Pathogenesis Of Depression Research Articles

Research progress on intestinal flora and depression

In recent years, the prevalence of depression and suicide rates have continued to increase, especially among adolescents, and existing treatment methods are still incomplete and have certain limitations. Although some progress has been made in studying the relationship between gut microbiota and depression, a clear explanation of the physiological mechanisms of the "Microbiota-Gut-Brain Axis" (MGBA) and a review of treatments for depression based on MGBA regulation are still lacking. This article examines the traits of the gut microbiota in patients with depression, highlighting that their richness and diversity are significantly lower compared to healthy controls. The neurological, endocrine and immune mechanisms of MGBA and its role in the pathogenesis of depression were further explored. This article also reviews MGBA-based treatments, such as Fecal Microbiota Transplantation (FMT) and probiotic therapy, noting their potential efficacy in alleviating depressive symptoms. This article unveils the pivotal role of gut microbiota in the development of depression, offering a new avenue for researching the pathological mechanisms of the disorder and laying a scientific foundation for creating novel antidepressant treatments. At present, there is no consistent conclusion about the changes in the composition of the intestinal flora in depression. Future studies can expand the sample size and conduct experiments on different groups to deeply reveal the changes in the intestinal flora of patients with depression.

Regulatory T cells administration reduces anxiety-like behavior in mice submitted to chronic restraint stress.

Major depression disorder (MDD) and anxiety are common mental disorders that significantly affect the quality of life of those who suffer from them, altering the person's normal functioning. From the biological perspective, the most classical hypothesis explaining their occurrence relies on neurotransmission and hippocampal excitability alterations. However, around 30% of MDD patients do not respond to medication targeting these processes. Over the last decade, the involvement of inflammatory responses in depression and anxiety pathogenesis has been strongly acknowledged, opening the possibility of tackling these disorders from an immunological point of view. In this context, regulatory T cells (Treg cells), which naturally maintain immune homeostasis by suppressing inflammation could be promising candidates for their therapeutic use in mental disorders. To test this hypothesis, C57BL/6 adult male mice were submitted to classical stress protocols to induce depressive and anxiety-like behavior; chronic restriction stress (CRS), and chronic unpredictable stress (CUS). Some of the stressed mice received a single adoptive transfer of Treg cells during stress protocols. Mouse behavior was analyzed through the open field (OFT) and forced swim test (FST). Blood and spleen samples were collected for T cell analysis using cell cytometry, while brains were collected to study changes in microglia by immunohistochemistry. Mice submitted to CRS and CUS develop anxiety and depressive-like behavior, and only CRS mice exhibit lower frequencies of circulating Treg cells. Adoptive transfer of Treg cells decreased anxiety-like behavior in the OFT only in CRS model, but not depressive behavior in FST in neither of the two models. In CRS mice, Treg cells administration lowered the number of microglia in the hippocampus, which increased due this stress paradigm, and restored its arborization. However, in CUS mice, Treg cells administration increased microglia number with no significant effect on their arborization. Our results for effector CD4+ T cells in the spleen and microglia number and morphology in the hippocampus add new evidence in favor of the participation of inflammatory responses in the development of depressive and anxiety-like behavior and suggest that the modulation of key immune cells such as Treg cells, could have beneficial effects on these disorders.

CircKat6b Mediates the Antidepressant Effect of Esketamine by Regulating Astrocyte Function.

The abundant expression of circular RNAs (circRNAs) in the central nervous system and their contribution to the pathogenesis of depression suggest that circRNAs are promising therapeutic targets for depression. This study explored the role and mechanism of circKat6b in esketamine's antidepressant effect. We found that intravenous administration of esketamine (5mg/kg) treatment decreased the circKat6b expression in the astrocytes of hippocampus induced by a chronic unpredictable mild stress (CUMS) mouse model, while the overexpression of circKat6b in the hippocampus significantly attenuated the antidepressant effects of esketamine in depressed mice. RNA-sequencing, RT-PCR, and western blot experiments showed that the stat1 and p-stat1 expression were significantly upregulated in mouse astrocytes overexpressing circKat6b. In the CUMS mouse model, overexpression of circKat6b in the hippocampus significantly reversed the downregulation of p-stat1 protein expression caused by esketamine. Our findings demonstrated that a novel mechanism of the antidepressant like effect of esketamine may be achieved by reducing the expression of circKat6b in the astrocyte of the hippocampus of depressed mice.

