Streptozotocin induced oxidative stress, innate immune system responses and behavioral abnormalities in male mice

Gut-brain barrier dysfunction bridge autistic-like behavior in mouse model of maternal separation stress: A behavioral, histopathological, and molecular study

Autism spectrum disorder (ASD) is a fast-growing neurodevelopmental disorder throughout the world. Experiencing early life stresses (ELS) like maternal separation (MS) is associated with autistic-like behaviors. It has been proposed that disturbance in the gut-brain axis-mediated psychiatric disorders following MS. The role of disruption in the integrity of gut-brain barrier in ASD remains unclear. Addressing this knowledge gap, in this study we aimed to investigate role of the gut-brain barrier integrity in mediating autistic-like behaviors in mouse models of MS stress. To do this, mice neonates are separated daily from their mothers from postnatal day (PND) 2 to PND 14 for 3 hours. During PND58-60, behavioral tests related to autistic-like behaviors including three-chamber sociability, shuttle box, and resident-intruder tests were performed. Then, prefrontal cortex (PFC), hippocampus, and colon samples were dissected out for histopathological and molecular evaluations. Results showed that MS is associated with impaired sociability and social preference indexes, aggressive behaviors, and impaired passive avoidance memory. The gene expression of CLDN1 decreased in the colon, and the gene expression of CLDN5, CLDN12, and MMP9 increased in the PFC of the MS mice. MS is associated with decrease in the diameter of CA1 and CA3 areas of the hippocampus. In addition, MS led to histopathological changes in the colon. We concluded that, probably, disturbance in the gut-brain barrier integrities mediated the autistic-like behavior in MS stress in mice.

Neurological recovery and neurogenesis by curcumin sustained-release system cross-linked with an acellular spinal cord scaffold in rat spinal cord injury: Targeting NLRP3 inflammasome pathway

In the context of treating spinal cord injury (SCI), the modulation of inflammatory responses, and the creation of a suitable region for tissue regeneration may present a promising approach. This study aimed to evaluate the effects of curcumin (Cur)-loaded bovine serum albumin nanoparticles (Cur-BSA NPs) cross-linked with an acellular spinal cord scaffold (ASCS) on the functional recovery in a rat model of SCI. We developed an ASCS using chemical and physical methods. Cur-BSA, and blank (B-BSA) NPs were fabricated and cross-linked with ASCS via EDC-NHS, resulting in the production of Cur-ASCS and B-ASCS. We assessed the properties of scaffolds and NPs as well as their cross-links. Finally, using a male rat hemisection model of SCI, we investigated the consequences of the resulting scaffolds. The inflammatory markers, neuroregeneration, and functional recovery were evaluated. Our results showed that Cur was efficiently entrapped at the rate of 42% ± 1.3 in the NPs. Compared to B-ASCS, Cur-ASCS showed greater effectiveness in the promotion of motor recovery. The implantation of both scaffolds could increase the migration of neural stem cells (Nestin- and GFAP-positive cells) following SCI with the superiority of Cur-ASCS. Cur-ASCS was successful to regulate the gene expression and protein levels of NLRP3, ASC, and Casp1in the spinal cord lesion. Our results indicate that using ASCS can lead to the entrance of cells into the scaffold and promote neurogenesis. However, Cur-ASCS had greater effects in terms of inflammation relief and enhanced neurogenesis.

Anethole via increase in the gene expression of PI3K/AKT/mTOR mitigates the autistic-like behaviors induced by maternal separation stress in mice

Autism spectrum disorder (ASD) is a neurodegenerative disease with increasing incidence in the world. The maternal separation (MS) stress at early life with its own neuroendocrine and neurostructural changes can provide the basis for development of ASD. Previously it has been reported neuroprotective characteristics for anethole. The PI3K/AKT/mTOR signaling pathway has pivotal role in the function of central nervous system (CNS). This study aimed to evaluate the possible effects of anethole on the autistic-like behaviors in the maternally separated (MS) mice focusing on the potential role of the PI3K/AKT/mTOR pathway. Forty male Naval Medical Research Institute (NMRI) mice were assigned to five groups (n = 8) comprising a control group (treated with normal saline) and four groups subjected to MS and treated with normal saline and or anethole at doses of 31.25, 62.5 and 125 mg/kg, respectively. All gents were administrated via intraperitoneal (i.p.) route for 14 constant days. Behavioral tests were conducted, including the three-chamber test, shuttle box and resident-intruder test. The gene expression of the PI3K, AKT and mTOR assessed in the hippocampus by qRT-PCR. Findings indicated that MS is associated with autistic-like behaviors. Anethole increased the sociability and social preference indexes in the three-chamber test, increased duration of secondary latency in the shuttle box test and decreased aggressive behaviors in the resident-intruder test. Also, anethole increased the gene expression of PI3K, AKT and mTOR in the hippocampus of MS mice. We concluded that anethole through increase in the gene expression of PI3K/ AKT/mTOR mitigated autistic-like behaviors induced by MS in mice.

