Arbutus andrachne L. Reverses Sleep Deprivation-Induced Memory Impairments in Rats

Sleep Deprivation-Induced Oxidative Stress in Rat Models: A Scoping Systematic Review

Sleep deprivation is highly prevalent in the modern world, possibly reaching epidemic proportions. While multiple theories regarding the roles of sleep exist (inactivity, energy conservation, restoration, brain plasticity and antioxidant), multiple unknowns still remain regarding the proposed antioxidant roles of sleep. The existing experimental evidence is often contradicting, with studies pointing both toward and against the presence of oxidative stress after sleep deprivation. The main goals of this review were to analyze the existing experimental data regarding the relationship between sleep deprivation and oxidative stress, to attempt to further clarify multiple aspects surrounding this relationship and to identify current knowledge gaps. Systematic searches were conducted in three major online databases for experimental studies performed on rat models with oxidative stress measurements, published between 2015 and 2022. A total of 54 studies were included in the review. Most results seem to point to changes in oxidative stress parameters after sleep deprivation, further suggesting an antioxidant role of sleep. Alterations in these parameters were observed in both paradoxical and total sleep deprivation protocols and in multiple rat strains. Furthermore, the effects of sleep deprivation seem to extend beyond the central nervous system, affecting multiple other body sites in the periphery. Sleep recovery seems to be characterized by an increased variability, with the presence of both normalizations in some parameters and long-lasting changes after sleep deprivation. Surprisingly, most studies revealed the presence of a stress response following sleep deprivation. However, the origin and the impact of the stress response during sleep deprivation remain somewhat unclear. While a definitive exclusion of the influence of the sleep deprivation protocol on the stress response is not possible, the available data seem to suggest that the observed stress response may be determined by sleep deprivation itself as opposed to the experimental conditions. Due to this fact, the observed oxidative changes could be attributed directly to sleep deprivation.

Medicinal plants of Jordan: Scoping review

Jordan is rich in the flora of ethnobotanical importance. This scoping review aims to highlight the ethnopharmacological value of Jordanian medicinal plants using the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A total of one hundred twenty-four articles published between 2000 and 2022 obtained from PubMed, EBSCO, and Google Scholar databases were included in this review. These plants own several classes of secondary bioactive metabolites, including alkaloids, flavonoids, phenolics, and terpenes. Jordanian plants exhibited potential therapeutic activity against various tumors, bacterial infections, elevated blood glucose levels, hyperlipidemia, platelets aggregation disorders, and gastrointestinal disorders. Phytochemicals' biological activities depend on their structures, parts used, methods of extraction, and evaluation model. In conclusion, this review highlights the need of researching Jordan's abundant naturally occurring medicinal plants and their phytochemicals as novel lead molecules in drug discovery and development. Studying active phytochemicals for disease treatment will help develop drugs for safe treatment and cure in the future.

Do Sleep Disturbances have a Dual Effect on Alzheimer's Disease?

Sleep disturbances and Alzheimer's disease have deleterious effects on various physiological and cognitive functions including synaptic plasticity, oxidative stress, neuroinflammation, and memory. In addition, clock genes expression is significantly altered following sleep disturbances, which may be involved in the pathogenesis of Alzheimer's disease. In this review article, we aimed to discuss the role of sleep disturbances and Alzheimer's disease in the regulation of synaptic plasticity, oxidative stress, neuroinflammation, and clock genes expression. Also, we aimed to find significant relationships between sleep disturbances and Alzheimer's disease in the modulation of these mechanisms. We referred to the controversial effects of sleep disturbances (particularly those related to the duration of sleep deprivation) on the modulation of synaptic function and neuroinflammation. We aimed to know that, do sleep disturbances have a dual effect on the progression of Alzheimer's disease? Although numerous studies have discussed the association between sleep disturbances and Alzheimer's disease, the new point of this study was to focus on the controversial effects of sleep disturbances on different biological functions, and to evaluate the potential dualistic role of sleep disturbances in the pathogenesis of Alzheimer's disease.