Proteomic characterization of the medial prefrontal cortex in chronic restraint stress mice

Depression is a prominent contributor to global disability. A growing body of data suggests that depression is associated with the pathophysiology of the medial prefrontal cortex (mPFC), but the underlying mechanisms remain poorly understood. Mice were subjected to chronic restraint stress (CRS) for 3 weeks to create depression models during this investigation. Protein tandem mass tag (TMT) quantification and LC-MS/MS analysis were conducted to examine proteome patterns. Afterwards, to further explore the enrichment of differential proteins and the signaling pathways involved, we annotated these differentially expressed proteins. We confirmed that CRS mice developed depression-like and anxiety-like behaviors. Among the 8081 measured proteins, a total of 15 proteins were found to be differentially expressed. These proteins exhibited functional enrichment in a variety of biological functions, and among these pathways, alterations in synaptic function and autophagy are noteworthy. In addition, we identified a differentially expressed protein called Wnt2b and found that CRS may disrupt synaptic plasticity by affecting the activation of the Wnt2b/β-catenin pathway. Our findings showed depression-like behaviors in the CRS mouse model and molecular alterations in the mPFC, which may help explain the pathogenesis of depression and identify novel antidepressant medication targets. SignificanceDepression is a prevalent and frequent chronic mental illness and is now a significant contributor to global disability. In this study, we used chronic restraint stress to establish a mouse model of depression, and differentially expressed proteins in the medial prefrontal cortex of depressed model mice were detected by TMT proteomics. Our study verified the presence of altered synaptic function and excessive autophagy in the mPFC of CRS-induced mice from a proteomic perspective. Furthermore, we demonstrated that CRS may disrupt synaptic plasticity by affecting the activation of the Wnt2b/β-catenin pathway, which may be a key link in the pathogenesis of depression and may provide new insights for identifying new antidepressant drug targets.

MiR-143-3p modulates depressive-like behaviors via Lasp1 in the mouse ventral hippocampus

Depression is a prevalent and intricate mental disorder. The involvement of small RNA molecules, such as microRNAs in the pathogenesis and neuronal mechanisms underlying the depression have been documented. Previous studies have demonstrated the involvement of microRNA-143-3p (miR-143-3p) in the process of fear memory and pathogenesis of ischemia; however, the relationship between miR-143-3p and depression remains poorly understood. Here we utilized two kinds of mouse models to investigate the role of miR-143-3p in the pathogenesis of depression. Our findings reveal that the expression of miR-143-3p is upregulated in the ventral hippocampus (VH) of mice subjected to chronic restraint stress (CRS) or acute Lipopolysaccharide (LPS) treatment. Inhibiting the expression of miR-143-3p in the VH effectively alleviates depressive-like behaviors in CRS and LPS-treated mice. Furthermore, we identify Lasp1 as one of the downstream target genes regulated by miR-143-3p. The miR-143-3p/Lasp1 axis primarily affects the occurrence of depressive-like behaviors in mice by modulating synapse numbers in the VH. Finally, miR-143-3p/Lasp1-induced F-actin change is responsible for the synaptic number variations in the VH. In conclusion, this study enhances our understanding of microRNA-mediated depression pathogenesis and provides novel prospects for developing therapeutic approaches for this intractable mood disorder.

Dynamic quantitative monitoring of cerebrospinal fluid monoamine neurotransmitter markers during the modeling process of chronic stress-induced depression in monkeys (Macaca mulatta).

