Sleep Deprivation-induced Memory Impairment Research Articles

Comparison between sub-chronic and chronic sleep deprivation-induced behavioral and neuroimmunological abnormalities in mice: Focusing on glial cell phenotype polarization

BackgroundSleep disorders, depression, and Alzheimer’s disease (AD) are extensively reported as comorbidity. Although neuroinflammation triggered by microglial phenotype M1 activation, leading to neurotransmitter dysfunction and Aβ aggregation, is considered as the leading cause of depression and AD, whether and how sub-chronic or chronic sleep deprivation (SD) contribute to the onset and development of these diseases remains unclear. MethodsMemory and depression-like behaviors were evaluated in both SDs, and then circadian markers, glial cell phenotype polarization, cytokines, depression-related neurotransmitters, and AD-related gene/protein expressions were measured by qRT-PCR, enzyme-linked immunosorbent assay, high-performance liquid chromatography, and western-blotting respectively. ResultsBoth SDs induced give-up behavior and anhedonia and increased circadian marker period circadian regulator 2 (PER2) expression, which were much worse in chronic than in the sub-chronic SD group, while brain and muscle ARNT-like protein-1 only decreased in the chronic-SD. Furthermore, increased microglial M1 and astrocyte A1 expression and proinflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α was observed in both SDs, which were more significant in chronic SD. Similarly, decreased norepinephrine and 5-hydroxytryptamine/5-hydroxyindoleacetic acid ratio were more significant, which corresponds to the worse depression-like behavior in chronic than sub-chronic-SD. With regard to AD, increased amyloid precursor protein (APP) and soluble (s)-APPβ and decreased sAPPα in both SDs were more significant in the chronic. However, sAPPα/sAPPβ ratio was only decreased in chronic SD. ConclusionThese findings suggest that both SDs induce depression-like changes by increasing PER2, leading to neuroinflammation and neurotransmitter dysfunction. However, only chronic SD induced memory impairment likely due to severer circadian disruption, higher neuroinflammation, and dysregulation of APP metabolism

CD33/TREM2 Signaling Mediates Sleep Deprivation-Induced Memory Impairment by Regulating Microglial Phagocytosis.

Sleep deprivation causes significant memory impairment in healthy adults. Extensive research has focused on identifying the biological mechanisms underlying memory impairment. Microglia-mediated synaptic elimination plays an indispensable role in sleep deprivation. Here, the potential role of the CD33/TREM2 signaling pathway in modulating memory decline during chronic sleep restriction (CSR) was evaluated. In this study, adult male C57BL/6 mice were sleep-restricted using an automated sleep deprivation apparatus for 20h per day for 7days. The Y-maze test revealed that spontaneous alternation was significantly reduced in CSR mice compared with control mice. The percentage of exploratory preference for the novel object in CSR mice was significantly decreased compared with that in control mice. These memory deficits correlated with aberrant microglial activation and increased phagocytic ability. Moreover, in CSR mice, the CD33 protein level in hippocampal tissue was significantly downregulated, but the TREM2 protein level was increased. In BV2 microglial cells, downregulation of CD33 increased TREM2 expression and improved microglial phagocytosis. Then, the sialic ligand monosialo-ganglioside 1 (GM1, 20mg/kg, i.p.) was administered to mice once a day during CSR. Our results further showed that GM1 activated CD33 and consequently disturbed TREM2-mediated microglial phagocytosis. Finally, GM1 reversed CSR-induced synaptic loss and memory impairment via the CD33/TREM2 signaling pathway in the CA1 region of the hippocampus. This study provides novel evidence that activating CD33 and/or inhibiting TREM2 activity represent potential therapies for sleep loss-induced memory deficits through the modulation of microglial phagocytosis.

An integrated targeted metabolomics and network pharmacology approach to exploring the mechanism of ellagic acid against sleep deprivation-induced memory impairment and anxiety.

