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

Omega-3 fatty acids supplementation prevents learning and memory impairment induced by chronic ethanol consumption in adolescent male rats through restoration of inflammatory and oxidative responses

OBJECTIVE

Ethanol (Eth) intake is known to cause numerous detrimental effects on the structure and function of the brain, and it is commonly used as a psychostimulant drug by adolescents. Conversely, omega-3 (O3) can reduce the risk of cognitive decline and promote the maintenance of neurophysiological functions. In this study, we investigated the protective effects of O3 on behavioral alterations, oxidative stress, and interleukin-6 (IL-6) levels induced by chronic Eth intake during adolescence in rats.

MATERIALS AND METHODS

Adolescent male rats (21 days old) were divided as follows: (1) Vehicle, (2) Eth (Eth in drinking water [20%]), (3-5) Eth + O3 (50/100/150 mg/kg), and (6) O3 (150 mg/kg). After 5 weeks, Morris water maze (MWM) and passive avoidance (PA) tests were performed, and the hippocampal and cortical levels of oxidative stress markers and inflammatory indices were measured.

RESULTS

Adolescent Eth intake impairs learning and memory function in MWM and PA tests (groups × day, p < 0.05 and p < 0.001, respectively). It was shown that Eth induced oxidative stress and neuroinflammation. O3 improved learning and impairment induced by Eth by reducing the adverse effects of Eth on the oxidant/antioxidant balance in the hippocampi (for malondialdehyde [MDA]/thiol: p < 0.01, p < 0.001, respectively) and for superoxide dismutase (SOD)/catalase (CAT): p < 0.01 and p < 0.05, respectively). Furthermore, we found that O3 prevented the Eth-induced increase of hippocampal IL-6 (p < 0.001).

CONCLUSION

O3 supplementation acts as an effective approach to prevent learning and memory impairments induced by chronic Eth consumption during adolescence. In this respect, the antioxidant and anti-inflammatory properties of O3 seem to be the main underlying mechanisms of neuroprotection.

Melatonin attenuates chronic sleep deprivation-induced cognitive deficits and HDAC3-Bmal1/clock interruption

BACKGROUND AND AIMS

Sleep is predicted as a key modulator of cognition, but the underlying mechanisms are poorly understood. In this study, we investigated the effects of melatonin on chronic rapid eye movement sleep deprivation (CRSD)-induced cognitive impairment and circadian dysfunction in rat models.

METHODS

Thirty-six Sprague-Dawley male rats were divided into three groups: CRSD with saline treatment, CRSD with chronic melatonin injection (20 mg/kg/day), and non-sleep-deprived control. The cognitive behavioral tests as well as the expression of clocks and HDAC3 were evaluated in all groups.

RESULTS

CRSD significantly reduced recognition index in novel object location, increased escape latency and distance traveling in Morris water maze while melatonin treatment attenuated CRSD-induced hippocampal-dependent spatial learning and memory deficits. Furthermore, the mRNAs of brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1(Bmal1) and circadian locomotor output cycles kaput (Clock) were globally down-regulated by CRSD with constant intrinsic oscillation in both hippocampus and peripheral blood. The protein levels of hippocampal Bmal1, Clock, and HDAC3 were also remarkably down-regulated following CRSD. Melatonin treatment reversed CRSD-induced alterations of Bmal1/Clock and HDAC3 on both mRNA levels and protein levels.

CONCLUSIONS

Our data indicate that melatonin treatment attenuates CRSD-induced cognitive impairment via regulating HDAC3-Bmal1/Clock interaction. These findings explore a broader understanding of the relationship between sleep and cognition and provide a potential new therapeutic target for cognitive impairment.

Dietary and Metabolic Approaches for Treating Autism Spectrum Disorders, Affective Disorders and Cognitive Impairment Comorbid with Epilepsy: A Review of Clinical and Preclinical Evidence

