymes of endocannabinoids, so this system was also investigated as another possible pathway for mediating the effects of DMTS. Trpa1 gene wild-type (WT) and knockout (KO) mice were used to confirm the role of the TRPA1 ion channel in mediating the effects of DMTS. C57BL/6J, NK1 gene KO, and Tac1 gene KO mice were used to evaluate the effect of DMTS on the release and expression of SP. Some C57BL/6J animals were treated with AM251, an inhibitor of the cannabinoid CB1 receptor, to elucidate the role of the endocannabinoid system in these processes. Open field test (OFT) and forced swim test (FST) were performed in each mouse strain. A tail suspension test (TST) was performed in Trpa1 WT and KO animals. C-FOS immunohistochemistry was carried out on Trpa1 WT and KO animals. The DMTS treatment increased the number of highly active periods and decreased immobility time in the FST in WT animals, but had no effect on the Trpa1 KO mice. The DMTS administration induced neuronal activation in the Trpa1 WT mice in the stress-related brain areas, such as the locus coeruleus, dorsal raphe nucleus, lateral septum, paraventricular nucleus of the thalamus, and paraventricular nucleus of the hypothalamus. DMTS may have a potential role in the regulation of stress-related processes, and the TRPA1 ion channel may also be involved in mediating the effects of DMTS. DMTS can be an ideal candidate for further study as a potential remedy for stress-related disorders.

Antidepressant effect of carvedilol on streptozotocin-induced diabetic peripheral neuropathy mice by altering gut microbiota

RationaleAlthough diabetic peripheral neuropathic pain (DPNP) and depression have been recognized for many years, their co-morbidity relationship and effective treatment choices remain uncertain. ObjectivesTo evaluate the antidepressant effect of carvedilol on streptozotocin-induced DPNP mice, and the relationship with gut microbiota. MethodsThe hyperalgesia and depressive behaviors of mice with comorbidity of DPNP and depression were confirmed by pain threshold of the mechanical sensitivity test (MST), immobility time of the tail suspension test (TST) and the forced swimming test (FST). The anti-depressive effect and fecal gut microbiota composition were studied in DPNP mice treated with carvedilol (10 mg/kg/day), and the relationships between them were analyzed by Spearman's correlation. ResultsDepression was successfully induced in DPNP mice. Carvedilol can reverse the decreased mechanical pain threshold and relieve the depressive behaviors of DPNP mice, while increasing the abundance of Prevotella, Ruminococcus, Helicobacter and Desulfovibrio, and decreasing the abundance of Akkermansia and Allobaculum. ConclusionsCarvedilol can alleviate the mechanical hyperalgesia and alter gut microbiota to ameliorate the depression-like behaviors which induced by DPNP.

Hippocampal Crhr1 conditional gene knockout ameliorated the depression-like behavior and pathological damage in male offspring mice caused by chronic stress during pregnancy

Numerous studies have demonstrated that chronic stress during pregnancy (CSDP) can induce depression and hippocampal damage in offspring. It has also been observed that high levels of corticotropin-releasing hormone (CRH) can damage hippocampal neurons, and intraperitoneal injection of a corticotropin releasing hormone receptor 1 (CRHR1) antagonist decreases depression-like behavior and hippocampal neuronal damage in a mouse depression model. However, whether CSDP causes hippocampal damage and depression in offspring through the interaction of CRH and hippocampal CRHR1 remains unknown and warrants further investigation. Therefore, hippocampal Crhr1 conditional gene knockout mice and C57/BL6J mice were used to study these questions. Depression-related indexs in male offspring mice were examined using the forced swim test (FST), sucrose preference test (SPT), tail suspension test (TST) and open field test (OFT). Serum CRH levels were measured by enzyme-linked immunosorbent assay (ELISA). Golgi-Cox staining was used to examine the morphological changes of hippocampal neuronal dendrites. Neuronal apoptosis in the hippocampal CA3 regions was detected by terminal deoxynucleotidy transferase dUTP nick end labeling (TUNEL) staining. The levels of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR) and protein kinase B (AKT) proteins were measured by Western blot analysis. This study showed that CSDP induces depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring mice. Conditional gene knockout of hippocampal Crhr1 in mice reduced CSDP-induced depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring, and counteracted the CSDP-induced decreased expression of p-Akt and mTOR activity in male offspring hippocampus. These findings demonstrated that CSDP might inhibit the Akt/mTOR pathway by increasing the levels of CRH, leading to increased CRH-mediated activation of hippocampal CRHR1, thereby inducing synaptic impairment and apoptosis in hippocampal neurons, which in turn leads to depression-like behavior in offspring.

