Preventive effects of ginsenoside Rg1 on post-traumatic stress disorder (PTSD)-like behavior in male C57/B6 mice

Advancements in research on the effects of panax notoginseng saponin constituents in ameliorating learning and memory disorders

Learning and memory disorder is a cluster of symptoms caused by neuronal aging and other diseases of the central nervous system (CNS). Panax notoginseng saponins (PNS) are a series of saponins derived from the natural active ingredients of traditional Chinese medicine (TCM) that have neuroprotective effects on the central nervous system. In this paper, we review the ameliorative effects and mechanisms of Panax notoginseng saponin-like components on learning and memory disorders to provide valuable references and insights for the development of new drugs for the treatment of learning and memory disorders. Our summary results suggest that Panax ginseng saponins have significant effects on improving learning and memory disorders, and these effects and potential mechanisms are mediated by their anti-inflammatory, anti-apoptotic, antioxidant, β-amyloid lowering, mitochondrial homeostasis in vivo, neuronal structure and function improving, neurogenesis promoting, neurotransmitter release regulating, and probiotic homeostasis in vivo activities. These findings suggest the potential of Panax notoginseng saponin-like constituents as drug candidates for improving learning and memory disorders.

Phytochemical interventions for post-traumatic stress disorder: A cluster co-occurrence network analysis using CiteSpace

OBJECTIVE

This study investigated trends in the study of phytochemical treatment of post-traumatic stress disorder (PTSD).

METHODS

The Web of Science database (2007-2022) was searched using the search terms "phytochemicals" and "PTSD," and relevant literature was compiled. Network clustering co-occurrence analysis and qualitative narrative review were conducted.

RESULTS

Three hundred and one articles were included in the analysis of published research, which has surged since 2015 with nearly half of all relevant articles coming from North America. The category is dominated by neuroscience and neurology, with two journals, Addictive Behaviors and Drug and Alcohol Dependence, publishing the greatest number of papers on these topics. Most studies focused on psychedelic intervention for PTSD. Three timelines show an "ebb and flow" phenomenon between "substance use/marijuana abuse" and "psychedelic medicine/medicinal cannabis." Other phytochemicals account for a small proportion of the research and focus on topics like neurosteroid turnover, serotonin levels, and brain-derived neurotrophic factor expression.

CONCLUSION

Research on phytochemicals and PTSD is unevenly distributed across countries/regions, disciplines, and journals. Since 2015, the research paradigm shifted to constitute the mainstream of psychedelic research thus far, leading to the exploration of botanical active ingredients and molecular mechanisms. Other studies focus on anti-oxidative stress and anti-inflammation. Please cite this article as: Gao B, Qu YC, Cai MY, Zhang YY, Lu HT, Li HX, Tang YX, Shen H. Phytochemical interventions for post-traumatic stress disorder: A cluster co-occurrence network analysis using CiteSpace. J Integr Med. 2023; Epub ahead of print.

Synergistic effects of combined therapy with cerebrolysin and enriched environment on anxiety-like behavior and spatial cognitive deficits in posttraumatic stress disorder-like mouse model

Posttraumatic stress disorder (PTSD) is a serious neuropsychiatric disorder that occurs after exposure to stressful, fearful, or troubling events. Cerebrolysin (CBL), consists of low molecular weights neurotrophic factors and amino acids obtained from purified porcine brain proteins. This study aimed to evaluate the possible therapeutic effects of enriched environment (EE) and CBL alone or combined for reducing anxiety and cognitive deficits in PTSD-like mouse models. For this purpose, inescapable electric foot shocks were delivered to Balb/c mice for two consecutive days. Then mice were treated with CBL (2.5 mL/kg) and/or were kept in EE (2 h per day) or received their combination for 14 consecutive days. The hole-board test and Lashley III paradigm were used to assess anxiety and spatial learning and memory, respectively. Changes in the serum corticosterone level and expression of synaptic elements, including; growth-associated protein 43, post-synaptic density 95, and synaptophysin were assessed in the hippocampus. This model caused anxiety and spatial memory impairment associated with increased serum corticosterone levels and decreased synaptic elements. Nevertheless, CBL and/or combination treatment could reverse behavioral and molecular alterations. Our findings indicated that CBL, separately or in combination with EE, is effective in reducing anxiety and spatial memory impairment in PTSD-like mice.

