Lipopolysaccharide-Induced Behavioral Alterations Are Alleviated by Sodium Phenylbutyrate via Attenuation of Oxidative Stress and Neuroinflammatory Cascade

Endoplasmic reticulum stress, autophagy, neuroinflammation, and sigma 1 receptors as contributors to depression and its treatment

The etiological factors contributing to depression and other neuropsychiatric disorders are largely undefined. Endoplasmic reticulum stress pathways and autophagy are well-defined mechanisms that play critical functions in recognizing and resolving cellular stress and are possible targets for the pathophysiology and treatment of psychiatric and neurologic illnesses. An increasing number of studies indicate the involvement of endoplasmic reticulum stress and autophagy in the control of neuroinflammation, a contributing factor to multiple neuropsychiatric illnesses. Initial inflammatory triggers induce endoplasmic reticulum stress, leading to neuroinflammatory responses. Subsequently, induction of autophagy by neurosteroids and other signaling pathways that converge on autophagy induction are thought to participate in resolving neuroinflammation. The aim of this review is to summarize our current understanding of the molecular mechanisms governing the induction of endoplasmic reticulum stress, autophagy, and neuroinflammation in the central nervous system. Studies focused on innate immune factors, including neurosteroids with anti-inflammatory roles will be reviewed. In the context of depression, animal models that led to our current understanding of molecular mechanisms underlying depression will be highlighted, including the roles of sigma 1 receptors and pharmacological agents that dampen endoplasmic reticulum stress and associated neuroinflammation.

Prophylactic Effects of n-Acethylcysteine on Inflammation-induced Depression-like Behaviors in Mice

Depression, affecting individuals worldwide, is a prevalent mental disease, with an increasing incidence. Numerous studies have been conducted on depression, yet its pathogenesis remains elusive. Recent advancements in research indicate that disturbances in synaptic transmission, synaptic plasticity, and reduced neurotrophic factor expression significantly contribute to depression's pathogenesis. In our study, we utilized adult male C57BL/6J mice. Lipopolysaccharide (LPS) can induce both chronic and acute depression-like symptoms in mice, a widely used model for studying depression associated with inflammation. N-acetylcysteine (NAC) exhibits anti-inflammatory and ameliorative effects on depressive symptoms. This study sought to determine whether NAC use could mitigate inflammatory depressive behavior through the enhancement of synaptic transmission, synaptic plasticity, and increasing levels of brain-derived neurotrophic factor (BDNF). In this study, we discovered that in mice modeled with depression-like symptoms, the expression levels of dendrites, BDNF, and miniature excitatory postsynaptic potential (mEPSC) in glutamatergic neurons, as well as the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid glutamate receptors (AMPARs) GluA1 and GluA2 subunits, were significantly decreased. These findings suggest an impairment in the synaptic transmission of glutamatergic neurons. Following treatment with NAC, the previously mentioned levels improved, indicating an enhancement in both synaptic transmission and synaptic plasticity. Our results suggest that NAC exerts a protective effect on mouse models of inflammatory depression, potentially through the enhancement of synaptic transmission and plasticity, as well as the restoration of neurotrophic factor expression. These findings offer vital animal experimental evidence supporting NAC's role in mitigating inflammatory depressive behaviors.

Recent advances in toxicological research of di-(2-ethylhexyl)-phthalate: Focus on endoplasmic reticulum stress pathway

The plasticizer di-(2-ethylhexyl)-phthalate (DEHP) is the most significant phthalate in production, usage, and environmental occurrence. DEHP is found in products such as personal care products, furniture materials, cosmetics, and medical devices. DEHP is noncovalently bind with plastic therefore, repeated uses lead to leaching out of it. Exposure to DEHP plasticizers leads to toxicity in essential organs of the body through various mechanisms. The main objective of this review article is to focus on the DEHP-induced endoplasmic reticulum (ER) stress pathway implicated in the testis, brain, lungs, kidney, heart, liver, and other organs. Not only ER stress, PPAR-related pathways, oxidative stress and inflammation, Ca2+ homeostasis disturbances in mitochondria are also identified as the relative mechanisms. ER is involved in various critical functions of the cell such as Protein synthesis, protein folding, calcium homeostasis, and lipid peroxidation but, DEHP exposure leads to augmentation of misfolded/unfolded protein. This review complies with various recently reported DEHP-induced toxicity studies and some pharmacological interventions that have been shown to be effective through ER stress pathway. DEHP exposure does assess health risks and vulnerability to populations across the globe. This study offers possible targets and approaches for addressing various DEHP-induced toxicity.

Acupressure bladder meridian alleviates anxiety disorder via HMGB1

The aim of this study was to investigate the effects of acupressure bladder meridian (ABM) on anxiety in rats with chronic stress.

METHODS

The sugar water preference (SPF), tail suspension time (TST) and forced swimming time (FST) of rats were measured. The levels of reactive oxygen species (ROS), myeloperoxidase (MPO) in hippocampus tissue, oxidative stress parameters and inflammatory cytokines were detected. Underlying mechanisms of ABM on anxiety were detected. lipopolysaccharide (LPS) stimulated PC12 cells were adopted in vitro. HMGB1 knockdown were used in PC12 cells, and related signaling was further detected.

RESULTS

ABM significantly increased SPF, decreased TST and FST. ABM decreased ROS, MPO levels, decreased the levels of inflammatory cytokines. Furthermore, ABM decreased the levels of oxidative stress index. ABM reduced the expression of inflammation-related proteins mediated by HMGB1, increased nuclear factor erythroid2-related factor 2 (Nrf-2) and hemeoxygenase-1 (HO-1). In vitro PC12 cells, Rat serum (RS-ABM) treated with ABM significantly decreased LPS induced inflammation-related proteins and increased Nrf-2/HO-1 pathway. HMGB1 knockdown inhibited LPS-induced PC12 cell inflammatory signaling pathway and increased Nrf-2/HO-1 pathway.

CONCLUSION

Our results demonstrated that ROS-dependent HMGB1 plays an important role in anxiety, and ABM exhibits inhibited inflammation in anxiety.

Prolonged stress-induced depression-like behaviors in aged rats are mediated by endoplasmic reticulum stress and apoptosis in the hippocampus

Structural and functional recovery from stress-induced depression is impaired in the context of aging brain. Since investigating the molecular substrates that facilitate behavioral recovery may have important implications for understanding brain plasticity and resilience of individuals, we studied depressive-like behaviors in young and aged rats 6 weeks after chronic stress exposure as a recovery period and examined the levels of TNF-α and IL-6 inflammatory cytokines, NADH oxidase activity, NADPH oxidase, endoplasmic reticulum (ER) stress markers, and apoptosis in the hippocampus. Young (3 months old) and aged (22 months old) male Wistar rats were divided into four groups; young control (Young), depression model of young rats that received chronic stress procedure followed by a 6-week recovery period (Young+S), aged control (Aged), and depression model of aged rats that received chronic stress procedure followed by a 6-week recovery period (Aged+S). After the recovery period, aged but not young rats showed depression-like behaviors, evaluated by the sucrose preference test (SPT) and forced swimming test (FST), coincided with the altered levels of TNF-α, IL-6, NADH oxidase activity, NADPH oxidase, GRP78, CHOP, and cleaved caspase-12 in the hippocampus of these animals. These data suggested that oxidative and ER stress-induced apoptosis in the aging hippocampus may affect the recovery-related outcomes after the stress paradigm.

