Rice Germ Ameliorated Chronic Unpredictable Mild Stress-Induced Depressive-like Behavior by Reducing Neuroinflammation

Moringa oleifera Lam. seed lectin (WSMoL) reduces chronic stress-induced anxiety and depression in mice by lessening inflammation and balancing brain chemicals

Phyto-based treatments for anxiety and depression are gaining attention. The efficacy of the water-soluble Moringa oleifera seed lectin (WSMoL) in reducing acute anxiolytic and depressive-like behaviors in mice has been previously demonstrated. In the present study, it was evaluated the effects of WSMoL on reducing anxiety and depressive-like symptoms in a mouse model of unpredictable chronic mild stress (UCMS). The animals were divided into groups and exposed to a four-week UCMS regimen. Following this, the mice received daily intraperitoneal injections of vehicle (non-stressed and UCMS control groups), WSMoL (2 or 4 mg/kg), or fluoxetine (10 mg/kg) for 21 days. Neurobehavioral tests included the open field test and elevated plus maze test to assess anxiety-like behavior, and the tail suspension test and sucrose preference test to evaluate depression-like behavior. Biochemical analyses measured serum corticosterone and cytokines as well brain levels of cytokines and monoamines. All tests indicated that WSMoL significantly (p < 0.05) reversed the anxiety and depression-like behaviors induced by UCMS. The stress protocol increased serum corticosterone levels and WSMoL treatment was not able to normalize corticosterone secretion. WSMoL treatment reduced serum and brain levels of IL-2, IL-6, and TNF-α, indicating reduced neuroinflammation, and increased brain levels of dopamine, serotonin, and noradrenaline. In summary, WSMoL mitigated UCMS-induced anxiety and depression-like behaviors by reducing neuroinflammation and modulating brain monoamine levels.

Du-moxibustion ameliorates depression-like behavior and neuroinflammation in chronic unpredictable mild stress-induced mice

BACKGROUND

Neuroinflammation is involved in the advancement of depression. Du-moxibustion can treat depression. Here, we explored whether Du-moxibustion could alleviate neuroglia-associated neuro-inflammatory process in chronic unpredictable mild stress (CUMS) mice.

METHODS

C57BL/6J mice were distributed into five groups. Except for the CON group, other four groups underwent CUMS for four consecutive weeks, and Du-moxibustion was given simultaneously after modeling. Behavioral tests were then carried out. Additionally, Western blot was conducted to measure the relative expression levels of high-mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B (NF-κB). Immunofluorescence was employed to evaluate the positive cells of ionized calcium binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP). Furthermore, interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were analyzed using an ELISA assay.

RESULTS

We found that CUMS induced depression-like behaviors, such as reduced sucrose preference ratio, decreased locomotor and exploratory activity, decreased the time in open arms and prolonged immobility. Furthermore, versus the CON group, the expression of HMGB1, TLR4, MyD88, NF-κB, positive cells of Iba-1, IL-1β and TNF-α were increased but positive cells of GFAP were decreased in CUMS group. However, the detrimental effects were ameliorated by treatment with CUMS+FLU and CUMS+DM.

LIMITATIONS

A shortage of this study is that only CUMS model of depression were used, while other depression model were not included.

CONCLUSIONS

Du-moxibustion alleviates depression-like behaviors in CUMS mice mainly by reducing neuroinflammation, which offers novel insights into the potential treatment of depression.

Chronic Stress-Induced Neuroinflammation: Relevance of Rodent Models to Human Disease

The brain is the central organ of adaptation to stress because it perceives and determines threats that induce behavioral, physiological, and molecular responses. In humans, chronic stress manifests as an enduring consistent feeling of pressure and being overwhelmed for an extended duration. This can result in a persistent proinflammatory response in the peripheral and central nervous system (CNS), resulting in cellular, physiological, and behavioral effects. Compounding stressors may increase the risk of chronic-stress-induced inflammation, which can yield serious health consequences, including mental health disorders. This review summarizes the current knowledge surrounding the neuroinflammatory response in rodent models of chronic stress-a relationship that is continually being defined. Many studies investigating the effects of chronic stress on neuroinflammation in rodent models have identified significant changes in inflammatory modulators, including nuclear factor-κB (NF-κB) and toll-like receptors (TLRs), and cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6. This suggests that these are key inflammatory factors in the chronic stress response, which may contribute to the establishment of anxiety and depression-like symptoms. The behavioral and neurological effects of modulating inflammatory factors through gene knockdown (KD) and knockout (KO), and conventional and alternative medicine approaches, are discussed.

Fermented foods: Harnessing their potential to modulate the microbiota-gut-brain axis for mental health

Over the past two decades, whole food supplementation strategies have been leveraged to target mental health. In addition, there has been increasing attention on the ability of gut microbes, so called psychobiotics, to positively impact behaviour though the microbiota-gut-brain axis. Fermented foods offer themselves as a combined whole food microbiota modulating intervention. Indeed, they contain potentially beneficial microbes, microbial metabolites and other bioactives, which are being harnessed to target the microbiota-gut-brain axis for positive benefits. This review highlights the diverse nature of fermented foods in terms of the raw materials used and type of fermentation employed, and summarises their potential to shape composition of the gut microbiota, the gut to brain communication pathways including the immune system and, ultimately, modulate the microbiota-gut-brain axis. Throughout, we identify knowledge gaps and challenges faced in designing human studies for investigating the mental health-promoting potential of individual fermented foods or components thereof. Importantly, we also suggest solutions that can advance understanding of the therapeutic merit of fermented foods to modulate the microbiota-gut-brain axis.