Depression is known as the "mental cold" and is also considered a major cause of disability worldwide. It is estimated that over 300 million people worldwide suffer from severe depression, equivalent to 4.4% of the world's population. The monoamine hypothesis of depression predicts the underlying pathophysiological mechanisms of depression, but in-depth research has failed to find convincing evidence. In this study, we will dynamically and strictly quantitatively monitor the concentration changes of monoamine transmitters in the cerebrospinal fluid (CSF) of macaques, based on our previous work. In the experiment, timed and quantitative collection of CSF samples from macaques was performed and the concentration of monoamine transmitters was determined. The results showed that after 2 months of chronic stress, the concentrations of high vanillin acid (HVA) and 3,4-dihydroxy-phenylacetic acid were significantly higher in the maternal separation (MS) group, whereas there was no significant difference in dopamine and 5-hydroxyindoleacetic acid. This study is the first to observe the long-term dynamic relationship between early adversity, chronic stress, adolescent depression, and CSF monoamine concentrations. The research suggests that MS and chronic stress play an undeniable role in the pathogenesis of depression and that concentrations of HVA and dihydroxyphenylacetic acid are likely to serve as early markers of depressive-like symptoms in macaques.

Depression and anxiety in multiple sclerosis. Review of a fatal combination.

Depression and anxiety are the most frequent neuropsychiatric symptoms of multiple sclerosis (MS), an autoimmune-mediated demyelinating neurodegenerative disease. Their prevalence is 25-65% and 20-54%, respectively, often associated with chronic fatigue and cognitive impairment, but usually not correlated with motor and other deficits, suggesting different pathophysiological mechanisms. Both disorders often arise before MS diagnosis, lead to faster disability and impair the quality of life. Risk factors are (young) age, genetic and family history burden. While no specific neuropathological data for depression (and anxiety) in MS are available, modern neuroimaging studies showed bilateral fronto-temporal, subcortical and limbic atrophies, microstructural white matter lesions and disruption of frontoparietal, limbic and neuroendocrine networks. The pathogenesis of both depression and anxiety in MS is related to shared mechanisms including oxidative stress, mitochondrial dysfunction, neuroinflammation and neuroendocrine mechanisms inducing complex functional and structural brain lesions, but they are also influenced by social and other factors. Unfortunately, MS patients with anxiety, major depression or suicidal thoughts are often underassessed and undertreated. Current treatment, in addition to antidepressant therapy include transcranial magnetic stimulation, cognitive, relaxation, dietary and other healthcare measures that must be individualized. The present state-of- the-art review is based on systematic analysis of PubMed, Google Scholar and Cochrane Library until May 2024, with focus on the prevalence, clinical manifestation, neuroimaging data, immune mechanisms and treatment options. Depression and anxiety in MS, like in many other neuroimmune disorders, are related, among others, to multi-regional patterns of cerebral disturbances and complex pathogenic mechanisms that deserve further elucidation as a basis for early diagnosis and adequate management to improve the quality of life in this disabling disease.

Hypothalamic-Pituitary-Adrenal (HPA) Axis: Unveiling the Potential Mechanisms Involved in Stress-Induced Alzheimer's Disease and Depression.

The hypothalamic-pituitary-adrenal (HPA) axis plays a pivotal role in the body's response to stress, orchestrating the release of glucocorticoids. In chronic scenarios, these glucocorticoids contribute to various neurological disorders, including Alzheimer's disease (AD) and depression. This abstract explores the potential mechanisms through which HPA axis dysregulation links stress-induced pathways to the pathogenesis of AD and subsequent depression. Chronic stress triggers prolonged HPA axis activation, resulting in elevated cortisol levels, which can lead to hippocampal atrophy, synaptic dysfunction, and neuroinflammation, recognized as key pathological features of AD. These alterations impair cognitive function and may exacerbate amyloid-beta plaque formation and tau hyperphosphorylation, hallmarks of AD. Concurrently, persistent cortisol elevation affects the prefrontal cortex and limbic structures, contributing to depressive symptoms. The interplay between chronic stress, HPA axis dysregulation, and neuroinflammation is crucial in understanding the comorbidity of AD and depression. Unveiling these mechanisms provides insights into potential therapeutic targets aimed at modulating the HPA axis and reducing stress-induced neurodegeneration, offering a dual benefit in managing both AD and depression. Further research is essential to elucidate the precise molecular pathways and develop effective interventions to mitigate the impact of chronic stress on brain health.