Potential antidepressant-like effects of N-3 polyunsaturated fatty acids through inhibition of endoplasmic reticulum stress

RATIONALE

The growing evidence has demonstrated the importance of endoplasmic reticulum stress (ERS) in the pathophysiology of depression. ERS genes were considered to be potential novel therapeutic targets for depression.

OBJECTIVES

To clarify the mechanisms of the chronic unpredictable mild stress (CUMS)-induced ERS response and the potential contributing pathways in depression, and further investigate the potential link between N-3 polyunsaturated fatty acids (PUFAs) and stress-induced ERS disturbances.

METHODS

This study analyzed the expression of ERS-related genes including GRP78, ATF-4, ATF-6, XBP-1, and CHOP, and sigma-1R with real-time PCR in peripheral blood mononuclear cell (PBMC) RNA samples from participants. All of the rats except for those in the control groups were subjected to 5 consecutive weeks of CUMS to establish the depression model, and the antidepressant effects of N-3 PUFAs were observed by behavior tests. Moreover, the effect of diet and stress on the ERS pathways was also investigated using the western blot.

RESULTS

Blood CHOP, ATF-4, and XBP-1 levels were notably elevated in depressed patients relative to healthy individuals. Moreover, increased sigma-1R and decreased ATF-6 implied the protective role of sigma-1R through modulating ERS in patients with depression. Animal studies disclosed the novel findings that supplementary N-3 PUFAs in rats alleviated CUMS-induced disturbance of ERS through the ATF-4/XBP-1/CHOP pathway, implying its potential strategy for depression.

CONCLUSION

CUMS-induced depressive-like behaviors are related to the disturbance of ERS. Furthermore, supplementary N-3 PUFAs might be an effective way to alleviate ERS.

Matrine exerts its neuroprotective effects by modulating multiple neuronal pathways

Recent evidence suggests that misfolding, clumping, and accumulation of proteins in the brain may be common causes and pathogenic mechanism for several neurological illnesses. This causes neuronal structural deterioration and disruption of neural circuits. Research from various fields supports this idea, indicating that developing a single treatment for several severe conditions might be possible. Phytochemicals from medicinal plants play an essential part in maintaining the brain's chemical equilibrium by affecting the proximity of neurons. Matrine is a tetracyclo-quinolizidine alkaloid derived from the plant Sophora flavescens Aiton. Matrine has been shown to have a therapeutic effect on Multiple Sclerosis, Alzheimer's disease, and various other neurological disorders. Numerous studies have demonstrated that matrine protects neurons by altering multiple signalling pathways and crossing the blood-brain barrier. As a result, matrine may have therapeutic utility in the treatment of a variety of neurocomplications. This work aims to serve as a foundation for future clinical research by reviewing the current state of matrine as a neuroprotective agent and its potential therapeutic application in treating neurodegenerative and neuropsychiatric illnesses. Future research will answer many concerns and lead to fascinating discoveries that could impact other aspects of matrine.

pNaktide mitigates inflammation-induced neuronal damage and behavioral deficits through the oxidative stress pathway

Neuroinflammation is closely related to the etiology and progression of neurodegenerative diseases such as Parkinson disease and Alzheimer disease. pNaktide, an Src inhibitor, exerts antioxidant effects by mimicking Na/K-ATPase. It has been verified that its anti-inflammation and anti-oxidation ability could be embodied in obesity, steatohepatitis, uremic cardiomyopathy, aging, and prostate cancer. This study aimed to investigate the effects and mechanisms of pNaktide in lipopolysaccharide (LPS)-induced behavioral damage, neuroinflammation, and neuronal damage. We found that pNaktide improved anxiety, memory, and motor deficits. pNaktide inhibited MAPK and NF-κB pathways induced by TLR4 activation, inhibited the NLRP3 inflammasome complex, and reduced the expression of inflammatory factors, complement factors, and chemokines. pNaktide inhibited the activation of Nrf2 and HO-1 antioxidant stress pathways by LPS and reduced the level of oxidative stress. Inhibition of autophagy and enhancement of apoptosis induced by LPS were also alleviated by pNaktide, which restored LPS-induced injury to newborn neurons in the hippocampus region. In summary, pNaktide attenuates neuroinflammation, reduces the level of oxidative stress, has neuroprotective effects, and may be used for the treatment of neuroinflammation-related diseases.

Tunicamycin induces depression-like behaviors in male rats, accompanied by initiated chaperon-mediated autophagy and decreased synaptic protein expression in the hippocampus

BACKGROUND AND AIM

Endoplasmic reticulum (ER) stress participates in the occurrence and development of depression, but the underlying mechanism is not fully understood. This study aimed to investigate the behavioral performance and intracerebral molecular changes in an ER stress model of male rats.

METHODS

Intrahippocampal injection of tunicamycin (TM) was performed on male rats as a model of ER stress. The body weight was determined, and behavioral tests, including sucrose preference test (SPT), open field test (OFT), and forced swimming test (FST), were performed to evaluate depressive and anxiety-like phenotypes within 8 days after injection. The levels of chaperone-mediated autophagy (CMA), synaptic proteins, and neuroinflammation related factors in this model were measured via real-time quantitative PCR and Western blot analysis.

RESULTS

Intrahippocampal injection of TM (2 or 1 μg) induced depression-like behaviors in rats, as indicated by the reduced body weight, sucrose preference in SPT, central time in OFT, and increased immobility time in FST. The mRNA and protein levels of GRP78, ATF4, CHOP, LAMP2A, IL-1β, IL-6, and TNF-α were significantly increased, while the expressions of MEF2D, PSD95, SYN, p-CREB (Ser133), and BDNF were significantly decreased in the hippocampus in the model group compared with the sham group.

CONCLUSIONS

These results confirmed that intrahippocampal injection of TM was a valid method to induce an ER stress rat model with depression-like behaviors accompanied by decreased synaptic protein expression and neuroinflammation. The alteration in CMA-related proteins in this ER stress depression model indicated the involvement of CMA in the development of depression.

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.

Sigma-1 receptor: A potential target for the development of antidepressants

Though a great many of studies on the development of antidepressants for the therapy of major depression disorder (MDD) and the development of antidepressants have been carried out, there still lacks an efficient approach in clinical practice. The involvement of Sigma-1 receptor in the pathological process of MDD has been verified. In this review, recent research focusing on the role of Sigma-1 receptor in the etiology of MDD were summarized. Preclinical studies and clinical trials have found that stress induce the variation of Sigma-1 receptor in the blood, brain and heart. Dysfunction and absence of Sigma-1 receptor result in depressive-like behaviors in rodent animals. Agonists of Sigma-1 receptor show not only antidepressant-like activities but also therapeutical effects in complications of depression. The mechanisms underlying antidepressant-like effects of Sigma-1 receptor may include suppressing neuroinflammation, regulating neurotransmitters, ameliorating brain-derived neurotrophic factor and N-Methyl-D-Aspartate receptor, and alleviating the endoplasmic reticulum stress and mitochondria damage during stress. Therefore, Sigma-1 receptor represents a potential target for antidepressants development.