Epilepsy often occurs with other neurological disorders, such as autism, affective disorders, and cognitive impairment. Research indicates that many neurological disorders share a common pathophysiology of dysfunctional energy metabolism, neuroinflammation, oxidative stress, and gut dysbiosis. The past decade has witnessed a growing interest in the use of metabolic therapies for these disorders with or without the context of epilepsy. Over one hundred years ago, the high-fat, low-carbohydrate ketogenic diet (KD) was formulated as a treatment for epilepsy. For those who cannot tolerate the KD, other diets have been developed to provide similar seizure control, presumably through similar mechanisms. These include, but are not limited to, the medium-chain triglyceride diet, low glycemic index diet, and calorie restriction. In addition, dietary supplementation with ketone bodies, polyunsaturated fatty acids, or triheptanoin may also be beneficial. The proposed mechanisms through which these diets and supplements work to reduce neuronal hyperexcitability involve normalization of aberrant energy metabolism, dampening of inflammation, promotion of endogenous antioxidants, and reduction of gut dysbiosis. This raises the possibility that these dietary and metabolic therapies may not only exert anti-seizure effects, but also reduce comorbid disorders in people with epilepsy. Here, we explore this possibility and review the clinical and preclinical evidence where available.

Comprehensive review: by-products from surimi production and better utilization

Over 1 million MT of surimi is produced globally, which theoretically would generate approximate 2 million MT of solid by-products and more than 1 million MT of wash water. Utilization of the by-products has increasingly become interested based on their nutritional, economical, and environmental issues. Surimi by-products represent an important source of valuable compounds such as functional protein, collagen, gelatin, fish oil, peptides, minerals, and enzymes. Better utilization of the by-products would make the surimi industry sustainable and profitable. This review paper characterizes sources and composition of the solid by-products and wash water generated from the surimi production as well as factors related to extraction and processing techniques. In addition, the potential food applications are explored including specialty foods and snacks, flavor ingredients, bioactive ingredients, and functional ingredients. Moreover, an outlook summarizing the challenges and prospects on the utilization of surimi by-products is provided.

Omega-3 fatty acids prevent nicotine withdrawal-induced impairment of learning and memory via affecting oxidative status, inflammatory response, cholinergic activity, BDNF and amyloid-B in rat hippocampal tissues

In the present study, the main objective was to reveal whether treatment by Omega-3 fatty acids could prevent the adverse effects of adolescent nicotine withdrawal on spatial and avoidance memory in male rats. For this purpose, Morris water maze and passive avoidance tests were performed on male Wistar rats and the hippocampal levels of oxidative stress markers, inflammatory indices, brain-derived neurotrophic factor, nitrite, amyloid-B and acetylcholinesterase (AChE) were measured. Moreover, density of dark neurons were assessed in CA1 and CA3 regions. Results showed that adolescent nicotine exposure followed by a period of drug cessation exacerbates the behavioral indices of learning and memory through affecting a variety of biochemical markers within the hippocampal tissues. These changes lead to elevation of oxidative and inflammatory markers, reduction of neurotrophic capacity and increased AChE activity in hippocampal tissues. In addition, it was observed that co-administration of nicotine with Omega-3 fatty acids significantly prevents nicotine withdrawal-induced adverse effects through restoration of the mentioned biochemical disturbances. Therefore, we suggest administration of Omega-3 fatty acids as a safe, inexpensive and effective therapeutic strategy for prevention of memory dysfunctions associated with nicotine abstinence during adolescence.

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.

The Devastating Effects of Sleep Deprivation on Memory: Lessons from Rodent Models

In this narrative review article, we discuss the role of sleep deprivation (SD) in memory processing in rodent models. Numerous studies have examined the effects of SD on memory, with the majority showing that sleep disorders negatively affect memory. Currently, a consensus has not been established on which damage mechanism is the most appropriate. This critical issue in the neuroscience of sleep remains largely unknown. This review article aims to elucidate the mechanisms that underlie the damaging effects of SD on memory. It also proposes a scientific solution that might explain some findings. We have chosen to summarize literature that is both representative and comprehensive, as well as innovative in its approach. We examined the effects of SD on memory, including synaptic plasticity, neuritis, oxidative stress, and neurotransmitters. Results provide valuable insights into the mechanisms by which SD impairs memory function.

