Sodium Phenylbutyrate and Edaravone Abrogate Chronic Restraint Stress-Induced Behavioral Deficits: Implication of Oxido-Nitrosative, Endoplasmic Reticulum Stress Cascade, and Neuroinflammation

Effect of Voluntary Wheel Running on Anxiety- and Depression-Like Behaviors in Fluoride-Exposed Mice

Fluoride, an environmental toxicant, could induce endoplasmic reticulum stress (ERS) in neuronal cells ultimately leading to apoptosis and emotional dysfunction. Meanwhile, voluntary wheel running contributes to mitigate anxiety and depression. Our investigation aimed to study the effect of voluntary wheel running on anxiety- and depression-like behaviors in fluoride-exposure mice. The results showed that exposure to 100 mg/L sodium fluoride (NaF) for 6 months can induce anxiety- and depression-like behavior in mice. Fluorosis mice subjected to voluntary wheel running have less anxiety- and depression-like behaviors. Nissl and TUNEL staining demonstrated that fluoride led to a reduced proportion of Nissl body area in the cerebral cortex and an increased apoptotic ratio of nerve cells in the cerebral cortex. In contrast, these pathologic damages were improved in voluntary wheel running mice exposed to NaF. Moreover, the expressions of mRNA in the cerebral cortex GABA, GAD65, GAD67, DR, vGLU, 5-HT1A, BDNF, NMDAR1, and Bcl2 were downregulated and the levels of c-fos, GRP78, PERK, eIF2α, CHOP, Caspase-12, and Caspase-3 mRNA were upregulated in mice exposed to fluoride. NaF treatment had increased the PERK, ATF6, IRE1, p-eIF2α, and Caspase-3 protein levels and reduced the expressions of proteins, including GAD67, VGAT, BDNF, NMDAR1, PSD95, and SYN. By contrast, fluorosis mice subjected to voluntary wheel running enhanced the expression of GAD65, GAD67, VGAT, and neuroplasticity-related proteins in mice and inhibited the PERK-CHOP pathway. It is worth noting that the correlation between the amount of exercise and the behavioral indicators as well as neurotransmitter levels was found. In conclusion, voluntary wheel running inhibits the fluoride-induced ERS and GRP78 expression through the PERK-CHOP pathway and plays an anti-apoptotic role, ultimately ameliorating emotional dysfunction in NaF-exposed mice.

CUMS induces depressive-like behaviors and cognition impairment by activating the ERS-NLRP3 signaling pathway in mice

BACKGROUND AND OBJECTIVE

Endoplasmic reticulum stress (ERS), as a primary defense mechanism against stress, is closely related to mental disorders, but its pathogenesis is still unclear. This research seeks to explore the influence of ERS-nucleotide-bound oligomerized domain-like receptor protein 3 (NLRP3) signaling on mice's depressive-like behaviors and cognitive impairment.

DESIGN AND METHOD

We carried out a study on 32 male C57BL/6J mice to investigate how chronic unpredictable mild stress (CUMS) can give rise to depressive-like behaviors and cognitive dysfunction, randomly dividing them into control, model, inhibitor, and agonist groups. We utilized ELISA to quantify dopamine (DA) and 5-hydroxytryptamine (5-HT) levels. Using Nissl and hematoxylin and eosin (H&E) staining, we assessed the number and morphology of hippocampal neurons and cells. Western blot and immunofluorescence staining detected the changes in ERS and inflammation-related pathways in the hippocampus.

RESULTS

CUMS could induce ERS and activate NLRP3 inflammasome, causing neuronal damage and histopathological changes, eventually leading to depressive-like behaviors and cognitive impairment in mice. The abnormal activation of NLRP3 inflammasome could be restored by ERS blocker 4-phenyl butyric acid (PBA), thus reducing neuronal damage, and ameliorating depressive-like behaviors and cognitive disorder in mice.

CONCLUSION

Our study demonstrates a previously unknown link between ERS and NLRP3 inflammasome in CUMS mice. The ERS-NLRP3 signaling pathway may be activated by CUMS, potentially resulting in mice exhibiting depressive-like behaviors and cognitive dysfunction. Theoretical foundations for elucidating the pathogenesis of depression, as well as its prevention and treatment, will be established through the results.

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.

Regulatory T cells administration reduces anxiety-like behavior in mice submitted to chronic restraint stress

Background

Major depression disorder (MDD) and anxiety are common mental disorders that significantly affect the quality of life of those who suffer from them, altering the person's normal functioning. From the biological perspective, the most classical hypothesis explaining their occurrence relies on neurotransmission and hippocampal excitability alterations. However, around 30% of MDD patients do not respond to medication targeting these processes. Over the last decade, the involvement of inflammatory responses in depression and anxiety pathogenesis has been strongly acknowledged, opening the possibility of tackling these disorders from an immunological point of view. In this context, regulatory T cells (Treg cells), which naturally maintain immune homeostasis by suppressing inflammation could be promising candidates for their therapeutic use in mental disorders.

Methods

To test this hypothesis, C57BL/6 adult male mice were submitted to classical stress protocols to induce depressive and anxiety-like behavior; chronic restriction stress (CRS), and chronic unpredictable stress (CUS). Some of the stressed mice received a single adoptive transfer of Treg cells during stress protocols. Mouse behavior was analyzed through the open field (OFT) and forced swim test (FST). Blood and spleen samples were collected for T cell analysis using cell cytometry, while brains were collected to study changes in microglia by immunohistochemistry.

Results

Mice submitted to CRS and CUS develop anxiety and depressive-like behavior, and only CRS mice exhibit lower frequencies of circulating Treg cells. Adoptive transfer of Treg cells decreased anxiety-like behavior in the OFT only in CRS model, but not depressive behavior in FST in neither of the two models. In CRS mice, Treg cells administration lowered the number of microglia in the hippocampus, which increased due this stress paradigm, and restored its arborization. However, in CUS mice, Treg cells administration increased microglia number with no significant effect on their arborization.

Conclusion

Our results for effector CD4+ T cells in the spleen and microglia number and morphology in the hippocampus add new evidence in favor of the participation of inflammatory responses in the development of depressive and anxiety-like behavior and suggest that the modulation of key immune cells such as Treg cells, could have beneficial effects on these disorders.

Effects of protocatechuic acid against cisplatin-induced neurotoxicity in rat brains: an experimental study

Aims/Objectives: Cisplatin (CIS) is widely used in the treatment of various malignant tumors. The aim of study is to determine the potential protective effects of protocatechuic acid (PCA) on the brain in neurotoxicity induced by CIS in rats.Materials and methods: Forty rats were divided into four groups: 1-Control group: 2- PCA group: PCA was administered orally at a dose of 100 mg/kg/day for 5 weeks. 3-CIS group: 5 mg/kg/week of CIS was administered intraperiteonally 4-PCA + CIS group: The rats were given PCA orally daily for 5 weeks and CIS of 5 mg/kg/week. The brain tissues were used for histopathological examinations and for total antioxidant capacity (TAC), total oxidative state (TOS), oxidative stress index (OSI), tumornecrosis factor-alpha (T NF-α), interleukin 6 (IL-6) Interleukin 1 beta (IL-1β), acetylcholinesterase (AChE), glutamate, gamma aminobutyric acid (GABA), dopamine analyzes in ELISA. WBC, RBC, hemoglobin and hematocrit levels were measured.Results: PCA + CIS group compared to CIS group TOS, OSI, T NF-α, IL-6, IL-1β, AChE, glutamate, WBC levels decreased significantly, while TAC and GABA levels increased statistically significant. With this study, P CA corrected the deterioration in the oxidant / antioxidant status, suppressed neuro-inflammation, decreased AChE activity, partially normalized neurotransmitters, and decreased the increased WBC count. Necrosis seen in the CIS group in histopathological examinations was never seen in the PCA + CIS group.Conclusions: PCA may provide therapeutic benefit when used in conjunction with CIS.

Edaravone dexborneol attenuates oxidative stress in experimental subarachnoid hemorrhage via Keap1/Nrf2 signaling pathway

Background

Subarachnoid hemorrhage (SAH) serves as a disease characterized by high incidence rate, which is exceedingly prevalent and severe. Presently, there is no unambiguous or efficacious intervention for the neurological impairment following SAH. Administering multi-targeted neuroprotective agents to reduce oxidative stress (OS) and neuroinflammation caused by early brain injury (EBI) has been demonstrated to improve neurological function and prognosis following SAH. Edaravone dexborneol (EDB), a novel multi targeted neuroprotective medication, combines four parts edaravone (EDA) with 1 part (+)-borneol in proportion. Clinical trials conducted in China have revealed during 2 days of acute ischemic stroke (AIS), early administration of EDB leads to improved therapeutic outcomes compared to treatment in EDA monotherapy. Currently, there is no clear evidence that EDB can effectively treat SAH, therefore, our study aims to investigate its potential therapeutic effects and mechanisms on EBI after SAH.