Anxiolytic and antidepressive potentials of rosmarinic acid: A review with a focus on antioxidant and anti-inflammatory effects

Depression and anxiety are the most prevalent neuropsychiatric disorders that have emerged as global health concerns. Anxiolytic and antidepressant drugs, such as benzodiazepines, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, and tricyclics, are the first line used in treating anxiety and depression. Although these drugs lack efficacy and have a delayed response time and numerous side effects, their widespread abuse and market continue to grow. Over time, traditional practices using natural and phytochemicals as alternative therapies to chemical drugs have emerged to treat many pathological conditions, including anxiety and depression. Recent preclinical studies have demonstrated that the phenolic compound, rosmarinic acid, is effective against several neuropsychiatric disorders, including anxiety and depression. In addition, rosmarinic acid showed various pharmacological effects, such as cardioprotective, hepatoprotective, lung protective, antioxidant, anti-inflammatory, and neuroprotective effects. However, the potentialities of the use of rosmarinic acid in the treatment of nervous system-related disorders, such as anxiety and depression, are less or not yet reviewed. Therefore, the purpose of this review was to present several preclinical and clinical studies, when available, from different databases investigating the effects of rosmarinic acid on anxiety and depression. These studies showed that rosmarinic acid produces advantageous effects on anxiety and depression through its powerful antioxidant and anti-inflammatory properties. This review will examine and discuss the possibility that the anxiolytic and anti-depressive effects of rosmarinic acid could be associated with its potent antioxidant and anti-inflammatory activities.

Plumbagin Alleviates Intracerebroventricular-Quinolinic Acid Induced Depression-like Behavior and Memory Deficits in Wistar Rats

Plumbagin, a hydroxy-1,4-naphthoquinone, confers neuroprotection via antioxidant and anti-inflammatory properties. The present study aimed to assess the effect of plumbagin on behavioral and memory deficits induced by intrahippocampal administration of Quinolinic acid (QA) in male Wistar rats and reveal the associated mechanisms. QA (300 nM/4 μL in Normal saline) was administered i.c.v. in the hippocampus. QA administration caused depression-like behavior (forced swim test and tail suspension tests), anxiety-like behavior (open field test and elevated plus maze), and elevated anhedonia behavior (sucrose preference test). Furthermore, oxidative–nitrosative stress (increased nitrite content and lipid peroxidation with reduction of GSH), inflammation (increased IL-1β), cholinergic dysfunction, and mitochondrial complex (I, II, and IV) dysfunction were observed in the hippocampus region of QA-treated rats as compared to normal controls. Plumbagin (10 and 20 mg/kg; p.o.) treatment for 21 days significantly ameliorated behavioral and memory deficits in QA-administered rats. Moreover, plumbagin treatment restored the GSH level and reduced the MDA and nitrite level in the hippocampus. Furthermore, QA-induced cholinergic dysfunction and mitochondrial impairment were found to be ameliorated by plumbagin treatment. In conclusion, our results suggested that plumbagin offers a neuroprotective potential that could serve as a promising pharmacological approach to mitigate neurobehavioral changes associated with neurodegeneration.

Alpinae Oxyphyllae Fructus alleviated LPS-induced cognitive impairments via PI3K/AKT/NF-κB signaling pathway

Herein, we aim to investigate the effect of Alpinae Oxyphyllae Fructus (AOF) on cognitive impairments and neuroinflammation in a lipopolysaccharide (LPS)-induced models of AD. Mice were injected intracerebroventricularly with LPS, and then administrated AOF using a gavage for 6 weeks. Spatial working memory was assessed using the Y-maze and Morris water maze test, whereas the levels of PI3K, AKT, p-AKT, p-GSK3β, GSK3β, NF-κB, IL-1β, IL-6, and TNF-α were evaluated using western blot and ELISA assay. Our data showed that AOF was able to significantly alleviate the memory decline in LPS-induced AD mice. Moreover, AOF was able to protect neurons through the PI3K/AKT signaling pathway and significantly decrease NF-κB, IL-6, IL-1β, and TNF-α levels in the hippocampal and cortex tissues, which were reversed through the use of LY294002. Additionally, we discovered that AOF could significantly decrease the high expression of cytokines as well as the expression and translocation of NF-κB induced by LPS in PC12 cells. These results demonstrate the anti-neuroinflammatory effect of AOF in both cell and animal models of AD, thereby slowing down the process and development of the disease.

Pomegranate juice moderates anxiety- and depression-like behaviors in AlCl3-treated male mice

PURPOSE

Aluminum trichloride (AlCl₃) exposure was proven to encourage some behavioral deficits and eventually induces anxiety and depression in rodents animals. Therefore, this experiment aimed to scout about the effects of pomegranate juice on anxiety- and depression-like behaviors caused by AlCl₃ in male mice.

METHODS

Six groups of male mice were administrated orally for 35 days by PJ and AlCl3. The control group (G-I) received tap water, while the PJ groups (G-II and G-III) were treated with 20 % and 40 % PJ, respectively. The AlCl₃ group (G-IV) was treated with 400 mg/kg/day of AlCl_3, and the last two groups (G-V and G-VI) were treated with AlCl₃ and 20 % PJ or 40 % PJ, respectively. Then, the open-field (O-F), elevated plus maze (EPM), tail suspension (TS), forced swimming (FS), and light/dark box (L/DB) tests were applied for anxiety- and depression-like behavior studies. In addition, neurotransmitters and oxidative parameters in the brain were evaluated. The plasma cortisol was measured at the end of the experiment.

RESULTS

Behavioral analyses showed that PJ inhibited AlCl₃-induced depressive and anxiogenic effects in the O-F, EPM, TS, FS, L/DB tests. In addition, neurochemical results indicated that PJ at 20 % concentration minimized the AlCl₃ toxicity on dopamine (DOP), serotonin (SER), and acetylcholinesterase (AChE) levels in the for-brain of male mice. Moreover, PJ moderated the AlCl₃ effects by decreasing the level of thiobarbituric acid reactive substances (TBARS), and enhancing catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione (GSH) activities. The plasma cortisol increased in male mice treated with AlCl3 and in a group treated with a high dose of PJ.

CONCLUSION

Our results proposed that the anxiety- and depression-like behaviors induced by AlCl₃ exposure in male mice can be ameliorated by PJ treatment, probably through the inhibition of oxidative damage and minimizing the changes in neurotransmitters and hormonal activity.

Reduced NLRP3 inflammasome expression in the brain is associated with stress resilience

Increased expression of the Nod-like receptor pyrin containing 3 (NLRP3) inflammasome and proinflammatory cytokines is associated with depressive behaviors. This study aimed to explore potential differences in neuroinflammation associated with stress resilience, as well as associated changes in autophagy, in a mouse model of chronic unpredictable mild stress (CUMS). Animals were classified as CUMS resilient or CUMS susceptible based on performance on behavioral tests following the CUMS protocol. Then the expression levels of NLRP3 inflammasome-related proteins, interleukin-1 beta (IL-1β), and Beclin 1 in stress-related brain regions (e.g., prefrontal cortex and hippocampus) were determined. Results showed that stress exposure triggered significant NLRP3 inflammasome increase in CUMS susceptible mice but not in CUMS resilient mice. These changes were accompanied by altered IL-1β and Beclin 1 expression levels. These findings indicate that stress resilience is associated with reduced pro-inflammatory signaling and autophagy activation, and suggest that therapeutically targeting these pathways might promote stress resilience.

A systematic review of the antidepressant effects of curcumin: Beyond monoamines theory

BACKGROUND

Depression is a severe, chronic, and recurring mental health disorder, which prevalence and morbimortality have increased in recent years. Several theories are proposed to elucidate the mechanisms of depression, such as the involvement of inflammation and the release of cytokines. Alternative treatments have been developed to improve outcomes of the commonly used drugs, and the use of Curcuma longa stands out. Its primary compound is named curcumin that exhibits antioxidant and anti-inflammatory effects.