Impact of chronic sleep deprivation and sleep recovery on hippocampal oligodendrocytes, anxiety-like behavior, spatial learning and memory of rats

Sleep and its quality play an important role in memory, cognition, and quality of life. Sleep deprivation-induced changes in hippocampal neurons and behavior have been studied widely, in contrast, the extent of damage to oligodendrocytes have not been fully understood. The present study aims to investigate chronic sleep deprivation (CSD) and sleep recovery-induced changes in oligodendrocytes of the hippocampus, cognition, and behavior of rats. Male Sprague-Dawley rats (n = 48) were grouped as control, sham control (SC), CSD, and CSD+sleep recovery (CSD+SR) (n = 12/group). CSD and CSD+SR group rats were sleep deprived for 21-days. After CSD, the CSD+SR group rats sleep recovered for 21-days. Oxidative markers, CNPase+ve oligodendrocytes, CNPase intensity, and CNPase gene expression were measured in the hippocampus, and the anxiety-like behavior, spatial learning, and memory were assessed. The 21-days of CSD significantly (p < 0.001) increased oxidative stress and significantly (p < 0.001) reduced the number of CNPase+ve oligodendrocytes, CNPase intensity, and CNPase gene expression when compared to controls. The increased oxidative stress was correlated with reduced CNPase+ve oligodendrocytes, CNPase intensity, and CNPase gene expression (r = -0.9). In-line with cellular changes, an increased (p < 0.01) anxiety-like behavior and impaired spatial memory were observed in the CSD group compared to controls. The 21-days of sleep recovery significantly (p < 0.01) reduced oxidative stress and anxiety-like behavior, improved spatial memory, increased CNPase intensity and CNPase gene expression, and non-significant (p > 0.05) increase in CNPase+ve oligodendrocytes compared to CSD. Overall, the 21-days of CSD reduced the number of CNPase+ve oligodendrocytes in the hippocampus, increased anxiety, and impaired spatial memory in rats. Though the 21-day sleep recovery showed an improvement in all parameters, it was not sufficient to completely reverse the CSD-induced changes to the control level.

A strategy for screening and identification of new amino acid-conjugated bile acids with high coverage by liquid chromatography-mass spectrometry

Bile acids (BAs) are a class of vital gut microbiota-host cometabolites, and they play an important role in maintaining gut microbiota-host metabolic homeostasis. Very recently, a new mechanism of BA anabolic metabolism mediated by gut microbiota (BA-amino acid conjugation) has been revealed, which provides a perspective for the research on BA metabolism and gut metabolome. In this study, we established a polarity-switching multiple reaction monitoring mass spectrometry-based screening method to mine amino acid-conjugated bile acids (AA-BAs) derived from host-gut microbiota co-metabolism. In addition, a retention time-based annotation strategy was further proposed to identify the AA-BA isomers and epimers. Using the developed methods, we successfully screened 118 AA-BA conjugates from mouse and human feces, 28 of them were confirmed by standards, and 62 putatively identified based on their predicted retention times. Moreover, we observed that the levels of most AA-BAs were significantly downregulated in the feces of chronic sleep deprivation mice, suggesting that the AA-BA metabolism was closely related to the physiological state of the host.

Melatonin upregulates BMAL1 to attenuate chronic sleep deprivation-related cognitive impairment by alleviating oxidative stress

PURPOSE

To investigate the mechanism underlying the regulatory effect of melatonin on chronic sleep deprivation-related cognitive impairment.

METHODS

Chronic sleep deprivation (CSD) model was established using the MMPM method. After the model was established, melatonin receptor agonist and inhibitor were given, respectively. Water maze was conducted to record the escape latency and the duration of crossing the platform of space exploration. The concentration of TNF-α, IL-6, MDA, and SOD was measured by ELISA. Immunofluorescence was used to determine the expression level of CD86 and CD206, while the mRNA expression of Bax, Bcl-2, P65, IκB, and BMAL1 was detected by qPCR. Western blotting assay was utilized to determine the protein expression of Bax, Bcl-2, P65, p-P65, IκB, p-I κB, and BMAL1.

RESULTS

Compared with the control, the escape latency was greatly increased on the second and third day, accompanied by the increased expression of TNF-α, IL-6, MDA, and SOD in serum. Furthermore, dramatically upregulated Bax, Bcl-2, P65, IκB, and CD86 were observed in the model group, accompanied by the declined expression level of BMAL1 and CD206. Compared with the model group, the escape latency was declined, the concentration of TNF-α, IL-6, MDA, and SOD was decreased, the expression level of Bax, Bcl-2, P65, IκB, and CD86 was declined, and the level of BMAL1 and CD206 was promoted by the treatment of the melatonin agonist, while the opposite results were observed under the treatment of the melatonin inhibitor.

CONCLUSION

Melatonin upregulates BMAL1 to attenuate chronic sleep deprivation-related cognitive impairment by alleviating oxidative stress.

