Edaravone abrogates LPS-induced behavioral anomalies, neuroinflammation and PARP-1

Oral edaravone ameliorates behavioral deficits and pathologies in a valproic acid-induced rat model of autism spectrum disorder

Autism spectrum disorder (ASD) is neurodevelopmental disorder with a high incidence rate, characterized by social deficits and repetitive behaviors. There is currently no effective management available to treat the core symptoms of ASD; however, oxidative stress has been implicated in its pathogenesis. Edaravone (EDA), a free-radical scavenger, is used to treat amyotrophic lateral sclerosis (ALS) and acute ischemic stroke (AIS). Here, we hypothesized that an oral formula of EDA may have therapeutic efficacy in the treatment of core ASD symptoms. A rat model of autism was established by prenatal exposure to valproic acid (VPA), and the offsprings were orally treated with EDA at low (3 mg/kg), medium (10 mg/kg), and high (30 mg/kg) doses once daily for 28 days starting from postnatal day 25 (PND25). Oral EDA administration alleviated the core symptoms in VPA rats in a dose-dependent manner, including repetitive stereotypical behaviors and impaired social interaction. Furthermore, oral administration of EDA significantly reduced oxidative stress in a dose-dependent manner, as evidenced by a reduction in oxidative stress markers and an increase in antioxidants in the blood and brain. In addition, oral EDA significantly attenuated downstream pathologies, including synaptic and mitochondrial damage in the brain. Proteomic analysis further revealed that EDA corrected the imbalance in brain oxidative reduction and mitochondrial proteins induced by prenatal VPA administration. Overall, these findings demonstrate that oral EDA has therapeutic potential for ASD by targeting the oxidative stress pathway of disease pathogenesis and paves the way towards clinical studies.

Schisandrin B alleviates testicular inflammation and Sertoli cell apoptosis via AR-JNK pathway

Bacterial testicular inflammation is one of the important causes of male infertility. Using plant-derived compounds to overcome the side effects of antibiotics is an alternative treatment strategy for many diseases. Schizandrin B (SchB) is a bioactive compound of herbal medicine Schisandra chinensis which has multiple pharmacological effects. However its effect and the mechanism against testicular inflammation are unknown. Here we tackled these questions using models of lipopolysaccharide (LPS)-induced mice and -Sertoli cells (SCs). Histologically, SchB ameliorated the LPS-induced damages of the seminiferous epithelium and blood-testicular barrier, and reduced the production of pro-inflammatory mediators in mouse testes. Furthermore, SchB decreased the levels of pro-inflammatory mediators and inhibited the nuclear factor kB (NF-κB) and MAPK (especially JNK) signaling pathway phosphorylation in LPS-induced mSCs. The bioinformatics analysis based on receptor prediction and the molecular docking was further conducted. We targeted androgen receptor (AR) and illustrated that AR might bind with SchB in its function. Further experiments indicate that the AR expression was upregulated by LPS stimulation, while SchB treatment reversed this phenomenon; similarly, the expression of the JNK-related proteins and apoptotic-related protein were also reversed after AR activator treatment. Together, SchB mitigates LPS-induced inflammation and apoptosis by inhibiting the AR-JNK pathway.

Mechanisms of mitophagy and oxidative stress in cerebral ischemia-reperfusion, vascular dementia, and Alzheimer's disease

