The ethanol extract of Aquilariae Lignum ameliorates hippocampal oxidative stress in a repeated restraint stress mouse model

Mitigating fatigue in long COVID patients with MYPplus: a clinical observation

PURPOSE

The COVID-19 pandemic has led to the emergence of a secondary public health crisis known as Long COVID. It is estimated that approximately 10% of individuals who contact COVID-19 develop Long COVID, with fatigue and brain fog being among the most commonly reported and debilitating symptoms. However, no standardized or effective treatments are currently available. This observational study aimed to evaluate the efficacy of MYPplus, an herbal formulation composed of Astragali Radix, Salviae Radix, and Aquilariae Lignum, in alleviating fatigue and brain fog in patients with Long COVID.

METHODS

Subjects with a score of 60 or higher on the Modified Korean version of the Chalder Fatigue scale (mKCFQ11) or a brain fog rating of 5 or higher on the visual analogue scale (VAS) took two capsules of MYPplus (500 mg per capsule) twice daily for 4 weeks. Changes in symptoms were assessed using the mKCFQ11, Multidimensional Fatigue Inventory (MFI-20), Fatigue VAS, Brain fog VAS, and overall quality of life using the Short-Form Health Survey (SF-12). Additionally, levels of three cytokines (TNF-α, TGF-β, IFN- γ) and cortisol were measured.

RESULTS

Fifty participants successfully completed the 4-week administration with MYPplus. At baseline, fatigue severity was 75.3 ± 10.9 in mKCFQ11, 70.9 ± 11.2 in MFI-20, 7.5 ± 1.2 in Fatigue VAS, 8.4 ± 1.1 in Brain fog VAS, and 45.3 ± 17.8 in SF-12. All parameters significantly improved (p < 0.01), with a decrease of 46% in mKCFQ11, 26% in MFI-20, 49% in Fatigue VAS, and 52% in Brain fog VAS, and an increase of 59% in SF-12, respectively. Unlikely others, the plasma level of TGF-β showed a declining pattern after MYPplus administration (from 765.0 ± 1759.7 to 243.9 ± 708.1 pg/mL, p = 0.07). No safety concerns were observed.

CONCLUSION

This pilot observational study suggests the clinical potential of MYPplus for managing patients with Long COVID, focusing on fatigue-related symptoms and quality of life. Further studies are required to confirm its efficacy and safety using large-scale randomized placebo-controlled trials in the future.

PROTOCOL REGISTRATION

This study has been retrospectively registered with the identifier number KCT0008948 on https://cris.nih.go.kr , as of 27/10/23.

Antidepressant Activity of Agarwood Essential Oil: A Mechanistic Study on Inflammatory and Neuroprotective Signaling Pathways

Background: Depression ranks among the most severe mental health conditions, and poses a burden on global health. Agarwood, an aromatic medicinal plant, has shown potential for improving mental symptoms. As a common folk medicine, agarwood has been applied as an alternative method for mental disorders such as depression through aromatherapy. Previous studies have found that the therapeutic effects of agarwood aromatherapy are primarily related to its volatile components. This study aimed to examine the antidepressant properties and underlying mechanisms of agarwood essential oil (AEO), a collection of the volatile components of agarwood utilized through aromatherapy inhalation and injection administration in mice. Methods: A lipopolysaccharide (LPS)-induced inflammatory depression model was used to evaluate the effects of AEO inhalation and injection on depression-like symptoms. Behavioral assessments included the open-field, tail suspension, and forced swimming tests. Western blot (WB) and ELISA techniques were used to further verify the mechanistic insights. Results: In the LPS-induced depression-like model, AEO inhalation and injection significantly improved depression-like symptoms, decreased immobility duration in both the tail suspension and forced swimming tests in model mice, and reduced the levels of inflammatory cytokines IL-1β, IL-6, and TNF-α. WB experiments demonstrated that AEO inhibited the NF-κB/IκB-α inflammatory pathway and activated the BDNF/TrkB/CREB pathway in the hippocampus of the LPS-depression model mice. Notably, AEO extracted by hydrodistillation was more effective in alleviating LPS-induced depressive-like behaviors than using supercritical CO2 fluid extraction. Conclusions: Both the inhalation and the injection administration of AEO exerted notable antidepressant effects, potentially associated with reducing inflammation levels in the brain, downregulating inflammatory NF-κB/IκB-α, and upregulating the neuroprotective BDNF/TrkB/CREB signaling pathway. In the future, it is necessary to further determine the pharmacodynamic components, key targets and specific molecular mechanisms of AEO's antidepressant effects so as to provide more support for the neuroprotective research of medicinal plants.

