Fish oil ameliorates neuropsychiatric behaviors and gut dysbiosis by elevating selected microbiota-derived metabolites and tissue tight junctions in rats under chronic sleep deprivation

Modifications in the Composition of the Gut Microbiota in Rats Induced by Chronic Sleep Deprivation: Potential Relation to Mental Disorders

Introduction

Sleep deprivation(SD) has numerous negative effects on mental health. A growing body of research has confirmed the implication of gut microbiota in mental disorders. However, the specific modifications in mammalian gut microbiota following SD exhibit variations across different studies.

Methods

Male specific-pathogen-free Wistar rats were given a modified multiple-platform exposure for 7 days of SD. Fecal samples were obtained from the control and SD groups both at baseline and after 7 days of SD. We utilized 16S rDNA gene sequencing to investigate the gut microbial composition and functional pathways in rats.

Results

Analysis of the microbiota composition revealed a significant change in gut microbial composition after chronic SD, especially at the phylum level. The relative abundances of p_Firmicutes, g_Romboutsia, and g_Enterococcus increased, whereas those of p_Bacteroidetes, p_Verrucomicrobia, p_Fusobacteria, g_Akkermansia, and g_Cetobacterium decreased in animals after chronic SD compared with controls or animals before SD. The ratio of Firmicutes to Bacteroidetes exhibited an increase following SD. The relative abundance of gut microbiota related to the functional pathways of GABAergic and glutamatergic synapses was observed to be diminished in rats following SD compared to pre-SD.

Conclusion

Collectively, these findings suggest that chronic SD causes significant alterations in both the structural composition and functional pathways of the gut microbiome. Further researches are necessary to investigate the chronological and causal connections among SD, the gut microbiota and mental disorders.

A Mixture of Soybean Oil and Lard Alleviates Postpartum Cognitive Impairment via Regulating the Brain Fatty Acid Composition and SCFA/ERK(1/2)/CREB/BDNF Pathway

Lard is highly appreciated for its flavor. However, it has not been elucidated how to consume lard while at the same time eliminating its adverse effects on postpartum cognitive function. Female mice were divided into three groups (n = 10): soybean oil (SO), lard oil (LO), and a mixture of soybean oil and lard at a ratio of 1:1 (LS). No significant difference was observed between the SO and LS groups in behavioral testing of the maternal mice, but the LO group was significantly worse compared with these two groups. Moreover, the SO and LS supplementation increased docosahexaenoic acid (DHA) and total n-3 polyunsaturated fatty acid (PUFA) levels in the brain and short-chain fatty acid (SCFA)-producing bacteria in feces, thereby mitigating neuroinflammation and lowering the p-ERK(1/2)/ERK(1/2), p-CREB/CREB, and BDNF levels in the brain compared to the LO group. Collectively, the LS group inhibited postpartum cognitive impairment by regulating the brain fatty acid composition, neuroinflammation, gut microbiota, and the SCFA/ERK(1/2)/CREB/BDNF signaling pathway compared to lard.

Protective Effect of Egg Yolk Lipids against Dextran Sulfate Sodium-Induced Colitis: The Key Role of Gut Microbiota and Short-Chain Fatty Acids

Egg yolk lipids significantly alleviate dextran sulfate sodium (DSS)-induced colitis by inhibiting NLRP3 inflammasome, reversing gut microbiota dysbiosis, and increasing short chain fatty acids (SCFAs) concentrations. However, the role of gut microbiota and the relationship between SCFAs and NLRP3 inflammasome are still unknown. Here, this study confirms that antibiotic treatment abolishes the protective effect of egg yolk lipids on DSS-induced colonic inflammation, intestinal barrier damage, and lipopolysaccharide translocation. Fecal microbiota transplantation also supports that egg yolk lipids alleviate colitis in a gut microbiota-dependent manner. Then, the study investigates the relationship between SCFAs and NLRP3 inflammasome, and finds that SCFAs significantly suppress colitis via inhibiting colonic NLRP3 inflammasome activation and proinflammatory cytokines secretions (interleukin, IL)-1β and IL-18, and combined treatment of SCFAs and MCC950 (NLRP3 inhibitor) shows a better activity against colitis and NLRP3 inflammasome activation. Together, these findings provide positive evidence for gut microbiorta-SCFAs-NLRP3 axis as a novel target involving in the therapy of inflammatory bowel disease.