Neurological diseases have consistently represented a significant challenge in both clinical treatment and scientific research. As research has progressed, the significance of mitochondria in the pathogenesis and progression of neurological diseases has become increasingly prominent. Mitochondria serve not only as a source of energy, but also as regulators of cellular growth and death. Both oxidative stress and mitophagy are intimately associated with mitochondria, and there is mounting evidence that mitophagy and oxidative stress exert a pivotal regulatory influence on the pathogenesis of neurological diseases. In recent years, there has been a notable rise in the prevalence of cerebral ischemia/reperfusion injury (CI/RI), vascular dementia (VaD), and Alzheimer's disease (AD), which collectively represent a significant public health concern. Reduced levels of mitophagy have been observed in CI/RI, VaD and AD. The improvement of associated pathology has been demonstrated through the increase of mitophagy levels. CI/RI results in cerebral tissue ischemia and hypoxia, which causes oxidative stress, disruption of the blood-brain barrier (BBB) and damage to the cerebral vasculature. The BBB disruption and cerebral vascular injury may induce or exacerbate VaD to some extent. In addition, inadequate cerebral perfusion due to vascular injury or altered function may exacerbate the accumulation of amyloid β (Aβ) thereby contributing to or exacerbating AD pathology. Intravenous tissue plasminogen activator (tPA; alteplase) and endovascular thrombectomy are effective treatments for stroke. However, there is a narrow window of opportunity for the administration of tPA and thrombectomy, which results in a markedly elevated incidence of disability among patients with CI/RI. It is regrettable that there are currently no there are still no specific drugs for VaD and AD. Despite the availability of the U.S. Food and Drug Administration (FDA)-approved clinical first-line drugs for AD, including memantine, donepezil hydrochloride, and galantamine, these agents do not fundamentally block the pathological process of AD. In this paper, we undertake a review of the mechanisms of mitophagy and oxidative stress in neurological disorders, a summary of the clinical trials conducted in recent years, and a proposal for a new strategy for targeted treatment of neurological disorders based on both mitophagy and oxidative stress.

Ferroptosis: a new antidepressant pharmacological mechanism

The incidence rate of depression, a mental disorder, is steadily increasing and has the potential to become a major global disability factor. Given the complex pathological mechanisms involved in depression, the use of conventional antidepressants may lead to severe complications due to their side effects. Hence, there is a critical need to explore the development of novel antidepressants. Ferroptosis, a newly recognized form of cell death, has been found to be closely linked to the onset of depression. Several studies have indicated that certain active ingredients can ameliorate depression by modulating the ferroptosis signaling pathway. Notably, traditional Chinese medicine (TCM) active ingredients and TCM prescriptions have demonstrated promising antidepressant effects in previous investigations owing to their unique advantages in antidepressant therapy. Building upon these findings, our objective was to review recent relevant research and provide new insights and directions for the development and application of innovative antidepressant strategies.

Immunological drivers of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS), a devastating motor neuron disease involving complex genetic and environmental factors, is associated with neuroinflammation. Preclinical and clinical studies support immune system involvement in ALS pathogenesis, thereby spurring investigations into potential pathogenic mechanisms, immune response biomarkers, and ALS therapeutics.

Baicalin attenuates chronic unpredictable mild stress-induced hippocampal neuronal apoptosis through regulating SIRT1/PARP1 signaling pathway

Baicalin (BA), a flavonoid glycoside extracts from Scutellaria baicalensis Georgi, has been reported to exert antidepressant effects. Emerging evidence indicates that neuronal apoptosis plays a crucial role in the pathogenesis of depression. Poly (ADP-ribose) polymerase-1 (PARP1) is established as a key regulator of the cellular apoptosis. In the present study, we explored whether BA exerts antidepressant effects by regulating PARP1 signaling pathway and elucidated the underlying mechanisms. We found that administration of BA (30 mg/kg, 60 mg/kg) alleviated chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors by increasing sucrose consumption in sucrose preference test (SPT), improving activity status in open field test (OFT) and reducing rest time in tail suspension test (TST). Hematoxylin and eosin (HE) staining and Nissl staining showed that BA ameliorated CUMS-induced neuronal damage in the hippocampus. Moreover, BA significantly upregulated anti-apoptotic protein Bcl-2, downregulated pro-apoptotic protein Bax and cleaved-caspase-3 after CUMS in hippocampal of mice. Intriguingly, western blot and immunohistochemistry (IHC) results showed that the protein level of PARP1 was significantly increased in hippocampal tissue after CUMS, which was reversed by BA treatment. In primary hippocampal neurons (PHNs), BA abrogated the neuronal apoptosis caused by PARP1 overexpression. Meanwhile, BA significantly increased the protein level of SIRT1, SIRT1 inhibitor (EX-527) treatment reversed the effect of BA on reducing the protein level of PARP1 and neuronal apoptosis in CUMS-induced mice. Overall, our results indicated that BA attenuated the CUMS-induced hippocampal neuronal apoptosis through regulating the SIRT1/PARP1 signaling pathway.