Anethole as a promising antidepressant for maternal separation stress in mice by modulating oxidative stress and nitrite imbalance

The occurrence of major depressive disorder is widespread and can be observed in individuals belonging to all societies. It has been suggested that changes in the NO pathway and heightened oxidative stress may play a role in developing this condition. Anethole is a diterpene aromatic compound found in the Umbelliferae, Apiaceae, and Schisandraceae families. It has potential pharmacological effects like antioxidant, anxiolytic, analgesic, anti-inflammatory, antidiabetic, gastroprotective, anticancer, estrogenic, and antimicrobial activities. This study aimed to investigate the potential antidepressant properties of Anethole in a mouse model experiencing maternal separation stress while also examining its impact on oxidative stress and nitrite levels. The research involved the participation of 40 male NMRI mice, separated into five distinct groups to conduct the study. The control group was administered 1 ml/kg of normal saline, while the MS groups were given normal saline and Anethole at 10, 50, and 100 mg/kg doses. The study comprised various behavioural tests, including the open field test (OFT), forced swimming test (FST), and splash test, to assess the effects of Anethole on the mice. In addition to the behavioural tests, measurements were taken to evaluate the total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrite levels in the hippocampus of the mice. According to the findings, maternal separation stress (MS) led to depressive-like conduct in mice, including a rise in immobility duration during the FST and a reduction in the duration of grooming behaviour in the splash test. Additionally, the results indicated that MS correlated with an increase in the levels of MDA and nitrite and a reduction in the TAC in the hippocampus. However, the administration of Anethole resulted in an increase in grooming activity time during the splash test and a decrease in immobility time during the FST. Anethole also exhibited antioxidant characteristics, as demonstrated by its ability to lower MDA and nitrite levels while increasing the TAC in the hippocampus. The results suggest that Anethole may have an antidepressant-like impact on mice separated from their mothers, likely partly due to its antioxidant properties in the hippocampus.

An intracerebroventricular injection of AΒ (1-42) modifies temporal profiles of spatial memory performance and oxidative status in the temporal cortex rat

Alzheimer's dementia (AD) is a neurodegenerative disorder that causes memory loss and dementia in older adults. Intracellular accumulation of Aβ causes an imbalance in the oxidative status and cognitive dysfunctions. Besides oxidative stress and loss of memory, Alzheimer's patients show dysfunction of the circadian rhythms. The objective of this work was to evaluate the consequences of an intracerebroventricular injection of Aβ (1-42) on temporal patterns of cognitive performance, as well as on lipid peroxidation, protein oxidation and total antioxidant capacity levels, in the rat temporal cortex. Holtzman male rats from control and Aβ-injected groups were used in this study. We found that MDA, protein carbonyls and total antioxidant capacity levels displayed day-night oscillations in the rat temporal cortex and spatial memory performance also varied rhythmically. An intracerebroventricular injection of Aβ (1-42) modified temporal patterns of cognitive performance as well as daily profiles of parameters of oxidative stress. Thus, elevated levels of Aβ aggregates induces alterations in daily rhythmicity of parameters of oxidative stress and, consequently, would affect cellular clock activity, affecting the spatial memory performance in the AD.

Metformin attenuates depressive-like behaviour of methamphetamine withdrawal in mice: A mechanistic approach

OBJECTIVES

Methamphetamine (METH) as a potent psychostimulant drug with a high potency of dependence rate that results in neurotoxicity has become a major drug of abuse in many parts of the world. Unfortunately, there is limited evidence regarding treatment of METH withdrawal syndrome. Therefore, we aimed to investigate whether metformin mitigate the methamphetamine (METH) withdrawal syndrome in male mice. Based on the literature, depression and anxiety are the major METH withdrawal symptoms.

METHODS

Here, METH (2 mg/kg) was administered to mice twice a day for 14 constitutive days to induce animal model of METH-induced withdrawal syndrome. To do this, mice in control group and those with METH withdrawal syndrome were divided into treatment (receiving metformin in 3 doses of 50, 100 and 200 mg/kg for 10 days) and non-treatment sub-groups. Following the behavioural test, the animals were sacrificed; their hippocampus was dissected to measure oxidative stress parameters and expression of cellular energy homeostasis and immune-inflammatory genes.

RESULTS

Our data revealed that metformin provoked antidepressant effects in behavioural tests through AMPK overexpression as an important mitochondrial energetic sensor and inhibition of Tlr4 overexpression in the immune system gene expression. In addition, metformin was able to improve oxidative stress biomarkers and neuronal damage in the hippocampus and restore cellular energy homeostasis and immune system gene expression.

CONCLUSIONS

The data suggested that metformin can influence the hippocampus through targeting mitochondria and their performance, and consequently, neuroinflammation responses and brain metabolic changes. It is supposed to be a new therapeutic option in clinical trials of depression and anxiety following METH withdrawal treatment.

Mitigated Oxidative Stress and Cognitive Impairments in Transient Global Ischemia using Niosomal Selegiline-NBP delivery

