Melatonin salvages lead-induced neuro-cognitive shutdown, anxiety, and depressive-like symptoms via oxido-inflammatory and cholinergic mechanisms

Abnormal Porphyrin Metabolism in Autism Spectrum Disorder and Therapeutic Implications

Autism spectrum disorder (ASD) is a mosaic of neurodevelopmental conditions composed of early-onset social interaction and communication deficits, along with repetitive and/or restricted patterns of activities, behavior, and interests. ASD affects around 1% of children worldwide, with a male predominance. Energy, porphyrin, and neurotransmitter homeostasis are the key metabolic pathways affected by heavy metal exposure, potentially implicated in the pathogenesis of ASD. Exposure to heavy metals can lead to an altered porphyrin metabolism due to enzyme inhibition by heavy metals. Heavy metal exposure, inborn genetic susceptibility, and abnormal thiol and selenol metabolism may play a significant role in the urinary porphyrin profile anomalies observed in ASD. Altered porphyrin metabolism in ASD may also be associated with, vitamin B6 deficiency, hyperoxalemia, hyperhomocysteinemia, and hypomagnesemia. The present review considers the abnormal porphyrin metabolism in ASD in relation to the potential pathogenic mechanism and discusses the possible metabolic therapies such as vitamins, minerals, cofactors, and antioxidants that need to be explored in future research. Such targeted therapeutic therapies would bring about favorable outcomes such as improvements in core and co-occurring symptoms.

Melatonin Attenuates Arsenic-Induced Neurotoxicity in Rats Through the Regulation of miR-34a/miR-144 in Sirt1/Nrf2 Pathway

Arsenic (As) exposure is known to cause several neurological disorders through various molecular mechanisms such as oxidative stress, apoptosis, and autophagy. In the current study, we assessed the effect of melatonin (Mel) on As-induced neurotoxicity. Thirty male Wistar rat were treated daily for 28 consecutive days. As (15 mg/kg, gavage) and Mel (10 and 20 mg/kg, i.p.) were administered to rats. Morris water maze test was done to evaluate learning and memory impairment in training days and probe trial. Oxidative stress markers including MDA and GSH levels, SOD activity, and HO-1 levels were measured. Besides, the levels of apoptosis (caspase 3, Bax/Bcl2 ratio) and autophagy markers (Sirt1, Beclin-1, and LC3 II/I ratio) as well as the expression of miR-144 and miR-34a in cortex tissue were determined. As exposure disturbed learning and memory in animals and Mel alleviated these effects. Also, Mel recovered cortex pathological damages and oxidative stress induced by As. Furthermore, As increased the levels of apoptosis and autophagy proteins in cortex, while Mel (20 mg/kg) decreased apoptosis and autophagy. Also, Mel increased the expression of miR-144 and miR-34a which inhibited by As. In conclusion, Mel administration attenuated As-induced neurotoxicity through anti-oxidative, anti-apoptotic, and anti-autophagy mechanisms, which may be recommended as a therapeutic target for neurological disorders.

Alcohol exacerbates psychosocial stress-induced neuropsychiatric symptoms: Attenuation by geraniol

Adaptation to psychosocial stress is psychologically distressing, initiating/promoting comorbidity with alcohol use disorders. Emerging evidence moreover showed that ethanol (EtOH) exacerbates social-defeat stress (SDS)-induced behavioral impairments, neurobiological sequelae, and poor therapeutic outcomes. Hence, this study investigated the effects of geraniol, an isoprenoid monoterpenoid alcohol with neuroprotective functions on EtOH escalated SDS-induced behavioral impairments, and neurobiological sequelae in mice. Male mice chronically exposed to SDS for 14 days were repeatedly fed with EtOH (2 g/kg, p. o.) from days 8-14. From days 1-14, SDS-EtOH co-exposed mice were concurrently treated with geraniol (25 and 50 mg/kg) or fluoxetine (10 mg/kg) orally. After SDS-EtOH translational interactions, arrays of behavioral tasks were examined, followed by investigations of oxido-inflammatory, neurochemicals levels, monoamine oxidase-B and acetylcholinesterase activities in the striatum, prefrontal-cortex, and hippocampus. The glial fibrillary acid protein (GFAP) expression was also quantified in the prefrontal-cortex immunohistochemically. Adrenal weights, serum glucose and corticosterone concentrations were measured. EtOH exacerbated SDS-induced low-stress resilience, social impairment characterized by anxiety, depression, and memory deficits were attenuated by geraniol (50 and 100 mg/kg) and fluoxetine. In line with this, geraniol increased the levels of dopamine, serotonin, and glutamic-acid decarboxylase enzyme, accompanied by reduced monoamine oxidase-B and acetylcholinesterase activities in the prefrontal-cortex, hippocampus, and striatum. Geraniol inhibited SDS-EtOH-induced adrenal hypertrophy, corticosterone, TNF-α, IL-6 release, malondialdehyde and nitrite levels, with increased antioxidant activities. Immunohistochemical analyses revealed that geraniol enhanced GFAP immunoreactivity in the prefrontal-cortex relative to SDS-EtOH group. We concluded that geraniol ameliorates SDS-EtOH interaction-induced behavioral changes via normalization of neuroimmune-endocrine and neurochemical dysregulations in mice brains.