AIMS

Several studies have shown that curcumin may play antidepressant actions and, therefore, this study aimed to perform a systematic review of the antidepressant effects of curcumin to evaluate the impact of this compound in the treatment of this condition.

METHODS

This systematic review has included studies available in MEDLINE-PubMed, EMBASE, and Cochrane databases, and the final selection included 10 randomized clinical trials.

CONCLUSION

Curcumin improves depressant and anxiety behavior in humans. It can increase monoamines and brain-derived neurotrophic factor levels and may inhibit the production of pro-inflammatory cytokines and neuronal apoptosis in the brain. Systemically, curcumin enhanced insulin sensitivity, reduced cortisol levels, and reversed metabolic abnormalities. Studies with larger samples and standardized dose and formulation are required to demonstrate the benefits of curcumin in depression treatment since there are many variations in this compound's use.

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.

The effect of dietary phytochemicals on nuclear factor erythroid 2-related factor 2 (Nrf2) activation: a systematic review of human intervention trials

We conducted a systematic review of human trials examining the effects of dietary phytochemicals on Nrf2 activation. In accordance with the PRISMA guidelines, Medline, Embase and CAB abstracts were searched for articles from inception until March 2020. Studies in adult humans that measured Nrf2 activation (gene or protein expression changes) following ingestion of a phytochemical, either alone or in combination were included. The study was pre-registered on the Prospero database (Registration Number: CRD42020176121). Twenty-nine full-texts were retrieved and reviewed for analysis; of these, eighteen were included in the systematic review. Most of the included participants were healthy, obese or type 2 diabetics. Study quality was assessed using the Cochrane Collaboration Risk of Bias Assessment tool. Twelve different compounds were examined in the included studies: curcumin, resveratrol and sulforaphane were the most common (n = 3 each). Approximately half of the studies reported increases in Nrf2 activation (n = 10); however, many were of poor quality and had an unclear or high risk of bias. There is currently limited evidence that phytochemicals activate Nrf2 in humans. Well controlled human intervention trials are needed to corroborate the findings from in vitro and animal studies.

Anti-depressant effect of cerebrolysin in reserpine-induced depression in rats: Behavioral, biochemical, molecular and immunohistochemical evidence

Depression is a major psychological disorder that contributes to global health problem. This study aimed to evaluate the anti-depressant effect of Cerebrolysin (CBL) in Reserpine-induced depressed rats, its effect on oxidative stress, inflammation, regulatory cyclic AMP-dependent response element binding protein (CREB)/brain derived neurotropic factor (BDNF) signaling pathways, brain monoamines and histopathological changes was assessed. Rats received either the vehicle or Reserpine (0.5 mg/kg, i.p.) for 14 days. The other three groups were pretreated with CBL (2.5, 5 ml/kg; i.p.) or fluoxetine (FLU) (5 mg/kg, p.o.), respectively for 14 days, 30 min before reserpine injection. Then analyses were conducted. CBL reversed Reserpine-induced reduction in latency to immobility and prolongation of immobility time in the forced swimming test (FST), reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), reduced tumor necrosis factor-alpha (TNF-ɑ), and elevated BDNF cortical and hippocampal brain contents. CBL elevated protein kinase A (PKA) and nuclear factor kappa-B (NF-κB) cortical and hippocampal protein expressions. CBL also ameliorated alterations in mRNA expressions of protein kinase B (AKT), CREB and BDNF in the cortical and hippocampal tissues. CBL elevated nor-epinephrine (NE), serotonin (5-HT), and dopamine (DA) and reduced 5-Hydroxyindoleacetic acid (5-HTAA), 3,4-Dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) cortical and hippocampal contents. CBL effects were in parallel to those observed with the standard anti-depressant drug, FLU. This study shows that CBL exerted anti-depressant effect evidenced by attenuation of oxidative stress and inflammation as well as enhancement of neurogenesis, amelioration of monoaminergic system and histopathological changes.

Chaperone Sigma1R and Antidepressant Effect

This review analyzes the current scientific literature on the role of the Sigma1R chaperone in the pathogenesis of depressive disorders and pharmacodynamics of antidepressants. As a result of ligand activation, Sigma1R is capable of intracellular translocation from the endoplasmic reticulum (ER) into the region of nuclear and cellular membranes, where it interacts with resident proteins. This unique property of Sigma1R provides regulation of various receptors, ion channels, enzymes, and transcriptional factors. The current review demonstrates the contribution of the Sigma1R chaperone to the regulation of molecular mechanisms involved in the antidepressant effect.

Matrine alleviates neurobehavioral alterations via modulation of JNK-mediated caspase-3 and BDNF/VEGF signaling in a mouse model of burn injury

RATIONALE

The c-Jun N-terminal kinase (JNK) pathway and neurotrophic factor dysregulation play a critical role in the pathogenesis of neurobehavioral disorders (anxiety and depression). Targeting the JNK pathway and BDNF/VEGF signaling may signify a new avenue for the treatment of neurobehavioral disorders.

OBJECTIVES

The present study investigated the effect of matrine (Mat) against anxiety- and depressive-like emotional status in an acute mouse model of burn injury and explores its underlying mechanism.

METHODS

In the mouse model of thermal injury, anxiety- and depression-related behaviors were evaluated using the elevated plus-maze test, the light-dark box test, the open-field test, the forced swimming test, and the tail suspension test. The JNK/caspase-3 and BDNF/VEGF proteins were determined by immunohistochemistry. Additionally, proinflammatory cytokine, antioxidant, nitric oxide, and corticosterone levels were also measured.

RESULTS

The results showed that treatment with Mat significantly improves anxiety- and depressive-like behaviors. It remarkably reduced the levels of proinflammatory cytokines, malondialdehyde, and nitric oxide in the hippocampus and prefrontal cortex of a mouse brain. It considerably improved burn-induced alteration in the antioxidant status, corticosterone, and BDNF/VEGF. It also inhibited burn-induced apoptotic signaling by downregulating the expression of JNK/caspase-3. Similarly, it prevented DNA damage and histopathological changes in the dentate gyrus of the hippocampus. Furthermore, molecular docking results showed that Mat possess better binding affinity for JNK/caspase-3 and BDNF/VEGF proteins.

CONCLUSIONS

These findings provide convincing evidence that Mat improves anxiety- and depressive-like emotional status through modulation of JNK-mediated inflammatory, oxidative stress, apoptotic, and BDNF/VEGF signaling in an acute mouse model of burn injury.