Stroke is the most common reason for adult disabilities and the second ground for death worldwide. Our previous study revealed that selegiline serves as an alternative candidate in transient hypoxia-ischemia. However, aggressive and restless behavior was observed in stroke-induced rats receiving 4 mg/kg selegiline. In comparison, 1 mg/kg selegiline could induce negligible therapeutic effects on mitochondrial dysfunction and histopathological changes. Therefore, we designed oral noisome-based selegiline attached to 4-(4-nitrobenzyl) pyridine to improve transient global ischemia by attenuating cognitive impairments, oxidative stress, and histopathological injury. The investigation was performed in transient hypoxia-ischemia-induced rats by oral administration of nanoformulation containing selegiline (0.25-1 mg/kg) for 4 weeks (3 times a week). Novel object recognition (NOR) was considered to evaluate their cognitive dysfunction. Oxidative stress parameters and brain histopathological assessments were determined following the scarification of rats. Outstandingly, our data demonstrated slower selegiline release from niosomes relative to free drug, which was also in a controlled manner. Our data confirmed significant improvement in cognitive behavior in the NOR test, an increase in glutathione level and total antioxidant power, a decline in MDA and protein carbonyl level, as well as a decreased number of dead cells in histopathological assessment after being exposed to (0.5-1 mg/kg) selegiline-NBP nanoformulation. These data manifested that the selegiline-NBP nanoformulation (0.5-1 mg/kg) could significantly reduce oxidative damage, cognitive dysfunction, and histopathological damage compared to transient hypoxia-ischemia rats, which is 20 times lower than the therapeutic dose in humans. Therefore, the proposed nanoformulation would be capable as an alternative candidate without side effects in stroke.

Neuroprotective Effect of Apigenin on Depressive-Like Behavior: Mechanistic Approach

Apigenin, as a natural flavonoid present in several plants is characterized with potential anticancer, antioxidant, and anti-inflammatory properties. Recent studies proposed that apigenin affects depression disorder through unknown mechanistic pathways. The effects of apigenin's anti-depressive properties on streptozocin-mediated depression have been investigated through the evaluation of behavioral tests, oxidative stress, cellular energy homeostasis and inflammatory responses. The results demonstrated anti-depressive properties of apigenin in behavioral test including forced swimming and splash tests and oxidative stress biomarkers such as reduced glutathione, lipid peroxidation, total antioxidant power and coenzyme Q₁₀ levels. Apigenin, also, demonstrated its regulatory potency in cellular energy homeostasis and immune system gene expression through inhibiting Nlrp3 and Tlr4 overexpression. Furthermore, failure in energy production as the key factor in various psychiatric disorders was reversed by apigenin modulating effect on AMPK gene expression. Overall, 20 mg/kg of apigenin was recognized as the dose suitable for minimizing the undesirable adverse effects in the STZ-mediated depression model proposed in this study. Our data suggested that apigenin could be able to adjust behavioral dysfunction, biochemical biomarkers and recovered cellular antioxidant level in depressed animals. The surprising results were achieved by raise in COQ₁₀ level, which could regulate the overexpression of the AMPK gene in stressful conditions. The regulatory effect of apigenin in inflammatory signaling pathways such as Nlrp3, and Tlr4 gene expression was studied at the surface part of the hippocampus.

Ghrelin restores memory impairment following olfactory bulbectomy in mice by activating hippocampal NMDA1 and MAPK1 gene expression

Ghrelin (Ghrl) is an orexigenic peptide with potential roles in the modulation of anxiety- and depressive-like symptoms induced by bilateral olfactory bulbectomy (OB) in rodents. In the present work, we assessed whether intrahippocampal Ghrl could reverse OB-induced depressive-like and amnesic effects by regulating molecular mechanisms related to neuroplasticity. Adult female albino Swiss mice were divided into sham and OB groups, and infused with saline (S) or Ghrl 0.03 nmol/μl, 0.3 nmol/μl, or 3 nmol/μl into the hippocampus before exposition to open-field test (OFT) and tail suspension test (TST) or immediately after training in the object recognition test (ORT). After test phase in ORT, animals were euthanized and their hippocampi were dissected to study the expression of genes related to memory. The OB-S animals presented hyperlocomotion in OFT, increased immobility in TST and memory impairment compared to sham-S (p < 0.05), but acute intrahippocampal infusion of Ghrl 0.3 nmol/μl produced an improvement on these parameters in OB animals (p < 0.05). In addition, this dose of Ghrl reversed OB-induced low expression of NMDA1 and MAPK1 iso1 and up-regulated the expression of CaMKIIa iso1 and iso2, and MAPK1 iso2 (p < 0.05). These results extend the existing literature regarding OB-induced behavioral and neurochemical changes, and provide mechanisms that could underlie the antidepressant effect of Ghrl in this model.

SAHA Improves Depressive Symptoms, Cognitive Impairment and Oxidative Stress: Rise of a New Antidepressant Class

Depression is a disabling psychiatric disorder affecting millions of people all around the world. Under current therapeutic choices, a portion of patients are not responsive, have relapses, or experience cognitive side effects. Hence, the present study aimed to find other antidepressant compounds lacking the mentioned deficiency. Since epigenetic regulations have attracted more attention in etiology of depression, histone deacetylase (HDAC) inhibitors have gained more importance due to their possible antidepressant activity. We selected a promising member of HDAC inhibitors named suberanilohydroxamic acid (SAHA) to evaluate its antidepressant properties. Early life stress disarrays many neurodevelopmental factors and consequently, leads to the destruction of hippocampus and prefrontal cortex synapses as areas highly related to emotion and memory so that any destruction on them can cause lasting impairments. For that reason, we used maternal separation (MS) paradigm to investigate depression in male mice. To compare the efficacy of SAHA with current treatment options, we also treated a group of MS mice with fluoxetine (FLX) as first-line pharmacological drugs of depression. The results demonstrated that depressive-like behavior, cognitive function and inflammatory response of MS mice were attenuated with SAHA. Our data showed that, besides anti-depressant and cognition-boosting effects similar to FLX, SAHA counteracted inflammatory response caused by depression and reversed the coenzyme Q₁₀ (CoQ₁₀) level in hippocampus. SAHA's effect on alleviating depressive behavior was accompanied with memory enhancement and hippocampus biochemical tests. These findings may propose SAHA as another therapeutic option for depressive symptoms, especially with comorbid cognitive impairment.