Dissecting the antidepressant effect of troxerutin: modulation of neuroinflammatory and oxidative stress biomarkers in lipopolysaccharide-treated mice

The role of neuroinflammation in the pathogenesis of depression has prompted the search for new antidepressants. Troxerutin, a bioflavonoid with anti-inflammatory and antioxidant properties, has shown promise, but its impact on neurobehavioral functions remains poorly understood. This study aimed to investigate the antidepressant potential of troxerutin and its effect on the neuroinflammatory response. Here, we exposed male Swiss mice (n = 5/group) to various treatments, including naive and negative controls receiving distilled water, troxerutin-treated groups administered at different doses (10, 20, 40 mg/kg, i.p.), and an imipramine-treated group (25 mg/kg, i.p.). After seven days of treatment, with the exception of the naive group, mice were administered a single dose of lipopolysaccharide (LPS, 0.83 mg/kg). Behavioral evaluations, consisting of the novelty-suppressed feeding (NSF) test, forced swim test (FST), and open field test (OFT), were conducted. Additionally, brain samples were collected for biochemical and immunohistochemical analyses. Troxerutin significantly reduced immobility time in the FST and mitigated behavioral deficits in the NSF test. Additionally, troxerutin increased glutathione (GSH) and superoxide dismutase (SOD) levels while reducing nitrite, malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interferon-gamma (IFN-γ) levels compared to the negative control. Immunohistochemistry analysis revealed decreased expression of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) in troxerutin-treated mice. Overall, these findings suggest that troxerutin exerts significant antidepressive-like effects, likely mediated by its anti-inflammatory and antioxidant mechanisms. The reduction in neuroinflammatory and oxidative stress biomarkers, along with the improvement in behavioral outcomes, underscores troxerutin's potential as a therapeutic agent for depression.

Unveiling the neuro-cognitive paradigm: a new approach to the treatment of anxiety: a comprehensive review

This study aimed to explore the neuro-cognitive paradigm in anxiety diseases by integrating neurobiological and cognitive perspectives. The ideal was to enhance our understanding of the complex interplay between neural and cognitive processes in anxiety and its counteraccusations for treatment. A comprehensive review of the literature was conducted, examining studies that delved into the neurobiological supplements and cognitive impulses in anxiety. The findings revealed the involvement of brain regions similar to the amygdala, prefrontal cortex, and hippocampus in anxiety diseases, along with dysregulation in neurotransmitter systems. Cognitive impulses, including attentional bias towards trouble, interpretation bias, and memory impulses, were constantly observed in individuals with anxiety. The results stressed the bidirectional relationship between neurobiology and cognition, demonstrating that neurobiological factors impact cognitive processes, and cognitive factors modulate neural exertion. Integrated interventions targeting both neurobiological and cognitive factors showed a pledge in treating anxiety diseases. The study linked gaps in the literature and emphasized the significance of considering artistic factors and developing individualized treatment approaches. Overall, this study contributes to a comprehensive understanding of anxiety diseases and informs unborn exploration and clinical practice.