Neuroprotective Efficacy of Edaravone against Arsenic-Induced Behavioral and Neurochemical Deficits in Rats: Amelioration of Cholinergic and Mitochondrial Functions

BACKGROUND

A substantial amount of evidence indicates that long-term arsenic exposure leads to various types of pathological complications, especially cognitive dysfunction.

OBJECTIVE

The present study was designed to assess the neuroprotective potential of edaravone (a potent free radical scavenger) against arsenic-induced neurotoxicity in Wistar rats.

METHODS

Adult male Wistar rats were randomly divided into five groups. Arsenic (20 mg/kg/day; p.o.) and Edaravone (5 and 10 mg/kg/day; i.p.) were administered in different experimental groups for 28 days.

RESULTS

The results of various behavioral test paradigms revealed that arsenic caused significant learning and memory deficits, along with anxiety-like behavior. In biochemical analysis, we found marked elevations of oxidative-nitrosative stress (indicated by augmentation of lipid peroxidation and nitrite) and a reduction of glutathione levels in the hippocampus and frontal cortex region of arsenictreated rats. Moreover, arsenic administration caused mitochondrial complexes impairment and reduction of acetylcholinesterase level. On the other hand, chronic treatment with edaravone (10 mg/kg) significantly ameliorated the arsenic-induced behavioral deficits and neurochemical anomalies.

CONCLUSION

This study suggests that edaravone confers neuroprotection against arsenic-induced memory impairment and anxiety-like behavior, which may be attributed to the inhibition of oxidativenitrosative stress and amelioration of cholinergic and mitochondrial functions.

Nrf2: An all-rounder in depression

The balance between oxidation and antioxidant is crucial for maintaining homeostasis. Once disrupted, it can lead to various pathological outcomes and diseases, such as depression. Oxidative stress can result in or aggravate a battery of pathological processes including mitochondrial dysfunction, neuroinflammation, autophagical disorder and ferroptosis, which have been found to be involved in the development of depression. Inhibition of oxidative stress and related pathological processes can help improve depression. In this regard, the nuclear factor erythroid 2-related factor 2 (Nrf2) in the antioxidant defense system may play a pivotal role. Nrf2 activation can not only regulate the expression of a series of antioxidant genes that reduce oxidative stress and its damages, but also directly regulate the genes related to the above pathological processes to combat the corresponding alterations. Therefore, targeting Nrf2 has great potential for the treatment of depression. Activation of Nrf2 has antidepressant effect, but the specific mechanism remains to be elucidated. This article reviews the key role of Nrf2 in depression, focusing on the possible mechanisms of Nrf2 regulating oxidative stress and related pathological processes in depression treatment. Meanwhile, we summarize some natural and synthetic compounds targeting Nrf2 in depression therapy. All the above may provide new insights into targeting Nrf2 for the treatment of depression and provide a broad basis for clinical transformation.

Exploring the effects of edaravone in rats with contrast-induced acute kidney injury

AIMS

Oxidative stress and inflammatory response play a vital role in the pathogenesis of contrast-induced acute kidney injury (CI-AKI). This study investigated the effects of edaravone in rats with CI-AKI.

MAIN METHODS

Male Sprague Dawley rats were randomly assigned into four groups (n = 11-14/group): control, edaravone (30 mg/kg/day intraperitoneally (IP)), CI-AKI, and edaravone with CI-AKI. The induction of CI-AKI was performed by dehydration and the administration of contrast media (iohexol) and inhibitors of prostaglandin (indomethacin) and nitric oxide synthesis (L-NAME: N-nitro L-arginine methyl ester). Edaravone was administered for two weeks before the induction of CI-AKI. Serum creatinine and urea, renal oxidative stress and inflammatory biomarkers, and histopathological alterations were evaluated after 48 h of contrast exposure.