Early stress in maternal deprivation affects the expression of OX1R in the limbic system of the brain and contributes to the development of anxiety-depressive symptoms in rats

BACKGROUND: Depressive states are becoming an increasingly common mental disorder and a serious social problem that places a heavy economic burden on society. Increasing data from preclinical and clinical studies indicate that orexins (neuropeptides, also known as hypocretins) and their receptors are involved in the pathogenesis of depression. The orexinergic system regulates disrupted functions in depressive states, such as sleep, reward system, eating behavior, stress response, and monoaminergic regulation. However, the exact role of orexins in behavioral and neurophysiological disorders in depression is still unclear. AIM: This study aimed to examine the effect of early postnatal stress on the expression of OX1R orexin in the limbic system and the development of anxiety-depressive symptoms in rats. MATERIALS AND METHODS: Maternal deprivation was used as a model of early postnatal stress (postpartum days 2–12). The animals were divided into the control (n = 20) and maternal deprivation (n = 20) groups. On day 90 of life, the influence of early postnatal stress on the development of anxiety-depressive symptoms in adult rats was analyzed using a package of behavioral tests, namely, raised cruciform maze, forced swimming Porsolt test, and two-bottle test. After the experiments, the animals were killed by decapitation, the brain was extracted and placed in the cold, and brain structures (hypothalamus and amygdala) were isolated, immediately frozen in liquid nitrogen, and stored at a temperature of −80°C for polymerase chain reaction analysis. RESULTS: In the “raised cruciform maze,” the maternal deprivation group spent less time in the open arms of the maze, and the time spent in the closed sleeves increased relative to the control, which can be assessed as an increase in anxiety levels. In the Porsolt test, the maternal deprivation group had increased immobilization time relative to the control group. In the two-bottle sucrose preference test, the maternal deprivation group demonstrated a decreased preference for sucrose solution, which indicates the development of anhedonia. In the hypothalamus, the mRNA expression level of OX1R significantly decreased in the experimental group compared with that in the control group. A twofold decrease in the mRNA expression level of OX1R was also observed in the amygdala of the experimental group compared with that of the control group. CONCLUSIONS: Early stress caused by maternal deprivation resulted in a decrease in OX1R orexin expression in the hypothalamus and amygdala and contributed to the development of anxiety-depressive symptoms in rats.

Integrating Molecular Biology and Network Pharmacology to Analyze the Antidepressant Mechanism of Glycyrrhizaglabra.

Antidepressants have adverse effects and induce drug resistance when used excessively or frequently. Therefore, adjuvants are needed to reduce the use of antidepressants during treatment. Traditional Chinese medicine (TCM) is an important adjunctive approach to depression with safety, environmental protection, and low toxicity. Glycyrrhizaglabra (licorice, GG) is a plant commonly used in various herbal remedies. We investigated the antidepressant activity of GG, its active constituents, and potential depression-related targets. We combined animal behavioral and molecular biological assays with network pharmacology to analyze the antidepressant mechanism of GG. GG extracts reversed lipopolysaccharide (LPS)-induced depression-like behavior in behavioral tests. We selected 56 active compounds and 695 target compounds of licorice from TCMSP. The PPI network screened 80 core targets for enrichment analysis. It shows that GG significantly affected neurodegeneration pathways, neuroactive ligand-receptor interaction, cAMP signaling pathway, serotonergic synapse, dopaminergic synapse, and MAPK signaling pathway. Mechanistic studies showed that GG reduced IL-1β, IL-6, and TNF-α levels, 5-HTRA1 expression, and GSK3β phosphorylation in mouse hippocampus. It also increased BDNF and DRD1 expression and CREB and ERK1/2 phosphorylation. It shows that GG acted on these proteins to affect multiple pathways that mediate the pathogenesis of depression.