Method

We used the intravascular threading method to establish a mouse model of SAH to explore whether EDA and EDB could produce anti-OS and anti-apoptosis effects. Behavioral assessment of mice was conducted using the balance beam experiment and the modified Garcia scoring system. Neuronal damage due to OS and Keap1/Nrf2 signaling pathway were detected through techniques of immunofluorescence, Western blotting, spectrophotometry. The group of EDA and EDB were injected intraperitoneally for 72 h after SAH.

Results

The experiment results indicated that EDB lead to remarkably positive results by significantly enhancing neurological function, reducing blood-brain barrier (BBB) injury, and effectively inhibiting neuronal apoptosis after SAH. Further examination indicated EDB significantly reduced the expression of Keap1 and increased the expression of Nrf2, and it inhibited MDA, and enhanced SOD activity after SAH. These outcomes surpassed the effectiveness observed in EDA monotherapy. However, the application of ML385 reversed the anti-OS effects of EDB and EDA.

Conclusion

Our experimental findings indicated that EDB could activate Keap1/Nrf2 signaling pathway to reduce OS damage, thereby protecting neurological function and enhancing behavioral abilities after SAH. These outcomes could facilitate the creation of new approaches for the clinical management of SAH.

Edaravone Alleviates Traumatic Brain Injury by Inhibition of Ferroptosis via FSP1 Pathway

Traumatic brain injury (TBI) is a highly severe form of trauma with complex series of reactions in brain tissue which ultimately results in neuronal damage. Previous studies proved that neuronal ferroptosis, which was induced by intracranial haemorrhage and other reasons, was one of the most primary causes of neuronal damage following TBI. However, the association between neuronal mechanical injury and ferroptosis in TBI and relevant treatments remain unclear. In the present study, we first demonstrated the occurrence of neuronal ferroptosis in the early stage of TBI and preliminarily elucidated that edaravone (EDA), a cerebroprotective agent that eliminates oxygen radicals, was able to inhibit ferroptosis induced by TBI. A cell scratching model was established in PC12 cells, and it was confirmed that mechanical injury induced ferroptosis in neurons at the early stage of TBI. Ferroptosis suppressor protein 1 (FSP1) plays a significant role in inhibiting ferroptosis, and we found that iFSP, a ferroptosis agonist which is capable to inhibit FSP1 pathway, attenuated the anti-ferroptosis effect of EDA. In conclusion, our results suggested that EDA inhibited neuronal ferroptosis induced by mechanical injury in the early phase of TBI by activating FSP1 pathway, which could provide evidence for future research on prevention and treatment of TBI.

Neuroprotective Role of Selenium Nanoparticles Against Behavioral, Neurobiochemical and Histological Alterations in Rats Subjected to Chronic Restraint Stress

Chronic stress induces changes in the prefrontal cortex and hippocampus. Selenium nanoparticles (SeNPs) showed promising results in several neurological animal models. The implementation of SeNPs in chronic restraint stress (CRS) remains to be elucidated. This study was done to determine the possible protective effects of selenium nanoparticles on behavioral changes and brain oxidative stress markers in a rat model of CRS. 50 rats were divided into three groups; control group (n = 10), untreated CRS group (n = 10) and CRS-SeNPs treated group (n = 30). Restraint stress was performed 6 h./day for 21 days. Rats of CRS-SeNPs treated group received 1, 2.5 or 5 mg/kg SeNPs (10 rats each) by oral gavage for 21 days. Rats were subjected to behavioral assessments and then sacrificed for biochemical and histological analysis of the prefrontal cortex and hippocampus. Prefrontal cortical and hippocampal serotonin levels, oxidative stress markers including malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GPx), tumor necrosis factor alpha (TNF-α) and caspase-3 were assessed. Accordingly, different doses of SeNPs showed variable effectiveness in ameliorating disease parameters, with 2.5 mg/kg dose of SeNPs showing the best improving results in all studied parameters. The present study exhibited the neuroprotective role of SeNPs in rats subjected to CRS and proposed their antioxidant, anti-inflammatory and anti-apoptotic effects as the possible mechanism for increased prefrontal cortical and hippocampal serotonin level, ameliorated anxiety-like and depressive-like behaviors and improved prefrontal cortical and hippocampal histological architecture.

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.

Placental transcriptomic signatures of prenatal and preconceptional maternal stress

Prenatal exposure to maternal psychological stress is associated with increased risk for adverse birth and child health outcomes. Accumulating evidence suggests that preconceptional maternal stress may also be transmitted intergenerationally to negatively impact offspring. However, understanding of mechanisms linking these exposures to offspring outcomes, particularly those related to placenta, is limited. Using RNA sequencing, we identified placental transcriptomic signatures associated with maternal prenatal stressful life events (SLEs) and childhood traumatic events (CTEs) in 1 029 mother-child pairs in two birth cohorts from Washington state and Memphis, Tennessee. We evaluated individual gene-SLE/CTE associations and performed an ensemble of gene set enrichment analyses combing across 11 popular enrichment methods. Higher number of prenatal SLEs was significantly (FDR < 0.05) associated with increased expression of ADGRG6, a placental tissue-specific gene critical in placental remodeling, and decreased expression of RAB11FIP3, an endocytosis and endocytic recycling gene, and SMYD5, a histone methyltransferase. Prenatal SLEs and maternal CTEs were associated with gene sets related to several biological pathways, including upregulation of protein processing in the endoplasmic reticulum, protein secretion, and ubiquitin mediated proteolysis, and down regulation of ribosome, epithelial mesenchymal transition, DNA repair, MYC targets, and amino acid-related pathways. The directional associations in these pathways corroborate prior non-transcriptomic mechanistic studies of psychological stress and mental health disorders, and have previously been implicated in pregnancy complications and adverse birth outcomes. Accordingly, our findings suggest that maternal exposure to psychosocial stressors during pregnancy as well as the mother's childhood may disrupt placental function, which may ultimately contribute to adverse pregnancy, birth, and child health outcomes.

Microbiota-Induced Epigenetic Alterations in Depressive Disorders Are Targets for Nutritional and Probiotic Therapies

Major depressive disorder (MDD) is a complex disorder and a leading cause of disability in 280 million people worldwide. Many environmental factors, such as microbes, drugs, and diet, are involved in the pathogenesis of depressive disorders. However, the underlying mechanisms of depression are complex and include the interaction of genetics with epigenetics and the host immune system. Modifications of the gut microbiome and its metabolites influence stress-related responses and social behavior in patients with depressive disorders by modulating the maturation of immune cells and neurogenesis in the brain mediated by epigenetic modifications. Here, we discuss the potential roles of a leaky gut in the development of depressive disorders via changes in gut microbiota-derived metabolites with epigenetic effects. Next, we will deliberate how altering the gut microbiome composition contributes to the development of depressive disorders via epigenetic alterations. In particular, we focus on how microbiota-derived metabolites such as butyrate as an epigenetic modifier, probiotics, maternal diet, polyphenols, drugs (e.g., antipsychotics, antidepressants, and antibiotics), and fecal microbiota transplantation could positively alleviate depressive-like behaviors by modulating the epigenetic landscape. Finally, we will discuss challenges associated with recent therapeutic approaches for depressive disorders via microbiome-related epigenetic shifts, as well as opportunities to tackle such problems.