KEY FINDINGS

Rats with CI-AKI showed a significant increase in serum creatinine and urea. The levels of antioxidant biomarkers including glutathione peroxidase, superoxide dismutase and reduced glutathione were significantly decreased in CI-AKI group versus control. Pre-treatment of rats with edaravone normalized kidney function and protected the kidney from oxidative damage as demonstrated by normalization of previous biomarkers. Furthermore, edaravone partially ameliorated renal histopathological alterations relative to the CI-AKI group, notably in the nephrons. No changes were observed in inflammatory biomarkers including tumour necrosis factor-alpha and interleukin-6 among all groups.

SIGNIFICANCE

The current findings suggest that edaravone could be a potential strategy to ameliorate developing CI-AKI possibly by improving renal antioxidant capacity. Further studies are warranted to expand the current understanding of the use of edaravone in the various models of AKI.

Targeting Molecular Mediators of Ferroptosis and Oxidative Stress for Neurological Disorders

With the acceleration of population aging, nervous system diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), anxiety, depression, stroke, and traumatic brain injury (TBI) have become a huge burden on families and society. The mechanism of neurological disorders is complex, which also lacks effective treatment, so relevant research is required to solve these problems urgently. Given that oxidative stress-induced lipid peroxidation eventually leads to ferroptosis, both oxidative stress and ferroptosis are important mechanisms causing neurological disorders, targeting mediators of oxidative stress and ferroptosis have become a hot research direction at present. Our review provides a current view of the mechanisms underlying ferroptosis and oxidative stress participate in neurological disorders, the potential application of molecular mediators targeting ferroptosis and oxidative stress in neurological disorders. The target of molecular mediators or agents of oxidative stress and ferroptosis associated with neurological disorders, such as reactive oxygen species (ROS), nuclear factor erythroid 2–related factor-antioxidant response element (Nrf2-ARE), n-acetylcysteine (NAC), Fe²⁺, NADPH, and its oxidases NOX, has been described in this article. Given that oxidative stress-induced ferroptosis plays a pivotal role in neurological disorders, further research on the mechanisms of ferroptosis caused by oxidative stress will help provide new targets for the treatment of neurological disorders.

Edaravone ameliorates depressive and anxiety-like behaviors via Sirt1/Nrf2/HO-1/Gpx4 pathway

Background

The inflammation and oxidative stress (OS) have been considered crucial components of the pathogenesis of depression. Edaravone (EDA), a free radical scavenger, processes strong biological activities including antioxidant, anti-inflammatory and neuroprotective properties. However, its role and potential molecular mechanisms in depression remain unclear. The present study aimed to investigate the antidepressant activity of EDA and its underlying mechanisms.

Methods

A chronic social defeat stress (CSDS) depression model was performed to explore whether EDA could produce antidepressant effects. Behaviors tests were carried out to examine depressive, anxiety-like and cognitive behaviors including social interaction (SI) test, sucrose preference test (SPT), open field test (OFT), elevated plus maze (EPM), novel object recognition (NOR), tail suspension test (TST) and forced swim test (FST). Hippocampal and medial prefrontal cortex (mPFC) tissues were collected for Nissl staining, immunofluorescence, targeted energy metabolomics analysis, enzyme-linked immunosorbent assay (ELISA), measurement of MDA, SOD, GSH, GSH-PX, T-AOC and transmission electron microscopy (TEM). Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) detected the Sirt1/Nrf2/HO-1/Gpx4 signaling pathway. EX527, a Sirt1 inhibitor and ML385, a Nrf2 inhibitor were injected intraperitoneally 30 min before EDA injection daily. Knockdown experiments were performed to determine the effects of Gpx4 on CSDS mice with EDA treatment by an adeno-associated virus (AAV) vector containing miRNAi (Gpx4)–EGFP infusion.