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

Melatonin mitigates manganese-induced neural damage via modulation of gut microbiota-metabolism in mice

Manganese (Mn), a common environmental and occupational risk factor for Parkinson's disease (PD), can cause central nervous system damage and gastrointestinal dysfunction. The melatonin has been shown to effectively improve neural damage and intestinal microbiota disturbances in animal models. This research investigated the mechanism by which exogenous melatonin prevented Mn-induced neurogenesis impairment and neural damage. Here, we established subchronic Mn-exposed mice model and melatonin supplement tests to evaluate the role of melatonin in alleviating Mn-induced neurogenesis impairment. Mn induced neurogenesis impairment and microglia overactivation, behavioral dysfunction, gut microbiota dysbiosis and serum metabolic disorder in mice. All these events were reversed with the melatonin supplement. The behavioral tests revealed that melatonin group showed approximately 30 % restoration of motor activity. According to quantitative real time polymerase chain reaction (qPCR) results, melatonin group showed remarkable restoration of the expression of dopamine neurons and neurogenesis markers, approximately 46.4 % (TH), 68.4 % (DCX in hippocampus) and 48 % (DCX in striatum), respectively. Interestingly, melatonin increased neurogenesis probably via the gut microbiota and metabolism modulation. The correlation analysis of differentially expressed genes associated with hippocampal neurogenesis indicated that Firmicutes-lipid metabolism might mediate the critical repair role of melatonin in neurogenesis in Mn-exposed mice. In conclusion, exogenous melatonin supplementation can promote neurogenesis, and restore neuron loss and neural function in Mn-exposed mice, and the multi-omics results provide new research ideas for future mechanistic studies.

Melatonin improves maternal sleep deprivation-induced learning and memory impairment, inflammation, and synaptic dysfunction in murine male adult offspring

INTRODUCTION

Maternal sleep deprivation (MSD), which induces inflammation and synaptic dysfunction in the hippocampus, has been associated with learning and memory impairment in offspring. Melatonin (Mel) has been shown to have anti-inflammatory, antioxidant, and neuroprotective function. However, the beneficial effect of Mel on MSD-induced cognitive impairment and its mechanisms are unknown.

METHODS

In the present study, adult offspring suffered from MSD were injected with Mel (20 mg/kg) once a day during postnatal days 61-88. The cognitive function was evaluated by the Morris water maze test. Levels of proinflammatory cytokines were examined by enzyme-linked immunosorbent assay. The mRNA and protein levels of synaptic plasticity associated proteins were examined using reverse transcription-polymerase chain reaction and western blotting.

RESULTS

The results showed that MSD impaired learning and memory in the offspring mice. MSD increased the levels of interleukin (IL)-1creIL-6, and tumor necrosis factor-α and decreased the expression levels of brain-derived neurotrophic factor, tyrosine kinase receptor B, postsynaptic density protein-95, and synaptophysin in the hippocampus. Furthermore, Mel attenuated cognitive impairment and restored markers of inflammation and synaptic plasticity to control levels.

CONCLUSIONS

These findings indicated that Mel could ameliorate learning and memory impairment induced by MSD, and these beneficial effects were related to improvement in inflammation and synaptic dysfunction.

Using Small Molecules for Targeting Heavy Metals in Neurotoxicity and Neuroinflammation

Pharmaceutical drugs, natural toxins, industrial chemicals, and various environmental toxins negatively impact the nervous system. A significant cause of many neurodegenerative diseases is neurotoxicity. Although trace amounts of heavy metals are required for the proper functioning of several metabolic pathways, their dysregulation can cause many cellular and molecular alterations, which can enhance the risks associated with several neurodegenerative diseases. For example, high levels of heavy metals like manganese (Mn) affect the central nervous system with implications in both higher-order cognitive and motor functions. In addition, the buildup of amyloid aggregates and metal ions in the brain of patients with Alzheimer's disease is associated with disease pathogenesis. Small molecules capable of targeting neuroinflammation and neuroprotection pathways would be valuable to elucidate the pathological pathways associated with metal toxicity in neurogenerative disease. This chapter will summarize the necessary steps involved in (1) culturing of cell lines and maintenance of animal models, (2) design and preparation of samples of small molecules and treatment methodologies, (3) RNA and protein isolation and preparation of tissue and cell culture samples for quantitative studies, and (4) quantitative estimation of cellular products.

Early-Life Lead Exposure: Risks and Neurotoxic Consequences

BACKGROUND

Lead (Pb) does not have any biological function in a human, and it is likely no safe level of Pb in the human body. The Pb exposure impacts are a global concern for their potential neurotoxic consequences. Despite decreasing both the environmental Pb levels and the average blood Pb levels in the survey populations, the lifetime redistribution from the tissues-stored Pb still poses neurotoxic risks from the low-level exposure in later life. The growing fetus and children hold their innate high-susceptible to these Pb-induced neurodevelopmental and neurobehavioral effects.