Depresion as a neurological manifestation in patients with post-COVID- 19 syndrome: A sysematic review

"An increase in the number of cases with persistence of symptoms following acute SARS-CoV-2 infection, known as post-COVID-19 syndrome has been acknowledge by the National Institute for Health and Care Excellence (NICE). This syndrome is associated with high rates of neuropsychiatric symptoms, suggesting an effect of COVID-19 on the central nervous system. However, a clear description of such an effect is currently lacking, and therefore there are no treatment guidelines for patients experiencing this syndrome or patients with neuropsychiatric manifestations in this context. Hence, the aim of this review is to analyze the available information regarding the association between the presence of depression in post-COVID-19 syndrome and describe the physio pathological process. For the completion of this review, a search was conducted in the PubMed database using the keywords COVID- 19, Depression, Post-COVID-19 syndrome, and SARS-CoV-2. The review was conducted according to the extended PRISMA guidelines for focused reviews. As significant findings, we identified that survivors of severe COVID-19 have higher rates of depression. Among the predictive factors for the development of post- COVID-19 depression are advanced age, longer hospital stays, symptom severity, and disease duration. While the pathogenesis of depression in post-COVID-19 syndrome is unknown, the main contributors to its development are recognized as cytokine-mediated inflammatory response and changes in neurotransmitters."

In Search for a Pathogenesis of Major Depression and Suicide-A Joint Investigation of Dopamine and Fiber Tract Anatomy Focusing on the Human Ventral Mesencephalic Tegmentum: Description of a Workflow.

Major depressive disorder (MDD) is prevalent with a high subjective and socio-economic burden. Despite the effectiveness of classical treatment methods, 20-30% of patients stay treatment-resistant. Deep Brain Stimulation of the superolateral branch of the medial forebrain bundle is emerging as a clinical treatment. The stimulation region (ventral tegmental area, VTA), supported by experimental data, points to the role of dopaminergic (DA) transmission in disease pathology. This work sets out to develop a workflow that will allow the performance of analyses on midbrain DA-ergic neurons and projections in subjects who have committed suicide. Human midbrains were retrieved during autopsy, formalin-fixed, and scanned in a Bruker MRI scanner (7T). Sections were sliced, stained for tyrosine hydroxylase (TH), digitized, and integrated into the Montreal Neurological Institute (MNI) brain space together with a high-resolution fiber tract atlas. Subnuclei of the VTA region were identified. TH-positive neurons and fibers were semi-quantitatively evaluated. The study established a rigorous protocol allowing for parallel histological assessments and fiber tractographic analysis in a common space. Semi-quantitative readings are feasible and allow the detection of cell loss in VTA subnuclei. This work describes the intricate workflow and first results of an investigation of DA anatomy in VTA subnuclei in a growing naturalistic database.

Effects of Ellagic Acid Supplementation on Antioxidant Status and Symptom Improvement in Patients with Major Depressive Disorder: A Double-blind Randomized Clinical Trial