Sleep deprivation alters pubertal timing in humans and rats: the role of the gut microbiome

STUDY OBJECTIVES

Evidence implied that sleeping duration is associated with the timing of puberty and that sleep deprivation triggers early pubertal onset in adolescents. Sleep deprivation can affect metabolic changes and gut microbiota composition. This study investigated the effects of sleep deprivation on pubertal onset and gut microbiota composition in animal models and a human cohort.

METHODS

This study comprised 459 boys and 959 girls from the Taiwan Pubertal Longitudinal Study. Sleep duration was evaluated using the self-report Pittsburgh Sleep Quality Index questionnaire. Early sexual maturation was defined by pediatric endocrinologist assessments. Mediation analyses were done to examine the association between sleep parameters, obesity, and early sexual maturation. Besides, Sprague Dawley juvenile rats were exposed to 4 weeks of chronic sleep deprivation. Vaginal opening (VO) and preputial separation (PS) were observed every morning to determine pubertal onset in female and male rats.

RESULTS

The sleep-deprived juvenile rats in the sleep-deprived-female (SDF) and sleep-deprived-male (SDM) groups experienced delayed VO (mean VO days: 33 days in control; 35 days in SDF; p-value < 0.05) and PS (mean PS days: 42 days in control; 45 days in SDM; p-value < 0.05), respectively. Relative to their non-sleep-deprived counterparts, the sleep-deprived juvenile rats exhibited lower body weight and body fat percentage. Significant differences in relative bacterial abundance at genus levels and decreased fecal short-chain-fatty-acid levels were identified in both the SDF and SDM groups. In the human cohort, insufficient sleep increased the risk of early sexual maturation, particularly in girls (OR, 1.44; 95% CI: 1.09 to 1.89; p-value < 0.01). Insufficient sleep also indirectly affected early sexual maturation in girls, with obesity serving as the mediator.

CONCLUSIONS

Overall, sleep deprivation altered the timing of puberty in both animal and human models but in different directions. In the rat model, sleep deprivation delayed the pubertal onset in juvenile rats through gut dysbiosis and metabolic changes, leading to a low body weight and body fat percentage. In the human model, sleep deprivation led to fat accumulation, causing obesity in girls, which increased the risk of early puberty.

Melatonin Ameliorates Neuropsychiatric Behaviors, Gut Microbiome, and Microbiota-Derived Metabolites in Rats with Chronic Sleep Deprivation

With the increasing prevalence of sleep deprivation (SD)-related disorders, the effective treatment of sleep disorders has become a critical health research topic. Thus, we hypothesized and investigated the effectiveness of a 3-week melatonin intervention on neuropsychiatric behavioral responses mediated throughout melatonin receptors, gut microbiota, and lipid metabolites in rats with chronic SD. Eighteen 6-week-old Wistar rats were used and divided into the control grup (C, n = 6), SD group (n = 6), and melatonin-supplemented group (SDM, n = 6). During weeks 0 to 6, animals were provided with the AIN-93M diet and free access to water. Four-week chronic SD was conducted from weeks 7 to 10. Exogenous melatonin administration (10 mg/kg BW) was injected intraperitoneally 1 h before the daily administration of SD for 3 weeks in the SDM group. SD rats exhibited anxiety-like behavior, depression-like behavior, and cognitive impairment. Exogenous melatonin administration ameliorated neuropsychiatric behaviors induced by chronic SD. Analysis of fecal metabolites indicated that melatonin may influence brain messaging through the microbiota-gut-brain axis by increasing the production of short-chain fatty acids (SCFA) and decreasing the production of secondary bile acids (SBA). Four-week SD reduced the cerebral cortex expression of MT1, but not in the colon. Chronic SD led to anxiety and depression-like behaviors and cognitive decline, as well as the reduced intestinal level of SCFAs and the enhanced intestinal level of SBAs in rats. In this work, we confirmed our hypothesis that a 3-week melatonin intervention on neuropsychiatric behavioral response mediated throughout melatonin receptors, gut microbiota, and lipid metabolites in rats with chronic SD.