Neuroprotective Effect of Boswellia serrata against 3-NP Induced Experimental Huntington’s Disease

Objectives:: The study aimed to assess the neuroprotective effect of Boswellia serrata against 3-NP-induced experimental Huntington’s disease. Background:: Previous studies have shown Boswellia to have sedative, analgesic, and anti-tumour effects. Boswellia serrata yields four pentacyclic triterpene acids and boswellic acid, a bioactive substance that prevents leukotriene biogenesis. Methods:: The potential neuroprotective effect of Boswellia serrata against 3-nitro propionic acid (3-NP)-induced Huntington's disease (HD) was examined at oral doses of 45 mg/kg, 90 mg/kg, and 180 mg/kg. In this study, HD was induced by 3-NP at a dose of 10 mg/kg in Wistar rats. The study used 56 Wistar rats (8 per group) for biochemical (inflammatory markers, acetylcholinesterase activity) and behavioural (elevated plus maze, Y-maze, open-field, tail suspension tests, etc.) assessments. Additionally, a histological examination of the brain was carried out. In addition, the analysis of Boswellia serrata extract was performed by different analytical techniques, like UV spectrophotometer, FTIR, and HPLC methods. Results:: In the brain, succinate dehydrogenase is a mitochondrial enzyme irreversibly inhibited by 3-NP. Administration of 3-NP resulted in HD with altered behavioural and motor changes in rats. Treatment with Boswellia serrata resulted in remarkable protection of rats against 3-NP-induced behaviour and motor deficits in a dose-dependent manner. Moreover, in rats administered with 3-NP, Boswellia serrata improved memory performance and lowered levels of inflammatory biomarkers. These results have also been supported by histopathological analysis. Acetyl-11-keto-p-boswellic acid was found to be the main active component of Boswellia serrata extract. Conclusion:: Boswellia serrata at a dose of 180 mg/kg exhibited better protection compared to the other doses against HD induced by 3-NP. More detailed studies based on molecular targets are needed for the Boswellia serrata to transition from the bench to the bedside for use as an adjuvant in HD patients.

A deep-learning-based threshold-free method for automated analysis of rodent behavior in the forced swim test and tail suspension test

BackgroundThe forced swim test (FST) and tail suspension test (TST) are widely used to assess depressive-like behaviors in animals. Immobility time is used as an important parameter in both FST and TST. Traditional methods for analyzing FST and TST rely on manually setting the threshold for immobility, which is time-consuming and subjective. New methodWe proposed a threshold-free method for automated analysis of mice in these tests using a Dual-Stream Activity Analysis Network (DSAAN). Specifically, this network extracted spatial information of mice using a limited number of video frames and combined it with temporal information extracted from differential feature maps to determine the mouse’s state. To do so, we developed the Mouse FSTST dataset, which consisted of annotated video recordings of FST and TST. ResultsBy using DSAAN methods, we identify immobility states at accuracies of 92.51 % and 88.70 % for the TST and FST, respectively. The predicted immobility time from DSAAN is nicely correlated with a manual score, which indicates the reliability of the proposed method. Importantly, the DSAAN achieved over 80 % accuracy for both FST and TST by utilizing only 94 annotated images, suggesting that even a very limited training dataset can yield good performance in our model. Comparison with existing method(s)Compared with DBscorer and EthoVision XT, our method exhibits the highest Pearson correlation coefficient with manual annotation results on the Mouse FSTST dataset. ConclusionsWe established a powerful tool for analyzing depressive-like behavior independent of threshold, which is capable of freeing users from time-consuming manual analysis.

Chronic stress intensify PTZ-induced seizures by triggering neuroinflammation and oxidative stress

BackgroundEpilepsy is a paroxysmal abnormal hypersynchronous electrical discharge characterized by recurrent seizures. It affects more than 50 million people worldwide. Stress is the leading cause of neurodegeneration and can produce seizures that may lead to or aggravate epilepsy. Inflammation plays a vital role in epilepsy by modulating oxidative stress, and levels of neuroinflammatory cytokines including NF-κB, TNF-α, and IL-1β. MethodsStress-induced changes in behavior were evaluated in mice by employing behavioral assessment tests such as an elevated plus maze, light-dark box, open field test, tail suspension test, Y-maze, novel object recognition test, and Morris water maze in pentylenetetrazole (PTZ) kindled mice. Behavioral changes in all these paradigms including seizure score, latency, and frequency showed an increase in symptoms in PTZ (35 mg/kg) induced seizures in stressed mice (RS-PTZ) as compared to PTZ, Stress, and normal animals. ResultsThe Enzyme-linked immunosorbent assay (ELISA) results confirmed increased in serum cortisol levels. Histological examinations showed neurodegenerative changes in the hippocampus and cortex regions. The spectrophotometric evaluation showed an increase in oxidative stress by decreasing antioxidant production i.e. reduced glutathione, glutathione -s- transferase, and catalase (CAT), and increasing oxidant levels such as maloaldehyde and nitric oxide. Immunohistochemistry results showed increased expression of NF-κB, TNF-α, and IL-1β in the cortex and hippocampus of mice brains. ConclusionsResults from the study conclude that stress increases the likelihood of eliciting an epileptic attack by increasing the level of reactive oxygen species and neuroinflammation.

A probiotic NVP1704 alleviates stress-induced sleeplessness/depression-like symptoms in mice by upregulating serotonergic and GABAergic systems and downregulating NF-κB activation.