Melatonin alleviates PTSD-like behaviors and restores serum GABA and cortisol levels in mice

RATIONALE

Melatonin is an endogenous hormone which modulates sleep-wake cycles. Previous studies have found a close correlation between melatonin and post-traumatic stress disorder (PTSD), a trauma- and stress-related psychiatric disorder with symptoms of sleep disturbance. However, it is still unclear if melatonin can have a therapeutic effect on PTSD.

OBJECTIVE

This study aimed to investigate the effects of melatonin on foot shocks induced PTSD-like behaviors and abnormal neuroendocrine levels in mice.

RESULTS

As compared to no-shock controls, PTSD-like mice spent significantly more time freezing and displayed less rearing in a contextual fear test, spent significantly less time in and had fewer entries into open arms in an elevated maze test, and spent significantly less time in and had fewer entries into a light box in a light-dark transition task. In addition, serum GABA and cortisol levels were both found to be significantly decreased, whereas epinephrine levels were significantly increased in the PTSD-like mice. Our results showed that intraperitoneal injections of melatonin (2 mM, but not 0.2 nor 20 mM, 0.1 ml/day for two consecutive weeks) alleviated PTSD-like behaviors and restored serum GABA and cortisol levels. Further, it was found that melatonin receptor 1/2 antagonist luzindole significantly blocked the beneficial effects of melatonin for PTSD-like behaviors and serum GABA and cortisol levels, whereas melatonin receptor 2 antagonist 4-P-PDOT slightly blocked these effects.

CONCLUSIONS

These results indicate that melatonin has a potential therapeutic effect on PTSD-like symptoms in mice, and melatonin receptor 1 mediated the effect.

Xiaoyao San, a Chinese herbal formula, ameliorates depression-like behavior in mice through the AdipoR1/AMPK/ACC pathway in hypothalamus

OBJECTIVE

Depression and metabolic disorders have overlapping psychosocial and pathophysiological causes. Current research is focused on the possible role of adiponectin in regulating common biological mechanisms. Xiaoyao San (XYS), a classic Chinese medicine compound, has been widely used in the treatment of depression and can alleviate metabolic disorders such as lipid or glucose metabolism disorders. However, the ability of XYS to ameliorate depression-like behavior as well as metabolic dysfunction in mice and the underlying mechanisms are unclear.

METHODS

An in vivo animal model of depression was established by chronic social defeat stress (CSDS). XYS and fluoxetine were administered by gavage to the drug intervention group. Depression-like behaviors were analyzed by the social interaction test, open field test, forced swim test, and elevated plus maze test. Glucose levels were measured using the oral glucose tolerance test. The involvement of certain molecules was validated by immunofluorescence, histopathology, and Western blotting. In vitro, hypothalamic primary neurons were exposed to high glucose to induce neuronal damage, and the neuroprotective effect of XYS was evaluated by cell counting kit-8 assay. Immunofluorescence and Western blotting were used to evaluate the influences of XYS on adiponectin receptor 1 (AdipoR1), adenosine 5'-monophosphate-activated protein kinase (AMPK), acetyl-coenzyme A carboxylase (ACC) and other related proteins.

RESULTS

XYS ameliorated CSDS-induced depression-like behaviors and glucose tolerance impairment in mice and increased the level of serum adiponectin. XYS also restored Nissl bodies in hypothalamic neurons in mice that exhibited depression-like behaviors and decreased the degree of neuronal morphological damage. In vivo and in vitro studies indicated that XYS increased the expression of AdipoR1 in hypothalamic neurons.

CONCLUSION

Adiponectin may be a key regulator linking depression and metabolic disorders; regulation of the hypothalamic AdipoR1/AMPK/ACC pathway plays an important role in treatment of depression by XYS.

Pharmacological strategies for post-traumatic stress disorder (PTSD): From animal to clinical studies

Post-traumatic stress disorder (PTSD) is a disabling psychiatric condition with a critical familiar, personal, and social impact. Patients diagnosed with PTSD show various symptoms, including anxiety, depression, psychotic episodes, and sleep disturbances, complicating their therapeutic management. Only sertraline and paroxetine, two selective serotonin reuptake inhibitors, are approved by different international agencies to treat PTSD. In addition, these drugs are generally combined with psychotherapy to achieve positive results. However, these pharmacological strategies present limited efficacy. Nearly half of the PTSD patients do not experience remission of symptoms, possibly due to the high prevalence of psychiatric comorbidities. Therefore, in clinical practice, other off-label medications are common, even though the effectiveness of these drugs needs to be further investigated. In this line, antipsychotics, antiepileptics, adrenergic blockers, benzodiazepines, and other emerging pharmacological agents have aroused interest as potential therapeutic tools to improve some specific symptoms of PTSD. Thus, this review is focused on the most widely used drugs for the pharmacological treatment of PTSD with a translational approach, including clinical and preclinical studies, to emphasize the need to develop safer and more effective medications.