Attenuation of oxidative stress and neurotoxicity involved in the antidepressant-like effect of the MK-801(dizocilpine) in Bacillus Calmette-Guerin-induced depression in mice

Background The emerging line of research suggests that neuro-inflammation and oxidative stress are linked to the development of depression-like behavior. The tryptophan metabolizing enzyme, indolamine 2,3-dioxygenase (IDO), serves as an important interface between chronic inflammation and depression. IDO is induced by pro-inflammatory cytokines and diverts tryptophan towards the kynurenine pathway, decreasing serotonin synthesis. Further, the metabolites of kynurenine pathway increase brain oxidative stress and also cause N-methyl-D-aspartate (NMDA) receptor-mediated exitotoxicity. The resulting oxidative damage and dysfunction in glutamatergic neurotransmission alters the network connectivity of the brain, which may be the further mechanism for emergence of depression-like symptoms. Methods A depression-like illness was induced in mice by injecting Bacillus Calmette-Guerin (BCG) suspended in isotonic saline at a dose of 107 CFU I.P. The mice were then divided into different groups and were administered MK-801 or normal saline for the next 21 days, after which a battery of behavior and biochemical tests were conducted to assess them. Results The BCG group had significantly reduced sucrose preference index and an increase in immobility time in forced swim test (FST) and Tail Suspension Test (TST) as compared to the saline group. There was also a significant increase in the brain MDA levels and a decline in the brain GSH levels. The hippocampal tissue from the BCG group had significantly more comet cells than the saline group. The NMDA receptor antagonist, MK-801, was able to reverse the BCG-induced depression-like behaviour. MK-801 also showed significant decrease in brain oxidative stress but failed to show significant protection against BCG-induced neurotoxicity observed in comet assay. Conclusions The NMDA receptor antagonist, MK-801, mitigated BCG-induced, depressive-like behavior in mice by improving the sucrose preference and decreasing the duration of immobility time in TST and FST. The overall improvement in depression-like behavior was accompanied by a reduction in brain oxidative stress and comet cells, thus suggesting the antioxidant and neuroprotective action of MK-801.

Neuroprotective effect of 25-Methoxyhispidol A against CCl4-induced behavioral alterations by targeting VEGF/BDNF and caspase-3 in mice

Brain oxidative stress and neuroinflammation have been implicated in various psychiatric disorders. The current study investigated the effect and mechanism of 25-Methoxyhispidol A (25-MHA) against CCl₄-induced anxiety and depression. Mice were challenged with CCl₄ (1 ml/kg; i.p.) after 30 min of 25-MHA (1, 5 and 10 mg/kg; i.p.) administration. Pretreatment with 25-MHA (10 mg/kg) significantly attenuated the anxiety and depression-like behavior in testing models. The oxidative stress induced by CCl₄ was significantly attenuated by pretreatment with 25-MHA. The immunohistochemical (IHC) analysis showed a reduction in kelch-like ECH-associated protein 1 (Keap1) and improvement in expression of nuclear factor erythroid-2-related factor (Nrf-2) and heme oxygenase (HO)-1. In addition, 25-MHA significantly attenuated the CCl₄-mediated depletion of antioxidant enzymes in hippocampus (HC) and prefrontal cortex (PFC) region and reduced the expression of toll-like receptor (TLR)-4 and nuclear factor kappa B (NF-κB), along with a decreased production of pro-inflammatory cytokines in HC and PFC region. Pretreatment with 25-MHA also showed an improved expression of neurotrophic factors i.e., brain derived growth factor (BDNF) and vascular endothelial growth factor (VEGF). Furthermore, 25-MHA inhibited malondialdehyde (MDA) and ammonia level in plasma, liver, HC and PFC regions of mice brain. 25-MHA also exhibited anti-apoptotic effect evident from the reduced expression of caspase-3 and decreased hippocampal DNA damage in comet assay. Furthermore, decreased serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and corticosterone level, along with prevention of CCl₄-induced alterations in thickness of dentate gyrus and intact hepatic cells morphology, represented by hippocampal and liver histopathology, indicated the neuroprotective effect of 25-MHA.

A novel role of NLRP3-generated IL-1β in the acute-chronic transition of peripheral lipopolysaccharide-elicited neuroinflammation: implications for sepsis-associated neurodegeneration

BACKGROUND

Sepsis-associated acute brain inflammation, if unresolved, may cause chronic neuroinflammation and resultant neurodegenerative diseases. However, little is known how the transition from acute to chronic neuroinflammation, which is critical for the following progressive neurodegeneration, occurs in sepsis. The goal of this study was to investigate potential immune factors regulating the transition process using a widely used endotoxemia LPS mouse model. This model shows distinct acute and chronic phases of neuroinflammation and recapitulates many cardinal features of Parkinson's disease, thus, providing a unique opportunity for studying phase transition of neuroinflammation.

METHODS

C57BL/6 J, NLRP3-/-, and IL-1R1-/- mice were employed. Mild and severe endotoxemia were produced by LPS ip injection at 1 or 5 mg/kg. Neuroinflammation in vitro and in vivo was assessed with proinflammatory cytokine expression by qPCR or ELISA and microglial activation by immunohistochemical analysis. Neurodegeneration was measured by manual and stereological counts of nigral dopaminergic neurons and immunohistochemical analysis of protein nitrosylation and α-synuclein phosphorylation.

RESULTS

LPS-elicited initial increases in mouse brain mRNA levels of TNFα, IL-6, IL-1β, and MCP-1, and nigral microglial activation were not dose-related. By contrast, the delayed increase in brain mature IL-1β levels was dependent on LPS doses and protracted nigral microglial activation was only observed in high dose of LPS-treated mice. LPS-elicited increase in brain mature IL-1β but not IL-1α level was NLRP3-dependent. After high dose LPS treatment, deficiency of NLRP3 or IL-1R1 did not prevent the initiation of acute neuroinflammation but abolished chronic neuroinflammation. Genetic or pharmacological inhibition of the NLRP3-IL-1β axis repressed LPS-stimulated upregulation of chronic neuroinflammatory mediators including MHC-II, NOX2, and Mac1, and protected dopaminergic neurons. Ten months after LPS-elicited severe endotoxemia, nigral persisted microglial activation, elevated nitrosylated proteins and phosphorylated α-synuclein, and significant neuronal degeneration developed in wild-type mice but not in NLRP3-/- or IL-1R1-/- mice.

CONCLUSIONS

This study uncovers a novel role of the NLRP3-IL-1β signaling pathway in gauging the severity of sepsis-associated inflammation and determining whether acute neuroinflammation will resolve or transition to low grade chronic neuroinflammation. These findings also provide novel targets for developing therapy for severe systemic infection-related neurodegeneration.

Evaluation of Brain Cytokines and the Level of Brain-Derived Neurotrophic Factor in an Inflammatory Model of Depression

INTRODUCTION

Major depressive disorder is considered a global public health problem. Inflammatory processes are likely involved in its pathophysiology, but the underlying mechanisms have remained uncertain.Here, we used the model of systemic lipopolysaccharide (LPS) injection to test the hypothesis that depressive-like behaviors occur along with changes in the levels of cytokines and brain-derived neurotrophic factor (BDNF) in the hippocampus (HC), prefrontal cortex (PFC), and hypothalamus (HT), and can be prevented by dexamethasone administration.

METHODS

Adult C57Bl/6 male mice were first isolated for 10 days, and thereafter received an injection of dexamethasone (6 mg/kg, intraperitoneal [i.p.]), saline followed by LPS (0.83 mg/kg, i.p.), or saline. After 6 h, animals were subjected to the forced-swim test (FST) and open-field tests. Immediately after the behavioral tests, they were euthanized and their brains were collected for the biochemical analyses.

RESULTS

LPS increased the immobility time and reduced the distance travelled in the FST and open-field test, respectively. Dexamethasone increased the immobility time in saline-treated mice but reduced this behavior in the LPS group. LPS increased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interferon (IFN)-γ in most of the regions evaluated. Dexamethasone prevented LPS-induced IL-6 in the HC, PFC, and HT. Interestingly, dexamethasone increased IL-4 and IL-10 levels in both the LPS- and saline-treated groups. Although dexamethasone reduced BDNF in saline-treated mice, it prevented LPS-induced reduction in this neurotrophic factor.

CONCLUSION

In summary, dexamethasone decreased proinflammatory and increased anti-inflammatory levels of cytokines and prevented a reduction in BDNF levels induced by the inflammatory stimulus. Thus, the attenuation of depressive-like behavior induced by dexamethasone may be related to the effects on these parameters.