Associations of α-linolenic acid dietary intake with very short sleep duration in adults

Objectives

This study aimed to investigate the association of α-linolenic acid (ALA; 18:3 ω-3) dietary intake with very short sleep duration (<5 h) in adults based on the CDC's National Health and Nutrition Examination Survey data.

Methods

Multinomial logistic regression was used to explore the association of ALA intake with very short sleep. To make the estimation more robust, bootstrap methods of 1,000 replications were performed. Rolling window method was used to investigate the trend of the odds ratios of very short sleep with age. A Kruskal-Wallis test was applied to estimate the differences in the ORs of very short sleep between genders and different age groups.

Results

Compared with the first tertile, the ORs of very short sleep and the corresponding 95% CIs for the second and the third tertile of dietary ALA intake in males were 0.618 (0.612, 0.624) and 0.544 (0.538, 0.551), respectively, and in females were 0.575 (0.612, 0.624) and 0.432 (0.427, 0.437). In most cases, the differences between different ages were more significant than those between different sexes. Men's very short sleep odds ratios for the second tertile of ALA intake increased linearly with age before 60.

Conclusions

The risk of a very short sleep duration was negatively related to the dietary intake of ALA. The effect of ALA on very short sleep is significantly different among groups of different genders and ages.

Potential Psychoactive Effects of Microalgal Bioactive Compounds for the Case of Sleep and Mood Regulation: Opportunities and Challenges

Sleep deficiency is now considered an emerging global epidemic associated with many serious health problems, and a major cause of financial and social burdens. Sleep and mental health are closely connected, further exacerbating the negative impact of sleep deficiency on overall health and well-being. A major drawback of conventional treatments is the wide range of undesirable side-effects typically associated with benzodiazepines and antidepressants, which can be more debilitating than the initial disorder. It is therefore valuable to explore the efficiency of other remedies for complementarity and synergism with existing conventional treatments, leading to possible reduction in undesirable side-effects. This review explores the relevance of microalgae bioactives as a sustainable source of valuable phytochemicals that can contribute positively to mood and sleep disorders. Microalgae species producing these compounds are also catalogued, thus creating a useful reference of the state of the art for further exploration of this proposed approach. While we highlight possibilities awaiting investigation, we also identify the associated issues, including minimum dose for therapeutic effect, bioavailability, possible interactions with conventional treatments and the ability to cross the blood brain barrier. We conclude that physical and biological functionalization of microalgae bioactives can have potential in overcoming some of these challenges.

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.

L-Carnitine prevents memory impairment induced by post-traumatic stress disorder

BACKGROUND

Post-traumatic stress disorder (PTSD) is a genuine obstructing mental disorder. As indicated by the name, it is related to the patients' stress augmented by life-threatening conditions or accidents. The PTSD has linked to oxidative stress that can result in neurodegeneration. L-carnitine (L-CAR) is known for its antioxidant properties, which can protect against neuronal damage.

OBJECTIVE

In the current study, we investigated the beneficial effects of L-CAR on the memory impairment induced by PTSD using a rat model.

METHODS

A model of single-prolonged stress (a cycle of restraining, forced swimming, rest, and finally diethyl ether exposure for 2 h, 20 min, 15 min, and 1-2 min, respectively) was used to induce PTSD-like behavior. Intraperitoneal L-CAR treatment (300 mg/kg/day) was introduced for four weeks. Both memory and special learning were evaluated utilizing the radial arm water maze (RAWM). Moreover, the levels of glutathione peroxidase (GPx), glutathione reduced (GSH), and glutathione oxidized (GSSG) were assessed as biomarkers oxidative stress in the hippocampus.

RESULTS

The results demonstrated that both the short and long-term memories were impaired by PTSD/SPS model (P <  0.05), while L-CAR treatment prevented this memory impairment in PTSD rats. Besides, L-CAR prevented the reduction in GPx activity and increase in GSSG, which were altered in the hippocampus of the PTSD/SPS rats (P <  0.05). Levels of GSH were not changed in PTSD and/or L-CAR rats.

CONCLUSIONS

L-CAR administration prevented short- and long-term memories' impairments induced in the PTSD/SPS rat model. This is probably related to its antioxidant effects in the hippocampus.