Torreya grandis oil attenuates cognitive impairment in scopolamine-induced mice

The oil of Torreya grandis (TGO), a common nut in China, is considered to be a bioactive edible oil and has a great value in functional food development. In this study, the neuroprotective effects of TGO were investigated on a scopolamine (SCOP)-induced C57BL/6J mouse model. The mice were pretreated with TGO for 30 days (1000 mg per kg per day and 3000 mg per kg per day, i.g.). Behavioral tests showed that the supplementation of TGO could prevent the cognitive deficits induced by SCOP. TGO rebalanced the disorder of the cholinergic system by upgrading the level of acetylcholine. TGO also alleviated the over-activation of microglia and inhibited neuroinflammation and oxidative stress. Additionally, TGO could regulate the composition of gut microbiota, increase the production of short-chain fatty acids, and decrease the content of lipopolysaccharides in the serum. In conclusion, TGO has the potential to prevent loss of memory and impairment of cognition, which may be related to its regulation of the gut microbiota-metabolite-brain axis.

Immunomodulatory effect of marine lipids on food allergy

Seafood is highly enriched in n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs), particularly eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3), in contrast to the ultra-processed foods included in the modern Western diet that have high levels of n-6 linoleic acid (LA, 18:2 n-6), precursor for the pro-inflammatory n-6 arachidonic acid (ARA, 20:4 n-6). The capacity of marine lipids to reduce plasmatic triglycerides and blood pressure have been well-described. Moreover, recent studies have also raised evidence of a potential regulatory action of marine lipids on inflammation, the immune system, and food allergy (FA). FA is considered one of the main concerns to become life threatening in food safety. The prevalence of this emerging global problem has been increasing during the last two decades, especially in industrialized countries. About a 6-8% of young children and 2-4% of adults is estimated to be affected by FA. The main objective of the current study is to update the existing knowledge, but also the limitations, on the potential impact of marine lipids and their lipid mediators in regulating immunity, inflammation, and ultimately, food allergies. In particular, the focus is on the effect of marine lipids in modulating the key factors that control the sensitization and effector phases of FA, including gut microbiota (GM), inflammation, and immune system response. Results in animal models highlight the positive effect that consuming marine lipids, whether as a supplement or through seafood consumption, may have a relevant role in improving gut dysbiosis and inflammation, and preventing or reducing the severity of FA. However, more systematic studies in humans are needed to optimize such beneficial actions to each particular FA, age, and medical condition to reach an effective clinical application of marine lipids to improve FAs and their outcomes.

REM sleep deprivation induced by the modified multi-platform method has detrimental effects on memory: A systematic review and meta-analysis

The modified multi-platform method (MMPM) is used to induce animal models of paradoxical sleep deprivation and impairs memory in rodents. However, variations in MMPM protocols have contributed to inconsistent conclusions across studies. This meta-analysis aimed to assess the variations of the MMPM and their effects on memory in rats and mice. A comprehensive search identified 60 studies, and 50 were included in our meta-analysis. Overall, the meta-analysis showed that the MMPM significantly reduced the percentage of time spent in target quadrants (I2 = 54 %, 95 % confidence interval [CI] = [-1.83, -1.18]) and the number of platform-area crossings (I2 = 26 %, 95 % CI = [-1.71, -1.07]) in the Morris water maze (MWM) and shortened the latency to entering the dark compartment in the passive avoidance task (I2 = 68 %, 95 % CI = [-1.36, -0.57]), but it increased the number of errors in the radial arm water maze (RAWM) (I2 = 59 %, 95 % CI = [1.29, 2.07]). Additionally, mice performed worse on the MWM, whereas rats performed worse on the passive avoidance task. More significant memory deficits were found in cross-learning and post-learning MMPM in the MWM and RAWM, respectively. This study provided evidence that the MMPM can be used in preclinical studies of memory deficits induced by paradoxical sleep deprivation.