Meloxicam Targets COX-2/NOX1/NOX4/Nrf2 Axis to Ameliorate the Depression-like Neuropathology Induced by Chronic Restraint Stress in Rats

Meloxicam has shown significant neuroprotection in experimental models of stroke, Alzheimer's disease, and Parkinson's disease. However, the potential of meloxicam to treat depression-like neuropathology in a chronic restraint stress (CRS) model and the associated molecular changes has been insufficiently explored. The current work aimed to explore the potential neuroprotective actions of meloxicam against CRS-evoked depression in rats. In the current experiments, animals received meloxicam (10 mg/kg/day; i.p.) for 21 days, and CRS was instigated by restraining the animals for 6 h/day during the same period. The sucrose preference test and the forced swimming test were used to explore the depression-linked anhedonia/despair, whereas the open-field test examined the animals' locomotor activity. The current findings revealed that CRS elicited typical depression behavioral anomalies in the animals, including anhedonia, despair, and diminished locomotor activity; these findings were reinforced with Z-normalization scores. These observations were corroborated by brain histopathological changes and increased damage scores. In CRS-exposed animals, serum corticosterone spiked, and the hippocampi revealed decreased monoamine neurotransmitter levels (norepinephrine, serotonin, and dopamine). Mechanistically, neuroinflammation was evident in stressed animals, as shown by elevated hippocampal TNF-α and IL-1β cytokines. Moreover, the hippocampal COX-2/PGE₂ axis was activated in the rats, confirming the escalation of neuroinflammatory events. In tandem, the pro-oxidant milieu was augmented, as seen by increased hippocampal 8-hydroxy-2'-deoxyguanosine alongside increased protein expression of the pro-oxidants NOX1 and NOX4 in the hippocampi of stressed animals. In addition, the antioxidant/cytoprotective Nrf2/HO-1 cascade was dampened, as evidenced by the lowered hippocampal protein expression of Nrf2 and HO-1 signals. Interestingly, meloxicam administration mitigated depression manifestations and brain histopathological anomalies in the rats. These beneficial effects were elicited by meloxicam's ability to counteract the corticosterone spike and hippocampal neurotransmitter decrease while also inhibiting COX-2/NOX1/NOX4 axis and stimulating Nrf2/HO-1 antioxidant pathway. Together, the present findings prove the neuroprotective/antidepressant actions of meloxicam in CRS-induced depression by ameliorating hippocampal neuroinflammation and pro-oxidant changes, likely by modulating COX-2/NOX1/NOX4/Nrf2 axis.

Chronic Restraint Stress Alters Rat Behavior Depending on Sex and Duration of Stress

Chronic restraint stress (CRS) can have different behavioral effects depending on variables associated with the stressor and the organism. This study aimed to verify the effect of the interaction between sex and duration of the CRS protocol in rats. Sprague-Dawley rats were divided by sex, intervention (CRS; control), and CRS duration (11 days; 22 days). Rats exposed to CRS showed better spatial learning than controls in the Morris water maze test, regardless of sex and stress duration. Males exposed to CRS for 11 days showed a higher rate of behaviors associated with anxiety than males exposed to 22 days of CRS at the elevated plus maze test, but the same was not observed in females. The weight gain of animals exposed to stress decreased in the first 11 days, showing a recovery from day 11 to day 22 of intervention. No effects of CRS were observed on behaviors associated with depression in the sucrose preference test. The results suggest habituation to the protocol, with a progressive decrease in the harmful effects of stress on and maintenance of the beneficial effects. It is possible that females are more resistant to the harmful effects of CRS on anxiety.

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.

Modulation of the endoplasmic reticulum stress and unfolded protein response mitigates the behavioral effects of early-life stress

BACKGROUND

Early-life stress (ELS) affects brain development and increases the risk of mental disorders associated with the dysfunction of the medial prefrontal cortex (mPFC). The mechanisms of ELS action are not well understood. Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are cellular processes involved in brain maturation through the regulation of pro-survival or proapoptotic processes. We hypothesized that ER stress and the UPR in the mPFC are involved in the neurobiology of ELS.

METHODS

We performed a maternal separation (MS) procedure from postnatal days 1 to 14 in rats. Before each MS, pups were injected with an inhibitor of ER stress, salubrinal or a vehicle. The mRNA and protein expression of UPR and apoptotic markers were evaluated in the mPFC using RT-qPCR and Western blot methods, respectively. We also estimated the numbers of neurons and glial cells using stereological methods. Additionally, we assessed behavioral phenotypes related to fear, anhedonia and response to psychostimulants.

RESULTS

MS slightly enhanced the activation of the UPR in juveniles and modulated the expression of apoptotic markers in juveniles and preadolescents but not in adults. Additionally, MS did not affect the numbers of neurons and glial cells at any age. Both salubrinal and vehicle blunted the expression of UPR markers in juvenile and preadolescent MS rats, often in a treatment-specific manner. Moreover, salubrinal and vehicle generally alleviated the behavioral effects of MS in preadolescent and adult rats.

CONCLUSIONS

Modulation of ER stress and UPR processes may potentially underlie susceptibility or resilience to ELS.

Targeting the Endoplasmic Reticulum Stress-Linked PERK/GRP78/CHOP Pathway with Magnesium Sulfate Attenuates Chronic-Restraint-Stress-Induced Depression-like Neuropathology in Rats

Magnesium sulfate has demonstrated marked neuroprotection in eclampsia, hypoxia, stroke, and post-traumatic brain injury rodent models. However, its potential impact against chronic-restraint-stress (CRS)-induced depression-like neuropathology and associated alterations in endoplasmic reticulum (ER) stress have not been adequately examined. The present study aimed to investigate the neuroprotective potential of magnesium sulfate in a rat model of CRS-triggered depression-like behavioral disturbance and the underlying molecular mechanisms. Herein, CRS was induced by placing rats into restraining tubes for 6 h/day for 21 days and the animals were intraperitoneally injected with magnesium sulfate (100 mg/kg/day) during the study period. After stress cessation, the depression-like behavior was examined by the open-field test, sucrose preference test, and forced swimming test. The present data demonstrated that CRS triggered typical depression-like behavioral changes which were confirmed by the Z-normalization scores. Mechanistically, serum circulating corticosterone levels spiked, and the hippocampi of CRS-exposed animals demonstrated a significant decline in serotonin, norepinephrine, and dopamine neurotransmitters. At the molecular level, the hippocampal pro-inflammatory TNF-alpha and IL-1β cytokines and the oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-HG) increased in stressed animals. In tandem, enhancement of hippocampal ER stress was evidenced by the activation of iNOS/PERK/GRP78/CHOP axis seen by increased protein expression of iNOS, PERK, GRP78, and CHOP signal proteins in the hippocampi of stressed rats. Interestingly, magnesium sulfate administration attenuated the depression-like behavioral outcomes and the histopathological changes in the brain hippocampi. These favorable actions were driven by magnesium sulfate's counteraction of corticosterone spike, and hippocampal neurotransmitter decline, alongside the attenuation of neuroinflammation, pro-oxidation, and ER stress. In conclusion, the current results suggest the promising neuroprotective/antidepressant actions of magnesium sulfate in CRS by dampening inflammation, ER stress, and the associated PERK/GRP78/CHOP pathway.

Transcriptome-wide analysis reveals the molecular mechanisms of cannabinoid type II receptor agonists in cardiac injury induced by chronic psychological stress

Background: Growing evidence has supported that chronic psychological stress would cause heart damage, However the mechanisms involved are not clear and effective interventions are insufficient. Cannabinoid type 2 receptor (CB2R) can be a potential treatment for cardiac injury. This study is aimed to investigate the protective mechanism of CB2R agonist against chronic psychological stress-induced cardiac injury. Methods: A mouse chronic psychological stress model was constructed based on a chronic unpredictable stress pattern. Mice were performed a three-week psychological stress procedure, and cardiac tissues of them were collected for whole-transcriptome sequencing. Overlap analysis was performed on differentially expressed mRNAs (DE-mRNAs) and ER stress-related genes (ERSRGs), and bioinformatic methods were used to predict the ceRNA networks and conduct pathway analysis. The expressions of the DE-ERSRGs were validated by RT-qPCR. Results: In the comparison of DE mRNA in Case group, Control group and Treatment group, three groups of ceRNA networks and ceRNA (circ) networks were constructed. The DE-mRNAs were mainly enriched in chromatid-relevant terms and Hematopoietic cell lineage pathway. Additionally, 13 DE-ERSRGs were obtained by the overlap analysis, which were utilized to establish a ceRNA network with 15 nodes and 14 edges and a ceRNA (circ) network with 23 nodes and 28 edges. Furthermore, four DE-ERSRGs (Cdkn1a, Atf3, Fkbp5, Gabarapl1) in the networks were key, which were mainly enriched in response to extracellular stimulus, response to nutrient levels, cellular response to external stimulus, and FoxO signaling pathway. Finally, the RT-qPCR results showed almost consistent expression patterns of 13 DE-ERSRGs between the transcriptome and tissue samples. Conclusion: The findings of this study provide novel insights into the molecular mechanisms of chronic psychological stress-induced cardiac diseases and reveal novel targets for the cardioprotective effects of CB2R agonists.

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.