Role of Oxidative Stress and Inflammation in Insomnia Sleep Disorder and Cardiovascular Diseases: Herbal Antioxidants and Anti-inflammatory Coupled with Insomnia Detection using Machine Learning

Insomnia is well-known as trouble in sleeping and enormously influences human life due to the shortage of sleep. Reactive Oxygen Species (ROS) accrue in neurons during the waking state, and sleep has a defensive role against oxidative damage and dissipates ROS in the brain. In contrast, insomnia is the source of inequity between ROS generation and removal by an endogenous antioxidant defense system. The relationship between insomnia, depression, and anxiety disorders damages the cardiovascular systems' immune mechanisms and functions. Traditionally, polysomnography is used in the diagnosis of insomnia. This technique is complex, with a long time overhead. In this work, we have proposed a novel machine learning-based automatic detection system using the R-R intervals extracted from a single-lead electrocardiograph (ECG). Additionally, we aimed to explore the role of oxidative stress and inflammation in sleeping disorders and cardiovascular diseases, antioxidants' effects, and the psychopharmacological effect of herbal medicine. This work has been carried out in steps, which include collecting the ECG signal for normal and insomnia subjects, analyzing the signal, and finally, automatic classification. We used two approaches, including subjects (normal and insomnia), two sleep stages, i.e., wake and rapid eye movement, and three Machine Learning (ML)-based classifiers to complete the classification. A total number of 3000 ECG segments were collected from 18 subjects. Furthermore, using the theranostics approach, the role of mitochondrial dysfunction causing oxidative stress and inflammatory response in insomnia and cardiovascular diseases was explored. The data from various databases on the mechanism of action of different herbal medicines in insomnia and cardiovascular diseases with antioxidant and antidepressant activities were also retrieved. Random Forest (RF) classifier has shown the highest accuracy (subjects: 87.10% and sleep stage: 88.30%) compared to the Decision Tree (DT) and Support Vector Machine (SVM). The results revealed that the suggested method could perform well in classifying the subjects and sleep stages. Additionally, a random forest machine learning-based classifier could be helpful in the clinical discovery of sleep complications, including insomnia. The evidence retrieved from the databases showed that herbal medicine contains numerous phytochemical bioactives and has multimodal cellular mechanisms of action, viz., antioxidant, anti-inflammatory, vasorelaxant, detoxifier, antidepressant, anxiolytic, and cell-rejuvenator properties. Other herbal medicines have a GABA-A receptor agonist effect. Hence, we recommend that the theranostics approach has potential and can be adopted for future research to improve the quality of life of humans.

Protective actions of nuclear factor erythroid 2-related factor 2 (NRF2) and downstream pathways against environmental stressors

Environmental risk factors, including noise, air pollution, chemical agents, ultraviolet radiation (UVR) and mental stress have a considerable impact on human health. Oxidative stress and inflammation are key players in molecular pathomechanisms of environmental pollution and risk factors. In this review, we delineate the impact of environmental risk factors and the protective actions of the nuclear factor erythroid 2-related factor 2 (NRF2) in connection to oxidative stress and inflammation. We focus on well-established studies that demonstrate the protective actions of NRF2 and its downstream pathways against different environmental stressors. State-of-the-art mechanistic considerations on NRF2 signaling are discussed in detail, e.g. classical concepts like KEAP1 oxidation/electrophilic modification, NRF2 ubiquitination and degradation. Specific focus is also laid on NRF2-dependent heme oxygenase-1 induction with detailed presentation of the protective down-stream pathways of heme oxygenase-1, including interaction with BACH1 system. The significant impact of all environmental stressors on the circadian rhythm and the interactions of NRF2 with the circadian clock will also be considered here. A broad range of NRF2 activators is discussed in relation to environmental stressor-induced health side effects, thereby suggesting promising new mitigation strategies (e.g. by nutraceuticals) to fight the negative effects of the environment on our health.

A comparative study of the effect of a gentle ketogenic diet containing medium-chain or long-chain triglycerides on chronic sleep deprivation-induced cognitive deficiency

The ketogenic diet (KD) is well known for its neuroprotective effect, but little is known about its prophylactic efficacy against chronic sleep deprivation (SD) induced cognitive deficiency. An emerging study indicated that ferroptosis plays an important role in neurologic diseases but has been rarely reported in chronic SD. Here, we investigated the prophylactic effects of a medium-chain triglyceride-enriched KD (MKD) and a long-chain triglyceride-enriched KD (LKD) on cognitive deficiency and revealed the underlying mechanism focused on ferroptosis in chronic SD model mice. The results showed that the MKD exhibited stronger effects than the LKD on improving cognitive deficiency via suppressing ferroptosis and improving synaptic plasticity. Further mechanism results indicated that MKD produced higher Sirt3 protein levels than LKD, which probably contributed to the synergistic effect of beta hydroxybutyric acid and decanoic acid. Our finds provide novel evidence for the KD as a safe and feasible dietary intervention to prevent chronic SD-induced cognitive deficiency, and suggest a better choice of medium-chain fatty acid-enriched KD.