A Novel Nutrient Intervention of Probiotics, Glutamine, and Fish Oil in Psychological Distress: A Concurrent Multiple Baseline Design

Objectives: The aim of this study was to investigate whether a combination of nutrients designed to promote gut and brain health also lowers psychological distress. The hypothesis is that a probiotic with fish oil, and glutamine supplement will reduce psychological distress. Design: A multiple baseline design was used to collect data from seven naturopathic patients in private naturopathic clinics in Australia. Patients were between 18 and 65 years of age, and had a Kessler-10 (K10) score between 16 and 30 and symptoms associated with mild gastrointestinal discomfort experienced several times most weeks for 3 months. They were randomized into one of three pathways to stagger the introduction of the intervention. Interventions: Participants received either a supplement incorporating a probiotic formulation (including Lactobacillus rhamnosus), a glutamine powder formulation, and fish oil, or matched placebos. The primary outcome measure was psychological distress as measured by the K10 scale of psychological distress. Results: The data showed a general trend toward lower K10 scores during the active phase compared with the baseline phase, with a marked reduction in the variances between phases. After controlling for time and baseline values, no significant difference between the phases for the K10 and the Perceived Stress Scale was found, but there was still a significant reduction in symptoms on the Gastrointestinal Symptom Rating Scale. Conclusions: A combination of a probiotic formulation, a glutamine powder formulation, and fish oil did not affect psychological distress and perceived stress, but had a significant beneficial effect on gastrointestinal symptoms in patients with high distress and concurrent gut symptomology. Clinical trial registration number: ACTRN12620000928910.

Targeting microbiota to alleviate the harm caused by sleep deprivation

Sleep deprivation has become a common health hazard, affecting 37-58% of the population and promoting the occurrence and development of many diseases. To date, effective treatment strategies are still elusive. Accumulating evidence indicates that modulating the intestinal microbiota harbors significant potential for alleviating the deleterious impacts of sleep deprivation. This paper first reviews the effects of sleep deprivation on gastrointestinal diseases, metabolic diseases, and neuropsychiatric diseases, discussing its specific mechanisms of influence. We then focus on summarizing existing interventions, including probiotics, melatonin, prebiotics, diet, and fecal microbiota transplantation (FMT). Finally, we have discussed the advantages and limitations of each strategy. Compared with other strategies, probiotics showed a high potential in alleviating sleep deprivation-related hazards due to their reduced risk and high security. We suggest that future research should focus on the specific mechanisms by which probiotics mitigate the harms of sleep deprivation, such insights may unveil novel pathways for treating diseases exacerbated by insufficient sleep.

Bile Acids and Short-Chain Fatty Acids Are Modulated after Onion and Apple Consumption in Obese Zucker Rats

Gut microorganisms are involved in the development and severity of different cardiovascular diseases, and increasing evidence has indicated that dietary fibre and polyphenols can interact with the intestinal microbiota. The study objective was to investigate the effect of onion and apple intake on the major types of microbial-derived molecules, such as short-chain fatty acids (SCFAs) and bile acids (BAs). Obese Zucker rats were randomly assigned (n = eight rats/group) to a standard diet (OC), a standard diet/10% onion (OO), or a standard diet/10% apple (OA). Lean Zucker rats fed a standard diet served as a lean control (LC) group. Faecal samples were collected at baseline, and 8 weeks later, the composition of the microbial community was measured, and BA and SCFA levels were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Rats fed onion- and apple-enriched diets had increased abundance of beneficial bacteria, such as Bifidobacterium spp. and Lactobacillus spp., enhanced SCFAs (acetic, propionic, isobutyric, and valeric acids), decreased excretion of some BAs, mainly of the primary (CA, α-MCA, and β-MCA) and secondary type (ω-MCA, HDCA, NCA, DCA, and LCA), and increased amount of taurine- and glycine-conjugated BAs compared to the OC group. The contribution of specific bioactive compounds and their metabolites in the regulation of the microbiome and the pathways linked to SCFA and BA formation and their relationship with some diseases needs further research.