Effect of chronic sleep deprivation and sleep recovery on hippocampal CA3 neurons, spatial memory and anxiety-like behavior in rats

Sleep deprivation-induced degenerative changes in the brain lead to the impairment of memory, anxiety, and quality of life. Several studies have reported the effects of sleep deprivation on CA1 and dentate gyrus regions of the hippocampus; in contrast, there is less known about the impact of chronic sleep deprivation (CSD) and sleep recovery on CA3 neurons and behavior. Hence, the present study aimed to understand the effect of CSD and sleep recovery on hippocampal CA3 neurons and spatial memory, and anxiety-like behavior in rats. Sixty male rats (Sprague Dawley) were grouped as control, environmental control (EC), CSD, 5 days sleep recovery (CSD + 5D SR), and 21 days sleep recovery (CSD + 21D SR). CSD, CSD + 5D SR and, CSD + 21D SR group rats were sleep deprived for 21 days (18 h/day). After CSD, the CSD + 5D SR and CSD + 21D SR rats were sleep recovered for 5- and 21-days respectively. Oxidative stress, dendritic arborization of CA3 neurons, spatial memory, and anxiety-like behavior was assessed. Spatial memory, basal, and apical dendritic branching points/intersections in hippocampal CA3 neurons were reduced, and anxiety-like behavior and oxidative stress increased significantly in the CSD group compared to control (p < 0.001). The CSD + 21D SR showed a significant improvement in spatial memory, reduction in anxiety-like behavior, and oxidative stress when compared to the CSD group (p < 0.05). The basal and apical dendritic branching points/intersections in hippocampal CA3 neurons were increased after CSD + 21D SR, however, it was not significant (p > 0.05). Even though the CSD + 21D SR showed a significant improvement in all the parameters, it did not reach the control level. There was an improvement in all the parameters after CSD + 5D SR but this was not significant compared to the CSD group (p > 0.05). Overall results indicate that the CSD-induced impairment of spatial memory and anxiety-like behavior was associated with oxidative stress and reduced dendritic arborization of hippocampal CA3 neurons. The CSD + 21D SR significantly reduced the damage caused by CSD, but it was not sufficient to reach the control level.

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.

H2S Attenuates Sleep Deprivation-Induced Cognitive Impairment by Reducing Excessive Autophagy via Hippocampal Sirt-1 in WISTAR RATS

Sleep deprivation (SD) is widespread in society causing serious damage to cognitive function. Hydrogen sulfide (H2S), the third gas signal molecule, plays important regulatory role in learning and memory functions. Inhibition of excessive autophagy and upregulation of silent information regulator 1 (Sirt-1) have been reported to prevent cognitive dysfunction. Therefore, this present work was to address whether H2S attenuates the cognitive impairment induced by SD in Wistar rats and whether the underlying mechanisms involve in inhibition of excessive autophagy and upregulation of Sirt-1. After treatment with SD for 72 h, the cognitive function of Wistar rats was evaluated by Y-maze, new object recognition, object location, and Morris water maze tests. The results shown that SD-caused cognitive impairment was reversed by treatment with NaHS (a donor of H2S). NaHS also prevented SD-induced hippocampal excessive autophagy, as evidenced by the decrease in autophagosomes, the down-regulation of Beclin1, and the up-regulation of p62 in the hippocampus of SD-exposed Wistar rats. Furthermore, Sirtinol, an inhibitor of Sirt-1, reversed the inhibitory roles of NaHS in SD-induced cognitive impairment and excessive hippocampal autophagy in Wistar rats. Taken together, our results suggested that H2S improves the cognitive function of SD-exposed rats by inhibiting excessive hippocampal autophagy in a hippocampal Sirt-1-dependent way.

Swimming exercise improves short- and long-term memories: Time-course changes

The beneficial effects of exercise training on memory formation are well documented. However, the memory enhancement profile following the time-course of exercise training remains unknown. In this investigation, changes in the spatial hippocampal memory following a time-course of swimming exercise training were examined. Young adult Wistar rats were tested for both short-term and long-term memories using the radial arm water maize (RAWM) paradigm following 0, 1, 7, 14, and 28 days of swimming exercise training (60 min per day, 5 days/week)s. The mean total errors on RAWM during the learning phase and memory testing remained the same (p > 0.5) after 1 day of swimming exercise. On the other hand, swimming exercise-induced significant enhancement to the learning phase and memory formation after 7 days of training (p < 0.01). Errors decreased (p < 0.0001) after 7 days of training and remained lower (p < 0.0001) than baseline without differences between 7, 14, and 28 days (p > 0.5). Similarly, short- and long-term memories improved after 7 days (p < 0.05) of training as compared to the baseline without differences between 7, 14, and 28 days (p > 0.05). The time course of improvement of learning and both short- and long-term memories after swimming exercise were evident after 7 days and plateaued thereafter. Results of the current study could form the base for future utilization of exercises to enhance cognitive function in healthy individuals.