Inflammation-induced behavioral changes is driven by alterations in Nrf2-dependent apoptosis and autophagy in mouse hippocampus: Role of fluoxetine

Inflammation has been associated with the progression of many neurological diseases. Peripheral inflammation has also been vaguely linked to depression-like symptoms in animal models, but the underlying pathways that orchestrate inflammation-induced behavioral or molecular changes in the brain are still elusive. We have recently shown that intraperitoneal injections of lipopolysaccharide (LPS) to Swiss albino mice triggers systemic inflammation, leading to an activated immune response along with changes in monoamine levels in the brain. Herein we pinpoint the fundamental pathways linking peripheral inflammation and depression-like behavior in a mouse model, thereby identifying suitable targets of intervention to combat the situation. We show that LPS-induced peripheral inflammation provoked a depression-like behavior in mice and a distinct pro-inflammatory bias in the hippocampus, as evident from increased microglial activation and elevated levels of pro-inflammatory cytokines IL-6 and TNF-α, and activation of NFκB-p65 pathway. Significant alterations in Nrf2-dependent cellular redox status, coupled with altered autophagy and increased apoptosis were noticed in the hippocampus of LPS-exposed mice. We and others have previously shown that, fluoxetine (an anti-depressant) has effective anti-inflammatory and antioxidant properties by virtue of its abilities to regulate NFκB and Nrf2 signaling. We observed that treatment with fluoxetine or the Nrf2 activator tBHQ (tert-butyl hydroquinone), could reverse depression-like-symptoms and mitigate alterations in autophagy and cell death pathways in the hippocampus by activating Nrf2-dependent gene expressions. Taken together, the data suggests that systemic inflammation potentiates Nrf2-dependent changes in cell death and autophagy pathway in the hippocampus, eventually leading to major pathologic sequelae associated with depression. Therefore, targeting Nrf2 could be a novel approach in combatting depression and ameliorating its associated pathogenesis.

Xiaoyao Pills Prevent Lipopolysaccharide-Induced Depression by Inhibiting Inflammation and Protecting Nerves

Lipopolysaccharides are pro-inflammation mediators that can induce inflammation in the serum, hippocampus, and cortex of animals. And lipopolysaccharide-induced neuroinflammatory state resulted in significant depression-like behaviors, including reduced locomotor activity in the open field test, reduced saccharin preference, added immobility time in tail suspension test and forced swimming test, decreased comb time in the splash test, and increased latency to food in the novelty suppressed feeding test time, and reduced the levels of neurotrophic factors and synaptic proteins, and decreased Nissl bodies. Treatment with Xiaoyao Pills ameliorated the depression-like behavior, decreased the levels of inflammatory indicators, increased those of neurotrophic factors and synaptic proteins, and restored Nissl bodies. Our study suggests that lipopolysaccharides induce inflammation and nerve injury, thereby leading to depression. Xiaoyao Pills could be considered a potential therapeutic candidate for inflammation-induced depression.

Role of endoplasmic reticulum stress in depression (Review)

Depression is a devastating mood disorder that causes profound disability worldwide. Despite the increasing number of antidepressant medications available, the treatment options for depression are limited. Therefore, understanding the etiology and pathophysiology of depression, and exploiting potential novel agents to treat and prevent this disorder are imperative. Endoplasmic reticulum (ER) stress activates the unfolded protein response and mediates the pathogenesis of psychiatric diseases, including depression. Emerging evidence in human and animal models suggests an intriguing link between ER stress and depression. The ER serves as an important subcellular organelle for the synthesis, folding, modification, and transport of proteins, a process that is highly developed in neuronal cells. Perturbations of ER homeostasis lead to ER stress, and ER stress helps to restore the normal ER function by restoring the protein-folding capacity of the ER. This biological defense mechanism is imperative to prevent the disease. However, excessive or persistent ER stress eventually causes cell death. If the damage occurs in the hippocampus, the amygdala and striatum and other areas of the neurons will be involved in the development of depression. In this review article, we explore how ER stress might have an important role in the pathophysiology of depression and how different drugs affect depression through ER stress.

Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.

Ameliorative effect of fisetin against lipopolysaccharide and restraint stress-induced behavioral deficits via modulation of NF-κB and IDO-1

BACKGROUND

Fisetin, a plant active polyphenol, is well known for its antioxidant and free radical scavenging activities. The present study was designed to explore the detailed molecular mechanism underlying its neuroprotective effects.

METHODS

The young male mice were either administered a single dose of lipopolysaccharide (0.83 mg/kg) or subjected to restraint stress (6 h per day for 28 days) to induce behavioral deficits in different groups. Fisetin (15 mg/kg) was orally administered for the last 14 days of the study.

RESULTS

Lipopolysaccharide (LPS) as well as restraint stress (RS) exposure caused behavioral alterations (anxiety and depressive-like behavior). Gene expression analysis showed upregulation of nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) and indoleamine 2,3-dioxygenase (IDO)-1 gene expression along with downregulation of Nrf-2 (nuclear factor erythroid 2-related factor 2), HO-1 (heme oxygenase-1), and ChAT (choline acetyltransferase) gene expression level in RS and RS+LPS groups. Fisetin administration significantly ameliorated behavioral and neurochemical deficits in LPS, RS, and RS+LPS groups.

CONCLUSION

These findings clearly indicated that fisetin administration improved behavioral functions and suppressed the NF-κB and IDO-1 (indoleamine 2,3-dioxygenase) activation along with their antioxidant effect, suggesting fisetin as an intriguing nutraceutical for the management of inflammation-associated neurological disorders.

Berberine ameliorates lipopolysaccharide-induced learning and memory deficit in the rat: insights into underlying molecular mechanisms

Systemic lipopolysaccharide (LPS) triggers neuroinflammation with consequent development of behavioral and cognitive deficits. Neuroinflammation plays a crucial role in the pathogenesis of neurodegenerative disorders including Alzheimer's disease (AD). Berberine is an isoquinoline alkaloid in Berberis genus with antioxidant and anti-inflammatory property and protective effects in neurodegenerative disorders. In this research, beneficial effect of this alkaloid against LPS-induced cognitive decline was assessed in the adult male rats. LPS was intraperitoneally administered at a dose of 1 mg/kg to induce neuroinflammation and berberine was given via gavage at doses of 10 or 50 mg/kg, one h after LPS, for 7 days. Treatment of LPS group with berberine at a dose of 50 mg/kg (but not at a dose of 10 mg/kg) improved spatial recognition memory in Y maze, performance in novel object recognition task (NORT), and prevented learning and memory dysfunction in passive avoidance tasks. Furthermore, berberine lowered hippocampal activity of acetylcholinesterase (AChE), malondialdehyde (MDA), protein carbonyl, activity of caspase 3, and DNA fragmentation and improved antioxidant capacity through enhancing glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase, and glutathione (GSH). Besides, berberine attenuated inflammation-related indices, as was evident by lower levels of nuclear factor-kappa B (NF-κB), toll-like receptor 4 (TLR4), tumor necrosis factor α (TNFα), and interleukin 6 (IL-6). Berberine also appropriately restored hippocampal 3-nitrotyrosine (3-NT), cyclooxygenase 2 (Cox 2), glial fibrillary acidic protein (GFAP), sirtuin 1, and mitogen-activated protein kinase (p38 MAPK) with no significant alteration of brain-derived neurotrophic factor (BDNF). In summary, berberine could partially ameliorate LPS-induced cognitive deficits via partial suppression of apoptotic cascade, neuroinflammation, oxido-nitrosative stress, AChE, MAPK, and restoration of sirtuin 1.