Results

The administrated of EDA dramatically ameliorated CSDS-induced depressive and anxiety-like behaviors. In addition, EDA notably attenuated neuronal loss, microglial activation, astrocyte dysfunction, oxidative stress damage, energy metabolism and pro-inflammatory cytokines activation in the hippocampus (Hip) and mPFC of CSDS-induced mice. Further examination indicated that the application of EDA after the CSDS model significantly increased the protein expressions of Sirt1, Nrf2, HO-1 and Gpx4 in the Hip. EX527 abolished the antidepressant effect of EDA as well as the protein levels of Nrf2, HO-1 and Gpx4. Similarly, ML385 reversed the antidepressant and anxiolytic effects of EDA via decreased expressions of HO-1 and Gpx4. In addition, Gpx4 knockdown in CSDS mice abolished EDA-generated efficacy on depressive and anxiety-like behaviors.

Conclusion

These findings suggest that EDA possesses potent antidepressant and anxiolytic properties through Sirt1/Nrf2/HO-1/Gpx4 axis and Gpx4-mediated ferroptosis may play a key role in this effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02400-6.

Pleiotropic effects of telomere length loci with brain morphology and brain tissue expression

Several studies have reported association between leukocyte telomere length (LTL) and neuropsychiatric disorders. Although telomere length is affected by environmental factors, genetic variants in certain loci are strongly associated with LTL. Thus, we aimed to identify the genomic relationship between genetic variants of LTL with brain-based regulatory changes and brain volume. We tested genetic colocalization of seven and nine LTL loci in two ancestry groups, European (EUR) and East-Asian (EAS), respectively, with brain morphology measures for 101 T1-magnetic resonance imaging-based region of interests (n = 21 821). The posterior probability (>90%) was observed for 'fourth ventricle', 'gray matter' and 'cerebellar vermal lobules I-IV' volumes. We then tested causal relationship using LTL loci for gene and methylation expression. We found causal pleiotropy for gene (EAS = four genes; EUR = five genes) and methylation expression (EUR = 17 probes; EAS = 4 probes) of brain tissues (P ≤ 2.47 × 10-6). Integrating chromatin profiles with LTL-single nucleotide polymorphisms identified 45 genes (EUR) and 79 genes (EAS) (P ≤ 9.78×10-7). We found additional 38 LTL-genes using chromatin-based gene mapping for EUR ancestry population. Gene variants in three LTL-genes-GPR37, OBFC1 and RTEL1/RTEL1-TNFRSF6B-show convergent evidence of pleiotropy with brain morphology, gene and methylation expression and chromatin association. Mapping gene functions to drug-gene interactions, we identified process 'transmission across chemical synapses' (P < 2.78 × 10-4). This study provides evidence that genetic variants of LTL have pleiotropic roles with brain-based effects that could explain the phenotypic association of LTL with several neuropsychiatric traits.

What Animal Models Can Tell Us About Long-Term Psychiatric Symptoms in Sepsis Survivors: a Systematic Review

Lower sepsis mortality rates imply that more patients are discharged from the hospital, but sepsis survivors often experience sequelae, such as functional disability, cognitive impairment, and psychiatric morbidity. Nevertheless, the mechanisms underlying these long-term disabilities are not fully understood. Considering the extensive use of animal models in the study of the pathogenesis of neuropsychiatric disorders, it seems adopting this approach to improve our knowledge of postseptic psychiatric symptoms is a logical approach. With the purpose of gathering and summarizing the main findings of studies using animal models of sepsis-induced psychiatric symptoms, we performed a systematic review of the literature on this topic. Thus, 140 references were reviewed, and most of the published studies suggested a time-dependent recovery from behavior alterations, despite the fact that some molecular alterations persist in the brain. This review reveals that animal models can be used to understand the mechanisms that underlie anxiety and depression in animals recovering from sepsis.

Mom's diet matters: Maternal prebiotic intake in mice reduces anxiety and alters brain gene expression and the fecal microbiome in offspring