Investigating the effect of crocin on memory deficits induced by total sleep deprivation (TSD) with respect to the BDNF, TrkB and ERK levels in the hippocampus of male Wistar rats

BACKGROUND

Sleep deprivation (SD) induces cognitive impairments such as memory deficit. Brain-derived neurotrophic factor (BDNF) is considered as the most critical neurotrophin in the central nervous system that is involved in sleep and memory. The main receptor of BDNF, tropomyosin receptor kinase B (TrkB), is dramatically expressed in the hippocampus. Also, extracellular signal-regulated kinase (ERK) has a significant role in memory function. Crocin is a carotenoid chemical compound and the active component of the flower Crocus sativus L. (saffron) that improves memory function and increases the level of BDNF, TrkB and ERK.

AIMS

In this research, we aimed to investigate the effect of total SD (TSD, 24 h) and crocin on memory performance, and BDNF, TrkB and ERK hippocampal levels.

METHODS

Passive avoidance memory was assessed using step-through, and working memory was measured using Y-maze tasks. The level of proteins in both hemispheres of the hippocampus was evaluated using Western blotting. Crocin was injected intraperitoneally at doses of 1, 5 and 15 mg/kg.

RESULTS

Twenty-four-hour TSD impaired both types of memories and decreased the level of all proteins in both hemispheres of the hippocampus. Crocin at all doses restored TSD-induced memory deficits. Crocin (15 mg/kg) reversed the effect of TSD on levels of all proteins.

CONCLUSIONS

The adverse effect of TSD on the level of proteins in the hippocampus may disrupt synaptic plasticity and transmission, which induces memory impairment. Additionally, the restoration effect of crocin on the decrease in protein levels may be involved in its improvement effect on memory performance.

N-3 PUFA Prevent Oxidative Stress in a Rat Model of Beta-Amyloid-Induced Toxicity

Polyunsaturated fatty acids (PUFA) are involved in brain disorders associated to amyloid beta (Aβ) toxicity for which oxidative stress, neurochemical dysfunctions, and neuroinflammation are underlying mechanisms. Here, mechanisms through which lifelong exposure to n-3 PUFA-enriched or n-6/n-3 balanced diets could elicit a protective role in a rat model of Aβ-induced toxicity were investigated. To this aim, we quantified hippocampal reactive oxygen species (ROS) amount, 8-hydroxy-2'-deoxyguanosine and interleukin-10 levels, NADPH oxidase (NOX) 1, NOX2, superoxide dismutase 1, and glutathione contents, as well as plasmatic malondialdehyde. Moreover, in the same experimental groups, we assessed tryptophan, serotonin, and its turnover, kynurenine, and noradrenaline amounts. Results showed increased hippocampal ROS and NOX2 levels, serotonin turnover, kynurenine, and noradrenaline contents in Aβ-treated rats. Both n-6/n-3 balanced and n-3 PUFA enriched diets reduced ROS production, NOX1 and malondialdehyde levels, serotonin turnover, and kynurenine amount in Aβ-injected rats, while increasing NOX2, superoxide dismutase 1, and serotonin contents. No differences in plasmatic coenzyme Q10, reduced glutathione (GSH) and tryptophan levels were detected among different experimental groups, whereas GSH + oxidized glutathione (GSSG) levels were increased in sham animals fed with n-3 PUFA enriched diet and in Aβ-treated rats exposed to both n-6/n-3 balanced and n-3 enriched diets. In addition, Aβ-induced decrease of interleukin-10 levels was prevented by n-6/n-3 PUFA balanced diet. N-3 PUFA enriched diet further increased interleukin-10 and 8-hydroxy-2'-deoxyguanosine levels. In conclusion, our data highlight the possible neuroprotective role of n-3 PUFA in perturbation of oxidative equilibrium induced by Aβ-administration.