Cellular and molecular mechanisms of curcumin in prevention and treatment of disease

Curcumin is a naturally occurring polyphenolic compound present in rhizome of Curcuma longa belonging to the family zingiberaceae. Growing experimental evidence revealed that curcumin exhibit multitarget biological implications signifying its crucial role in health and disease. The current review highlights the recent progress and mechanisms underlying the wide range of pharmacological effects of curcumin against numerous diseases like neuronal, cardiovascular, metabolic, kidney, endocrine, skin, respiratory, infectious, gastrointestinal diseases and cancer. The ability of curcumin to modulate the functions of multiple signal transductions are linked with attenuation of acute and chronic diseases. Numerous preclinical and clinical studies have revealed that curcumin modulates several molecules in cell signal transduction pathway including PI3K, Akt, mTOR, ERK5, AP-1, TGF-β, Wnt, β-catenin, Shh, PAK1, Rac1, STAT3, PPARγ, EBPα, NLRP3 inflammasome, p38MAPK, Nrf2, Notch-1, AMPK, TLR-4 and MyD-88. Curcumin has a potential to prevent and/or manage various diseases due to its anti-inflammatory, anti-oxidant and anti-apoptotic properties with an excellent safety profile. In contrast, the anti-cancer effects of curcumin are reflected due to induction of growth arrest and apoptosis in various premalignant and malignant cells. This review also carefully emphasized the pharmacokinetics of curcumin and its interaction with other drugs. Clinical studies have shown that curcumin is safe at the doses of 12 g/day but exhibits poor systemic bioavailability. The use of adjuvant like piperine, liposomal curcumin, curcumin nanoparticles and curcumin phospholipid complex has shown enhanced bioavailability and therapeutic potential. Further studies are warranted to prove the potential of curcumin against various ailments.

Neuroprotective Effects of dl-3-n-Butylphthalide against Doxorubicin-Induced Neuroinflammation, Oxidative Stress, Endoplasmic Reticulum Stress, and Behavioral Changes

Doxorubicin (DOX) is a broad-spectrum antitumor drug while its use is limited due to its neurobiological side effects associated with depression. We investigated the neuroprotective efficacy of dl-3-n-butylphthalide (dl-NBP) against DOX-induced anxiety- and depression-like behaviors in rats. dl-NBP was given (30 mg/kg) daily by gavage over three weeks starting seven days before DOX administration. Elevated plus maze (EPM) test, forced swimming test (FST), and sucrose preference test (SPT) were performed to assess anxiety- and depression-like behaviors. Our study showed that the supplementation of dl-NBP significantly mitigated the behavioral changes induced by DOX. To further explore the mechanism of neuroprotection induced by dl-NBP, several biomarkers including oxidative stress markers, endoplasmic reticulum (ER) stress markers, and neuroinflammatory cytokines in the hippocampus were quantified. The results showed that dl-NBP treatment alleviated DOX-induced neural apoptosis. Meanwhile, DOX-induced oxidative stress and ER stress in the hippocampus were significantly ameliorated in dl-NBP pretreatment group. Our study found that dl-NBP alleviated the upregulation of malondialdehyde (MDA), nitric oxide (NO), CHOP, glucose-regulated protein 78 kD (GRP-78), and caspase-12 and increased the levels of reduced glutathione (GSH) and activities of catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx) in the hippocampus of rats exposed to DOX. Additionally, the gene expression of interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) and protein levels of inducible nitric oxide synthase (iNOS) were significantly increased in DOX-treated group, whereas DOX-induced neuroinflammation was significantly attenuated in dl-NBP supplementation group. In conclusion, dl-NBP could alleviate DOX-induced anxiety- and depression-like behaviors via attenuating oxidative stress, ER stress, inflammatory reaction, and neural apoptosis, providing a basis as a therapeutic potential against DOX-induced neurotoxicity.

Antidepressant and anxiolytic like effects of Urtica dioica leaves in streptozotocin induced diabetic mice

The present study was aimed to investigate the effect of Urtica dioica Linn. (UD) extract against chronic diabetes mediated anxiogenic and depressive like behavior in mice. Streptozotocin (STZ) (50 mg/kg, i.p.) for 5 consecutive days was used to induce diabetes followed by treatment with UD leaves extract (50 mg/kg, p.o.) and rosiglitazone (ROSI) (5 mg/kg, p.o.) for 8 weeks. STZ induced chronic diabetes significantly induced anxiety and depressive like behavior in mice. Chronic diabetes significantly downregulated BDNF (p < 0.001), TrKB (p < 0.001), Cyclin D1 (p < 0.001), Bcl2 (p < 0.05) and autophagy7 (p < 0.001), while upregulated iNOS (p < 0.05) mRNA expression in the hippocampus as compared to control mice. In addition, chronic diabetes significantly increased the expression of TNF-α in CA1 (p < 0.001), CA2 (p < 0.01), CA3 (p < 0.001) and DG (p < 0.001) regions of hippocampus as compared to control mice. Chronic diabetes mediated neuronal damage in the CA2, CA3 and DG regions of hippocampus. Chronic administration of UD leaves extract significantly reversed diabetes mediated anxiogenic and depressive like behavior in mice. Further, UD treatment significantly upregulated BDNF (p < 0.01), TrKB (p < 0.001), Cyclin D1 (p < 0.001), Bcl2 (p < 0.01), autophagy5 (p < 0.01) and autophagy7 (p < 0.001), while downregulated iNOS (p < 0.05) mRNA expression in the hippocampus of diabetic mice. Concomitantly, UD administration significantly decreased the expression of TNF-α in hippocampal CA1 (p < 0.001), CA2 (p < 0.01), CA3 (p < 0.001) and DG (p < 0.001) regions of diabetic mice. Diabetes mediated neuronal damage and DNA fragmentation in the hippocampus was substantially attenuated following UD treatment. UD leaves extract might prove to be effective for diabetes mediated anxiety and depressive like behavior.

AQP4‑knockout alleviates the lipopolysaccharide‑induced inflammatory response in astrocytes via SPHK1/MAPK/AKT signaling

To date, aquaporin‑4 (AQP4) has been considered as a critical contributor to neuroinflammation, but little is known about the underlying mechanism. Previous studies have shown that a critical enzyme involved in the sphingomyelin cycle, sphingosine kinase 1 (SPHK1), is implicated in inflammatory processes and contributes to chronic neuroinflammation. The present study investigated the role of AQP4 in proinflammatory cytokine release from astrocytes, with an emphasis on the SPHK1/mitogen‑activated protein kinase (MAPK)/protein kinase B (AKT) pathway. Using primary cultures isolated from AQP4+/+ and AQP4‑/‑ embryos, the production of tumor necrosis factor‑α (TNF‑α)/interleukin‑6 (IL‑6) from astrocytes challenged by lipopolysaccharide (LPS) was compared. The results showed increased secretion of TNF‑α/IL‑6 in the two groups following LPS treatment, but a significantly lower level was observed in the AQP4‑/‑ group compared with that in the AQP4+/+ group. Although upregulation of SPHK1 was detected in the two genotypes, only a mild increase in SPHK1 was found in the AQP4‑/‑ genotype. The phosphorylation of MAPK/AKT was also confirmed to be attenuated in the AQP4‑/‑ group, suggesting decreased MAPK/AKT signaling over time in AQP4‑/‑ astrocytes. Overall, the study findings demonstrated that AQP4 deficiency alleviates proinflammatory cytokine release from astrocytes, in association with the SPHK1/MAPK/AKT pathway. This data improves our understanding of AQP4 in neuroinflammatory events, highlighting a novel profile of SPHK1 as a potential target for the treatment of CNS inflammation.