OBJECTIVE

This article aims to evaluate cumulative studies and insights on the topic of Pb neurotoxicology while assessing the emerging trends in the field.

RESULTS

The Pb-induced neurochemical and neuro-immunological mechanisms are likely responsible for the high-level Pb exposure with the neurodevelopmental and neurobehavioral impacts at the initial stages. Early-life Pb exposure can still produce neurodegenerative consequences in later life due to the altered epigenetic imprints and the ongoing endogenous Pb exposure. Several mechanisms contribute to the Pb-induced neurotoxic impacts, including the direct neurochemical effects, the induction of oxidative stress and inflammation through immunologic activations, and epigenetic alterations. Furthermore, the individual nutritional status, such as macro-, micro-, or antioxidant nutrients, can significantly influence the neurotoxic impacts even at low-level exposure to Pb.

CONCLUSION

The prevention of early-life Pb exposure is, therefore, the critical determinant for alleviating various Pb-induced neurotoxic impacts across the different age groups.

Sesamin mitigates lead-induced behavioral deficits in male rats: The role of oxidative stress

Lead (Pb) is a well-known toxic pollutant that has negative effects on behavioral functions. Sesamin, a phytonutrient of the lignan class, has shown neuroprotective effects in various neurological disorder models. The present study was undertaken to evaluate the putative protective effects of sesamin against Pb-induced behavioral deficits and to identify the role of oxidative stress in male rats. The rats were exposed to 500 ppm of Pb acetate in their drinking water and simultaneously treated orally with sesamin at a dose of 30 mg/kg/day for eight consecutive weeks. Standard behavioral paradigms were used to assess the behavioral functions of the animals during the eighth week of the study. Subsequently, oxidative stress factors were evaluated in both the cerebral cortex and hippocampal regions of the rats. The results of this study showed that Pb exposure triggered anxiety-/depression-like behaviors and impaired object recognition memory, but locomotor activity was indistinguishable from the normal control rats. These behavioral deficiencies were associated with suppressed enzymatic and non-enzymatic antioxidant levels, and enhanced lipid peroxidation in the investigated brain regions. Notably, correlations were detected between behavioral deficits and oxidative stress generation in the Pb-exposed rats. Interestingly, sesamin treatment mitigated anxio-depressive-like behaviors, ameliorated object recognition memory impairment, and modulated oxidative-antioxidative status in the rats exposed to Pb. The results suggest that the anti-oxidative properties of sesamin may be one of the underlying mechanisms behind its beneficial effect in ameliorating behavioral deficits associated with Pb exposure.

Melatonin Prevents Depression but Not Anxiety-like Behavior Produced by the Chemotherapeutic Agent Temozolomide: Implication of Doublecortin Cells and Hilar Oligodendrocytes

Melatonin is a hormone synthesized by the pineal gland with neuroprotective and neurodevelopmental effects. Also, melatonin acts as an antidepressant by modulating the generation of new neurons in the dentate gyrus of the hippocampus. The positive effects of melatonin on behavior and neural development may suggest it is used for reverting stress but also for the alterations produced by chemotherapeutic drugs influencing behavior and brain plasticity. In this sense, temozolomide, an alkylating/anti-proliferating agent used in treating brain cancer, is associated with decreased cognitive functions and depression. We hypothesized that melatonin might prevent the effects of temozolomide on depression- and anxiety-like behavior by modulating some aspects of the neurogenic process in adult Balb/C mice. Mice were treated with temozolomide (25 mg/kg) for three days of two weeks, followed by melatonin (8 mg/kg) for fourteen days. Temozolomide produced short- and long-term decrements in cell proliferation (Ki67-positive cells: 54.89% and 53.38%, respectively) and intermediate stages of the neurogenic process (doublecortin-positive cells: 68.23% and 50.08%, respectively). However, melatonin prevented the long-term effects of temozolomide with the increased number of doublecortin-positive cells (47.21%) and the immunoreactivity of 2' 3'-Cyclic-nucleotide-3 phosphodiesterase (CNPase: 82.66%), an enzyme expressed by mature oligodendrocytes, in the hilar portion of the dentate gyrus. The effects of melatonin in the temozolomide group occurred with decreased immobility in the forced swim test (45.55%) but not anxiety-like behavior. Thus, our results suggest that melatonin prevents the harmful effects of temozolomide by modulating doublecortin cells, hilar oligodendrocytes, and depression-like behavior tested in the forced swim test. Our study could point out melatonin's beneficial effects for counteracting temozolomide's side effects.