Selegiline (L-Deprenyl) Mitigated Oxidative Stress, Cognitive Abnormalities, and Histopathological Change in Rats: Alternative Therapy in Transient Global Ischemia

Selegiline (L-deprenyl) is the major drug which is used in the treatment of Parkinson's disease because of its neurotrophic and antiapoptotic properties. Previous studies suggested that low dose of L-methamphetamine (L-METH) caused lower mortality rate in patients with severe traumatic brain injury. As L-methamphetamine is one of the metabolites of selegiline, the present study aims to examine whether L-deprenyl can improve cognitive, biochemical, and histopathological injury in animal model of transient global ischemia. The animals were randomized in ten groups orally gavaged three times a week for 28 days. Then, novel object recognition (NOR) was conducted to assess their behavioral abnormality. After scarification of the rats, their brains were divided into two sections to measure oxidative stress parameters and perform pathological evaluations in rats. Our data revealed the involvement of oxidative stress, behavioral despair, and pathological data in transient global ischemia rats. Significant recovery in cognitive behavior, oxidative stress biomarker, and number of dead cell in histopathological assay was observed in rats treated with 1,2 and 4 mg/kg of selegiline. So, selegiline appears to be useful in alternative therapy of transient global ischemia.

The selenocompound 1-methyl-3-(phenylselanyl)-1H-indole attenuates depression-like behavior, oxidative stress, and neuroinflammation in streptozotocin-treated mice

Major depressive disorder (MDD) is a chronic mental illness affecting a wide range of people worldwide. The pathophysiology of MDD is not completely elucidated, but it is believed that oxidative stress and neuroinflammation are involved. In light with this, the aim of the present study was to investigate whether a single administration of the antioxidant 1-methyl-3-(phenylselanyl)-1H-indole (MFSeI) was able to reverse the streptozotocin-induced depression-like behavior, oxidative stress, and neuroinflammation in mice. MFSeI (10 mg/kg) was administered intragastrically (i.g.) 24 h after the intracerebroventricular injection of STZ (0.2 mg/4 μL/per mouse). Thirty minutes after MFSeI administration, behavioral tests and neurochemical analyses were performed. Fluoxetine (10 mg/kg, i.g.) was used as a positive control. MFSeI and fluoxetine were able to reverse the STZ-induced depression-like behavior, as evidenced by decreased immobility time in the forced swimming test and increased grooming time in the splash test. Mechanistically, MFSeI reversed the increased levels of reactive species and lipid peroxidation in the prefrontal cortices and hippocampi of STZ-treated mice. Additionally, neuroinflammation (i.e. expression of NF-κB, IL-1β, and TNF-α) and the reduced mRNA levels of BDNF in the and hippocampi of depressed mice were reversed by treatment with MFSeI. Fluoxetine did not improve the STZ-induced alterations at the levels of reactive species, NF-κB and BDNF in the prefrontal cortices neither the levels of TNF-α in both brain regions. Together, these data suggest that the MFSeI may be a promising compound with antidepressant-like action, reducing oxidative stress and modulating inflammatory pathways in the brain of depressed mice.

Ferulic acid through mitigation of NMDA receptor pathway exerts anxiolytic-like effect in mouse model of maternal separation stress

Background Experiencing early-life stress plays an important role in the pathophysiology of anxiety disorders. Ferulic acid is a phenolic compound found in some plants which has several pharmacological properties. N-methyl-D-aspartate (NMDA) receptors are involved in the pathophysiology of mood disorders. In this study we aimed to assess the anxiolytic-like effect of ferulic acid in a mouse model of maternal separation (MS) stress by focusing on the possible involvement of NMDA receptors. Methods Mice were treated with ferulic acid (5 and 40 mg/kg) alone and in combination with NMDA receptor agonist/antagonist. Valid behavioral tests were performed, including open field test (OFT) and elevated plus maze test (EPM), while quantitative real time polymerase chain reaction (qRT-PCR) was used to evaluate gene expression of NMDA subunits (GluN2A and GluN2B) in the hippocampus. Results Findings showed that treatment of MS mice with ferulic acid increased the time spent in the central zone of the OFT and increased both open arm time and the percent of open arm entries in the EPM. Ferulic acid reduced the expression of NMDA receptor subunit genes. We showed that administration of NMDA receptor agonist (NMDA) and antagonist (ketamine) exerted anxiogenic and anxiolytic-like effects, correspondingly. Results showed that co-administration of a sub-effective dose of ferulic acid plus ketamine potentiated the anxiolytic-like effect of ferulic acid. Furthermore, co-administration of an effective dose of ferulic acid plus NMDA receptor agonist (NMDA) attenuated the anxiolytic-like effect of ferulic acid. Conclusions In deduction, our findings showed that NMDA, partially at least, is involved in the anxiolytic-like effect of ferulic acid in the OFT and EPM tests.