Compelling evidence links enteric microbes to brain function and behavior. Galacto-oligosaccharide prebiotics have been shown to modulate the composition of gut flora and induce metabolic, neurochemical, and behavioral changes in adult rodents. Despite the brain being most susceptible to environmental factors, such as nutrients and toxins, during the earliest stages of development, it is unknown whether maternal prebiotic supplementation during gestation and lactation influences the offspring gut microbiome, brain, or behavior. The aim of this study was to test whether maternal galacto-oligosaccharide intake during pregnancy and lactation alters the brain and behavior in naïve and endotoxin-challenged offspring. CD1 female mice received either normal drinking water or water supplemented with Bimuno® galacto-oligosaccharides (B-GOS) during gestation and suckling. Offspring behavior was tested at weaning age or adulthood, and a cross-foster design was employed in a separate cohort to differentiate between effects of prenatal and postnatal maternal B-GOS intake. Lipopolysaccharide was also administered to pups at postnatal day 9 to determine whether maternal B-GOS influences the neurobiological and behavioral effects of a neonatal pro-inflammatory challenge in adulthood. Fecal microbiome composition and metabolites were analyzed to explore potential relationships between the maternal microbiome, the offspring gut microbiome, and the offspring brain and behavior. Maternal B-GOS supplementation increased exploratory behavior and reduced expression of hippocampal glutamate receptor genes in young, weaning-age offspring. In addition, postnatal, but not prenatal, B-GOS supplementation increased fecal butyrate and propionate levels. Finally, in adult offspring, perinatal B-GOS intake increased cortical glutamate receptor subunits in females, increased social preference, and reduced anxiety. We provide novel and comprehensive evidence for the influence of maternal prebiotic intake on offspring behavior, brain gene expression, and gut microbiome composition in mice.

Protective effect of edaravone against radiation-induced ovarian injury: a histopathological and immunohistochemical evaluation in an experimental rat model

PURPOSE

We aimed to evaluate the protective effect of edaravone on radiation-induced ovarian damage in an experimental rat model.

METHODS

Thirty-two Wistar albino female rats were randomly divided into four groups. Group 1: control, no treatment, and radiation was applied throughout the study; Group 2: sham, only radiation was applied; Group 3: 45 mg/kg edaravone and radiation were applied; Group 4: 450 mg/kg edaravone and radiation were applied. Edaravone was administered intraperitoneally 30 min before radiotherapy (5 Gy). Two days after radiation exposure, the rats were sacrificed and the ovaries were removed. Histologic changes under light microscopy and immunoreactivity for anti-caspase-3 were noted and compared between the four groups.

RESULTS

There was a statistically significant difference in follicle counts, vascular congestion, edema, cytoplasmic vacuolization, hemorrhage, and interstitial cell degeneration between the groups. Radiation causes deterioration in most histopathological parameters. Administration of edaravone at different doses seems to reverse these alterations and alleviate the injury. Antioxidant defense mechanisms appear to be enhanced by edaravone as shown by histopathologically and decreased apoptosis by reducing the expression of anti-caspase-3 activity as demonstrated immunohistochemically.

CONCLUSION

This is the first study evaluating the protective effects of edaravone on radiation-induced ovarian damage. Edaravone decreased the follicular apoptosis and attenuates the radiation-induced ovarian damage in rats.

Mangiferin prevents corticosterone-induced behavioural deficits via alleviation of oxido-nitrosative stress and down-regulation of indoleamine 2,3-dioxygenase (IDO) activity

BACKGROUND

In recent years, a substantial amount of experimental studies have demonstrated that exogenous administration of corticosterone causes anxiety and depressive-like behaviour in rodents which involves hypothalamic-pituitary-adrenal axis dysregulation. Our present study aimed to explore the neuroprotective potential of mangiferin against corticosterone-induced anxiety and depressive-like behaviour.

METHODS

Corticosterone (40 mg/kg; subcutaneously) was administered once daily in swiss albino mice for 21 days. Mice were treated simultaneously with mangiferin (40 mg/kg; p.o.), 30 min prior to the corticosterone injection.

RESULTS

Chronic administration of corticosterone caused anxiety and depressive-like behaviour in mice which was significantly alleviated by mangiferin treatment. Biochemical analysis revealed that mangiferin treatment significantly attenuated corticosterone-induced oxido-nitrosative stress and neuroinflammation in the hippocampus region. Furthermore, concomitant treatment with mangiferin significantly enhanced the hippocampal brain-derived neurotrophic factor (BDNF) level and decreased the serum corticosterone level in the corticosterone-treated animals. Western blotting analysis revealed that corticosterone administration significantly up-regulated the indoleamine 2,3-dioxygenase (IDO) protein expression level in the hippocampus which was significantly reduced by mangiferin treatment.