Nutraceutical Interventions for Post-Traumatic Stress Disorder in Animal Models: A Focus on the Hypothalamic–Pituitary–Adrenal Axis

Post-traumatic stress disorder (PTSD) occurs after exposure to traumatic events and is characterized by overwhelming fear and anxiety. Disturbances in the hypothalamic–pituitary–adrenal (HPA) axis are involved in the pathogenesis of mood disorders, including anxiety, PTSD, and major depressive disorders. Studies have demonstrated the relationship between the HPA axis response and stress vulnerability, indicating that the HPA axis regulates the immune system, fear memory, and neurotransmission. The selective serotonin reuptake inhibitors (SSRIs), sertraline and paroxetine, are the only drugs that have been approved by the United States Food and Drug Administration for the treatment of PTSD. However, SSRIs require long treatment times and are associated with lower response and remission rates; therefore, additional pharmacological interventions are required. Complementary and alternative medicine therapies ameliorate HPA axis disturbances through regulation of gut dysbiosis, insomnia, chronic stress, and depression. We have described the cellular and molecular mechanisms through which the HPA axis is involved in PTSD pathogenesis and have evaluated the potential of herbal medicines for PTSD treatment. Herbal medicines could comprise a good therapeutic strategy for HPA axis regulation and can simultaneously improve PTSD-related symptoms. Finally, herbal medicines may lead to novel biologically driven approaches for the treatment and prevention of PTSD.

Ginsenoside Rg1 Prevents PTSD-Like Behaviors in Mice Through Promoting Synaptic Proteins, Reducing Kir4.1 and TNF-α in the Hippocampus

Ginsenoside Rg1 is efficient to prevent or treat mental disorders. However, the mechanisms underlying the effects of ginsenoside Rg1 on post-traumatic stress disorder (PTSD) are still not known. In this study, single-prolonged stress (SPS) regime, as well as injection of lipopolysaccharide (LPS), was used to produce PTSD-like behaviors in C57 mice, and the effects of ginsenoside Rg1 (10, 20, 40 mg/kg/d, ip, for 14 days) on PTSD-like behaviors were evaluated. Our results showed that ginsenoside Rg1 promoted fear extinction and prevented depression-like behaviors in both LPS and SPS models. Importantly, ginsenoside Rg1 alleviated LPS- or SPS-stimulated expression of pro-inflammatory cytokines (IL-1β and TNF-α), activation of astrocytes and microglia, and reduction of hippocampal synaptic proteins (PSD95, Arc, and GluA1). Ginsenoside Rg1 also reduced the increase of hippocampal Kir4.1 and GluN2A induced by PTSD regime. Importantly, reducing hippocampal astroglial Kir4.1 expression promoted fear extinction and improved depression-like behaviors in LPS-treated mice. Additionally, intracerebroventricular injection of TNF-α caused an impairment of fear extinction and promoted Kir4.1 expression in the hippocampus. Together, our study reveals novel protective effects of ginsenoside Rg1 against PTSD-like behaviors in mice, likely via promoting synaptic proteins, reducing Kir4.1 and TNF-α in the hippocampus.

Acetate supplementation produces antidepressant-like effect via enhanced histone acetylation

BACKGROUND

Abnormal energy metabolism is often documented in the brain of patients and rodents with depression. In metabolic stress, acetate serves as an important source of acetyl coenzyme A (Ac-CoA). However, its exact role and underlying mechanism remain to be investigated.

METHOD

We used chronic social failure stress (CSDS) to induce depression-like phenotype of C57BL/6J mice. The drugs were administered by gavage. We evaluated the depressive symptoms by sucrose preference test, social interaction, tail suspension test and forced swimming test. The dendritic branches and spine density were detected by Golgi staining, mRNA level was analyzed by real-time quantitative RT-PCR, protein expression level was detected by western blot, and the content of Ac-CoA was detected by ELISA kit.