Parkinson's Disease: A Narrative Review on Potential Molecular Mechanisms of Sleep Disturbances, REM Behavior Disorder, and Melatonin

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. There is a wide range of sleep disturbances in patients with PD, such as insomnia and rapid eye movement (REM) sleep behavior disorder (or REM behavior disorder (RBD)). RBD is a sleep disorder in which a patient acts out his/her dreams and includes abnormal behaviors during the REM phase of sleep. On the other hand, melatonin is the principal hormone that is secreted by the pineal gland and significantly modulates the circadian clock and mood state. Furthermore, melatonin has a wide range of regulatory effects and is a safe treatment for sleep disturbances such as RBD in PD. However, the molecular mechanisms of melatonin involved in the treatment or control of RBD are unknown. In this study, we reviewed the pathophysiology of PD and sleep disturbances, including RBD. We also discussed the potential molecular mechanisms of melatonin involved in its therapeutic effect. It was concluded that disruption of crucial neurotransmitter systems that mediate sleep, including norepinephrine, serotonin, dopamine, and GABA, and important neurotransmitter systems that mediate the REM phase, including acetylcholine, serotonin, and norepinephrine, are significantly involved in the induction of sleep disturbances, including RBD in PD. It was also concluded that accumulation of α-synuclein in sleep-related brain regions can disrupt sleep processes and the circadian rhythm. We suggested that new treatment strategies for sleep disturbances in PD may focus on the modulation of α-synuclein aggregation or expression.

Melatonin reduces β-amyloid accumulation and improves short-term memory in streptozotocin-induced sporadic Alzheimer's disease model

Melatonin is a hormone secreted by the pineal gland, it can be associated with circadian rhythms, aging and neuroprotection. Melatonin levels are decreased in sporadic Alzheimer's disease (sAD) patients, which suggests a relationship between the melatonergic system and sAD. Melatonin may reduce inflammation, oxidative stress, TAU protein hyperphosphorylation, and the formation of β-amyloid (Aβ) aggregates. Therefore, the objective of this work was to investigate the impact of treatment with 10 mg/kg of melatonin (i.p) in the animal model of sAD induced by the intracerebroventricular (ICV) infusion of 3 mg/kg of streptozotocin (STZ). ICV-STZ causes changes in the brain of rats similar to those found in patients with sAD. These changes include; progressive memory decline, the formation of neurofibrillary tangles, senile plaques, disturbances in glucose metabolism, insulin resistance and even reactive astrogliosis characterized by the upregulation of glucose levels and glial fibrillary acidic protein (GFAP). The results show that ICV-STZ caused short-term spatial memory impairment in rats after 30 days of STZ infusion without locomotor impairment which was evaluated on day 27 post-injury. Furthermore, we observed that a prolonged 30-day treatment with melatonin can improve the cognitive impairment of animals in the Y-maze test, but not in the object location test. Finally, we demonstrated that animals receiving ICV-STZ have high levels of Aβ and GFAP in the hippocampus and that treatment with melatonin reduces Aβ levels but does not reduce GFAP levels, concluding that melatonin may be useful to control the progression of amyloid pathology in the brain.

Ganoderma lucidum ethanol extract promotes weight loss and improves depressive-like behaviors in male and female Swiss mice

Metabolic and mood-related disturbances can increase the risks of developing adverse mental health problems. The medicinal mushroom, Ganoderma lucidum, is utilized in indigenous medicine to improve quality of life, promote health, and boost vitality. This study investigated the effects of Ganoderma lucidum ethanol extract (EEGL) on feeding behavioral parameters, depressive-like symptoms, and motor activity in Swiss mice. We hypothesized that EEGL would have beneficial effect on metabolic and behavioral outcomes in a dose-related manner. The mushroom was identified and authenticated via techniques of molecular biology. Forty Swiss mice (n = 10/group) of either sex were given distilled water (10 mL/kg) and graded doses of EEGL (100, 200, and 400 mg/kg) orally for 30 days, during which feed and water intake, body weight, neurobehavioral, and safety data were documented. The animals experienced a significant decrease in body weight gain and feed intake while water intake increased in a dose-dependent manner. Furthermore, EEGL significantly diminished immobility time in forced swim test (FST) and tail suspension test (TST). At the 100 and 200 mg/kg, EEGL did not cause significant alteration in motor activity in the open field test (OFT). Meanwhile, an increase in motor activity in male mice without remarkable difference in female mice was observed at the highest dose (400 mg/kg). Eighty percent of mice treated with 400 mg/kg survived till day 30. These findings suggest that EEGL at 100 and 200 mg/kg reduces the amount of weight gained and elicits antidepressant-like effects. Thus, EEGL might be useful for the management of obesity and depressive-like symptoms.