Modulatory effect of n-3 polyunsaturated fatty acids on depressive-like behaviors in rats with chronic sleep deprivation: potential involvement of melatonin receptor pathway and brain lipidome

Clinical evidence suggests that a bidirectional relationship is present between sleep loss and psychiatric disorders. Both melatonin receptor agonist ramelteon (RMT) and n-3 polyunsaturated fatty acids (n-3 PUFAs) exhibit antidepressant effects, while their underlying molecular mechanisms might be different. Thus, the present study aims to investigate the add-on effects and possible mechanisms of how RMT and different n-3 PUFAs modulate the melatonin receptor pathway as well as brain lipidome to ameliorate the neuropsychiatric behaviors displayed in rats under chronic sleep deprivation. Thirty-one 6-week-old male Wistar rats were divided into five groups: control (C), sleep deprivation (S), sleep deprivation treated with RMT (SR), sleep deprivation treated with RMT and eicosapentaenoic acid (C20:5n-3, EPA) (SRE), and sleep deprivation treated with RMT and docosahexaenoic acid (C22:6n-3, DHA) (SRD) groups. The results reveal that RMT plus EPA alleviated depressive-like behavior when the rats were subjected to the forced swimming test, whereas RMT plus DHA alleviated anxiety-like behavior when the rats were subjected to the elevated plus maze test. The results of a western blot analysis further revealed that compared with the rats in the S group, those in the SRE and SRD groups exhibited a significantly increased expression of MT₂ in the prefrontal cortex, with greater benefits observed in the SRE group. In addition, decreased BDNF and TrkB expression levels were upregulated only in the SRE group. Lipidomic analysis further revealed possible involvement of aberrant lipid metabolism and neuropsychiatric behaviors. RMT plus EPA demonstrated promise as having the effects of reversing the levels of the potential biomarkers of depressive-like behaviors. RMT plus EPA or DHA could ameliorate depressive- and anxiety-like behaviors in sleep-deprived rats through the alteration of the lipidome and MT₂ receptor pathway in the brain, whereas EPA and DHA exerted a differential effect.

Synergistic antidepressant-like effect of n-3 polyunsaturated fatty acids and probiotics through the brain-gut axis in rats exposed to chronic mild stress

N-3 polyunsaturated fatty acids (PUFA) and probiotics have antidepressant-like effects, but the underlying mechanisms are unclear. We hypothesized that n-3 PUFA combined with live and dead probiotics synergistically improves depression by modulating the hypothalamic-pituitary-adrenal (HPA) axis and serotonergic pathways through the brain-gut axis. Rats were randomly divided into seven groups (n = 8/group): non-chronic mild stress (CMS) with n-6 PUFA, CMS with n-3 PUFA, n-6 PUFA, live probiotics, dead probiotics, n-3 PUFA and live probiotics, and n-3 PUFA and dead probiotics. Diets of n-6 and n-3 PUFA and oral supplementation of live and dead probiotics were provided for 12 weeks, and CMS was performed for the last 5 weeks. N-3 PUFA and probiotics improved depressive behaviors and modulated the brain and gut HPA axis by synergistically increasing glucocorticoid receptor expression and decreasing corticotropin-releasing factor expression and blood levels of adrenocorticotropic hormone and corticosterone. N-3 PUFA and probiotics upregulated the brain serotonergic pathway through serotonin levels and expression of brain-derived neurotrophic factor, phosphorylated cAMP response binding protein, and 5-hydroxytryptamine 1A receptor while downregulating the gut serotonergic pathway. Furthermore, n-3 PUFA and probiotics increased the abundance of Ruminococcaceae, brain and gut short chain fatty acid levels, and occludin expression while decreasing the expression of tumor necrosis factor-α, interleukin-1β, and prostaglandin E₂ and blood lipopolysaccharides levels. There was no significant difference between the live and dead probiotics. In conclusion, n-3 PUFA and probiotics had synergistic antidepressant-like effects on the HPA axis and serotonergic pathways of the brain and gut through the brain-gut axis.