Trigonelline mitigates lipopolysaccharide-induced learning and memory impairment in the rat due to its anti-oxidative and anti-inflammatory effect

Brain inflammation is associated with cognitive dysfunction, especially in elderly. Trigonelline is a plant alkaloid and a major component of coffee and fenugreek with anti-diabetic, antioxidant, anti-inflammatory, and neuroprotective effects. In this study, the beneficial effect of trigonelline against lipopolysaccharide (LPS)-induced cognitive decline was assessed in the rat. LPS was injected i.p. at a dose of 500 μg/kg to induce neuroinflammation and trigonelline was administered p.o. at doses of 20, 40, or 80 mg/kg/day 1 h after LPS that continued for one week. Trigonelline-treated LPS-challenged rats showed improved spatial recognition memory in Y maze, discrimination ratio in novel object discrimination test, and retention and recall in passive avoidance paradigm. Additionally, trigonelline lowered hippocampal malondialdehyde (MDA) and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD), catalase, and glutathione (GSH). Furthermore, trigonelline depressed hippocampal nuclear factor-kappaB (NF-κB), toll-like receptor 4 (TLR4), and tumor necrosis factor α (TNF α) in LPS-challenged rats. All of the effects of trigonelline followed a dose-dependent pattern and in some aspects, it acted even better than the routinely-used anti-inflammatory drug dexamethasone. Collectively, trigonelline is capable to diminish LPS-induced cognitive decline via suppression of hippocampal oxidative stress and inflammation and appropriate modulation of NF-κB/TLR4 and AChE activity.

Tauroursodeoxycholic acid produces antidepressant-like effects in a chronic unpredictable stress model of depression via attenuation of neuroinflammation, oxido-nitrosative stress, and endoplasmic reticulum stress

Depression is a common psychiatric disorder with heavy economic and social burdens. Searching new agents with better antidepressant-like activities is of great significance for depression therapy. Tauroursodeoxycholic acid (TUDCA), a clinical drug for gallstone treatment, possesses neuroprotective effects in different brain disorders. However, whether it affects depression remains unclear. We addressed this issue by evaluating the effect of TUDCA on depression induced by chronic unpredictable stress (CUS). Results showed that TUDCA treatment at 200 but not 100 mg/kg prevented the 5 weeks of CUS-induced increases in the immobile time of C57BL6/J mice in the experiments of forced swimming test and tail suspension test as well as the CUS-induced decrease in sucrose intake and crossing numbers in the open-field test, and did not enhance the antidepressant-like effect of fluoxetine. Attenuation of neuroinflammation may be involved in the antidepressant-like effect of TUDCA, as TUDCA treatment (200 mg/kg) normalized the levels of tumor necrosis factor-α and interleukin-6 in both hippocampus and prefrontal cortex. The increases in inflammasome and microglial activation markers, including interleukin-β, nod-like receptor protein 3, and Iba-1, in CUS-treated mice were reduced by TUDCA treatment (200 mg/kg). TUDCA treatment (200 mg/kg) also normalized the changes in markers reflecting the oxidative-nitrosative and endoplasmic reticulum (ER) stress induced by CUS, such as nitric oxide, reduced glutathione, malondialdehyde, glucose-regulated protein 78, and C/EBP homologous protein. These results revealed that TUDCA improved the CUS-induced depression-like behaviors likely through attenuation of neuroinflammation, oxido-nitrosative, and ER stress.

Soy isoflavone genistein attenuates lipopolysaccharide-induced cognitive impairments in the rat via exerting anti-oxidative and anti-inflammatory effects

Systemic inflammation during infectious disorders usually accompanies chronic complications including cognitive dysfunction. Neuroinflammation and cognitive deficit are also observed in some debilitating neurological disorders like Alzheimer's and Parkinson's diseases. Genistein is a soy isoflavone with multiple beneficial effects including anti-inflammatory, anti-oxidative, and protective properties. In this research study, the effect of genistein in prevention of lipopolysaccharide (LPS)-induced cognitive dysfunction was investigated. LPS was given i.p. (500 μg/kg/day) and genistein was orally given (10, 50, or 100 mg/kg) for one week. Findings showed that genistein could dose-dependently attenuate spatial recognition, discrimination, and memory deficits. Additionally, genistein treatment of LPS-challenged group lowered hippocampal level of malondialdehyde (MDA) and increased activity of superoxide dismutase (SOD) and catalase and glutathione (GSH) level. Furthermore, genistein ameliorated hippocampal acetylcholinesterase (AChE) activity in LPS-challenged rats. Furthermore, genistein administration to LPS-injected group lowered hippocampal level of interleukin 6 (IL-6), nuclear factor-kappaB (NF-κB) p65, toll-like receptor 4 (TLR4), tumor necrosis factor α (TNFα), cyclooxygenase-2 (COX2), inducible nitric oxide synthase (iNOS), glial fibrillary acidic protein (GFAP), and increased hippocampal level of antioxidant element nuclear factor (erythroid-derived 2)-like 2 (Nrf2). In conclusion, genistein alleviated LPS-induced cognitive dysfunctions and neural inflammation attenuation of oxidative stress and AChE activity and appropriate modulation of Nrf2/NF-κB/IL-6/TNFα/COX2/iNOS/TLR4/GFAP.

Dihydromyricetin exerts a rapid antidepressant-like effect in association with enhancement of BDNF expression and inhibition of neuroinflammation

RATIONALE

Major depressive disorder (MDD) is a highly prevalent illness that affects large populations across the world, and increasing evidence suggests that neuroinflammation and levels of brain-derived neurotrophic factor (BDNF) are closely related to depression. Dihydromyricetin (DHM) is a kind of flavonoid natural product that has been reported to display multiple pharmacological effects, including anti-inflammatory and anti-oxidative properties, and these may contribute to ameliorate MDD.

OBJECTIVE

This study investigated the effect of DHM on depression-related phenotypes in various experimental animal models.

METHODS

The antidepressant-like effect of DHM was validated via depression-related behavioral tests in naïve male C57BL/6 mice, as well as in the acute lipopolysaccharide-induced mouse model of depression. The chronic unpredicted mild stress (CUMS) mouse model of depression was also used to assess the rapid antidepressant-like effect of DHM by tail suspension test (TST), forced swimming test (FST), locomotor activity, and sucrose preference test (SPT). The expression of BDNF and inflammatory factors were determined through Western blotting and enzyme-linked immunosorbent assay, respectively.

RESULTS

DHM reduced immobility time in the TST and FST both in mice and the acute LPS-induced mouse model of depression. Seven days of DHM treatment ameliorated depression-related behaviors induced by CUMS, whereas similar treatment with the typical antidepressant venlafaxine did not. DHM activated the ERK1/2-CREB pathway and increased glycogen synthase kinase-3 beta (GSK-3β) phosphorylation at ser-9, with upregulation of BDNF expression, in both hippocampal tissues and cultured hippocampal cells.

CONCLUSION

The present data indicate that DHM exerts a more rapid antidepressant-like effect than does a typical antidepressant, in association with enhancement of BDNF expression and inhibition of neuroinflammation.