Rapamycin ameliorates chronic intermittent hypoxia and sleep deprivation-induced renal damage via the mammalian target of rapamycin (mTOR)/NOD-like receptor protein 3 (NLRP3) signaling pathway

Rapamycin inhibits the activation of NOD-like receptor protein 3 (NLRP3) by regulating the mammalian target of rapamycin (mTOR) to treat obstructive sleep apnea-related renal injury. Sleep deprivation (SD) and chronic intermittent hypoxia (CIH) mouse models were used to assess the effects of autophagy in vivo. Compared with the control, SD, and CIH groups, the SD+CIH group had lower body weight and higher levels of blood urea nitrogen (BUN), creatinine, and urinary albumin (U-Alb) (P < 0.05); renal injury and oxidative damage occurred in the SD+CIH group, the kidney cell nucleus ruptured, and morphological structure of the cells was unclear in the SD+CIH group. The SD+CIH group demonstrated increased apoptosis compared with the control, SD, and CIH groups using Western blot analysis. Compared to the control, SD, and CIH groups, the SD+CIH group showed a higher degree of microtubule-associated protein light chain 3\ staining. Compared to the SD+CIH group, BUN, creatinine, and U-Alb levels decreased, and apoptosis increased in the SD+CIH+rapamycin group, and the structure of the kidney after rapamycin treatment was well preserved. The mTOR expression was increased in the kidneys of the SD+CIH group. The NLRP3, Gasdermin D (GMDSD), interleukin (IL)-18, IL-1β, and cleaved-caspase-1 protein levels were higher in the SD+CIH group than the SD+CIH+rapamycin group, and the NLRP3, GMDSD, IL-18, IL-1β, and cleaved-caspase-1 mRNA levels were higher in the SD+CIH group than the SD+CIH+rapamycin group. Following rapamycin treatment, pyroptosis was suppressed. Rapamycin ameliorates renal damage by inhibiting the mTOR/NLRP3 signaling pathway.

Evaluating the effect of selenium on spatial memory impairment induced by sleep deprivation

Sleep deprivation (SD) impairs memory due to disturbing oxidative stress parameters. Selenium is a main component of several antioxidant enzymes and provides a neuroprotective effect. The present study aimed to investigate the potential neuroprotective effect of chronic selenium administration on cognitive impairments induced by chronic SD. Adult male Wister rats were randomly assigned into five groups (n = 12/group). The SD was induced in rats using modified multiple platform model. Selenium (6 µg/kg of animal's body weight) was administered to rats via oral gavage for 6 weeks. The spatial learning and memory were assessed using the radial arm water maze (RAWM). Moreover, we measured the levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG, catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS) and brain derived neurotrophic factor (BDNF) in the hippocampus. The results indicate that short- and long-term memory were impaired by chronic sleep deprivation (P < 0.05), while selenium administration prevented this effect. Moreover, selenium normalized antioxidants activities which were reduced by SD such as: catalase (P < 0.05), and SOD (P < 0.05), and significantly enhanced the ratio of GSH/GSSG in sleep-deprived rats (P < 0.05), without significant alteration of BDNF (P > 0.05), GSH (P > 0.05), or TBARS levels (P > 0.05). In conclusion, chronic SD induced memory impairment, and chronic treatment with selenium prevented this impairment by normalizing antioxidant enzymes activities in the hippocampus.

Modulating role of serotonergic signaling in sleep and memory

Serotonin is an important neurotransmitter with various receptors and wide-range effects on physiological processes and cognitive functions including sleep, learning, and memory. In this review study, we aimed to discuss the role of serotonergic receptors in modulating sleep-wake cycle, and learning and memory function. Furthermore, we mentioned to sleep deprivation, its effects on memory function, and the potential interaction with serotonin. Although there are thousands of research articles focusing on the relationship between sleep and serotonin; however, the pattern of serotonergic function in sleep deprivation is inconsistent and it seems that serotonin has not a certain role in the effects of sleep deprivation on memory function. Also, we found that the injection type of serotonergic agents (systemic or local), the doses of these drugs (dose-dependent effects), and up- or down-regulation of serotonergic receptors during training with various memory tasks are important issues that can be involved in the effects of serotonergic signaling on sleep-wake cycle, memory function, and sleep deprivation-induced memory impairments. This comprehensive review was conducted in the PubMed, Scopus, and ScienceDirect databases in June and July 2021, by searching keywords sleep, sleep deprivation, memory, and serotonin.

The beneficial effects of green tea on sleep deprivation-induced cognitive deficits in rats: the involvement of hippocampal antioxidant defense

BACKGROUND

The weight of evidence suggests that sleep is essential for the processes of memory consolidation and sleep deprivation (SD) impairs the retention of long-term memory in both humans and experimental animals, which is associated with oxidative stress damage within the brain. Green tea polyphenols have revealed carcinogenic, antioxidant, anti-, and anti-mutagenic properties. We aimed to investigate the possible protective effect of green tea extract (GTE) and its main active catechin, epigallocatechin-3-gallate (EGCG), on post-training total sleep deprivation (TSD) -induced spatial memory deficits and oxidative stress profile in the hippocampus of the rat.