Background: Depression is one of the most common mood disorders and a major public health concern. Ellagic acid (EA), a type of polyphenol, acts as a strong hydrogen bond network as an electron receptor, enabling it to participate in various reactions. Objectives: Major depression is a critical medical condition that has emerged as a public health issue due to its high incidence, mortality, and suicide rates. One significant factor in the pathogenesis of depression is oxidative stress. This study aimed to evaluate the effects of ellagic acid supplementation on antioxidant status and symptom improvement in patients with major depressive disorder, considering the antioxidant capabilities of ellagic acid. Methods: A total of 40 patients diagnosed with major depressive disorder based on DSM-V criteria were assessed using the Beck Depression and Hamilton Depression Questionnaires. The dietary and caloric intake of the patients were monitored. Additionally, height and weight were measured, and patients with similar age, gender, and weight were matched. The individuals were randomly assigned to either the intervention group or the placebo group using a randomization table. The intervention group received a daily dose of 200 mg of ellagic acid in capsule form. The placebo group received a daily dose of one capsule containing 200 mg of wheat flour, identical in appearance to the intervention substance. The study period lasted for 8 weeks. Venous blood samples were collected before and after the study from all 40 individuals, and after serum separation, oxidative stress markers (malondialdehyde and total antioxidant capacity). were measured using a specific kit and ELISA method. Results: The study results showed a significant reduction in depression scores in the ellagic acid group during the study (P: 0.001)., with these alterations being significant when compared to the placebo group. In the ellagic acid group, a significant increase in total antioxidant capacity (P: 0.027). and a significant decrease in malondialdehyde levels (P: 0.014). were observed at the end of the study, and these changes were significant compared to the placebo group. In contrast, significant changes in total antioxidant capacity and malondialdehyde levels were not observed in the placebo group. Conclusions: The current study indicates that ellagic acid intervention may have a favorable effect on depression in patients with major depressive disorder. This is achieved by reducing BDI scores and serum levels of MDA, as well as increasing serum levels of TAC in these patients compared to the placebo group. However, further investigation is necessary to explore the mechanisms underlying the different alterations of ellagic acid in depression.

Abnormal white matter integrity of anterior-inferior hypothalamus in mild cognitive impairment patients with depression symptoms

BackgroundThe hypothalamus is a key brain structure involved in the pathogenesis of depression, and its abnormal activity is considered an important pathological mechanism for the formation of depression. The presence of abnormalities in the white matter integrity of hypothalamic subregions in mild cognitive impairment with depressive symptoms (D-MCI) remains unknown. MethodsIn this study, we used diffusion tensor imaging (DTI) to explore the white matter integrity of hypothalamic subregions in D-MCI. On a 3 T magnetic resonance imaging scanner, we collected DTI data from 63 subjects. The subjects included 20 healthy controls (HC), 23 MCI patients without depression (nD-MCI), and 20 patients with D-MCI. The differences in DTI metrics of hypothalamic subregions of the three groups were compared using analysis of variance and post hoc t-tests. We looked at the relationship between clinical variables and DTI metrics in hypothalamus subregions using Pearson correlation analysis. ResultsCompared with nD-MCI and HC groups, D-MCI group showed increased fractional anisotropy (FA) in anterior-inferior hypothalamus. There was a weak negative correlation between FA values in the anterior-inferior hypothalamus and depression scores in D-MCI patients. ConclusionsOur findings suggest that depressive symptoms in MCI patients are associated with abnormal white matter integrity in the anterior-inferior hypothalamus.

MiR-204-5p Plays a Critical Role in the Pathogenesis of Depression and Anti-depression Action of Venlafaxine in the Hippocampus of Mice.

Venlafaxine has been demonstrated to treat diseases such as social anxiety disorder and depression. Most of antidepressants including venlafaxine have a certain effect, but significant side effects. Therefore, it is necessary for us to research the development of novel antidepressants for effective treatment in practice. MicroRNA-204 (miR-204) is highly expressed in brain tissue, and plays a critical role in the synaptic plasticity of hippocampal neurons in rats. However, the underlying molecular mechanism of miR-204 remains unclear to date, this study aims to offer unique insights into depression and provide a theoretical basis for clinical physicians. A chronic social defeat stress (CSDS) was initially adopted for establishing a mice model of depression in this research and depression-like behaviors were evaluated by a series of behavioral experiments including the sucrose preference test (SPT), the tail suspension test (TST), the forced swim test (FST) and the social interaction test (SIT). Quantitative real-time reverse transcription PCR (qRT-PCR) was also conducted to test the expression levels of miR-204 and BDNF in the hippocampus of mice. Finally, gene interference of miR-204-5p was further adopted to test whether miR-204-5p played an effective role in the antidepressant effects of venlafaxine in mice. Our data implicated that CSDS significantly increased the miR-204-5p but not miR-204-3p levels in the hippocampus of mice. The treatment of venlafaxine obviously relieved depression- like behaviors of CSDS-induced mice. The usage of venlafaxine abolished the increasing effects on the expression of miR-204-5p but up-regulated the BDNF expression level in CSDS-exposured mice. More importantly, we found that genetic overexpression of miR-204-5p decreased the reverse effects of venlafaxine on depressive-like behaviors and genetic knockdown of hippocampal miR-204-5p relieved the depressive-like behaviors and neurogenesis in CSDS-induced mice. miR-204-5p played an effective role in the antidepressant effects of venlafaxine in CSDS-induced mice.