Effects of α-Mangostin Derivatives on the Alzheimer's Disease Model of Rats and Their Mechanism: A Combination of Experimental Study and Computational Systems Pharmacology Analysis

α-Mangostin (α-M) is a natural xanthone from the pericarp of fruit Garcinia mangostana and possesses versatile biological activities. α-M has a therapeutic potential to treat Alzheimer's disease (AD) because of its anti-inflammatory, antioxidative, and neuroprotective activities. However, the use of α-M for AD treatment is limited due to its cytotoxic activities and relatively low potency. Modifications of its chemical structure were needed to reduce its cytotoxicity and improve its therapeutic potential against AD. For this purpose, 16 α-M carbamate derivatives were synthesized. An animal model of AD was established, and the effects of AMG-1 on the spatial learning ability and memory ability were evaluated using behavioral tests. The effect on neuropathology was tested by histopathological evaluation, Nissl staining, and silver staining. Computational systems pharmacology analysis using the chemogenomics knowledgebase was applied for network studies. Compound-target, target-pathway, and target-disease networks were constructed, integrating both in silico analysis and reported experimental data. The results show that AMG-1 can demonstrate its therapeutic effects in a one-molecule, multiple-targets manner to remarkably ameliorate neurological changes and reverse behavioral deficits in AD model rats. The improved cognitive function and alleviated neuronal injury can be observed. The ability of AMG-1 to scavenge β-amyloid in the hippocampus was validated in AD model rats.

Shared cerebral metabolic pathology in non-transgenic animal models of Alzheimer's and Parkinson's disease

Parkinson's disease (PD) and Alzheimer's disease (AD) are the most common chronic neurodegenerative disorders, characterized by motoric dysfunction or cognitive decline in the early stage, respectively, but often by both symptoms in the advanced stage. Among underlying molecular pathologies that PD and AD patients have in common, more attention is recently paid to the central metabolic dysfunction presented as insulin resistant brain state (IRBS) and altered cerebral glucose metabolism, both also explored in animal models of these diseases. This review aims to compare IRBS and alterations in cerebral glucose metabolism in representative non-transgenic animal PD and AD models. The comparison is based on the selectivity of the neurotoxins which cause experimental PD and AD, towards the cellular membrane and intracellular molecular targets as well as towards the selective neurons/non-neuronal cells, and the particular brain regions. Mitochondrial damage and co-expression of insulin receptors, glucose transporter-2 and dopamine transporter on the membrane of particular neurons as well as astrocytes seem to be the key points which are further discussed in a context of alterations in insulin signalling in the brain and its interaction with dopaminergic transmission, particularly regarding the time frame of the experimental AD/PD pathology appearance and the correlation with cognitive and motor symptoms. Such a perspective provides evidence on IRBS being a common underlying metabolic pathology and a contributor to neurodegenerative processes in representative non-transgenic animal PD and AD models, instead of being a direct cause of a particular neurodegenerative disorder.

The Therapeutic Effect of Exercise on Anxiety and Bowel Oxidative Stress in the Maternal Separation Animal Model

Introduction:

According to evidence, Early-Life Stress (ELS), mood disorders, and medical comorbidities, i.e. Irritable Bowel Syndrome (IBS), are correlated; however, the direct contribution of ELS to IBS manifestations is less understood. The current study aimed at evaluating the effect of voluntary exercise on the mitochondrial dysfunction of the bowel fibroblasts, following the confirmation of anxiety behavior.

Methods:

In this study, Postnatal Day (PND) rats underwent Maternal Separation (MS), as a valid animal model of the brain-gut axis dysfunction, in the days 2–14; three hours daily. On day 21, the study animals were divided into 4 groups, as follows: control, Running Wheel (RW) exercise, MS, and MS+RW groups. The study groups were housed in separate cages (4 rats per cage) until the onset of intervention. On day 60, the elevated plusmaze was used to assess anxiety-like behaviors; the level of oxidative stress biomarkers, i.e. Reactive Oxygen Species (ROS), Glutathione (GSH), as well as Adenosine Triphosphate (ATP) was measured to determine the gut mitochondrial function.

Results:

Findings revealed that ELS affected the gut energy metabolism in the studied rats; the negative effects of MS on anxiety and the gut mitochondrial dysfunction decreased via RW exercise during adolescence.

Conclusion:

Overall, anxiety behaviors and ROS production, leading to increased GSH and ATP levels, improved after RW exercise; this significantly impacts the function of colon secretory mitochondria. According to the positive effects of RW exercise on mitochondrial dysfunction in an ELS animal model, a potential relationship was found between the brain and gut in the study rats.

Implication of NMDA-NO pathway in the antidepressant-like effect of ellagic acid in male mice

Depression is one the common psychiatric disorders through the world. Nitric oxide (NO) and N-methyl-d-aspartate receptor (NMDA-R) are involved in the pathophysiology of depression. Previous studies have been reported various pharmacological properties for ellagic acid (EA). We aimed to evaluate possible involvement of NMDA-NO pathway in the antidepressant-like effect of EA. To do this, we used relevant behavioral tests to evaluate depressive-like behavior. In order to find effective and sub-effective doses of agents, mice treated with EA (6.25, 12.5, 25, 50 and 100 mg/kg), L-NAME (5 and 10 mg/kg), L-arg (25 and 50 mg/kg), NMDA (75 and 150 mg/kg) and ketamine (0.25 and 0.5 mg/kg). Furthermore, mice were treated with combination of sub-effective dose of EA plus sub-effective doses of L-NAME and/or ketamine as well as treated with effective dose of EA in combination of effective doses of L-arg and/or NMDA. Level of NO and gene expression of NR2A and NR2B subunits of NMDA-R were assessed in the hippocampus. Results showed that EA dose dependently provoked antidepressant-like effects and also decreased the hippocampal NO level as well as expression of NMDA-Rs. Co-administration of sub-effective doses of L-NAME or ketamine with sub-effective dose of EA potentiated the effect of EA on behaviors, NO level as well as NMDA-Rs gene expression in the hippocampus. However, co-treatment of effective dose of EA with effective doses of L-arg or NMDA mitigated effects of EA. In conclusion, our data suggested that NMDA-NO, partially at least, are involved in the antidepressant-like effect of EA.