Intervention Effects of Okra Extract on Brain-Gut Peptides and Intestinal Microorganisms in Sleep Deprivation Rats

Objective

Okra, possessing various bioactive components, is used to treat different diseases. This study sought to estimate the intervention effects of okra extract (OE) on brain-gut peptides (BGPs) and intestinal microorganisms in sleep deprivation (SD) rats.

Methods

SD rat models were established using the modified multiple platform method and then treated with normal saline, diazepam tablets, or different doses of OE. Body weight and average daily water consumption of rats were recorded. Depressive behaviors of rats were assessed by the open field test and sucrose preference test. Serum levels of noradrenaline, melatonin, inflammatory factors (IL-1β/IL-6/TNF-α/IL-4/IL-10), and BGP indexes, including gastrin (GAS), motilin (MTL), 5-hydroxytryptamine (5-HT), cholecystokinin (CCK), and vasoactive intestinal peptide (VIP) were measured by ELISA. Additionally, the DNA relative contents of representative intestinal microorganisms in the collected rat feces were determined using RT-qPCR.

Results

SD decreased body weight and average daily water consumption and induced depressive behaviors as well as stress and inflammatory responses in rats. SD rats exhibited lowered GAS, MTL, 5-HT, and VIP but elevated CCK and showed diminished DNA relative contents of Bacteroidetes and probiotics (Bifidobacteria and Lactobacilli) but increased Clostridium perfringens. OE at different doses ameliorated the depressive behaviors and mitigated the stress and inflammatory responses in SD rats, raised the serum contents of GAS, MTL, 5-HT, and VIP, reduced CCK level, elevated the DNA relative contents of Bacteroidetes and probiotics, but diminished Clostridium perfringens. OE exhibited similar intervention effects to diazepam tablets (positive control).

Conclusion

OE exerts intervention effects on BGPs and intestinal microorganisms in SD rats.

N-3 PUFA Ameliorates the Gut Microbiota, Bile Acid Profiles, and Neuropsychiatric Behaviours in a Rat Model of Geriatric Depression

The brain−gut−microbiome (BGM) axis affects host bioinformation. N-3 polyunsaturated fatty acids (PUFAs) alleviate cognitive impairment and depression in older adults. This study investigated altered microbiota−bile acid signalling as a potential mechanism linking fish oil-induced gut changes in microbiota to alleviate psychological symptoms. Sprague Dawley rats were fed a fish oil diet and administered D-galactose combined with chronic unpredictable mild stress (CUMS) to simulate geriatric depression. The cognitive function, psychological symptoms, microbiota compositions, and faecal bile acid profiles of the rats were assessed thereafter. A correlation analysis was conducted to determine whether the fish oil-induced alteration of the rats’ microbiota and bile acid profiles affected the rats’ behaviour. D-galactose and CUMS resulted in lower concentrations of Firmicutes, significantly altered bile acid profiles, and abnormal neurobehaviours. Fish oil intake alleviated the rats’ emotional symptoms and increased the abundance of Bacteroidetes, Prevotellaceae, Marinifilaceae, and Bacteroidesuniformis. It also elevated the concentrations of primary bile acids and taurine-conjugated bile acids in the rats’ faeces. The rats’ taurine-conjugated bile acid levels were significantly correlated with their behavioural outcomes. In short, fish oil intake may alleviate psychological symptoms by altering the microbial metabolites involved in the BGM axis, especially in the conjugation of bile acids.