Dissecting the antidepressant effect of troxerutin: modulation of neuroinflammatory and oxidative stress biomarkers in lipopolysaccharide-treated mice.

The role of neuroinflammation in the pathogenesis of depression has prompted the search for new antidepressants. Troxerutin, a bioflavonoid with anti-inflammatory and antioxidant properties, has shown promise, but its impact on neurobehavioral functions remains poorly understood. This study aimed to investigate the antidepressant potential of troxerutin and its effect on the neuroinflammatory response. Here, we exposed male Swiss mice (n = 5/group) to various treatments, including naive and negative controls receiving distilled water, troxerutin-treated groups administered at different doses (10, 20, 40mg/kg, i.p.), and an imipramine-treated group (25mg/kg, i.p.). After seven days of treatment, with the exception of the naive group, mice were administered a single dose of lipopolysaccharide (LPS, 0.83mg/kg). Behavioral evaluations, consisting of the novelty-suppressed feeding (NSF) test, forced swim test (FST), and open field test (OFT), were conducted. Additionally, brain samples were collected for biochemical and immunohistochemicalanalyses. Troxerutin significantly reduced immobility time in the FST and mitigated behavioral deficits in the NSF test. Additionally, troxerutin increased glutathione (GSH) and superoxide dismutase (SOD) levels while reducing nitrite, malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interferon-gamma (IFN-γ) levels compared to the negative control. Immunohistochemistry analysis revealed decreased expression of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) in troxerutin-treated mice. Overall, these findings suggest that troxerutin exerts significant antidepressive-like effects, likely mediated by its anti-inflammatory and antioxidant mechanisms. The reduction in neuroinflammatory and oxidative stress biomarkers, along with the improvement in behavioral outcomes, underscores troxerutin's potential as a therapeutic agent for depression.

The Etiology, Pathogenesis and Clinical Treatment of Depression Were Analyzed from the Perspective of Traditional Chinese Medicine

As the pace of life quickens, the prevalence of depression rises. Due to the incomplete understanding of depression and various causes, it is still unable to fully effective prevention and treatment in clinical practice. Western medicine treatment of depression has high cost and side effects, while Chinese medicine treatment has advantages, according to different syndromes, different treatment means and Chinese medicine drugs can be used, efficient and targeted. Traditional Chinese medicine believes that the cause of depression lies in the poor operation of Qi and blood, which leads to the dysfunction of multiple viscera, and the symptoms such as emotional depression appear in the light, and the serious phenomena such as loss of survival motivation appear. This article will discuss the causes and treatment methods of depression from the perspective of traditional Chinese medicine, and provide new ideas for clinical treatment.

Pathogenesis of depression and the potential for traditional Chinese medicine treatment.

Depression is a prevalent mental disorder that significantly diminishes quality of life and longevity, ranking as one of the primary causes of disability globally. Contemporary research has explored the potential pathogenesis of depression from various angles, encompassing genetics, neurotransmitter systems, neurotrophic factors, the hypothalamic-pituitary-adrenal axis, inflammation, and intestinal flora, among other contributing factors. In addition, conventional chemical medications are plagued by delayed onset of action, persistent adverse effects, and restricted therapeutic efficacy. In light of these limitations, the therapeutic approach of traditional Chinese medicine (TCM) has gained increasing recognition for its superior effectiveness. Numerous pharmacological and clinical studies have substantiated TCM's capacity to mitigate depressive symptoms through diverse mechanisms. This article attempts to summarize the mechanisms involved in the pathogenesis of depression and to describe the characteristics of herbal medicines (including compounded formulas and active ingredients) for the treatment of depression. It further evaluates their effectiveness by correlating with the multifaceted pathogenesis of depression, thereby furnishing a reference for future research endeavors.