Repeated administration of a selenium-containing indolyl compound attenuates behavioural alterations by streptozotocin through modulation of oxidative stress in mice

Although the pathophysiology of major depression disorder (MDD) is still poorly understood, mounting evidence suggests that the brains of depressed patients are under oxidative stress, leading to depressive symptoms that may include anxiety and cognitive impairment. This study aimed to investigate if the seleno-organic compound 1-methyl-3-(phenylselanyl)-1H-indole (MFSeI) reverses the depression- and anxiogenic-like behaviour, cognitive impairment and oxidative stress induced by the intra-cerebroventricular injection of streptozotocin (STZ; 0.2 mg/4 μl/per mouse) in Swiss male mice. Twenty-four hours after the STZ injection, mice were treated with MFSeI (10 mg/kg, intra-gastrically), or vehicle solution, once daily for seven days. The behavioural tests were performed 30 min after the final MFSeI administration, followed by euthanasia and collection of the cerebral cortex and hippocampus. Administration of MFSeI reversed the depression- and anxiogenic-like behaviour and cognitive impairment induced by STZ, in mice. Neurochemical analyses demonstrated that MFSeI reversed the STZ-increased levels of reactive species, nitrite, lipid peroxidation and acetylcholinesterase activity in the cerebral cortex and hippocampus of mice. Moreover, a single administration of MFSeI (300 mg/kg, intra-gastrically) did not cause acute toxicity in Swiss male mice. Altogether, our data suggest that MFSeI exhibits antidepressant- and anxiolytic-like effects and improves the cognition of STZ-treated mice, without any toxicity.

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) Induces the Apoptosis of Dopaminergic Neurons via Oxidative Stress and Neuroinflammation

Several in vitro studies have revealed the neurotoxicity of 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo). However, the underlying mechanism has not been completely elucidated, particularly in vivo. This study was designed to study the neurotoxicity of TaClo in vivo by stereotactically injecting TaClo into the striatum of Wistar rats. After the TaClo injections, rats were subjected to an open field test, and their distance travelled and tracks showed decreasing trends over time. The results of liquid chromatography-mass spectrometry analysis showed that the motor dysfunction of the TaClo-treated rats was accompanied by reduced dopamine levels in the striatum. Based on the diffusion tensor imaging data, the apparent diffusion coefficient of the nigrostriatal pathway was significantly increased, and subsequent histological staining revealed the demyelination of nigrostriatal fibres after the TaClo treatment. TaClo induced a loss of tyrosine hydroxylase-positive cells in the substantia nigra compacta. Regarding the underlying mechanism, TaClo caused oxidative stress in the nigrostriatal system by increasing the production of reactive oxygen species and reducing the mitochondria membrane potential. Meanwhile, the elevated expression of Iba-1, TNF-α, IL-6, Cox-2, and iNOS indicated microglial activation and a strong innate immune response in the nigrostriatal system. In addition, activated caspase-3 levels were increased. Thus, both mitochondrial impairments and the innate immune response are involved in TaClo-induced neurotoxicity.

On the role of corticosterone in behavioral disorders, microbiota composition alteration and neuroimmune response in adult male mice subjected to maternal separation stress

Experiencing psychosocial adversities in early life such as maternal separation (MS) increases the risk of psychiatric disorders. Immune-inflammatory responses have imperative roles in the pathophysiology of psychiatric disorders. MS relatively changes the composition of intestinal microbiota leading to an overactivation of the hypothalamic-pituitary-adrenal (HPA) axis, and subsequently increases the corticosterone level. In this study, we aimed to evaluate the role of corticosterone in behavioral changes and microbiota modifications in a mouse model of MS afflicted neuroinflammatory response in the hippocampus. For this purpose, 180 min of MS stress was applied to mice at postnatal day (PND) 2-14 followed by behavioral tests including forced swimming test (FST), splash test, open field test (OFT) and elevated plus maze (EPM) at PND 50-52. For evaluating the role of corticosterone, mice were subjected to adrenalectomy. Using real-time RT-PCR, the expression of inflammatory genes was determined in the hippocampus and colon tissues. We found that MS provoked depressive- and anxiety-like behaviors in adult male mice. In addition, MS was able to active a neuroimmune response in the hippocampus, motivate inflammation and histopathologic changes in the colon tissue and modify the composition of gut microbiota as well. Interestingly, our findings showed that adrenalectomy (decline in the corticosterone level), could modulate the above-mentioned negative effects of MS. In conclusion, our results demonstrated that overactivation of HPA axis and the subsequent increased level of corticosterone could act, possibly, as the deleterious effects of MS on behavior, microbiota composition changes and activation of neuroimmune response.