Antidepressant-Like Effects of Edaravone and Minocycline: Investigation of Oxidative Stress, Neuroinflammation, Neurotrophic, and Apoptotic Pathways

Depression is a very common mental disorder and mechanism that is associated with mitochondrial dysfunction. In the present study, we examined the mechanisms of action of isolated brain mitochondria in rats with depression for the first time. This will help identify the mitochondrial protective pathways of the two drugs and shed light on new therapeutic goals for developing antidepressants. Forced swimming, tail suspension, and sucrose preference tests were used to assess depressive-like behaviors and the oxidative stress factors of brain tissue, and measure the gene expression of apoptotic and anti-apoptotic, neuroplasticity, and neuroinflammatory factors by RT-PCR and acetylcholinesterase (AChE) activity in brain tissue (hippocampus and prefrontal) and the serum levels of corticosterone and fasting blood sugar. The results showed that the separation of neonatal rats from their mothers induced depressive-like behaviors, weight loss, mitochondrial dysfunction, increased expression of genes involved in neuroinflammation, apoptosis, genes involved in the depressive process, and decreased expression of genes involved in mood in both the hippocampus and prefrontal cortex. Maternal separation increased serum corticosterone levels, caused dysfunction of the cholinergic system, and also increased AChE activity. Treatment with different concentrations of minocycline and edaravone (1, 20, and 50 mg/kg), 5MTHF, and citalopram for 14 days showed that these drugs improved depression-like behaviors and mitochondrial function. It also reduced the expression of genes involved in neuroinflammation, apoptosis, and depression and increased the expression of genes involved in mood. In conclusion, minocycline and edaravone have neuroprotective, mitochondrial protective, antioxidant, anti-inflammatory, and anti-apoptotic effects against depressive-like behaviors caused by chronic stress.

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.

Systematic metabolic characterization of mental disorders reveals age-related metabolic disturbances as potential risk factors for depression in older adults

Mental disorders are associated with dysregulated metabolism, but comprehensive investigations of their metabolic similarities and differences and their clinical relevance are few. Here, based on the plasma metabolome and lipidome of subcohort1, comprising 100 healthy participants, 55 cases with anxiety, 52 persons with depression, and 41 individuals with comorbidity, which are from WCHAT, a perspective cohort study of community-dwelling older adults aged over 50, multiple metabolites as potential risk factors of mental disorders were identified. Furthermore, participants with mental illnesses were classified into three subtypes (S1, S2, and S3) by unsupervised classification with lipidomic data. Among them, S1 showed higher triacylglycerol and lower sphingomyelin, while S2 displayed opposite features. The metabolic profile of S3 was like that of the normal group. Compared with S3, individuals in S1 and S2 had worse quality of life, and suffered more from sleep and cognitive disorders. Notably, an assessment of 6,467 individuals from the WCHAT showed an age-related increase in the incidence of depression. Seventeen depression-related metabolites were significantly correlated with age, which were validated in an independent subcohort2. Collectively, this work highlights the clinical relevance of metabolic perturbation in mental disorders, and age-related metabolic disturbances may be a bridge-linking aging and depressive.

Granulocyte Colony-Stimulating Factor Improved Core Symptoms of Autism Spectrum Disorder via Modulating Glutamatergic Receptors in the Prefrontal Cortex and Hippocampus of Rat Brains

Chronic neuroinflammation-induced anomalous glutamate receptor activation has been identified as one of the important factors in the pathogenesis of autism spectrum disorder (ASD). Thus, the current study was designed to elucidate the neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF), a haemopoietic growth factor, an anti-inflammatory, and a neuroprotectant to decipher the underlying mechanism(s) in the valproic acid (VPA)-induced experimental model of ASD. Experimentally, the ASD rat model was induced by a single dose of VPA (600 mg/kg; i.p.) on gestation day 12.5 to the pregnant female rats. After birth, pups were treated with vehicle, normal saline 0.9% i.p., risperidone (2.5 mg/kg; i.p.), and G-CSF (10, 35, and 70 μg/kg; i.p.) from postnatal day (PND) 23 to 43. All the groups were subjected to various developmental and behavior tests from birth. The rats were sacrificed on PND 55, and their brain was excised and processed for biochemical parameters (oxidative stress, inflammatory markers, BDNF), histological examination (H&E, Nissl staining), NMDA, and AMPA receptor expression by immunohistochemistry, western blot, and real-time polymerase chain reaction evaluation. Also, the possible interaction of the G-CSF with NMDA and AMPA receptors was evaluated using the in-silico method. The results of the study showed that in VPA-exposed rats, postnatal treatment of G-CSF rescued all the behavioral abnormalities, oxidative stress, and inflammatory parameters in a dose-dependent manner while risperidone did not show any significant results. The in-silico analysis showed the direct interaction of G-CSF with NMDA and AMPA receptors. The upregulated expression of NMDA and AMPA both in the prefrontal cortex as well as hippocampus was alleviated by G-CSF thereby validating its anti-inflammatory and excitoprotective properties. Thus, G-CSF demonstrated neuroprotection against the core symptoms of autism in the VPA-induced rodent model, making it a potential candidate for the treatment of ASD.

Arginine-Containing Peptides Derived from Walnut Protein Against Cognitive and Memory Impairment in Scopolamine-Induced Zebrafish: Design, Release, and Neuroprotection

The purpose of this study was to investigate the neuroprotective effect of Arg-containing peptides from walnut storage protein sequences in scopolamine-induced zebrafish and further to validate the potential neuroprotection of Arg-containing peptide enriched walnut hydrolysates prepared by in silico hydrolysis and controlled enzymatic release. Results showed that walnut derived Arg-containing peptides with high abundance and great bioactivity predicted by bioinformatics displayed potent neuroprotection in scopolamine-induced zebrafish, and regulation of neurotransmitter level and antioxidant enzyme activity might be the main target for Arg-containing peptides to exert neuroprotection. Notably, Arg-containing peptides (not free arginine) contributed greater neuroprotection, and the positive charge and cell-penetrating properties also affected their neuroprotection. Subsequently, Arg-containing peptides could be released efficiently from walnut protein following hydrolysis by trypsin, pepsin, papain, and thermolysin (bound arginine content: ranging from 110.43 ± 1.58 to 121.82 ± 1.02 mg/g). Among them, trypsin had excellent potential for releasing Arg-containing peptides in silico hydrolysis, and its hydrolysate was confirmed to have neuroprotective capacity, indicating that the combination of in silico hydrolysis and controlled enzymatic release might be an effective approach to obtain Arg-containing neuroprotective peptides.

Taurine ameliorates volatile organic compounds-induced cognitive impairment in young rats via suppressing oxidative stress, regulating neurotransmitter and activating NMDA receptor

Long-term exposure to volatile organic compounds (VOCs) in children leads to intellectual and cognitive impairment. Taurine is an essential nutritional amino acid for children, which can improve neurological development in children. However, the neuroprotective effect of taurine on VOCs-induced cognitive impairment in children remains unclear. The aim of this study was to investigate the neuroprotective effects of taurine on VOCs-induced cognitive impairment in young rats. The rats were nose-only exposed to VOCs for a period of 4 weeks to create a model of cognitive impairment, and 0.5% and 1% taurine in tap water were administered throughout the trial period, respectively. Our results showed that young rats adjusted the recovery of their physiological functions by voluntarily increasing the intake of taurine in tap water when exposed to excessive VOCs by inhalation. In addition, taurine enhanced grasp, shortened the latency period of escape, and improved the learning and memory function of young rats. Moreover, taurine decreased malondialdehyde (MDA), γ-aminobutyric acid (GABA), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Urea, Creatinine (CREA) and injury biomarker level, enhanced superoxide dismutase (SOD), reduced glutathione (GSH) and glutamic acid (Glu) activities, up-regulated the protein expression of brain derived neurotrophic factor (BDNF) and N-Methyl-d-aspartate receptor 1 (NMDAR1) in model rats, and in most of cases 1% but not 0.5%, ameliorated the defects induced by VOCs. Collectively, these findings suggested that taurine protected against VOCs-induced cognitive-behavioral impairment in young rats through inhibiting oxidative stress and regulating neurotransmitter homeostasis. In addition, taurine were capable of restoring abilities of learning and memory in young rats exposed to VOCs by activating the N-Methyl-d-aspartate (NMDA) receptor. The findings suggest taurine as a potential novel drug for the treatment of cognitive behavioral disorders in children.