Neuroprotective efficacy of the bacterial metabolite, prodigiosin, against aluminium chloride-induced neurochemical alternations associated with Alzheimer's disease murine model: Involvement of Nrf2/HO-1/NF-κB signaling

Prodigiosin (PDG) is a bacterial metabolite with numerous biological and pharmaceutical properties. Exposure to aluminium is considered a root etiological factor in the pathological progress of Alzheimer's disease (AD). Here, in this investigation, we explored the neuroprotective potential of PDG against aluminium chloride (AlCl₃ )-mediated AD-like neurological alterations in rats. For this purpose, rats were gavaged either AlCl₃ (100 mg/kg), PDG (300 mg/kg), or both for 42 days. As a result of the analyzes performed on the hippocampal tissue, it was observed that AlCl₃ induced biochemical, molecular, and histopathological changes like those related to AD. PDG pre-treatment significantly decreased acetylcholinesterase activity and restored the levels of brain-derived neurotrophic factor, monoamines (dopamine, norepinephrine, and serotonin), and transmembrane protein (Na⁺ /K⁺ -ATPase). Furthermore, PDG boosted the hippocampal antioxidant capacity, as shown by the increased superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione contents. These findings were accompanied by decreases in malondialdehyde and nitric oxide levels. The antioxidant effect may promote the upregulation of the expression of antioxidant genes (Nrf2 and HO-1). Moreover, PDG exerted notable anti-inflammatory effects via the lessening of interleukin-1 beta, tumor necrosis factor-alpha, cyclooxygenase-2, nuclear factor kappa B, and decreases in the gene expression of inducible nitric oxide synthase. In addition, noteworthy decreases in pro-apoptotic (Bax and caspase-3) levels and increases in anti-apoptotic (Bcl-2) biomarkers suggested an anti-apoptotic effect of PDG. In support, the hippocampal histological examination validated the aforementioned changes. To summarize, the promising neuromodulatory, antioxidative, anti-inflammatory, and anti-apoptotic activities of PDG establish it as a potent therapeutic option for AD.

Mechanisms underpinning Carpolobia lutea G. Don ethanol extract's neurorestorative and antipsychotic-like activities in an NMDA receptor antagonist model of schizophrenia

ETHNOPHARMACOLOGICAL RELEVANCE

Persistent ketamine insults to the central nervous system block NMDA receptors and disrupt putative neurotransmission, oxido-nitrosative, and inflammatory pathways, resulting in schizophrenia-like symptoms in animals. Previously, the ethnomedicinal benefits of Carpolobia lutea against insomnia, migraine headache, and insanity has been documented, but the mechanisms of action remain incomplete.

AIM OF THE STUDY

Presently, we explored the neuro-therapeutic role of Carpolobia lutea ethanol extract (C. lutea) in ketamine-induced schizophrenia-like symptoms in mice.

MATERIALS AND METHODS

Sixty-four male Swiss (22 ± 2 g) mice were randomly assigned into eight groups (n = 8/group) and exposed to a reversal ketamine model of schizophrenia. For 14 days, either distilled water (10 mL/kg; p.o.) or ketamine (20 mg/kg; i.p.) was administered, following possible reversal treatments with C. lutea (100, 200, 400, and 800 mg/kg; p.o.), haloperidol (1 mg/kg, p.o.), or clozapine (5 mg/kg; p.o.) beginning on days 8-14. During the experiment, a battery of behavioral characterizations defining schizophrenia-like symptoms were obtained using ANY-maze software, followed by neurochemical, oxido-inflammatory and histological assessments in the mice brains.

RESULTS

A 7-day reversal treatment with C. lutea reversed predictors of positive, negative and cognitive symptoms of schizophrenia. C. lutea also mitigated ketamine-induced neurochemical derangements as evidenced by modulations of dopamine, glutamate, norepinephrine and serotonin neurotransmission. Also, the increased acetylcholinesterase activity, malondialdehyde nitrite, interleukin-6 and tumor necrosis-factor-α concentrations were reversed by C. lutea accompanied with elevated levels of catalase, superoxide dismutase and reduced glutathione. Furthermore, C. lutea reversed ketamine-induced neuronal alterations in the prefrontal cortex, hippocampus and cerebellum sections of the brain.