As a neuroprotective agent, ellagic acid (EA) is extremely beneficial. Our previous study found that EA can alleviate sleep deprivation (SD)-induced abnormal behaviors, although the mechanisms underlying this protective effect have not yet been fully elucidated. An integrated network pharmacology and targeted metabolomics approach was utilized in this study to investigate the mechanism of EA against SD-induced memory impairment and anxiety. Behavioral tests were conducted on mice after 72 h of SD. Hematoxylin and eosin staining and nissl staining were then carried out. Integration of network pharmacology and targeted metabolomics was performed. Eventually, the putative targets were further verified using molecular docking analyses and immunoblotting assays. The present study findings confirmed that EA ameliorated the behavioral abnormalities induced by SD and prevented histopathological and morphological damage to hippocampal neurons. Through multivariate analysis, clear clustering was obtained among different groups, and potential biomarkers were identified. Four key targets, catechol-O-methyltransferase (COMT), cytochrome P450 1B1 (CYP1B1), glutathione S-transferase A2 (GSTA2), and glutathione S-transferase P1 (GSTP1), as well as the related potential metabolites and metabolic pathways, were determined by further integrated analysis. Meanwhile, in-silico studies revealed that EA is well located inside the binding site of CYP1B1 and COMT. The experimental results further demonstrated that EA significantly reduced the increased expression of CYP1B1 and COMT caused by SD. The findings of this study extended our understanding of the underlying mechanisms by which EA treats SD-induced memory impairment and anxiety, and suggested a novel approach to address the increased health risks associated with sleep loss.

Peptide WCPFSRSF alleviates sleep deprivation-induced memory impairment by inhibiting neuroinflammation and modulating IL-6/JAK/STAT signaling pathway

Our previous study revealed that Trp-Cys-Pro-Phe-Ser-Arg-Ser-Phe (WCPFSRSF) exerted memory-improving ability in sleep-deprived mice; however, the underlying regulatory network was still unclear. The purpose of this study was to evaluate the effects of WCPFSRSF in sleep-deprived mice and to clarify the main regulatory networks. Our results showed that WCPFSRSF ameliorated the abnormal morphology of neurons and loss of neurons in hippocampus of sleep-deprived mice. Furthermore, WCPFSRSF inhibited oxidative stress via enhancing the activities of antioxidant enzymes, reducing MDA levels and activating the Nrf2 pathway. Transcriptome analysis showed that WCPFSRSF mainly regulated inflammation-related pathways, such as IL-17, TNF and JAK/STAT pathways. Further analysis showed that WCPFSRSF reduced the release of pro-inflammatory cytokines and the expression of microglia marker Iba-1 and astrocyte marker GFAP, thereby inhibiting neuroinflammation. Western Blotting analysis showed that WCPFSRSF regulated the IL-6/JAK/STAT pathway. In addition, WCPFSRSF and its in silico gastrointestinal digested fragments WCP and FSR were potential JAK2/STAT3 inhibitors. WCPFSRSF and WCP could reduce the NO levels in LPS-treated BV-2 cells. Collectively, our results indicated that WCPFSRSF improved memory impairment induced by sleep deprivation through inhibiting glial cell activation and neuroinflammation.

Peptide Wcpfsrsf Alleviates Sleep Deprivation-Induced Memory Impairment by Inhibiting Neuroinflammation and Modulating Il-6/Jak/Stat Signaling Pathway

Peptide Wcpfsrsf Alleviates Sleep Deprivation-Induced Memory Impairment by Inhibiting Neuroinflammation and Modulating Il-6/Jak/Stat 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.

Sericin protects against acute sleep deprivation-induced memory impairment via enhancement of hippocampal synaptic protein levels and inhibition of oxidative stress and neuroinflammation in mice

Sleep deprivation (SD) induces learning and memory deficits via inflammatory responses and oxidative stress. On the other hand, sericin (Ser) possesses potent antioxidant and neuroprotective effects. We investigated the effect of different doses of Ser on the SD-induced cognitive impairment. Ser (100, 200, and 300 mg/kg) was administered to animals via oral gavage for 8 days, 5 days before to SD, and during SD. SD was induced in mice using a modified multiple platform model, starting on the 6th day for 72 h. Spatial learning and memory were assessed using the Lashley III maze. Serum corticosterone level, and hippocampal malondialdehyde (MDA), total antioxidant capacity (TAC), and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes were evaluated. The expression of growth‐associated protein 43 (GAP-43), post‐synaptic density‐95 (PSD-95), synapsin 1 (SYN-1), and synaptophysin (SYP), and inflammation markers were detected by western blotting. SD caused cognitive impairment, while Ser pretreatment prevented such an effect. Serum corticosterone also increased with SD, but its levels were suppressed in SD mice receiving Ser. Furthermore, Ser normalized SD-induced reduction in the hippocampus activity of SOD and GPx, increased TAC, and decreased MDA levels. Besides, Ser pretreatment increased GAP-34, SYP, SYN-I, and PSD-95 and reduced IL1-β and TNF-α in the hippocampus. SD induced memory impairment and pretreatment with Ser improved memory via its antioxidant, anti-inflammation, and up-regulation of synaptic proteins in the hippocampus.