Homotaurine ameriolates the core ASD symptomatology in VPA rats through GABAergic signalling: Role of GAD67

Dysregulated GABAergic signaling is reported in Autism Spectrum disorder (ASD). In the present study, we evaluated a GABA structural mimicker homotaurine (HT) via in-silico docking and investigated the therapeutic efficacy of this drug to ameliorate ASD symptoms in the valproic acid (VPA) rat model of ASD. For the in-vivo study, animals were divided into two groups [Normal control (NC, 0.9% saline; i.p) and disease control (VPA 600mg/kg; i.p)] on gestational day (GD) 12.5. Male pups from VPA-exposed mothers were further divided into five groups (n=6 in each group): disease control (DC, no-further treatment), standard treatment (risperidone (RES) 2.5mg/kg; i.p, consecutively from PND 23-43), HT (10, 25 and 50mg/kg; i.p, consecutively from PND 23-43). In in-silico studies, the binding pattern of homotaurine to GABA-A receptor was found similar to GABA with Tyr205, Glu155, Tyr157, Arg6, and Thr 130 as shared residues. In the in-vivo phase, the early developmental parameters (from PND 7-23) and behavioral parameters (from PND 43-54) were assessed. The offspring of the VPA exposed group exhibited significant (p<0.05) developmental delays, behavioral deficits [decreased sociability and social novelty (three-chamber sociability test), spatial memory (Morris water maze), increased stereotypy (self-grooming)], increased oxidative stress (decreased GSH, SOD, Catalase, and increased MDA), increased pro-inflammatory (IL-1β, 6, TNF-α) and decreased anti-inflammatory (IL-10) cytokines, Purkinje cell loss in the cerebellum and pyknosis in PFC (H/E, Nissil staining) and decreased GAD67 expression in the cerebellum (RT-PCR & immunohistochemistry). Compared to the DC, HT treatment (50mg/kg) was able to ameliorate the aberrant core behavioral deficits, decreased oxidative stress, decreased pro-inflammatory and increased anti-inflammatory cytokine profile with preservation of the Purkinje cell density in the cerebellum, decreased pyknosis in the prefrontal cortex and normalised the expression of GAD67. Thus, HT can be a useful therapeutic agent in ASD and requires further clinical evaluation.

Antidepressant-like effects of Rehmannioside A on rats induced by chronic unpredictable mild stress through inhibition of endoplasmic reticulum stress and apoptosis of hippocampus

Depression is one of the most prevalent psychiatric mood diseases worldwide, whose therapy is in urgent need of development. Although the neuroprotective effects of Rehmannioside A (Rea) have been demonstrated, its anti-depressive effect remains unclear. Here, a depression model was induced with chronic unpredictable mild stress (CUMS) in rats. The behavioral trails, including sucrose preference test, forced swim test and open field test were used to determine the success of the CUMS-induced model. The effect of Rea on the neuronal protection, apoptosis and endoplasmic reticulum stress (ERS) was evaluated by HE, NISSL, IF and TUNEL staining, and western blot assays. Mechanically, the MAPK signaling pathway-related proteins expressions were examined by western blot. The results showed that CUMS stimulation evoked a prominent reduction of rat body weight, sucrose preference, and numbers of crossing, rearing and grooming with the enhanced immobility times. Besides, CUMS exposure induced the nuclear shrinkage and damage, as well as the decreased ISSL⁺ numbers. Moreover, CUMS stimulation increased the relative protein expressions of Bax and Cleaved caspase-3 and the percent of TUNEL positive cells, and decreased the relative protein expressions of Bcl-2. Furthermore, CUMS exposure also increased the relative protein expression of GRP-78, XBP-1, ATF-6, ATF-4 and CHOP. However, the CUMS-induced changes of all these indicators were reversed with Rea introduction in a dose-dependent fashion. Mechanically, Rea supply observably antagonized the CUMS-induced the relative protein levels of p-p38/p-38, p-ERK1/2/ERK1/2 and p-JNK/JNK. Therefore, Rea attenuated depression through suppressing ERS and apoptosis in hippocampus of CUMS-induced rats involved in MAPK signaling.

Neuroprotective effect of the standardised extract of Bacopa monnieri (BacoMind) in valproic acid model of autism spectrum disorder in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bacopa monnieri (BM) is commonly employed in the Indian traditional system of medicines, i.e. Ayurveda as a memory booster, antioxidant, anti-inflammatory, antipyretic, analgesic, sedative and anti-epileptic for decades.

AIM OF THE STUDY

To evaluate the neuroprotective effect of Bacopa monnieri (BM) in experimental model of autism spectrum disorder (ASD) in Wistar rats and explore its mechanism of action.

MATERIALS AND METHODS

BacoMind, was evaluated for its neuroprotective effect in valproic acid (VPA) model of ASD. For in-vivo study, the pregnant female Wistar rats were divided in two groups; normal control (NC) and VPA group who received single dose of normal saline (0.9%) or 600 mg/kg dose of VPA respectively on gestation day (G.D) 12.5. After the birth, all pups were segregated according to the sex. All the male pups from the dams were divided into six groups: Group 1 (NC, treated with only 0.9% normal saline, group 2 (VPA, treated 600 mg/kg on G.D12.5 and normal saline from post natal day (PND) 23 to 43), group 3 (risperidone 2.5 mg/kg, PND 23 to 43) and groups 4, 5 and 6 (BM 20, 40, 80 mg/kg, PND 23 to 43). All experimental groups were subjected to batteries of behavior parameters (three chamber sociability test, Morris Water Maze, elevated plus maze, open field and rota rod test), biochemical parameters such as oxidative stress (GSH, SOD, Catalase, MDA), inflammatory cytokines (Il-1β, IL-6, IL-10, TNF-α), histopathological examination (cresyl violet staining) of hippocampus (HC) and prefrontal cortex (PFC) regions. Further, the mRNA as well as protein expression of AMPA receptor was evaluated using RT-PCR and western blot respectively to study the mechanism of neuroprotective effect of BM. The in-silico analysis followed evaluating the binding profile of different constituents of BacoMind with AMPA receptor.

RESULTS

The results of the in-vivo study indicated BM at 80 mg/kg ameliorated abnormal behavioral paradigms such as social deficits, repetitive behavior, learning and memory impairments, and motor coordination exhibited by the VPA model of ASD in rats. Furthermore, BM was found to have a significant anti-oxidant (increasing GSH, SOD, and catalase and decreasing MDA levels) and anti-inflammatory properties (decreasing IL-1β, 6, TNF- α). The histopathological score was also found to be significantly improved by BM in a dose dependent manner in both HC and PFC. In addition to this, the up-regulated mRNA as well as protein expression of AMPA receptor was significantly reduced by 80 mg/kg dose of BM in both HC and PFC. Further, the in-silico analysis of different constituents of BacoMind with AMPA receptor demonstrated that luteolin and apigenin showed good binding to both the competitive antagonist binding site, non-competitive antagonist binding site and allosteric modulator site while Bacosaponin C showed good binding to the non-competitive antagonist binding site.

CONCLUSION

The present study concluded that BM can be a potential candidate for ameliorating the ASD symptoms in rats and acts via modulating the up-regulated AMPA receptor expression.

Clinical Efficacy and Potential Mechanisms of Acupoint Stimulation Combined With Chemotherapy in Combating Cancer: A Review and Prospects

Although chemotherapy is the first-line treatment strategy for a variety of tumors, its side effects have limited its efficacy. This review summarizes the progress on the use of acupoint stimulation to combat chemotherapy-associated side effects, including chemotherapy-induced peripheral neuropathy (CIPN), cognitive impairment (CICI), and gastrointestinal toxicity (GI), as well as myelosuppression and immunosuppression. It was found that acupoint stimulation attenuated CIPN and GI by modulating the 5-hydroxytryptamine system in dorsal root ganglia, the dorsal horn of the spinal cord, and the duodenum by reducing oxidative stress and neuroinflammation. Acupoint stimulation also alleviated GI by activating vagal activity in the nucleus tractus solitarius and promoting the secretion of gastrointestinal neuropeptide hormones. Acupoint stimulation restored both bone marrow hematopoiesis and immune function to combat cancer. In addition, the combination of acupoint stimulation and chemotherapy could inhibit tumor growth by promoting tumor cell apoptosis and the enrichment of chemotherapeutic agents in tumor tissue and by modulating the tumor immune microenvironment and normalizing the vasculature. Multiple evidence also indicates that neuroimmune regulation may be involved in the effects of acupoint stimulation. In conclusion, the evidence suggests that acupoint stimulation can alleviate the side effects of chemotherapy and can also assist chemotherapeutic agents in inhibiting tumor growth, which expands the clinical application of acupoint stimulation in cancer treatment. However, more high-quality clinical studies are needed to confirm the clinical value of acupoint stimulation.

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.

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.

Forkhead Box 1(FoxO1) mediates psychological stress-induced neuroinflammation

OBJECTIVES

 Neuroinflammation plays a key role in cerebrovascular disease (CVD). Neuropsychiatric disorders appear to share an epidemiological association with inflammation, but the mechanisms are unclear. Forkhead box 1 (FoxO1) regulates inflammatory signaling in diabetes and cardiovascular diseases, but its role in psychological stress-induced neuroinflammation remains unknown. Therefore, we investigated the potential involvement of FoxO1 in repeated social defeat stress (RSDS)-induced neuroinflammation.