Lactobacillus brevis-Fermented Gamma-Aminobutyric Acid Ameliorates Depression- and Anxiety-Like Behaviors by Activating the Brain-Derived Neurotrophic Factor-Tropomyosin Receptor Kinase B Signaling Pathway in BALB/C Mice

This study investigated the effects of Lactobacillus brevis-fermented gamma-aminobutyric acid (LB-GABA) on depressive and anxiety-like behaviors with the underlying molecular mechanism in a chronic stress model of BALB/c mice. LB-GABA attenuates both neuronal cell death and the increase of monoamine oxidase activity induced by hydrogen peroxide. Behavioral tests revealed that GABA significantly increased sucrose preference and reduced immobility time in both tail suspension and forced swimming tests. LB-GABA increased exploration of the open arms in the elevated plus maze and restored activity in the open field. Moreover, LB-GABA lowered stress hormone and inflammatory mediator levels. Mechanistically, LB-GABA increased protein levels of BDNF and TrkB, activating downstream targets (AKT, ERK, and CREB), crucial for neuronal survival and plasticity. Furthermore, LB-GABA protected hippocampal neurons from stress-induced cell death and increased serotonin and dopamine levels. Overall, LB-GABA has the potential to alleviate stress-induced depression and anxiety-like symptoms and neuroinflammation by activating the BDNF-TrkB signaling pathway.

A unique inflammation-related mechanism by which high-fat diets induce depression-like behaviors in mice

BACKGROUND

High-fat diet (HFD) consumption is an important reason for promoting depression, but the mechanism is unclear. The present study aims to explore the relationship between metabolic disturbance and HFD-induced depression-like behaviors.

METHODS

Depression models were established by HFD consumption and chronic unpredictable mild stress (CUMS) in mice. Enzyme-linked immunosorbent assay, western blotting, real-time polymerase chain reaction, gas chromatography and metabolomic analysis were undertaken to investigate the 5-hydroxytryptamine (5-HT) system, neuroinflammation and to identify altered lipid metabolic pathways.

RESULTS

Depression-like behaviors, impaired 5-HT neurotransmission and disordered lipid metabolism were observed upon HFD consumption. Despite a similar reduction of high-density lipoprotein cholesterol in CUMS and HFD group, high levels of body low-density lipoprotein cholesterol in the HFD group could help distinguish HFD from CUMS. Levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and inflammation-related metabolites were increased in HFD mice, so a link between depression and inflammation was postulated. Different metabolites were enriched in the two groups. The linoleic acid (LA) metabolic pathway and expression of fatty acid desaturase (FADS)1 and FADS2 (key enzymes in LA metabolic pathway) were enhanced significantly in HFD mice compared with the control group.

LIMITATIONS

Causality analyses for HFD and inflammation-related features were not undertaken.

CONCLUSIONS

HFD-induced depression-like behaviors was characterized by more severely disordered metabolism of lipids (especially in the LA metabolic pathway) and increased levels of inflammatory mediators, which might be the reasons for the disturbance of serotonergic system in hippocampus.

Rice Germ Attenuates Chronic Unpredictable Mild Stress-Induced Muscle Atrophy

Chronic stress leads to hypothalamic-pituitary-adrenal axis dysfunction, increasing cortisol levels. Glucocorticoids (GCs) promote muscle degradation and inhibit muscle synthesis, eventually causing muscle atrophy. In this study, we aimed to evaluate whether rice germ supplemented with 30% γ-aminobutyric acid (RG) attenuates muscle atrophy in an animal model of chronic unpredictable mild stress (CUMS). We observed that CUMS raised the adrenal gland weight and serum adrenocorticotropic hormone (ACTH) and cortisol levels, and these effects were reversed by RG. CUMS also enhanced the expression of the GC receptor (GR) and GC-GR binding in the gastrocnemius muscle, which were attenuated by RG. The expression levels of muscle degradation-related signaling pathways, such as the Klf15, Redd-1, FoxO3a, Atrogin-1, and MuRF1 pathways, were enhanced by CUMS and attenuated by RG. Muscle synthesis-related signaling pathways, such as the IGF-1/AKT/mTOR/s6k/4E-BP1 pathway, were reduced by CUMS and enhanced by RG. Moreover, CUMS raised oxidative stress by enhancing the levels of iNOS and acetylated p53, which are involved in cell cycle arrest, whereas RG attenuated both iNOS and acetylated p53 levels. Cell proliferation in the gastrocnemius muscle was reduced by CUMS and enhanced by RG. The muscle weight, muscle fiber cross-sectional area, and grip strength were reduced by CUMS and enhanced by RG. Therefore, RG attenuated ACTH levels and cortisol-related muscle atrophy in CUMS animals.