Electrocorticographic Recording of Cerebral Cortex Areas Manipulated Using an Adeno-Associated Virus Targeting Cofilin in Mice

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. Adeno-associated viruses (AAVs) are increasingly used to improve understanding of brain circuits and their functions. The AAV-mediated manipulation of specific cell populations and/or of precise molecular components has been tremendously useful to identify new sleep regulatory circuits/molecules and key proteins contributing to the adverse effects of sleep loss. For instance, inhibiting activity of the filamentous actin-severing protein cofilin using AAV prevents sleep deprivation-induced memory impairment. Here, a protocol is described that combines the manipulation of cofilin function in a cerebral cortex area with the recording of ECoG activity to examine whether cortical cofilin modulates the wakefulness and sleep ECoG signals. AAV injection is performed during the same surgical procedure as the implantation of ECoG and electromyographic (EMG) electrodes in adult male and female mice. Mice are anesthetized, and their heads are shaved. After skin cleaning and incision, stereotaxic coordinates of the motor cortex are determined, and the skull is pierced at this location. A cannula prefilled with an AAV expressing cofilinS3D, an inactive form of cofilin, is slowly positioned in the cortical tissue. After AAV infusion, gold-covered screws (ECoG electrodes) are screwed through the skull and cemented to the skull with gold wires inserted in the neck muscles (EMG electrodes). The animals are allowed three weeks to recover and to ensure sufficient expression of cofilinS3D. The infected area and cell type are verified using immunohistochemistry, and the ECoG is analyzed using visual identification of vigilance states and spectral analysis. In summary, this combined methodological approach allows the investigation of the precise contribution of molecular components regulating neuronal morphology and connectivity to the regulation of synchronized cerebral cortex activity during wakefulness and sleep.

Electrocorticographic Recording of Cerebral Cortex Areas Manipulated Using an Adeno-Associated Virus Targeting Cofilin in Mice.

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. Adeno-associated viruses (AAVs) are increasingly used to improve understanding of brain circuits and their functions. The AAV-mediated manipulation of specific cell populations and/or of precise molecular components has been tremendously useful to identify new sleep regulatory circuits/molecules and key proteins contributing to the adverse effects of sleep loss. For instance, inhibiting activity of the filamentous actin-severing proteincofilinusing AAV prevents sleep deprivation-induced memory impairment. Here, a protocol isdescribed that combines the manipulation of cofilin function in a cerebral cortex area with the recording of ECoG activity to examine whether cortical cofilin modulates the wakefulness and sleep ECoG signals. AAV injection is performed during the same surgical procedure as the implantation of ECoG and electromyographic (EMG) electrodes in adult male and female mice. Mice are anesthetized, and their heads are shaved. After skin cleaning and incision, stereotaxic coordinates of the motor cortex are determined, and the skull is pierced at this location. A cannula prefilled with an AAV expressing cofilinS3D, an inactive form of cofilin, is slowly positioned in the cortical tissue. After AAV infusion, gold-covered screws (ECoG electrodes) are screwed through the skull and cemented to the skull with gold wires inserted in the neck muscles (EMG electrodes). The animals are allowed three weeks to recover and to ensure sufficient expression of cofilinS3D. The infected area and cell type are verified using immunohistochemistry, and the ECoG is analyzed using visual identification of vigilance states and spectral analysis. In summary, this combined methodological approach allows the investigation of the precise contribution of molecular components regulating neuronal morphology and connectivity to the regulation of synchronized cerebral cortex activity during wakefulness and sleep.