METHODS

 6-week-old male C57BL/6 J mice were randomly divided into RSDS or control groups. In the RSDS group, mice (18-22 g) were individually subjected to social defeat by an 8-week-old CD-1 mouse (28-32 g) for 10 min daily for 10 consecutive days. At 24 h after this 10-day process, corticosterone (CORT), epinephrine (EPI), hydrogen peroxide, and inflammatory factors (TNF-α, IL-6, IL-1β, and VCAM-1) from serum and brain tissues were assayed using ELISA, real-time PCR, and Western blot. Iba-1 was determined by immunofluorescence (IF), and FoxO1 siRNA was transfected into BV2 cells to further analyze the expression of inflammatory factors.

RESULTS

RSDS significantly increased the levels of TNF-α, IL-6, IL-1β, and VCAM-1 in the serum; it also increased both mRNA and protein expression of these in the brain. FoxO1 was significantly increased after stress, while its knockdown significantly suppressed stress-induced inflammation. Immunofluorescence demonstrated the activation of microglia in the setting of RSDS.

CONCLUSION

RSDS induced a measurable inflammatory response in the blood and brain, and FoxO1 was demonstrated in vitro to aggravate stress-induced inflammation.

Antidepressant-like Effects of Combined Fluoxetine and Zinc Treatment in Mice Exposed to Chronic Restraint Stress Are Related to Modulation of Histone Deacetylase

Chronic stress is the key factor contributing to the development of depressive symptoms. Chronic restraint stress (CRS) is well validated and is one of the most commonly used models to induce depressive-like behavior in rodents. The present study aimed to evaluate whether fluoxetine (FLU 5 mg/kg) and zinc (Zn 10mg/kg) given simultaneously induce a more pronounced antidepressant-like effect in the CRS model than both those compounds given alone. Behavioral assessment was performed using the tail suspension and splash tests (TST and ST, respectively). Furthermore, the effects of CRS, FLU and Zn given alone and combined treatment with FLU + Zn on the expression of proteins involved in the apoptotic, inflammatory, and epigenetic processes were evaluated in selected brain structures (prefrontal cortex, PFC; and hippocampus, Hp) using Western blot analysis or enzyme-linked immunosorbent assays (ELISA). The results obtained indicated that three hours (per day) of immobilization for 4 weeks induced prominent depressive symptoms that manifested as increased immobility time in the TST, as well as decreased number and grooming time in the ST. Behavioral changes induced by CRS were reversed by both FLU (5 and 10 mg/kg) or Zn (10 mg/kg). Zinc supplementation (10 mg/kg) slightly increases the effectiveness of FLU (5 mg/kg) in the TST. However, it significantly increased the activity of FLU in the ST compared to the effect induced by FLU and Zn alone. Biochemical studies revealed that neither CRS nor FLU and Zn given alone or in combined treatment alter the expression of proteins involved in apoptotic or inflammatory processes. CRS induced major alterations in histone deacetylase (HDAC) levels by increasing the level of HADC1 and decreasing the level of HADC4 in the PFC and Hp, decreasing the level of HADC6 in the PFC but increasing it in Hp. Interestingly, FLU + Zn treatment reversed CRS-induced changes in HDAC levels in the Hp, indicating that HDAC modulation is linked to FLU + Zn treatment and this effect is structure-specific.

Cellular Response to Unfolded Proteins in Depression

Despite many scientific studies on depression, there is no clear conception explaining the causes and mechanisms of depression development. Research conducted in recent years has shown that there is a strong relationship between depression and the endoplasmic reticulum (ER) stress. In order to restore ER homeostasis, the adaptive unfolded protein response (UPR) mechanism is activated. Research suggests that ER stress response pathways are continuously activated in patients with major depressive disorders (MDD). Therefore, it seems that the recommended drugs should reduce ER stress. A search is currently underway for drugs that will be both effective in reducing ER stress and relieving symptoms of depression.

Lipopolysaccharide exacerbates chronic restraint stress-induced neurobehavioral deficits: Mechanisms by redox imbalance, ASK1-related apoptosis, autophagic dysregulation

Major depressive disorder (MDD) is the foremost leading psychiatric illness prevailing around the globe. It usually exists along with anxiety and other clinical conditions (cardiovascular, cancer, neurodegenerative diseases, and infectious diseases). Chronic restraint stress (RS) and LPS-induce neurobehavioral alterations in rodent models however their interaction studies in association with the pathogenesis of MDD are still unclear. Therefore, the current study was aimed to investigate the LPS influence on chronic RS mediated redox imbalance, apoptosis, and autophagic dysregulation in the hippocampus (HIP) and frontal cortex (FC) of mice brain. Male Balb/c mice were exposed to 28 days consecutive stress (6h/day) with a single-dose LPS challenge (0.83 mg/kg, i.p.) on the last day (Day 28). In addition, we also carried out separate study to understand physiological relevance, where we used the DSS (dextran sulfate sodium), a water soluble polysaccharide (negatively charged) and studied its influence on RS induced neurobehavioral and certain neurochemical anomalies. The obtained results in RS and RS + LPS animal groups showed significant immune dysfunction, depleted monoamines, lowered ATP & NAD level, elevated serum CORT level, serum and brain tissues IL-1β/TNF-α/IL-6, SOD activity but reduced CAT activity. Furthermore, the redox perturbation was found where significantly upregulated P-NFκB p65, Keap-1, Prx-SO3 and downregulated Nrf2, Srx1, Prx2 protein expression was seen in RS + LPS mice. The apoptosis signaling (P-ASK1, P-p38 MAPK, P-SAPK/JNK, cleaved PARP, cleaved Caspase-3, Cyto-C), autophagic impairment (p62, LC3II/I) were noticed in HIP and FC of RS and RS + LPS grouped animals. Our new findings provide a complex interplay of chemical (LPS) and physical (RS) stressors where both single dose LPS challenge and 3% DSS in drinking water (for 7 days) exaggerated chronic RS-induced inflammation, lowered redox status, increased apoptosis and dysregulated autophagy leading drastic neurobehavioral alterations in the mice.

A next-generation probiotic: Akkermansia muciniphila ameliorates chronic stress-induced depressive-like behavior in mice by regulating gut microbiota and metabolites

Major depressive disorder (MDD) is a neurasthenic disease, which is the second-largest burden of disease globally. Increasing studies have revealed that depression is associated with abnormalities in gut microbiota and metabolites. Several species of bacteria have been classified as psychobiotics, which confer mental health benefits through interactions with commensal gut microbiota. Therefore, it is essential to identify new psychobiotics and elucidate their mechanisms in the treatment of depression. This study aims to evaluate the antidepressant effect of Akkermansia muciniphila (AKK) in a mouse model of depression induced by chronic restraint stress (CRS). C57BL/6 male mice were divided into three groups: mice subjected to CRS, mice not subjected to CRS, and mice treated with AKK for 3 weeks. Behavioral tests were performed, and hormone, neurotransmitter, and brain-derived neurotrophic factor (BDNF) levels were measured. Cecal microbiota was analyzed using 16S rRNA gene sequencing, and serum metabolites were detected using untargeted metabolomics. In addition, correlations between altered gut microbiota and metabolites with significant variations in serum associated with AKK ameliorating depression were analyzed using Pearson's correlation coefficient. The results revealed that AKK significantly ameliorated depressive-like behavior and restored abnormal variations in depression-related molecular (corticosterone, dopamine, and BDNF). Moreover, AKK altered chronic stress-induced gut microbial abnormalities. Untargeted metabolomics analysis revealed 23 potential biomarkers in serum that could be associated with the mechanisms underlying CRS-induced depression and the therapeutic effects of AKK. Pearson's correlation coefficient analysis revealed that AKK predominantly upregulated β-alanyl-3-methyl-L-histidine and edaravone to relieve depression. Furthermore, β-alanyl-3-methyl-L-histidine and edaravone exhibited the antidepressant phenotype in mice subjected to CRS. In conclusion, the study demonstrated that AKK ameliorates chronic stress-induced depressive symptoms in mice by regulating gut microbiota and metabolites. KEY POINTS: • AKK reduces depressive-like behaviors induced by chronic stress. • AKK regulates the gut microbial structure and metabolomics of serum under the chronic stress. • Antidepressant effect of AKK correlates with the increase of β-alanyl-3-methyl-l-histidine and edaravone.

Kai-Xin-San Attenuates Doxorubicin-Induced Cognitive Impairment by Reducing Inflammation, Oxidative Stress, and Neural Degeneration in 4T1 Breast Cancer Mice

Objective

This study explored the potential therapeutic effect and possible mechanism of Kai-Xin-San (KXS) on doxorubicin-induced cognitive impairment in 4T1 breast cancer mice.