METHODS

Male rats were treated with saline, GTE (100 and 200 mg/kg/day), and EGCG (50 mg/kg/day) intraperitoneally for 21 days and then trained in Morris water maze (MWM) in a single day protocol. Immediately after the end of MWM training, animals were sleep deprived for 6 h by the gentle handling method, and then evaluated for spatial memory. Hippocampal levels of malondialdehyde, (MDA), and thiol was assessed as oxidant and antioxidant markers.

RESULTS

Spatial memory was impaired in the TSD group and GTE at the dose of 200 mg/kg/day as well as EGCG at the dose of 50 mg/kg/day could reverse the impairment to the saline-treated levels. Despite the unchanged MDA levels, hippocampal total thiol was significantly decreased after TSD and EGCG increased it to the basal levels.

CONCLUSION

In conclusion, green tea and its main catechin, EGCG, could prevent memory impairments during 6 h of TSD; probably through normalizing the antioxidant thiol defense system which was impaired during TSD.

Hydroalcoholic extract from Abelmoschus manihot (Linn.) Medicus flower reverses sleep deprivation-evoked learning and memory deficit

Previous researches have indicated that sleep plays a vital role in cognitive functions. Sleep deprivation (SD) causes learning and memory damage, which is associated with oxidative stress. This study was performed to investigate the neuroprotective effects of an extract of Abelmoschus manihot flower (EAM) against memory deficit induced by SD in mice. The SD model was evoked by multiple platform method for 5 days, successively. The learning and memory-improving effects of EAM were assessed by behavioral trials and the underlying mechanism was investigated by measuring the oxidative stress alteration. Our findings indicated that the SD-induced memory deficit and the EAM treatment improved the cognitive functions of mice in the object location recognition test and passive avoidance task. In addition, EAM effectively improved the activities of the antioxidant enzyme, decreased the content of malondialdehyde (MDA), and restored the protein expression of the brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB) and glutamate receptor 1 (GluR1) in brain tissues. In conclusion, EAM could improve the SD-evoked learning and memory impairments. The possible underlying mechanisms of EAM may be related to its antioxidant capacity and enhanced BDNF/TrkB/GluR1 levels in the hippocampal memory.

The effects of glucagon-like peptide 1 receptor agonist (exenatide) on memory impairment, and anxiety- and depression-like behavior induced by REM sleep deprivation

Previous investigations have shown that REM sleep deprivation impairs the hippocampus-dependent memory, long-term potentiation and causing mood changes. The aim of the present study was to explore the effects of exenatide on memory performance, anxiety- and depression like behavior, oxidative stress markers, and synaptic protein levels in REM sleep deprived rats. A total of 40 male Wistar rats were randomly divided to control, exenatide-treated control, sleep deprivation (SD), wide platform (WP) and exenatide-treated SD groups. During experiments, exenatide treatment (0.5 μg/kg, subcutaneously) was applied daily in a single dose for 9 days. Modified multiple platform method was employed to generate REM sleep deprivation for 72 h. The Morris water maze test was used to assess memory performance. Anxiety- and depression-like behaviors were evaluated by open field test (OFT), elevated plus maze (EPM) forced swimming test (FST), respectively 72 h after REMSD. The levels of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and postsynaptic density proteins 95 (PSD95) were measured in tissues of hippocampus and prefrontal cortex. The content of malondialdehyde (MDA) and reduced glutathione (GSH) were also measured. In the present study, an impairment in memory was observed in SD rats at the 24th hour of SD in compare to those of other groups. REMSD increased depression-like behavior in FST as well as the number of rearing and crossing square in OFT. Anxiety is the most common comorbid condition with depressive disorders. Contents of CaMKII and PSD95 decreased in hippocampus of SD rats. Exenatide treatment improved the impaired memory of SD rats and increased CaMKII content in hippocampus There was no difference in MDA and GSH levels among groups. Exenatide treatment also diminished locomotor activity in OFT. In conclusion, treatment with exenatide, at least in part, prevented from these cognitive and behavioral changes possibly through normalizing CaMKII levels in the hippocampus.

Inconsistent effects of sleep deprivation on memory function

In this review article, we aimed to discuss the role of sleep deprivation (SD) in learning and memory processing in basic and clinical studies. There are numerous studies investigating the effect of SD on memory, while most of these studies have shown the impairment effect of SD. However, some of these studies have reported conflicting results, indicating that SD does not impair memory performance or even improves it. So far, no study has discussed or compared the conflicting results of SD on learning and memory. Thus, this important issue in the neuroscience of sleep remains unknown. The main goal of this review article is to compare the similar mechanisms between the impairment and the improvement effects of SD on learning and memory, probably leading to a scientific solution that justifies these conflicting results. We focused on the inconsistent effects of SD on some mechanisms involved in learning and memory, and tried to discuss the inconsistent effects of SD on learning and memory.