Ellagic acid protects mice against sleep deprivation-induced memory impairment and anxiety by inhibiting TLR4 and activating Nrf2.

Sleep disorder has become a prevalent issue in current society and is connected with the deterioration of neurobehaviors such as mood, cognition and memory. Ellagic acid (EA) is a phenolic phytoconstituent extracted from grains and fruits that has potent neuroprotective properties. This research aimed to study the alleviative effect and mechanism of EA on memory impairment and anxiety caused by sleep deprivation (SD). EA ameliorated behavioral abnormalities in SD mice, associated with increased dendritic spine density, and reduced shrinkage and loss of hippocampal neurons. EA reduced the inflammatory response and oxidative stress injury caused by SD, which may be related to activation of the Nrf2/HO-1 pathway and mitigation of the TLR4-induced inflammatory response. In addition, EA significantly reduced the mortality and ROS levels in glutamate (Glu)-induced hippocampal neuron injury, and these effects of EA were enhanced in TLR4 siRNA-transfected neurons. However, knockdown of Nrf2 dramatically restrained the protective impact of EA on Glu-induced toxicity. Taken together, EA alleviated memory impairment and anxiety in sleep-deprived mice potentially by inhibiting TLR4 and activating Nrf2. Our findings suggested that EA may be a promising nutraceutical ingredient to prevent cognitive impairment and anxiety caused by sleep loss.

Corilagin ameliorates sleep deprivation-induced memory impairments by inhibiting NOX2 and activating Nrf2

Sleep deprivation (SD) can induce cognitive and memory impairments. This impairment is in part due to oxidative stress damage in the hippocampus region of the brain. Corilagin (CL), a polyphenol belonging to the tannin family and extracted from Terminalia chebula and Phyllanthus emblica, shows strong antioxidant and neuroprotective effects. NF-E2-related factor (Nrf2)/heme oxygenase-1 (HO-1) and NADPH oxidase (NOX) are critical targets involved in cellular defense mechanisms against oxidative injury. Thus, we hypothesized that CL could be a preventive treatment for SD-induced memory impairments by inhibiting NOX2 and activating Nrf2. The results from behavioral tests showed that administration of CL resulted in significantly better performance compared to the SD mice. CL significantly normalized the elevated MDA level and the reduced activity of GPx and SOD (P <0.05, p<0.01) caused by SD. In hippocampal tissues, CL effectively activated Nrf2/HO-1 signaling and downregulated NOX2 protein expression compared with SD (P <0.05, P <0.01). Meanwhile, in vitro findings showed that knockdown of Nrf2 blocked the protective effect of CL versus Glu-induced toxicity, while the effect of CL was enhanced in NOX2 siRNA-transfected neurons. Overall, these findings provided evidence that CL ameliorates SD-induced memory impairments in mice by inhibiting NOX2 and activating Nrf2.

Activation of brain-derived neurotrophic factor signaling in the basal forebrain reverses acute sleep deprivation-induced fear memory impairments.

IntroductionThe mechanisms underlying sleep deprivation‐induced memory impairments and relevant compensatory signaling pathways remain elusive. We tested the hypothesis that increased brain‐derived neurotrophic factor (BDNF) expression in the basal forebrain following acute sleep deprivation was a compensatory mechanism to maintain fear memory performance.MethodsAdult male Wistar rats were deprived of 6‐hr total sleep from the beginning of the light cycle. The effects of sleep deprivation on BDNF protein expression and activation of downstream tropomyosin receptor kinase B (TrkB)/phospholipase C‐γ1 (PLCγ1) signaling in the basal forebrain and fear memory consolidation were examined. BDNF or selective downstream TrkB receptor antagonist ANA‐12 was further injected into the basal forebrain bilaterally to observe the changes in fear memory consolidation in response to modulation of the BDNF/TrkB signaling.ResultsSix hours of sleep deprivation‐induced both short‐ and long‐term fear memory impairments. Increased BDNF protein expression and TrkB and PLCγ1 phosphorylation in the basal forebrain were observed after sleep deprivation. Microinjection of BDNF into the basal forebrain partly reversed fear memory deficits caused by sleep deprivation, which were accompanied by increased BDNF protein levels and TrkB/PLCγ1 activation. After ANA‐12 microinjection, sleep deprivation‐induced activation of the BDNF/TrkB pathway was inhibited and impairments of fear memory consolidation were further aggravated.ConclusionsAcute sleep deprivation induces compensatory increase of BDNF expression in the basal forebrain. Microinjection of BDNF into the basal forebrain mitigates the fear memory impairments caused by sleep deprivation by activating TrkB/PLCγ1 signaling.