Methods

A model of chemotherapy-induced cognitive impairment (CICI) was established with the injection of doxorubicin (DOX, 5 mg/kg) at a 7-day interval in a 4T1 breast cancer mouse. KXS was given (1 g/kg) daily by gavage over three weeks starting at the first week while giving DOX. The Morris water maze task was performed to measure the CICI-like behaviors. Oxidative stress markers in the hippocampus, inflammatory cytokines in the serum and hippocampus, Nissl staining, immunofluorescence staining, and analysis for Glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 of the hippocampus were examined to explore the effect and mechanism of KXS on DOX-induced CICI. Meanwhile, tumor growth and survival time were tested in this study.

Results

CICI-like behaviors induced by DOX occurred earlier and were severer than the cognitive impairment induced by the tumor, and the effect of KXS on improving the cognitive impairment was obvious. KXS protected against DOX-induced neuroinflammation by decreasing levels of proinflammatory cytokines interleukin-6, interleukin-12p70, and tumor necrosis factor-alpha in both serum and brain and interleukin-1β in the brain, increasing the anti-inflammatory cytokines interleukin-4 in the serum and interleukin-10 in the hippocampus, and inhibiting the astrocytic hyperplasia and microglial polarization in the hippocampus. KXS reduced neural degeneration and protected against DOX-induced oxidative stress according to decreased malondialdehyde level, increased glutathione level, and enhanced activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, KXS recovered the lost body weights after DOX administration and prolonged the survival times of mice.

Conclusions

KXS may attenuate DOX-induced cognitive impairment by regulating inflammatory responses and reducing oxidative stress and neural degeneration. These findings also presented the role of KXS in improving the quality of life and prolonging survival time in breast cancer mice that received chemotherapy.

Chemical and Green ZnO nanoparticles ameliorated adverse effects of cisplatin on histological structure, antioxidant defense system and neurotrophins expression in rat hippocampus

Cisplatin (CP) is a chemotherapy agent used in the treatment of cancer, but it has various side effects, in particular, neurotoxicity. Zinc oxide nanoparticles (ZnO NPs) are a potent antioxidant. However, there is limited knowledge about the protective effects of ZnO NPs against CP-induced hippocampal toxicity. The present study aimed to explore the potential protective effects of ZnO NPs against CP-induced oxidative stress, loss of neurotrophins support, and tissue damage in the hippocampus of the rats. Eighty adult male Wistar rats were dividing into ten groups including: control (Con), sham, ZnO Bulk (ZnB), chemical ZnO NPs (ChZnO NPs), Green ZnO NPs (GrZnO NPs), CP, CP + ZnB, CP + ChZnO NPs, CP + GrZnO NPs and CP + AE. CP was administrated (5 mg/kg/weekly) for four weeks, and animals were treated simultaneously with different forms of ZnO (5 mg/kg/day). At the end of the experiment, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA), changes of reduced glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG ratio, histological changes, expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) genes were assessed in the hippocampus. The results revealed that a decrease in BDNF and NGF mRNA expression, GSH concentration and GSH/GSSG ratio, increasing of GSSG and MDA levels, and neuronal loss in the CP-treated rats were reversed following the administration of different forms of ZnO, especially Gr ZnO NPs and ch ZnO NPs. Co-administration of ZnO NPs to CP-treated rats restored the suppressive effects of CP on activities of antioxidant enzymes (SOD, GPX, CAT). The results showed that in most of the evaluated factors, Gr ZnO NPs showed a greater protective effect than other forms of ZnO. The results suggest that ZnO NPs, in particular Green ZnO NPs (GrZnO NPs) had more potential protective effects against CP-induced oxidative stress, inadequate support neurotrophin and tissue damage in rat hippocampus.

Inhibition of the ERK1/2 Phosphorylation by Dextromethorphan Protects against Core Autistic Symptoms in VPA Induced Autistic Rats: In Silico and in Vivo Drug Repurposition Study

The imbalance between excitatory and inhibitory neurotransmitters is explicitly related to the pathophysiology of autism spectrum disorder (ASD). The role of an NMDA receptor antagonist, dextromethorphan, was studied in ameliorating the ASD-like symptoms by regulating the excitatory and inhibitory imbalance using the valproic acid (VPA) model of ASD. Female Wistar rats were administered VPA [600 mg/kg on embryonic day ED-12.5] through intraperitoneal (ip) injection to induce ASD in pups. Autistic pups were then given dextromethorphan (10, 15, and 30 mg/kg; ip) and risperidone (2.5 mg/kg; ip) from PND 23 to 43 in different groups. Behavioral tests (three chamber sociability, self-grooming, Morris water maze, elevated plus maze, open field, rotarod, grip strength), oxidative stress and inflammatory markers, histological evaluation (H&E, Nissil staining), and NMDA and ERK1/2 expression by immunohistochemistry and RT-PCR were done. The in silico modeling of dextromethorphan against PPDA, TCN-201, MK-22, EVT-101 on NMDA receptors was also performed. Dextromethorphan (30 mg/kg) rescued the impaired behavioral patterns including social excitability, hyperactivity, repetitive and restricted behaviors as well as mitigation of the memory and motor coordination. The levels of various oxidative stress markers (GSH, SOD, catalase, MDA) and inflammatory markers (IL-1β, IL-6, IL-10, TNF-α) were ameliorated by different doses of dextromethorphan. It also reduced the neuronal injury score and rescued the overly expressed pERK1/2 and NMDA signaling in both the prefrontal cortex and hippocampus of the autistic pups. In silico results showed favorable binding of dextromethorphan against TCN-201 and MK-22 binding sites. The present study provided experimental evidence for the potential therapeutic role of dextromethorphan in attenuating autism symptomatology in the ASD model of rats. Thus, modulation of the glutamatergic signaling can be a potential target for ASD treatment.

Adiponectin Mediates the Protection of H2S Against Chronic Restraint Stress-Induced Cognitive Impairment via Attenuating Hippocampal Damage

Emerging evidence shows that chronic restraint stress (CRS) can induce cognitive dysfunction, which involves in hippocampal damage. Our recent research reveals that hydrogen sulfide (H2S), a novel gasotransmitter, protects against CRS-induced cognitive impairment, but the underlying mechanism remains unclear. Adiponectin, the most abundant plasma adipokine, has been shown to elicit neuroprotective property and attenuate cognitive impairment. Hence, the present work was aimed to explore whether adiponectin mediates the protective effect of H2S on CRS-induced cognitive impairment by inhibiting hippocampal damage. Results found that administration of Anti-Acrp30, a neutralizing antibody of adiponectin, obviously reverses sodium hydrosulfide (NaHS, an exogenous H2S donor)-induced the inhibition on CRS-induced cognitive impairment according to Y-maze test, Novel object recognition (NOR) test, and Morris water maze (MWM) test. In addition, Anti-Acrp30 blocked the protective effect of NaHS on hippocampal apoptosis in rats-subjected with CRS as evidenced by the pathological changes in hippocampus tissues in hematoxylin and eosin (HE) staining and the increases in the amount of the condensed and stained to yellowish-brown or brownish yellow neuron nucleuses in terminal deoxynucleotidyl transferase transfer-mediated dUTP nick end-labeling (TUNEL) staining as well as the expression of hippocampal pro-apoptotic protein (Bax), and a decrease in the expression of hippocampal anti-apoptotic protein (Bcl-2). Furthermore, Anti-Acrp30 mitigated the inhibitory effect of NaHS on CRS-induced oxidative stress as illustrated by the up-regulation of malondialdehyde (MDA) content and the down-regulation of superoxide dismutase (SOD) activity and glutathione (GSH) level in the hippocampus. Moreover, Anti-Acrp30 eliminated NaHS-induced the reduction of endoplasmic reticulum (ER) stress-related proteins including binding immunoglobulin protein (BIP), C/EBP homologous protein (CHOP), and Cleaved Caspase-12 expressions in the hippocampus of rats-exposed to CRS. Taken together, these results indicated that adiponectin mediates the protection of H2S against CRS-induced cognitive impairment through ameliorating hippocampal damage.