Therapeutic activities of naringenin on efavirenz-induced sleep-like disorder in the midbrain of white albino mice

OBJECTIVES

Efavirenz, has proven to be effective in suppressing human immunodeficiency virus (HIV) viral load; however, complaints of sleep disorders including hallucination, and insomnia have greatly contributed to non-adherence to antiretroviral therapy. This study aimed at investigating therapeutic activities of naringenin on efavirenz-induced sleep disorder.

MATERIALS AND METHODS

Sixty mice were divided into six groups of control, combination antiretroviral therapy (cART), efavirenz, naringenin, naringenin/efavirenz and naringenin/cART. Efavirenz, cART, and naringenin were administered orally and daily at 15 mg/kg, 24 mg/kg and 50 mg/kg, respectively for 28 days. Post neurobehavioral test, oxidative stress, histology and immunohistochemistry for dopamine were carried out after administration process.

RESULTS

Efavirenz (P<0.0001) and cART (P<0.01) significantly increased immobility during open field (P<0.01), escape time in seconds (sec) in Morris water maze (P<0.001) and numbers of head-twitch response (HTR) (P<0.0001). Similarly, there was a significant increase in malondialdehyde (MDA) (P<0.0001) and decreased superoxide dismutase (SOD) (P<0.001) and reduced glutathione (GSH) (P<0.001); however, naringenin-treated groups potentiated anti-oxidant function by reducing oxidative stress (P<0.01). Histological evaluation demonstrated severe neurodegeneration, vacuolization and pyknosis in efavirenz and cART compared to naringenin groups. Dopaminergic neurons using immunohistochemial antibody (tyrosine hydroxylase) staining showed poor immunoreactivity in efavirenz and cART in contrast to naringenin groups.

CONCLUSION

Efavirenz and cART have the potential of inducing sleep disorder possibly due to their capability to trigger inflammation and deplete dopamine level. However, naringenin has proven to be effective in ameliorating these damages.

The neuroprotective effect of osthole against chronic sleep deprivation (CSD)-induced memory impairment in rats

AIM

Sleep deprivation (SD) is a frequent health problem in modern society. Osthole (Ost), a natural coumarin, has antioxidant and neuroprotective properties. This study examined the functions of Ost in chronic sleep deprivation (CSD)-induced memory deficits in rats.

MAIN METHODS

The CSD rat model was constructed by applying Sleep Interruption Apparatus (SIA). The protective effect of Ost on memory ability of CSD rats was evaluated through behavioral tests. Modafinil (MOD) was a positive control for investigating the mechanisms underlying the actions of Ost. The oxidative stress changes in the cortex and hippocampus of the rats, histological changes in CA1 region in the hippocampus and the protein expressions of neural plasticity markers were measured. The hippocampal neurons were isolated from rats for evaluating the neuroprotective effects of Ost on glutamate-induced neuron injury in vitro.

KEY FINDINGS

Ost administration significantly enhanced the cognitive performance of CSD rats in the open field test, object location recognition experiment, novel object recognition experiment, and Morris water maze test. Ost could effectively normalize the levels/activities of the antioxidant enzyme system in the cortex and hippocampus. Moreover, Ost administration reversed CSD-induced abnormal state of CA1 neurocytes and the down-regulated expressions of plasticity-related genes in vivo and in vitro. Additionally, Ost also notably up-regulated the expressions of Nrf2 and HO-1 previously down-regulated in CA1 neurocytes of CSD rats and in vitro.

SIGNIFICANCE

Our findings showed that Ost alleviated CSD-induced cognitive deficits, and the activation of the Nrf2/HO-1 pathway might be involved in the neuroprotective action of Ost.