Histone deacetylase inhibitor MGCD0103 protects the pancreas from streptozotocin-induced oxidative stress and β-cell death

Inhibition of histone deacetylase (HDAC) suppresses inflammation of pancreatic islets and apoptosis of β-cells. However, the underlying molecular mechanism is unclear. In the present study, we demonstrate that MGCD0103 (MGCD), an HDAC inhibitor, protects the pancreas from streptozotocin (STZ)-induced oxidative stress and cell death. Sprague-Dawley rats were intraperitoneally injected with STZ (40 mg/kg) to induce type I diabetes. MGCD (10 μg/day) was infused with osmotic mini-pump for 4 weeks. Pancreatic insulin and macrophage infiltration were analyzed by immunohistochemistry. Cellular level of reactive oxygen species (ROS) was evaluated with fluorescence-activated cell sorting. Tetramethylrhodamine ethyl ester was used to analyze mitochondrial membrane potential. Activation of caspase-3 was analyzed by western blotting. Chromatin immunoprecipitation was performed to investigate the binding affinity of specificity protein 1 (SP1) on the promoters of target genes. mRNA expression was analyzed by quantitative real-time polymerase chain reaction. As a result, we found that MGCD infusion ameliorated STZ-induced hyperglycemia, islet deformation, decreased insulin level, and macrophage infiltration. STZ injection promoted the production of ROS, which induced caspase activity and β-cell death. 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL), a mimetic of superoxide dismutase (SOD), reduced STZ-induced caspase activity and β-cell death. MGCD treatment increased SOD expression and histone acetylation level on promoters. Infusion of MGCD promoted acetylation of SP1 and its enrichment on SOD promoters. Thus, MGCD protects pancreatic β-cells from STZ-induced oxidative stress and cell death through the induction of antioxidant enzymes such as SODs.

Involvement of opioid system in behavioral despair induced by social isolation stress in mice

Social isolation stress (SIS) as a type of chronic stress could induce depressive- and anxiety-like behaviors. Our study evaluates the role of opioid system on negative behavioral impacts of SIS in male NMRI mice. We investigated effects of morphine, a nonselective opioid receptor (OR) agonist, naltrexone (NLX), an OR antagonist, naltrindole (NLT), a delta opioid receptor (DOR) antagonist, SNC80, a DOR agonist, U-69593, a kappa opioid receptor (KOR) agonist, nor-Binaltorphimine, a selective KOR antagonist and cyprodime hydrochloride a selective mu opioid receptor (MOR) antagonist on depressive- and anxiety-like behaviors. Using RT-PCR we evaluated ORs gene expression in mice brain. Our findings showed that SIS induced anxiety- and depressive-like behavior in the forced swimming test, open field test, splash test and hole-board test. Moreover, administration of SNC-80 significantly mitigated anxiety- and depressive-like behaviors. NLT decreased grooming-activity in the splash test. Excitingly, administration of agents affecting KOR failed to alter the negative effects of SIS. RT-PCR demonstrated that MOR and KOR gene expression decreased in socially isolated mice; however, SIS did not affect DORs expression. Our findings suggest that SIS at least in part, probably via altering endogenous opioids particularly MORs and KORs but not DORs mediated negative impacts on behavior; also, it could be concluded that DORs might be considered as a novel target for studying depression and anxiety.

Evaluation of the toxicity effects of silk fibroin on human lymphocytes and monocytes

Silk fibroin nanoparticles (SFNPs) as a natural polymer have been utilized in biomedical applications such as suture, tissue engineering-based scaffolds, and drug delivery carriers. Since there is little data regarding the toxicity effects on different cells and tissues, we aimed to determine the toxicity mechanisms of SFNPs on human lymphocytes and monocytes based on reliable methods. Our results showed that SFNPs (0.5, 1, and 2 mg/mL) induced oxidative stress via increasing reactive oxygen species production, mitochondrial membrane potential (∆Ψ) collapse, which was correlated to cytochrome c release and Adenosine diphosphate (ADP)/Adenosine tri phosphate (ATP) ratio increase as well as lysosomal as another toxicity mechanism, which led to cytosolic release of lysosomal digestive proteases, phosphor lipases, and apoptosis signaling. Taken together, these data suggested that SFNPs toxicity was associated with mutual mitochondrial/lysosomal cross-talk and oxidative stress on human lymphocytes and monocytes with activated apoptosis signaling.

The Hippocampus is a Critical Site Mediating Antidepressant-like Activity of Apelin-13 in Rats

The peptide apelin and its receptor APJ are found to express in multiple brain regions, especially in the regions such as the hippocampus and hypothalamus that play important roles in stress and depression. The distribution of apelin and APJ suggests that the apelinergic signaling may be a key mediator in the development of stress-related depressive behavior. We recently demonstrated that intracerebroventricular (i.c.v) injection of apelin-13 exerts an antidepressant-like activity in the rat forced swimming test (FST). However, the possible brain region mediating apelin-13's antidepressant-like activity remains unclear. In the present study, we determined whether the hippocampus and hypothalamus are the possible regions mediating antidepressant-like activity of apelin-13. We found that forced swimming exposure upregulated apelin and APJ protein expression levels in the hippocampus but not hypothalamus in rats. Further, intrahippocampal injection of apelin-13 exerted an antidepressant-like activity (as indicated by a decreased immobility behavior), and intrahippocampal infusion of APJ receptor antagonist F13A blocked the antidepressant-like activity produced by i.c.v injection of apelin-13 in the FST. Moreover, intrahypothalamic injection of apelin-13 did not affect the immobility behavior in the FST. These findings suggest that the hippocampus, but not hypothalamus, is a critical site mediating antidepressant-like activity of apelin-13 in rats.