Cerebrolysin prevents sleep deprivation induced memory impairment and oxidative stress

Sleep plays a critical role in body health maintenance and well-being throughout a lifetime. Sleeplessness is the most prevalent feature in the modernist societies, which impairs memory. Studies have shown a strong correlation between sleep deprivation and memory impairment in humans and animals, which is related to oxidative stress induced damage within the brain. Cerebrolysin (CBL) is a neuropeptide that is used to treat vascular dementia. In this study, the effect of CBL on sleep-deprivation induced memory impairment was investigated. Sleep deprivation was induced in rats using the modified multiple platform model (8 h/day for 4 weeks). Concurrently, CBL was administered intraperitoneally for four weeks. Animal's performance (spatial learning and memory) was assessed using the radial arm water maze (RAWM). Additionally, oxidative stress biomarkers including reduced glutathione (GSH), oxidized Glutathione (GSSG), GSH/GSSG ratio, glutathione peroxidase (GPx), and catalase were assessed in the hippocampus. Current results showed that sleep deprivation impaired both short- and long- term memories (P < 0.05), and that chronic CBL administration prevented such impairment. Additionally, CBL prevented decreases in hippocampal GPx, catalase, GSH and GSH/GSSG ratio and normalized increases in GSSG levels, which were impaired by the sleep deprivation model (P < 0.05). In conclusion, result showed a protective effect for CBL administration against sleep-deprivation induced memory impairment, which could be related to CBL induced prevention of oxidative stress 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

AimsThe 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 methodsAnimals 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 findingsAnimals 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. SignificanceIn 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.

Fear memory consolidation in sleep requires protein kinase A.

It is well established that protein kinase A (PKA) is involved in hippocampal dependent memory consolidation. Sleep is also known to play an important role in this process. However, whether sleep-dependent memory consolidation involves PKA activation has not been clearly determined. Using behavioral observation, animals were categorized into sleep and awake groups. We show that intrahippocampal injections of the PKA inhibitor Rp-cAMPs in post-contextual fear conditioning sleep produced a suppression of long-term fear memory, while injections of Rp-cAMPs during an awake state, at a similar time point, had no effect. In contrast, injections of the PKA activator Sp-cAMPs in awake state, rescued sleep deprivation-induced memory impairments. These results suggest that following learning, PKA activation specifically in sleep is required for the consolidation of long-term memory.

Restorative effects of curcumin on sleep-deprivation induced memory impairments and structural changes of the hippocampus in a rat model

The present study examined the consequences of rapid eye-movement sleep-deprivation (REM-SD) with or without curcumin treatment. The outcome measures comprised quantitative features in the three-dimensional reconstruction (3DR) CA1 and dentate gyrus in experimental and control animals using stereological procedures.Male rats were arbitrarily assigned to nine groups based on the intervention and treatment administered including: 1-cage control+distilled water, 2-cage control+curcumin (100mg/kg/day), 3-cage control+olive oil, 4-REM-SD+distilled water, 5-REM-SD+curcumin, 6-REM-SD+olive oil, 7-grid-floor control+distilled water, 8-grid-floor control+curcumin, and 9-grid-floor control+olive oil. Animals in the latter three groups were placed on wire-mesh grids in the sleep-deprivation box. REM-SD was induced by an apparatus comprising a water tank and multiple platforms. After a period of 21days, rats were submitted to the novel object-recognition task. Later, their brains were excised and evaluated using stereological methods.Our results indicated a respective 29% and 31% reduction in the total volume of CA1, and dentate gyrus in REM-SD+distilled water group as compared to the grid-floor control+distilled water group (p<0.05). Other than the above, the overall number of the pyramidal cells of CA1 and granular cells of dentate gyrus in the sleep-deprived group were found to be reduced by 48% and 25%, respectively. The REM-SD+distilled water group also exhibited impaired object recognition memory and deformed three-dimensional reconstructions of these regions. The volume, cell number, reconstruction, object recognition time, and body weight were however recovered in the REM-SD+curcumin compared to the REM-SD+distilled water group. This suggests the potential neuro-restorative effects of curcumin in our model.