Edaravone alleviated propofol-induced neural injury in developing rats by BDNF/TrkB pathway

As a variety of free radical scavenger, edaravone has shown its potential in producing antioxidant, anti-inflammatory and neuroprotective effects in various disease models. However, the underlying mechanism behind the neuroprotective effects of edaravone remained unclear. This study is aimed at determining the effects of edaravone on neuroprotection and anti-inflammatory through a propofol-induced neural injury rat model. Firstly, an observation was made of apoptosis and neuroinflammation in the hippocampus of developing under the influence of propofol. It was found out that propofol could produce inflammatory effects in the hippocampus by enhancing the astrogliosis (GFAP) activation and elevating the level of neuronal nitric oxide synthase (nNOS), pro-inflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α). Meanwhile, the increase of apoptosis cells and the decrease of neurons (NeuN) were speculated to aggravate neural injury. Furthermore, it was demonstrated that edaravone intervention can reverse the neural apoptosis and inflammation. Additionally, the intraperitoneal injection of edaravone, the intraperitoneal injection of the brain-derived neurotrophic factor (BDNF)-mimicking small compound (7,8 dihydroxyflavone) and the intracranial injection of the exogenous BDNF were all respectively effective in alleviating the propofol-induced neural apoptosis and inflammation in the hippocampus. It was also found out that edaravone-activated downstream signalling through tyrosine kinase receptor B (TrkB) receptors in astrocyte, microglia and neuron. However, the neural injury of propofol had no impact on long-term learning and memory, except causing a short-term neurotoxicity. In conclusion, edaravone could alleviate the propofol-induced neural injury in developing rats through BDNF/TrkB pathway.

Chronic Voluntary Alcohol Drinking Causes Anxiety-like Behavior, Thiamine Deficiency, and Brain Damage of Female Crossed High Alcohol Preferring Mice

The central nervous system is vulnerable to chronic alcohol abuse, and alcohol dependence is a chronically relapsing disorder which causes a variety of physical and mental disorders. Appropriate animal models are important for investigating the underlying cellular and molecular mechanisms. The crossed High Alcohol Preferring mice prefer alcohol to water when given free access. In the present study, we used female cHAP mice as a model of chronic voluntary drinking to evaluate the effects of alcohol on neurobehavioral and neuropathological changes. The female cHAP mice had free-choice access to 10% ethanol and water, while control mice had access to water alone at the age of 60-day-old. The mice were exposed to alcohol for 7 months then subjected to neurobehavioral tests including open field (OF), elevated plus maze (EPM), and Morris water maze (MWM). Results from OF and EPM tests suggested that chronic voluntary drinking caused anxiety-like behaviors. After behavior tests, mice were sacrificed, and brain tissues were processed for biochemical analyses. Alcohol altered the levels of several neurotransmitters and neurotrophic factors in the brain including gamma-Aminobutyric acid (GABA), corticotropin-releasing factor, cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor. Alcohol increased the expression of neuroinflammation markers including interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) and C-C chemokine receptor 2 (CCR2). Alcohol also induced cleaved caspase-3 and glial fibrillary acidic protein, indicative of neurodegeneration and gliosis. In addition, alcohol inhibited the expression of thiamine transporters in the brain and reduced thiamine levels in the blood. Alcohol also caused oxidative stress and endoplasmic reticulum (ER) stress, and stimulated neurogenesis.

Differential Levels of Endoplasmic Reticulum Stress in Peripheral Blood Mononuclear Cells from Patients with Sudden Sensorineural Hearing Loss

Background

Sudden sensorineural hearing loss (SSNHL) is currently treated with a combination of drugs, predominantly with glucocorticoids (GCs). However, the mechanisms of action of GCs in SSNHL are unknown. This study aimed to analyze the role of endoplasmic reticulum stress (ERS) in SSNHL pathogenesis and prognosis.

Material/Methods

In this study, we evaluated the expression and activation status of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-C/EBP homologous protein (CHOP) pathway in peripheral blood mononuclear cells (PBMCs) from patients with SSNHL and compared them with those in healthy controls. We also compared differences in expression of activating transcription factor 4 (ATF4) and CHOP before and after glucocorticoid treatment in patients with improved and unimproved SSNHL.

Results

Treatment with GCs significantly improved hearing in 55% of patients with SSNHL. Levels of phosphorylated PERK (p-PERK) and phosphorylated eukaryotic initiation factor 2α were increased in PBMCs from patients with SSNHL compared with healthy controls. ATF4 and CHOP expression were also significantly elevated. After treatment, the amount of ATF4 and CHOP proteins in PBMCs in the patients whose SSNHL improved was significantly reduced compared with the levels measured before treatment in all patients with SSNHL. The expression of the ATF4 and CHOP proteins in PBMCs in the unimproved group, however, was not significantly changed relative to pretreatment levels.

Conclusions

ERS may play a significant role in the pathogenesis of SSNHL, and the responsiveness of the condition to GC-mediated mitigation of ERS may be one of the key factors that affect patient prognosis.

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.

Methylphenidate causes cytotoxicity on photoreceptor cells via autophagy

Methylphenidate (MPH) is used as the first-line treatment for attention-deficit hyperactivity disorder. However, there are concerns that this treatment may be associated with increased risk of retinal damage. This study was to investigate cytotoxicity of MPH on photoreceptor cells and explore its underlying mechanisms. MPH-caused cell toxicity was established in 661 W cells. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium-bromid and lactate dehydrogenase assays. Oxidative stress was measured by the markers: glutathione (GSH) reductase, catalase, and superoxide dismutase activities as well as GSH, reactive oxygen species, and malondialdehyde levels. Gene and protein expression was detected by real-time polymerase chain reaction (PCR) and western blot, respectively. Results showed that MPH decreased 661 W cell viability, increased caspase-3/9 activities, and induced oxidative stress. Furthermore, MPH treatment increased messenger RNA (mRNA) expression of Beclin-1 and microtubule-associated protein 1A/1B-light chain 3B (LC3B) protein expression in 661 W cells, suggesting autophagy was induced. MPH treatment also upregulated p-JAK1/p-STAT1 protein expression. These data demonstrated that MPH could increase oxidative stress in photoreceptor cells to cause cell toxicity via autophagy, providing the scientific rationale for the photoreceptor cell damage caused by the MPH administration.

Phenylbutyrate ameliorates prefrontal cortex, hippocampus, and nucleus accumbens neural atrophy as well as synaptophysin and GFAP stress in aging mice

Recent reports on brain aging suggest that oxidative stress and inflammatory processes contribute to aging. Interestingly, sodium phenylbutyrate (PBA) is an inhibitor of histone deacetylase, which has anti-inflammatory properties. Several reports have suggested the effect of PBA on learning and memory processes, however there are no studies of the effect of this inhibitor of histone deacetylase on aging. Consequently, in the present study, the effect of PBA was studied in 18-month-old mice. The animals were administered PBA for 2 months after locomotor activity treatment and Morris water maze tests were performed. The Golgi-Cox staining technique and immunohistochemistry for glial fibrillary acidic protein (GFAP) and synaptophysin were performed for the morphological procedures. The administration of PBA improves learning and memory according to the Morris water maze test compared to vehicle-treated animals, which had unchanged locomotor activity. Using Golgi-Cox staining, dendritic length and the number of dendritic spines were measured in limbic regions, such as the nucleus accumbens (NAcc), prefrontal cortex (PFC) layer 3, and the CA1 of the dorsal hippocampus. In addition, PBA increased the number of dendritic spines in the PFC, NAcc, and CA1 subregions of the hippocampus with an increase in dendritic length only in the CA1 region. Moreover, PBA reduced the levels of the GFAP and increased the levels of synaptophysin in the studied regions. Thus, PBA can be a useful pharmacological tool to prevent or delay synaptic plasticity damage and cognitive impairment caused by age.

Amelioration of Repeated Restraint Stress-Induced Behavioral Deficits and Hippocampal Anomalies with Taurine Treatment in Mice

Taurine, an essential neutraceutical, has been reported to exhibit antioxidant and anti-inflammatory properties. Substantial evidence indicates that prolonged stress is one of the leading causes of psychological and physiological anomalies. Restraint stress (RS) rat model is the most widely used experimental model for the induction of chronic psycho-emotional stress. In the present study, Swiss albino male mice were restrained for 6 h/day for 28 consecutive days. Animals were divided into four groups: control, RS, RS + taurine, and taurine control group. Taurine, a potent antioxidant, was administered (200 mg/kg) orally along with RS for 28 days. The taurine intervention significantly restored the RS-induced neurobehavioral alterations evident by the elevated plus-maze, Morris water maze test, forced swim test, tail suspension test, and a sucrose preference test. Moreover, taurine significantly prevented hippocampal oxidative stress (lipid peroxidation, reduced glutathione, and nitrite) and other neurochemical (acetylcholinesterase, and IL-1β) anomalies. Using western blotting analyses, we demonstrate that taurine treatment significantly ameliorated the alterations in Brain-derived neurotrophic factor, caspase-3, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) level in the hippocampus. Thus, Taurine effectively inhibited RS-induced oxidative stress, neuroinflammation, and apoptosis via a mechanism involving the inhibition of the NF-κB signaling pathway. In summary, our study is the first to demonstrate that NF-κB and caspase-3 inhibition, as well as BDNF augmentation, was involved in neuroprotective potential of taurine against RS-induced behavioural anomalies.