Lipid profile and fatty acid composition of marine fish species from Northeast coast of Brazil

Total lipid content, fatty acid composition and nutritional profile of lipid fraction of fourteen fish species from the Brazilian Northeastern coast were evaluated. Lipid content was determined by Bligh and Dyer methodology, whereas the fatty acid composition was determined by gas chromatography with flame ionization detector. The indices of atherogenicity, thrombogenicity and hypocholesterolemic/hypercholesterolemic ratio were used to evaluate the nutritional quality of lipid fraction. The total lipid content ranged from 0.25 to 3.09%, with higher values in L. synagris. A significant difference (p < 0.05) were noted in fatty acids composition between the fourteen fish species. PUFA were the major fatty acids in twelve of fourteen species and C. leiarchus showed the highest content. The n-3 content ranged from 69.83 to 270.62 mg g^-1 of total lipids, being EPA and DHA the major fatty acids in most of the species studied. The species L. synagris, M. bonaci and S. brasiliensis exceeded the WHO daily intake recommendation of 250 mg per day from those fatty acids. The quality indexes of the lipid fraction as well as the n-6/n-3 and PUFA/SFA ratios indicated that all fish species can be healthy nutritional options, and can bring many benefits to human health. The principal component analysis resulted in a two-principal-component model that described 79.78% of data variance. Also, it highlighted that despite the differences between the breeding strategies of fish families, the species could be grouped according to their similarity in fatty acids composition.

The effect of alpha lipoic acid on passive avoidance and social interaction memory, pain perception, and locomotor activity in REM sleep-deprived rats

BACKGROUND

Evidence shows the vital role of sleep in the modulation of cognitive functions. Sleep deprivation (SD) can disrupt learning and memory processes. SD also affects pain perception and locomotor activity. Furthermore, alpha lipoic acid (ALA) may induce antioxidant and neuroprotective effects. ALA affects memory processes, pain subthreshold, and locomotor activity. The goal of the present study was to investigate the effect of REM (rapid-eye movement) SD and ALA on social and passive avoidance memory, locomotor activity, and pain perception.

METHODS

Multiple-platform apparatus was used to induce REM SD for 24 h. Three-chamber paradigm test, the shuttle box, locomotion apparatus, and hot plate were used to assess social interaction memory, passive avoidance memory, locomotor activity, and pain perception, respectively. ALA was injected intraperitoneally at the doses of 35 and 70 mg/kg.

RESULTS

24 h REM SD impaired both types of memory. In addition, ALA (35 mg/kg) reversed REM SD-induced memory impairments. However, ALA (70 mg/kg) impaired social memory with no effect on REM SD-induced memory impairments. ALA (70 mg/kg) also decreased pain subthreshold in REM SD rats.

CONCLUSION

REM SD impairs social interaction and passive avoidance memory. Furthermore, ALA may exhibit a dose-dependent manner in some cognitive tasks. ALA can induce a therapeutic effect at one dose, and an impairment effect at another dose (lower or higher), while the cognitive task and the conditions are equal.

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.

The effect of fish oil on social interaction memory in total sleep-deprived rats with respect to the hippocampal level of stathmin, TFEB, synaptophysin and LAMP-1 proteins

Fish oil (FO) is one of the richest natural sources of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA is essential for brain functions and EPA has been approved for brain health. On the other hand, stathmin, TFEB, synaptophysin and LAMP-1 proteins are involved in synaptic plasticity, lysosome biogenesis and synaptic vesicles biogenesis. In this study, we aimed to investigate the effect of FO on social interaction memory in sleep-deprived rats with respect to level of stathmin, TFEB, synaptophysin and LAMP-1 in the hippocampus of rats. All rats received FO through oral gavage at the doses of 0.5, 0.75 and 1 mg/kg. The water box was used to induce total sleep deprivation (TSD) and the three-chamber paradigm test was used to assess social behavior. Hippocampal level of proteins was assessed using Western blot. The results showed, FO impaired social memory at the dose of 1 mg/kg in normal and sham groups. SD impaired social memory and FO did not restore this effect. Furthermore, FO at the dose of 0.75 mg/kg decreased social affiliation and social memory in all groups of normal rats, compared with related saline groups, and at the dose of 1 mg/kg impaired social memory for stranger 2 compared with saline group. In sham groups, FO at the dose of 1 mg/kg impaired social memory for stranger 2 compared with saline group. SD decreased hippocampal level of all proteins (except stathmin), and FO (1 mg/kg) restored these effects. In conclusion, FO negatively affects social interaction memory in rats.