The protective effect of alpha lipoic acid (ALA) on social interaction memory, but not passive avoidance in sleep-deprived rats

Sleep is involved in maintaining energy, regulating heat, and recovering tissues. Furthermore, proper cognitive functions need sufficient sleep. Many studies have revealed the impairment effect of sleep deprivation (SD) on cognitive functions including learning and memory. Alpha lipoic acid (ALA) is a potent free radical scavenger, biological antioxidant, and neuroprotective agent. Furthermore, ALA improves learning and memory performance, decreases oxidative stress, and enhances antioxidant biomarkers. In this study, we aimed to investigate the effect of ALA on social interaction and passive avoidance memories in sleep-deprived rats. Total sleep deprivation (TSD) apparatus was used to induce SD (for 24 h). Three-chamber paradigm test and shuttle box apparatus were used to evaluate social interaction and passive avoidance memory, respectively. Rats' locomotor apparatus was used to assess locomotion. ALA was administered intraperitoneally at doses of 17 and 35 mg/kg for 3 consecutive days. The results showed SD impaired both types of memories. ALA at the dose of 35 mg/kg restored social interaction memory in sleep-deprived rats; while, at the dose of 17 mg/kg attenuated impairment effect of SD. Moreover, ALA at the dose of 35 mg/kg impaired passive avoidance memory in sham-SD rats and at both doses did not rescue passive avoidance memory in sleep-deprived rats. In conclusion, ALA showed impairment effect on passive avoidance memory, while improved social interaction memory in sleep-deprived rats.

Hydrogen Sulfide Prevents Sleep Deprivation-Induced Hippocampal Damage by Upregulation of Sirt1 in the Hippocampus

Sleep deprivation (SD) induces hippocampal damage. Hydrogen sulfide (H₂S) is a neuronal protective factor. Silence information regulating factor 1 (Sirt1) plays an important role in neuroprotection. Therefore, this study was aimed at exploring whether H₂S meliorates SD-induced hippocampal damage and whether Sirt1 mediates this protective role of H₂S. We found that sodium hydrosulfide (NaHS, a donor of H₂S) alleviated SD-generated hippocampal oxidative stress, including increases in the activation of SOD and the level of GSH as well as a decrease in the level of MDA. Meanwhile, we found that NaHS reduced SD-exerted hippocampal endoplasmic reticulum (ER) Stress, including downregulations of GRP78, CHOP, and cleaved-caspase-12 expression. Moreover, NaHS reduced the apoptosis in the SD-exposed hippocampus, and this included decreases in the number of apoptotic cells and the activation of caspase-3, downregulation of Bax expression, and upregulation of Bcl-2 expression. NaHS upregulated the expression of Sirt1 in the hippocampus of SD-exposed rats. Furthermore, Sirtinol, the inhibitor of Sirt1, abrogated the protection of NaHS against SD-exerted hippocampal oxidative stress, ER stress, and apoptosis. These results suggested that H₂S alleviates SD-induced hippocampal damage by upregulation of hippocampal Sirt1.

Edaravone prevents memory impairment in an animal model of post-traumatic distress

Post-traumatic stress disorder (PTSD) is a mental health problem that develops in a proportion of individuals after experiencing a potential life-threatening traumatic stress event. Edaravone is a free radical scavenger, with a neuroprotective effect against cognitive impairment in several animal models. In the present study, the protective effect of edaravone on PTSD-induced memory impairment was investigated. Single prolonged stress was used as an animal model of PTSD, comprising 2 h of restrain, 20-min forced swimming, 15-min rest, and 1-2-min diethyl ether exposure. Concurrently, edaravone was given at a dose of 6 mg/kg/day, intraperitoneally, for 21 days. The radial arm water maze was used to assess learning and memory. Antioxidant biomarkers were measured in hippocampus tissues. Chronic administration of edaravone prevented impairment of short-term and long-term memory. Edaravone also prevented the stress-induced decrease in the ratio of reduced glutathione/oxidized glutathione and the activities of glutathione peroxidase and catalase enzymes in the hippocampus, as well as increases in the levels of oxidized glutathione and thiobarbituric acid reactive substances. In conclusion, edaravone ameliorated oxidative stress and cognitive impairment associated with a PTSD model, probably by supporting antioxidant mechanism in the hippocampus.

The protective effect of edaravone on memory impairment induced by chronic sleep deprivation

Sleep plays a critical role in body health maintenance, whereas sleep deprivation (SD) negatively affects cognitive function. Cognitive defects mainly memory impairment resulting from sleep deprivation were related to an increase in the level of oxidative stress in the body, including the brain hippocampus region. Edaravone is a potent free radical scavenger having antioxidant effect. In the current study, edaravone's ability to prevent SD induced cognitive impairment was tested in rats. Animals were sleep deprived 8 h/day for 4 weeks. Concurrently, edaravone was administrated intraperitoneally for four weeks. Animals performance during cognitive testing was evaluated to display if edaravone has a role in the prevention of sleep deprivation induced memory impairment. Additionally, the role of antioxidant biomarkers glutathione peroxidase (GPx), catalase, glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG in this effect was investigated. The results showed that SD impaired both short- and long- term memories, and chronic edaravone administration prevented such effect. Additionally, edaravone prevented decreases in hippocampal GPx, catalase, GSH/GSSG ratio and normalized increases in GSSG levels, which were impaired by SD model. In conclusion, current result showed a protective effect of edaravone administration against SD induction that could be related to edaravone's ability to normalizing mechanisms related to oxidative balance.