Tempol prevents chronic sleep-deprivation induced memory impairment.

Sleep deprivation is associated with oxidative stress that causes learning and memory impairment. Tempol is a nitroxide compound that promotes the metabolism of many reactive oxygen species (ROS) and has antioxidant and neuroprotective effect. The current study investigated whether chronic administration of tempol can overcome oxidative stress and prevent learning and memory impairment induced by sleep deprivation. Sleep deprivation was induced in rats using multiple platform model. Tempol was administered to rats via oral gavages. Behavioral studies were conducted to test the spatial learning and memory using radial arm water maze. The hippocampus was dissected; antioxidant biomarkers (GSH, GSSG, GSH/GSSG ratio, GPx, SOD, and catalase) were assessed. The result of this project revealed that chronic sleep deprivation impaired both short and long term memory (P<0.05), while tempol treatment prevented such effect. Furthermore, tempol normalized chronic sleep deprivation induced reduction in the hippocampus activity of catalase, GPx, and SOD (P<0.05). Tempol also enhanced the ratio of GSH/GSSG in chronically sleep deprived rats treated with tempol as compared with only sleep deprived rats (P<0.05). In conclusion chronic sleep deprivation induced memory impairment, and treatment with tempol prevented this impairment probably through normalizing antioxidant mechanisms in the hippocampus.

Chronic Melatonin Treatment Prevents Memory Impairment Induced by Chronic Sleep Deprivation.

Sleep deprivation (SD) has been associated with memory impairment through induction of oxidative stress. Melatonin, which promotes the metabolism of many reactive oxygen species (ROS), has antioxidant and neuroprotective properties. In this study, the effect of melatonin on memory impairment induced by 4weeks of SD was investigated using rat animal model. Animals were sleep deprived using modified multiple platform model. Melatonin was administered via oral gavage (100mg/kg/day). Spatial learning and memory were assessed using the radial arm water maze (RAWM). Changes in oxidative stress biomarkers in the hippocampus following treatments were measured using ELISA procedure. The result revealed that SD impaired both short- and long-term memory (P < 0.05). Use of melatonin prevented memory impairment induced by SD. Furthermore, melatonin normalized SD-induced reduction in the hippocampus activity of catalase, glutathione peroxidase (GPx), and superoxide dismutase (SOD). In addition, melatonin enhanced the ratio of reduced to oxidized glutathione GSH/GSSG in sleep-deprived rats (P < 0.05) without affecting thiobarbituric acid reactive substance (TBARS) levels (P > 0.05). In conclusion, SD induced memory impairment, which was prevented by melatonin. This was correlated with normalizing hippocampus antioxidant mechanisms during chronic SD.

Exploring the effect of vitamin C on sleep deprivation induced memory impairment.

In the current study, the possible beneficial effect of vitamin C (VitC) against sleep deprivation induced memory impairment was examined. Chronic sleep deprivation was induced via placing rats in a modified multiple platform apparatus for 8h/day for a period of 6 weeks. Concomitantly, VitC was administered to animals at doses of 150 and 500 mg/kg/day. After 6 weeks of treatment, the radial arm water maze (RAWM) was used to test for spatial learning and memory performance. Moreover, the hippocampus was dissected; and levels/activities of antioxidant defense biomarkers glutathione reduced (GSH), glutathione oxidized (GSSG), GSH/GSSG ratio, catalase, superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS), were evaluated. Results revealed that chronic sleep deprivation impaired short- and long-term memories (P<0.05). This impairment was prevented by chronic VitC treatments. In addition, VitC normalized sleep deprivation induced decreases in hippocamppal GSH/GSSG ratio (P<0.05), and activities of catalase, and SOD, and increase in GSSG levels (P<0.05). Collectively, spatial memory impairment was induced by chronic sleep deprivation, and VitC treatment prevented such impairment. This was possibly achieved via normalizing antioxidant defense mechanisms of the hippocampus.