RESULT

The present study found that acetate supplementation significantly improved the depression-like behaviors of mice either in acute forced swimming test (FST) or in CSDS model and that acetate administration enhanced the dendritic branches and spine density of the CA1 pyramidal neurons. Moreover, the down-regulated levels of BDNF and TrkB were rescued in the acetate-treated mice. Of note, chronic acetate treatment obviously lowered the transcription level of HDAC2, HDAC5, HDAC7, HDAC8, increased the transcription level of HAT and P300, and boosted the content of Ac-CoA in the nucleus, which facilitated the acetylation levels of histone H3 and H4.

LIMITATIONS

The effect of acetate supplementation on other brain regions is not further elucidated.

CONCLUSION

These findings indicate that acetate supplementation can produce antidepressant-like effects by increasing histone acetylation and improving synaptic plasticity in hippocampus.

Advances in Treatment of Post-Traumatic Stress Disorder with Chinese Medicine

"Timely, near, and expectation" is the main principle of battlefield rescue for military combat stress reaction (CSR). Post-traumatic stress disorder (PTSD) is the most common form of CSR and a long-term persistent mental disorder that is caused by unusual threatening or catastrophic psychological trauma. Chinese medicine (CM) has abundant resources, is simple, easy to master, with few side effects. This article summarizes the cellular and animal experimental mechanisms of CM treatment on PTSD, suggesting that traditional Chinese herbs and acupuncture can protect brain functional areas, and adjust hypothalamus-pituitary-adrenal axis. Traditional Chinese herbs and acupuncture have shown good anti-stress efficacy and fewer side effects in clinical application, which may improve the CSR in the battlefield.

Metformin ameliorates stress-induced depression-like behaviors via enhancing the expression of BDNF by activating AMPK/CREB-mediated histone acetylation

BACKGROUND

Metformin, a first-line antiglycemic drug, has been reported to have anti-depressant effects in patients with type 2 diabetes; however, its exact role and underlying mechanism still need to be investigated.

METHOD

C57BL/6J mice were subjected to the Chronic social defeat stress (SDS) and drug administration (Control + Vehicle, SDS + Vehicle, SDS + MET (200 mg kg^-1), SDS + FLUOX (3 mg kg^-1), SDS + MET + FLUOX). And the depression phenotypes were evaluated by the sucrose preference test, social interaction, tail suspension test and forced swimming test. The potential mechanisms underlying the effects of metformin on depression was discussed by using Chromatin immunoprecipitation, Quantitative real-time PCR mRNA expression analysis and Western blot in vivo and in primary cultured hippocampal neurons.

RESULT

The metformin treatment counteracted the development of depression-like behaviors in mice suffering SDS when administered alone and enhanced the anti-depressant effect of fluoxetine when combined with fluoxetine. Further RNA sequencing analysis revealed that metformin treatment prevented the transcriptional changes in the medial prefrontal cortex (mPFC) of the animals and Golgi staining indicated favorable morphological changes in the neurite plasticity of CA1 pyramidal neurons, which approximated to those found in unstressed mice. At a molecular level, metformin significantly upregulated the expression of the brain-derived neurotrophic factor (BDNF) by increasing the histone acetylation along with the BDNF promoter, which was attributed to the activation of AMP-activated protein kinase (AMPK) and cAMP-response element binding protein (CREB).

CONCLUSION

Our findings suggest that metformin can produce antidepressant effects, which provides empirical insights into the clinical value of metformin in the prevention and therapy of depression.

The anxiolytic-like effects of ginsenoside Rg3 on chronic unpredictable stress in rats

The present study is to evaluate the anxiolytic-like activities underlying ginsenoside Rg3 (GRg3). The anxiolytic-like activities were induced by GRg3 (20 and 40 mg/kg, i.g), evidenced by blocking the decreased time and entries in the open arms in elevated plus maze test and by reversing the increased latency to feed in novelty-suppressed feeding test. In addition, the decreased levels on progesterone, allopregnanolone, serotonin (5-HT) in the prefrontal cortex and hippocampus of chronic unpredictable stress (CUS) were blocked by GRg3 (20 and 40 mg/kg, i.g). Furthermore, the increased corticotropin releasing hormone, corticosterone and adrenocorticotropic hormone were blocked by GRg3 (20 and 40 mg/kg, i.g). Collectively, the anxiolytic-like effects produced by GRg3 were associated with the normalization of neurosteroids biosynthesis, serotonergic system as well as HPA axis dysfunction.