Omega-3 fatty acids protects against chronic sleep-deprivation induced memory impairment

AIMS

The current study aims to evaluate the possible protective effect of omega-3 fatty acids on memory impairment induced by sleep-deprivation in rats.

MATERIALS AND METHODS

Animals were chronically sleep deprived using the modified multiple platform model (8 h/day for 8 weeks). Omega-3 fatty acids were administered as fish oil via oral gavage at a daily dose of 100 mg omega-3 PUFA/100 g BWT. The spatial learning and memory were evaluated using the radial arm water maze (RAWM). Additionally, the following oxidative stress biomarkers were measured in the hippocampus: glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), and thiobarbituric acid reactive substance (TBARS).

KEY FINDINGS

Animals in the SD group committed significantly more errors in both short- and long- term memory tests of the RAWM compared to other groups. On the other hand, animals that were sleep deprived and treated with omega-3 fatty acids committed similar number of errors compared to the control group. This indicates that SD impaired both short- and long- term memories, and that chronic omega-3 fatty acids administration prevented these effects. Omega-3 fatty acids also prevented the decreases in hippocampal GPx, catalase and GSH/GSSG ratio and normalized the increases in GSSG levels, which were impaired by SD model. No changes were observed on hippocampal TBARS levels, or activity of SOD among experimental groups.

SIGNIFICANCE

In conclusion, a protective effect of omega-3 fatty acids administration has been observed against chronic SD-induced memory impairment probably via improving hippocampus antioxidant effects.

Omega-3 Fatty Acids Prevent Post-Traumatic Stress Disorder-Induced Memory Impairment

Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can happen after exposure to a traumatic event. Post-traumatic stress disorder is common among mental health disorders that include mood and anxiety disorders. Omega-3 fatty acids (OMGs) are essential for the maintenance of brain function and prevention of cognition dysfunctions. However, the possible effect of OMG on memory impairment induced by PTSD has not been studied. In here, such an effect was explored using a rat model of PTSD. The PTSD-like behavior was induced in animals using a single-prolonged stress (SPS) rat model of PTSD (2 h restraint, 20 min forced swimming, 15 min rest, 1–2 min diethyl ether exposure). The OMG was administered orally at a dose of 100 mg omega-3 polyunsaturated fatty acid (PUFA)/100 g body weight/day. Spatial learning and memory were assessed using the radial arm water maze (RAWM) method. Changes in oxidative stress biomarkers, thiobarbituric acid reactive substances (TBARS), and brain derived neuroptrophic factor (BDNF) in the hippocampus following treatments were measured. The results revealed that SPS impaired both short- and long-term memory (p < 0.05). Use of OMG prevented memory impairment induced by SPS. Furthermore, OMG normalized SPS induced changes in the hippocampus that reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG ratios, the activity of catalase, glutathione peroxidase (GPx), and TBARSs levels. In conclusion, the SPS model of PTSD-like behavior generated memory impairment, whereas OMG prevented this impairment, possibly through normalizing antioxidant mechanisms in the hippocampus.

Walnut ( Juglans regia) Peptides Reverse Sleep Deprivation-Induced Memory Impairment in Rat via Alleviating Oxidative Stress

The aim of this study was to determine the neuroprotective effects of walnut protein hydrolysates (WPH) against memory deficits induced by sleep deprivation (SD) in rat and further to identify and characterize the potent neuroprotective peptides against glutamate-induced apoptosis in PC12 cells. Results showed that a remarkable amelioration effect on behavioral performance in Morris water maze test was observed for WPH and its low molecular weight fraction WPHL, especially for WPHL. Additionally, a reduction of antioxidant defense (catalase, glutathione peroxidase (GSH-px), and superoxide dismutase (SOD)) and an increase of malondialdehyde content induced by SD were normalized in brain of rat after oral administration of WPH and WPHL. Then three neuroprotective peptides including GGW, VYY, and LLPF were identified from WPHL, which could protect PC12 cells against glutamate-induced apoptosis with relative cell viability of 78.29 ± 3.09%, 80.65 ± 1.74%, and 83.97 ± 3.06%, respectively, versus glutamate group 48.61 ± 3.99%. The possible mechanism underlying their protective effects of GGW and VYY could be related to their strong radical scavenging activity as well as their ability to reduce reactive oxygen species production and the depletion of SOD and GSH-px in PC12 cells. Notably, the marked neuroprotective effects of LLPF, which did not show obvious free-radical scavenging activity in vitro, could be attributed to its strong effects on inhibiting Ca²⁺ influx and mitochondrial membrane potential collapse. Additionally, all these peptides could regulate the expression of apoptosis-related proteins (Bax and Bcl-2). Therefore, walnut peptides might be regarded as the potential nutraceuticals against neurodegenerative disorders associated with memory deficits.