Edible alginate/chitosan-based nanocomposite microspheres as delivery vehicles of omega-3 rich oils

A new series of alginate/chitosan-based nanocomposite microspheres was developed to achieve the maximum health benefit and to minimize the oxidation of omega-3 rich oils (flaxseed or fish oils). The nanocomposite microspheres incorporate curcumin (Cur) as natural antioxidant, and have been prepared using a three-step procedure (oil-in-water (o/w) emulsification, gelation and microencapsulation). The average particle size of Cur-free and Cur-loaded nanocomposites ranged between 139 and 153 nm. The presence of omega-3 rich oils in core of the formulated microspheres was confirmed by XRD and FTIR. Optical microscopy, stereo microscopy, SEM and AFM showed a spherical shape of the microspheres. Microencapsulation efficiency, oxidative stability, release profile of oils as well as the antioxidant and antibacterial activities were investigated. The results suggested that the microspheres could be applied as effective and safe edible vehicles for hydrophobic nutraceuticals like omega-3 rich oils with broad spectrum antibacterial activity.

Carious Lesion Severity Induces Higher Antioxidant System Activity and Consequently Reduces Oxidative Damage in Children's Saliva

Oxidative stress biomarkers can be found at detectable concentrations in saliva. These salivary biomarkers reflect specific oxidation pathways associated with caries and periodontitis. Our study evaluated the influence of dental caries severity (assessed using the ICCMS™ criteria) on the levels of oxidative stress biomarkers in saliva from children. Unstimulated saliva samples were collected from patients (from one to three years old) in a day care center in Birigui, SP, Brazil, two hours after fasting. Children were divided into four groups (n = 30/group), according to caries severity: caries free (group A), early carious lesions (group B), moderate carious lesions (group C), and advanced carious lesions (group D). The following salivary biomarkers were determined: total proteins (TP), measured by the Lowry method; oxidative damage, measured by the TBARS method; total antioxidant capacity (TAC); superoxide dismutase (SOD) enzymatic antioxidant activity; and uric acid (UA) non-enzymatic antioxidant activity. Data were analyzed by ANOVA, followed by the Student-Newman-Keuls test, Pearson and Spearman correlation coefficients, and multivariable linear regression (p < 0.05). TP, TAC, SOD enzymatic antioxidant activity, and UA non-enzymatic antioxidant activity increased with caries severity, consequently reducing salivary oxidative damage. It was concluded that higher caries severity increases salivary antioxidant system activity, with consequent reduction in salivary oxidative damage.

Dietary intake of polyunsaturated fatty acids alleviates cognition deficits and depression-like behaviour via cannabinoid system in sleep deprivation rats

Sleep deprivation (SD) is a common feature in modern society. Prolonged sleep deprivation causes cognition deficits and depression-like behavior in the model of animal experiments. Endocannabinoid system are key modulators of synaptic function, which were related to memory and mood. Although the underlying mechanism remains unknown, several studies indicated the benefits of polyunsaturated fatty acids (PUFAs, linolenic acid, 39.7 %; linoleic acid, 28 %; and oleic acid, 22 %) on brain function through the endocannabinoid system. The present study aimed to evaluate the influence of dietary PUFAs on cognition deficits induced by sleep deprivation in Sprague Dawley rats. The rats were sleep deprivation continuously for 7 days and fed with PUFAs at three different dosages (2, 4 and 8 μl/g body weight) at the meantime. The effect of PUFAs on cognition was investigated by object recognition test while depressive-like behavior were detected using sucrose preference test and forced swim test. The mechanism of PUFAs was elucidated by hippocampal synaptic transmission analyses. The resluts revealed that SD led to the disorder of cognition and mood which was improved by the supplement of PUFAs. SD significantly increased the mEPSC frequency, and decreased the protein level of cannabinoid type-1 receptors (CB₁R). These changes were restored by supplement of PUFAs, which showed a similar level to the control group. Behaviour tests showed that the positive effects on repairing cognition and anxiety disorders were almost completely abolished when the CB₁R receptor antagonist rimonabant was applied to the SD rats. These findings indicated that PUFAs are a factor regulating cognition deficits and depression induced by SD via cannabinoid type-1 receptors.

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.