Involvement of NO/NMDA-R pathway in the behavioral despair induced by amphetamine withdrawal

Abrupt discontinuation of chronic amphetamine consumption leads to withdrawal symptoms including depression, anhedonia, dysphoria, fatigue, and anxiety. These irritating symptoms may result in continuing to take the drug or can lead to suicidal behavior. Past studies have shown the involvement of various biologic systems in depression induced following amphetamine withdrawal (AW). However, there is no evidence about the relation between nitric oxide (NO) with NMDA receptors on depression following AW. In this study, we examined the involvement of the NO/NMDA pathways on depressive-like behaviors after 24 h withdrawal following 5 continuous days of amphetamine administration in male NMRI mice. Behavioral tasks used for depression assessment included the forced swimming test (FST), the Splash test and the open field test (OFT). In order to evaluate the role of NO/NMDA pathways animals treated with MK-801 (NMDA-R antagonist), Aminoguanidine (AG), a selective iNOS inhibitor, Nω-Nitro-l-arginine (L-NNA), a non-selective NOS inhibitor and 7-Nitro indazole (7-NI), a selective nNOS inhibitor. We also measured the level of nitrite in the hippocampus. Our data showed that AW induced the depressive-like effect in the FST and the Splash test. We showed that administration of AG, L-NNA, and MK-801 mitigated AW induced depression, however, 7-NI was failed to decrease depressive-like behaviors. Also, the antidepressant-like effect of co-injection of sub-effective doses of MK-801 with AG suggested that inducible nitric oxide synthase (iNOS) is associated with NMDA-R in AW induced depression. In conclusion, both NO and NMDA-R pathways are involved and related to each other in depression induced following AW.

Oxytocin mitigated the depressive-like behaviors of maternal separation stress through modulating mitochondrial function and neuroinflammation

Mother-infant contact has a critical role on brain development and behavior. Experiencing early-life adversities (such as maternal separation stress or MS in rodents) results in adaptations of neurotransmission systems, which may subsequently increase the risk of depression symptoms later in life. In this study, we show that Oxytocin (OT) exerted antioxidant and anti-inflammatory properties. Previous studies indicate that neuroinflammation and mitochondrial dysfunction are associated with the pathophysiology of depression. To investigate the antidepressant-like effects of OT, we applied MS paradigm (as a valid animal model of depression) to male mice at postnatal day (PND) 2 to PND 14 (3h daily, 9AM to 12AM) and investigated the depressive-like behaviors of these animals at PND 60 in different groups. Animals in this work were divided into 4 experimental groups: 1) saline-treated, 2) OT-treated, 3) atosiban (OT antagonist)-treated and, 4) OT+ atosiban-treated mice. We used forced swimming test (FST), splash test, sucrose preference test (SPT) and open field test (OFT) for behavioral assessment. Additionally, we used another set of animals to investigate the effects of MS and different treatments on mitochondrial function and the expression of the relevant genes for neuroinflammation. Our results showed that MS provoked depressive- like behaviors in the FST, SPT and splash test. In addition, our molecular findings revealed that MS is capable of inducing abnormal mitochondrial function and immune-inflammatory response in the hippocampus. Further, we observed that treating stressed animals with OT (intracerebroventricular, i.c.v. injection) attenuated the MS-induced depressive-like behaviors through improving mitochondrial function and decreasing the hippocampal expression of immune-inflammatory genes. In conclusion, we showed that MS-induced depressive-like behaviors in adult male mice are associated with abnormal mitochondrial function and immune-inflammatory responses in the hippocampus, and activation of OTergic system has protective effects against negative effects of MS on brain and behavior of animals.

Rat brain glucose transporter-2, insulin receptor and glial expression are acute targets of intracerebroventricular streptozotocin: risk factors for sporadic Alzheimer's disease?

Accumulated evidence suggests that the insulin-resistant brain state and cerebral glucose hypometabolism might be the cause, rather than the consequence, of the neurodegeneration found in a sporadic Alzheimer's disease (sAD). We have explored whether the insulin receptor (IR) and the glucose transporter-2 (GLUT2), used here as their markers, are the early targets of intracerebroventricularly (icv) administered streptozotocin (STZ) in an STZ-icv rat model of sAD, and whether their changes are associated with the STZ-induced neuroinflammation. The expression of IR, GLUT2 and glial fibrillary acidic protein (GFAP) was measured by immunofluorescence and western blot analysis in the parietal (PC) and the temporal (TC) cortex, in the hippocampus (HPC) and the hypothalamus. One hour after the STZ-icv administration (1.5 mg/kg), the GFAP immunoreactivity was significantly increased in all four regions, thus indicating the wide spread neuroinflammation, pronounced in the PC and the HPC. Changes in the GLUT2 (increment) and the IR (decrement) expression were mild in the areas close to the site of the STZ injection/release but pronounced in the ependymal lining cells of the third ventricle, thus indicating the possible metabolic implications. These results, together with the finding of the GLUT2-IR co-expression, and also the neuronal IR expression in PC, TC and HPC, indicate that the cerebral GLUT2 and IR should be further explored as the possible sAD etiopathogenic factors. It should be further clarified whether their alterations are the effect of a direct STZ-icv toxicity or they are triggered in a response to STZ-icv induced neuroinflammation.