Ginsenoside Rh2 reverses sleep deprivation-induced cognitive deficit in mice

Sleep deprivation (SD) negatively caused cognitive deficit, which was associated with oxidative stress induced damage. Ginsenoside Rh2 had the ability to protect against damage caused by reactive oxygen species in vitro, showing antioxidant property. Therefore, it was hypothesized that Ginsenoside Rh2 could prevent SD-induced cognitive deficit via its antioxidant properties. In this study, the effect of Ginsenoside Rh2 on memory impairment induced by sleep deprivation was investigated. The mice were sleep deprived continuously for 14 days using our self-made Sleep Interruption Apparatus (SIA). Ginsenoside Rh2 was administered intraperitoneally at two doses (20 and 40 μmol/kg) for 20 days. Thereafter, behavioral studies were conducted to test the learning and memory ability using object location recognition (OLR) experiment and passive avoidance (PA) test. Additionally, the oxidative stress parameters in the serum and the brain tissues (cortex and hippocampus) were assessed, including the superoxide dismutase (SOD) enzyme activity, the total antioxidant reactivity (TAR), the malondialdehyde (MDA) level, the glutathione (GSH) level, and the lipid peroxidation (LPO) content. The results revealed that SD impaired both spatial and non-spatial memory (P < 0.05). Treatment with Ginsenoside Rh2 at both doses prevented memory impairment induced by SD. Moreover, Ginsenoside Rh2 normalized the reduction of SOD and TAR activities in the serum (P < 0.01) and the decrease of GSH content in both the cortex and hippocampus (P < 0.05) induced by SD. Furthermore, Ginsenoside Rh2 significantly decreased the MDA level in the serum (P < 0.05) and the LPO content in both the cortex and hippocampus (P < 0.05) compared to SD group. In conclusion, sleep deprivation impaired both spatial and non-spatial memory and Ginsenoside Rh2 reversed this impairment, probably by preventing the oxidative stress damage in the body, including the serum and brain during sleep deprivation.

Transcranial near-infrared photobiomodulation attenuates memory impairment and hippocampal oxidative stress in sleep-deprived mice

Sleep deprivation (SD) causes oxidative stress in the hippocampus and subsequent memory impairment. In this study, the effect of near-infrared (NIR) photobiomodulation (PBM) on learning and memory impairment induced by acute SD was investigated. The mice were subjected to an acute SD protocol for 72 h. Simultaneously, NIR PBM using a laser at 810 nm was delivered (once a day for 3 days) transcranially to the head to affect the entire brain of mice. The Barnes maze and the What-Where-Which task were used to assess spatial and episodic-like memories. The hippocampal levels of antioxidant enzymes and oxidative stress biomarkers were evaluated. The results showed that NIR PBM prevented cognitive impairment induced by SD. Moreover, NIR PBM therapy enhanced the antioxidant status and increased mitochondrial activity in the hippocampus of SD mice. Our findings revealed that hippocampus-related mitochondrial damage and extensive oxidative stress contribute to the occurrence of memory impairment. In contrast, NIR PBM reduced hippocampal oxidative damage, supporting the ability of 810 nm laser light to improve the antioxidant defense system and maintain mitochondrial survival. This confirms that non-invasive transcranial NIR PBM therapy ameliorates hippocampal dysfunction, which is reflected in enhanced memory function.

Melatonin prevents memory impairment induced by high-fat diet: Role of oxidative stress

Consumption of high-fat diet (HFD) induces oxidative stress in the hippocampus that leads to memory impairment. Melatonin has antioxidant and neuroprotective effects. In this study, we hypothesized that chronic administration of melatonin can prevent memory impairment induced by consumption of HFD. Melatonin was administered to rats via oral gavage (100mg/kg/day) for 4 weeks. HFD was also instituted for the same duration. Behavioral studies were conducted to test spatial memory using the radial arm water maze. Additionally, oxidative stress biomarkers were assessed in the hippocampus. Results showed that HFD impaired both short- and long- term memory (P<0.05), while melatonin treatment prevented such effects. Furthermore, melatonin prevented HFD-induced reduction in levels of GSH, and ratio of GSH/GSSG, and increase in GSSG in the hippocampus. Melatonin also prevented reduction in the catalase activity in hippocampus of animals on HFD. In conclusion, HFD induced memory impairment and melatonin prevented this impairment probably by preventing alteration of oxidative stress in the hippocampus.