CONCLUSION

These findings suggest that C. lutea reverses the cardinal symptoms of ketamine-induced schizophrenia in a dose-dependent fashion by modulating the oxido-inflammatory and neurotransmitter-related mechanisms.

Pergularia tomentosa coupled with selenium nanoparticles salvaged lead acetate-induced redox imbalance, inflammation, apoptosis, and disruption of neurotransmission in rats’ brain

In this study, the neuroprotective potential of either Pergularia tomentosa leaf methanolic extract (PtE) alone or in combination with selenium nanoparticles (SeNPs-PtE) was investigated against lead acetate (PbAc)-induced neurotoxicity. Experimental rats were pretreated with PtE (100 mg/kg) or SeNPs-PtE (0.5 mg/kg) and injected intraperitoneally with PbAc (20 mg/kg) for 2 weeks. Notably, SeNPs-PtE decreased brain Pb accumulation and enhanced the level of dopamine and the activity of AChE compared to the control rats. In addition, elevated neural levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione along with decreased lipid peroxidation levels were noticed in pretreated groups with SeNPs-PtE. Moreover, SeNPs-PtE significantly suppressed neural inflammation, as indicated by lower levels of interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, nuclear factor-kappa B p65, and nitric oxide in the examined brain tissue. The molecular results also unveiled significant down-regulation in iNOS gene expression in the brains of SeNPs-PtE-treated rats. In addition, SeNPs-PtE administration counteracted the neural loss by increasing B-cell lymphoma 2 (Bcl-2) and brain-derived neurotrophic factor levels as well as decreasing BCL2-associated X protein and caspase-3 levels. To sum up, our data suggest that P. tomentosa extract alone or in combination with SeNPs has great potential in reversing the neural tissue impairment induced by PbAc via its antioxidant, anti-inflammatory, and anti-apoptotic activities. This study might have therapeutic implications in preventing and treating several lead-induced neurological disorders.

Melatonin Protects Against Titanium Oxide-Induced Neurotoxicity: Neurochemical, Neurobehavioral, and Histopathological Evidences

titania (titanium dioxide, TiO₂) is known to induce neurotoxicity and CNS dysfunctions. Numerous studies have explored the neuroprotective effects of melatonin against neurotoxicity. This study evaluates the potential of melatonin to protect against titania-induced neurotoxicity and the role of the Keap1/Nrf2/ARE signaling pathway. One group of animals were treated with Titania (0.045 and 0.075 g/rat) alone while the other with added melatonin (1 mg/kg and 3 mg/kg) and behavioral alterations were assessed using OFT (open field test). Neurochemical and histopathological changes were also studied in the hippocampus by analyzing kelch ECH associating protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). It was seen that the animals with added Melatonin had improved behavioral scores in the OFT, like anxiety and motor dysfunction triggered by TiO₂. Melatonin also reduced lipid peroxidation, ROS, GSSG, IL1β, TNFα, Bax, and Keap1 levels, but boosted GSH, GPx, GR, SOD,IL10,IL4, Bcl2, Nrf2, and ARE levels and improved quadruple mitochondrial enzyme complex activity in titania-treated animals. Histopathological examination showed melatonin induced cytoprotection against vacuolization and necrosis in granular cells of DG and pyramidal cells of CA1 area of the hippocampus. In our study, pretreatment with melatonin reduced titania-induced neurotoxicity in the hippocampus through a mechanism potentially mediated by the Keap-1/Nrf2/ARE pathway.

Pretreatment with Carpolobia lutea ethanol extract prevents schizophrenia-like behavior in mice models of psychosis

ETHNOPHARMACOLOGICAL RELEVANCE

Carpolobia lutea decoction is widely used as a phytotherapeutic against central nervous system-related disorders including insomnia, migraine headache, and mental illness in West and Central Tropical Africa.

AIM

This study was designed to investigate the antipsychotic activity of Carpolobia lutea (EECL) in mice models of psychosis.

METHODS

Male Swiss mice (n = 5/group) were given EECL (100, 200, 400, and 800 mg/kg), haloperidol (1 mg/kg), clozapine (5 mg/kg) and vehicle (10 mL/kg) orally before amphetamine (5 mg/kg)-induced hyperlocomotion and stereotypy, apomorphine (2 mg/kg)-induced stereotypy, or ketamine (10, 30, and 100 mg/kg)-induced hyperlocomotion, enhancement of immobility and cognitive impairment.