Sleeplessness (insomnia) is a potential symptom of depression. A probiotic NVP1704 alleviates depression-like behavior and neuroinflammation in mice. Therefore, to understand whether NVP1704 could be effective against sleeplessness in vivo, we exposed immobilization stress (IS) in mice, then orally administered NVP1704 for 5 days, and assayed depression/anxiety-like behavior in the open field, elevated plus maze, and tail suspension tests, sleeping latency time, and sleep duration, euthanized then by exposure to CO2, and analyzed their related biomarkers. Oral administration of NVP1704 decreased IS-induced depression/anxiety-like behavior and sleeping latency time and increased IS-suppressed sleeping duration. NVP1704 increased IS-suppressed expression of γ-aminobutyric acid (GABA), GABAA receptor α1 (GABAARα1) and α2 subunits (GABAARα2), serotonin, 5-HT receptors (5-HT1AR and 5-HT1BR), and melatonin receptors (MT1R and MT2R) in the prefrontal cortex and thalamus. NVP1704 also increased the IS-suppressed GABAARα1-positive cell population in the prefrontal cortex and decreased IS-induced corticosterone, TNF-α, and IL-6 expression and the NF-κB+Iba1+ cell population in the brain and myeloperoxidase, TNF-α, and IL-6 expression and the NF-κB+CD11c+ cell population in the colon. Based on these findings, NVP1704 may alleviate depression/anxiety/sleeplessness-like behaviors through the upregulation of serotonergic and GABAergic systems and downregulation of NF-κB activation.

MiR-204-5p Plays a Critical Role in the Pathogenesis of Depression and Anti-depression Action of Venlafaxine in the Hippocampus of Mice.

Venlafaxine has been demonstrated to treat diseases such as social anxiety disorder and depression. Most of antidepressants including venlafaxine have a certain effect, but significant side effects. Therefore, it is necessary for us to research the development of novel antidepressants for effective treatment in practice. MicroRNA-204 (miR-204) is highly expressed in brain tissue, and plays a critical role in the synaptic plasticity of hippocampal neurons in rats. However, the underlying molecular mechanism of miR-204 remains unclear to date, this study aims to offer unique insights into depression and provide a theoretical basis for clinical physicians. A chronic social defeat stress (CSDS) was initially adopted for establishing a mice model of depression in this research and depression-like behaviors were evaluated by a series of behavioral experiments including the sucrose preference test (SPT), the tail suspension test (TST), the forced swim test (FST) and the social interaction test (SIT). Quantitative real-time reverse transcription PCR (qRT-PCR) was also conducted to test the expression levels of miR-204 and BDNF in the hippocampus of mice. Finally, gene interference of miR-204-5p was further adopted to test whether miR-204-5p played an effective role in the antidepressant effects of venlafaxine in mice. Our data implicated that CSDS significantly increased the miR-204-5p but not miR-204-3p levels in the hippocampus of mice. The treatment of venlafaxine obviously relieved depression- like behaviors of CSDS-induced mice. The usage of venlafaxine abolished the increasing effects on the expression of miR-204-5p but up-regulated the BDNF expression level in CSDS-exposured mice. More importantly, we found that genetic overexpression of miR-204-5p decreased the reverse effects of venlafaxine on depressive-like behaviors and genetic knockdown of hippocampal miR-204-5p relieved the depressive-like behaviors and neurogenesis in CSDS-induced mice. miR-204-5p played an effective role in the antidepressant effects of venlafaxine in CSDS-induced mice.

Optimizing a mouse model of exertional heat stroke to simulate multiorgan and brain injuries.

Exertional heat stroke (EHS) is a clinical entity characterized by abnormalities of the central nervous system (CNS) and is associated with multiple organ injury, some of which may be irreversible. It is valuable to establish an optimized model of EHS that is able to induce and assess damage to the CNS and multiple organs. We induced EHS by using an environmental chamber with adjustable temperature and humidity and a mice forced running wheel. The endpoint for the EHS was defined as either exhaustion or a core temperature of 42.5°C being reached. Injury to the liver, kidney, and CNS of mice in the EHS group was revealed through pathological studies using hematoxylin and eosin staining of harvested organs at different time points and detection of biomarkers. The depressive-like behavior of EHS mice was assessed through open field tests, forced swimming tests, and tail suspension tests. The favorable environmental conditions for induction of EHS based on this presented model are 38°C, 70% RH. The EHS mice developed thermoregulatory dysfunction and experienced a significantly higher weight loss ratio compared to the SHE (sham heat exercise) group. The liver, kidney, and brain tissues of EHS mice were significantly damaged, and the pathological damage scores for each organ were significantly higher than those of the SHE group. In the open field test (OFT), compared to the SHE group, there was a significant reduction in the number and time of EHS mice entering the center of the open field. Additionally, there was a significant increase in immobile time during forced swimming test (FST) and tail suspension test (TST). This study presents an improved animal model that has the potential to assess for neurological and multiple organ injury caused by EHS and simultaneously, while accurately reflecting the clinical characteristics observed in EHS patients.