Role of mitochondria-associated membranes in the hippocampus in the pathogenesis of depression

BackgroundPathological changes, such as microglia activation in the hippocampus frequently occur in individuals with animal models of depression; however, they may share a common cellular mechanism, such as endoplasmic reticulum (ER) stress and mitochondrial dysfunction. Mitochondria associated membranes (MAMs) are communication platforms between ER and mitochondria. This study aimed to investigate the role of intracellular stress responses, especially structural and functional changes of MAMs in depression. MethodsWe used chronic social defeat stress (CSDS) to mimic depression in C57 mice to investigate the pathophysiological changes in the hippocampus associated with depression and assess the antidepressant effect of electroacupuncture (EA). Molecular, histological, and electron microscopic techniques were utilized to study intracellular stress responses, including the ER stress pathway reaction, mitochondrial damage, and structural and functional changes in MAMs in the hippocampus after CSDS. Proteomics technology was employed to explore protein-level changes in MAMs caused by CSDS. ResultsCSDS caused mitochondrial dysfunction, ER stress, closer contact between ER and mitochondria, and enrichment of functional protein clusters at MAMs in hippocampus along with depressive-like behaviors. Also, EA showed beneficial effects on intracellular stress responses and depressive-like behaviors in CSDS mice. LimitationThe cellular specificity of MAMs related protein changes in CSDS mice was not explored. ConclusionsIn the hippocampus, ER stress and mitochondrial damage occur, along with enriched mitochondria-ER interactions and MAM-related protein enrichment, which may contribute to depression's pathophysiology. EA may improve depression by regulating intracellular stress responses.

Saikosaponin antidepressant mechanism: Improving the sphingolipid metabolism in the cortex via Apolipoprotein E and triggering neurovascular coupling

BackgroundSince the pathogenesis of depression is complex, antidepressant therapy remains unsatisfactory. Recent evidence suggests a link between depression and lipid metabolism. Saikosaponin (SS) exhibits antidepression and lipid-regulating effects in modern pharmacology. However, it is unknown whether lipid regulation is the key mechanism of the SS antidepressant effect and how it works. PurposeIn this study, we investigated the relationship between the antidepressant activity of SS and the regulation of lipid metabolism and explored potential mechanisms. MethodsAPOE-/- mice, in combination with the chronic unpredictable mild stress (CUMS) model, were used to study the relationship between SS antidepressant activity and lipid metabolism through behavioral, electrophysiological techniques, and non-targeted lipidomics. Western blot, primary cell culture technology, and laser speckle cerebral blood flow imaging were employed to elucidate potential mechanisms. GraphPad Prism was used for statistical analysis, and p < 0.05 was considered statistically significant. ResultsAPOE-/- mice exhibit more severe depressive-like behavior and dysregulation of sphingolipid metabolism in CUMS. SS alleviates depressive behavior and cortical sphingolipid metabolism disorder caused by CUMS, but has no effect on APOE-/- mice. SS alleviates the imbalance between ceramide (Cer) and sphingomyelin (SM) through acidic sphingomyelinase (AMSase). In addition, SS regulates neuronal glutamate release via sphingolipid metabolism, thereby alleviating the CUMS-induced inhibition of neurovascular coupling (regulates metabotropic glutamate receptor and IP3 receptor), which ameliorates the reduction of cerebral blood flow in depressed mice. ConclusionOur study highlights the role of lipid metabolism in the antidepressant activity of SS and explores its underlying mechanisms. This study provided new insights into the better understanding of the antidepressant mechanisms of phytomedicine while increasing the possibility of lipid metabolism as a therapeutic strategy for depression.