CONCLUSION

Taken together, our results suggest that mangiferin exerts anti-anxiety and antidepressant effect in corticosterone-treated rats, which is probably mediated through up-regulation of BDNF level along with inhibition of oxido-nitrosative stress, neuroinflammation and IDO up-regulation in the hippocampus region.

Piperine Augments the Protective Effect of Curcumin Against Lipopolysaccharide-Induced Neurobehavioral and Neurochemical Deficits in Mice

The aim of the present study was to investigate the protective effects of curcumin alone and in combination with piperine against lipopolysaccharide (LPS)-induced neurobehavioral and neurochemical deficits in the mice hippocampus. Mice were treated with curcumin (100, 200, and 400 mg/kg, p.o.) and piperine (20 mg/kg, p.o.) for 7 days followed by LPS (0.83 mg/kg, i.p.) administration. Animals exhibited anxiety and depressive-like phenotype after 3 and 24 h of LPS exposure, respectively. LPS administration increased the oxido-nitrosative stress as evident by elevated levels of malondialdehyde, nitrite, and depletion of glutathione level in the hippocampus. Furthermore, we found raised level of pro-inflammatory cytokines (IL-1β and TNF-α) in the hippocampus of LPS-treated mice. Pretreatment with curcumin alleviated LPS-induced neurobehavioral and neurochemical deficits. Furthermore, co-administration of curcumin with piperine significantly potentiated the neuroprotective effect of curcumin. These results demonstrate that piperine enhanced the neuroprotective effect of curcumin against LPS-induced neurobehavioral and neurochemical deficits.

Edaravone alleviates cisplatin-induced neurobehavioral deficits via modulation of oxidative stress and inflammatory mediators in the rat hippocampus

Cisplatin is a chemotherapeutic agent used in the treatment of malignant tumors. A major clinical limitation of cisplatin is its potential toxic effects, including neurotoxicity. Edaravone, a potent free radical scavenger, has been reported to have the neuroprotective effect against neurological deficits. The aim of the present study was to determine the neuroprotective effect of edaravone against cisplatin-induced behavioral and biochemical anomalies in male Wistar rats. Our results showed that cisplatin (5mg/kg/week, i.p.) administration for seven weeks caused marked cognitive deficits and motor incoordination in rats. This was accompanied by oxido-nitrosative stress, neuroinflammation, NF-κB activation and down-regulation of Nrf2/HO-1 gene expression level in the hippocampus. Edaravone (10mg/kg/week, i.p.) treatment for seven weeks inhibited the aforementioned neurobehavioral and neurochemical deficits. Furthermore, edaravone was found to up-regulate the gene expression level of Nrf2/HO-1 and prevented the cisplatin-induced NF-κB activation. These findings demonstrated that oxido-nitrosative stress and inflammatory signaling mediators play a key role in the development of cisplatin-induced neurobehavioral deficits which were prevented by edaravone treatment.

Inflammation Models of Depression in Rodents: Relevance to Psychotropic Drug Discovery

Inflammation and depression are closely inter-related; inflammation induces symptoms of depression and, conversely, depressed mood and stress favor an inflammatory phenotype. The mechanisms that mediate the ability of inflammation to induce symptoms of depression are intensively studied at the preclinical level. This review discusses how it has been possible to build animal models of inflammation-induced depression based on clinical data and to explore critical mechanisms downstream of inflammation. Namely, we focus on the ability of inflammation to increase the activity of the tryptophan-degrading enzyme, indoleamine 2,3 dioxygenase, which leads to the production of kynurenine and downstream neuroactive metabolites. By acting on glutamatergic neurotransmission, these neuroactive metabolites play a key role in the development of depression-like behaviors. An important outcome of the preclinical research on inflammation-induced depression is the identification of potential novel targets for antidepressant treatments, which include targeting the kynurenine system and production of downstream metabolites, altering transport of kynurenine into the brain, and modulating glutamatergic transmission.