RESULTS

EECL (200, 400, and 800 mg/kg) prevented amphetamine- and apomorphine-induced stereotypies, as well as reduced hyperlocomotion induced by amphetamine and ketamine, all of which are predictors of positive symptoms. Regardless of the dose administered, EECL prevented the index of negative symptoms induced by ketamine. Furthermore, higher doses of EECL (400 and 800 mg/kg) also prevented ketamine-induced cognitive impairment, a behavioral phenotype of cognitive symptoms.

CONCLUSION

Pretreatment with EECL demonstrated antipsychotic activity in mice, preventing amphetamine-, apomorphine-, and ketamine-induced schizophrenia-like symptoms, with 800 mg/kg being the most effective dose.

Night shift hormone: How does melatonin affect depression?

Melatonin is the main hormone secreted by the pineal gland that modulates the circadian rhythm and mood. Previous studies have shown the therapeutic effects of melatonin, or its important analogue, agomelatine, on depression. In this review study, we aimed to discuss the potential mechanisms of melatonin involved in the treatment of depression. It was noted that disrupted circadian rhythm can lead to depressive state, and melatonin via regulating circadian rhythm shows a therapeutic effect. It was also noted that melatonin induces antidepressant effects via promoting antioxidant system and neurogenesis, and suppressing oxidative stress, neuroinflammation, and apoptosis. The interaction effect between melatonin or agomelatine and serotonergic signaling has a significant effect on depression. It was noted that the psychotropic effects of agomelatine are induced by the synergistic interaction between melatonin and 5-HT_2C receptors. Agomelatine also interacts with glutamatergic signaling in brain regions involved in regulating mood and circadian rhythm. Interestingly, it was concluded that melatonin exerts both pro- and anti-inflammatory effects, depending on the grade of inflammation. It was suggested that synergistic interaction between melatonin and 5-HT_2C receptors may be able to induce therapeutic effects on other psychiatric disorders. Furthermore, dualistic role of melatonin in regulating inflammation is an important point that can be examined at different levels of inflammation in animal models of depression.

Melatonin salvages lead-induced neuro-cognitive shutdown, anxiety, and depressive-like symptoms via oxido-inflammatory and cholinergic mechanisms

INTRODUCTION

Lead is the most used nonphysiological neurotoxic heavy metal in the world that has been indicated to interfere with the cognitive and noncognitive processes via numerous mechanisms. The neuroprotective effect of melatonin is well known, but the effect of its interaction with lead in the brain remains inconclusive.

OBJECTIVE

To assess the therapeutic role of melatonin on cognitive deficit, anxiety and depressive-like symptoms in matured male Wistar rats exposed to a subchronic lead chloride (PbCl₂ ).

METHODS

Twenty male Wistar rats were blindly randomized into four groups (n = 5/group): group 1 to 4 underwent intragastric administration of physiological saline (10 ml/kg; vehicle), PbCl₂ (50 mg/kg), melatonin (10 mg/kg) and PbCl₂ + melatonin respectively for a period of 4 weeks during which neurobehavioral data were extracted, followed by neurochemical and histopathological evaluations.

RESULTS

Exposure to PbCl₂ reduced cognitive performance by increasing the escape latency and average proximity to the platform zone border, decreasing average path length in the platform zone, cognitive score, and time spent in probing. It raised the thigmotaxis percentage, time spent in rearing, number of pellet-like feces, and time spent in the dark compartment of a bright/dark box which are predictors of anxiety. It also induced depressive-like behavior as immobility time was enhanced. PbCl₂ deranged neurochemicals; malondialdehyde, interlukin-1β, and tumor necrotic factor-α were increased while superoxide dismutase and acetylcholinesterase were decreased without remarkable alteration in reduced glutathione and nitric oxide. Administration of PbCl₂ further disrupted neuronal settings of hippocampal proper and dentate gyrus. In contrast, the supplementation of melatonin reversed all the neurological consequences of PbCl₂ neurotoxicity by eliciting its properties against oxidative and nonoxidative action of PbCl₂ .

CONCLUSION

These findings suggest that melatonin down-regulates neurotoxicant interplays in the brain systems. Therefore, this study suggests the use of melatonin as an adjuvant therapy in neuropathological disorders/dysfunctions.