Neuroprotective Effects of Thymol and p-Cymene in Immobilized Male rats through Alterations in Molecular, Biochemical, Histological, and Behavioral Parameters

The research was conducted to examine the neuroprotective effect of thymol and its precursor p-cymene on chronic immobility stress in adult male Wistar rats. The rats were subjected to 2.5 h of stress every day for 14 consecutive days by placing them inside a restrainer. Thymol (10 mg/kg) and p-cymene (50 mg/kg) were given to the rats during the same period. The results showed that thymol and p-cymene prevented the increase of MDA level, decline of GSH level, and decrease of SOD and GPx activity in the hippocampus of rats exposed to stress. These monoterpenes also prevented the increase in the expression of Tnfa, Il1b, Tlr4, and Nfkb, and the decrease in the expression of Nrf2, Ho1, and Bdnf. In addition, thymol and p-cymene inhibited the increase in the expression and activity of acetylcholinesterase in the hippocampus of animals exposed to immobility and enhanced the expression of A7nachr. They also reduced neuronal death in the CA1 region of stressed animals and improved their performance in the Morris water maze and elevated plus maze tests. Based on these findings, thymol and p-cymene may be effective in preventing neurodegenerative diseases as they reduce oxidative stress and neuroinflammation, strengthen ACh signaling, and stimulate Bdnf expression.

Transportation Noise Pollution and Cardiovascular Health

Epidemiological studies have found that transportation noise increases the risk for cardiovascular morbidity and mortality, with solid evidence for ischemic heart disease, heart failure, and stroke. According to the World Health Organization, at least 1.6 million healthy life years are lost annually from traffic-related noise in Western Europe. Traffic noise at night causes fragmentation and shortening of sleep, elevation of stress hormone levels, and increased oxidative stress in the vasculature and the brain. These factors can promote vascular (endothelial) dysfunction, inflammation, and arterial hypertension, thus elevating cardiovascular risk. The present review focusses on the indirect, nonauditory cardiovascular health effects of noise. We provide an updated overview of epidemiological research on the effects of transportation noise on cardiovascular risk factors and disease, and mechanistic insights based on the latest clinical and experimental studies and propose new risk markers to address noise-induced cardiovascular effects in the general population. We will discuss the potential effects of noise on vascular dysfunction, oxidative stress, and inflammation in humans and animals. We will elaborately explain the underlying pathomechanisms by alterations of gene networks, epigenetic pathways, circadian rhythm, signal transduction along the neuronal-cardiovascular axis, and metabolism. We will describe current and future noise mitigation strategies. Finally, we will conduct an overall evaluation of the status of the current evidence of noise as a significant cardiovascular risk factor.

Health position paper and redox perspectives - Disease burden by transportation noise

Transportation noise is a ubiquitous urban exposure. In 2018, the World Health Organization concluded that chronic exposure to road traffic noise is a risk factor for ischemic heart disease. In contrast, they concluded that the quality of evidence for a link to other diseases was very low to moderate. Since then, several studies on the impact of noise on various diseases have been published. Also, studies investigating the mechanistic pathways underlying noise-induced health effects are emerging. We review the current evidence regarding effects of noise on health and the related disease-mechanisms. Several high-quality cohort studies consistently found road traffic noise to be associated with a higher risk of ischemic heart disease, heart failure, diabetes, and all-cause mortality. Furthermore, recent studies have indicated that road traffic and railway noise may increase the risk of diseases not commonly investigated in an environmental noise context, including breast cancer, dementia, and tinnitus. The harmful effects of noise are related to activation of a physiological stress response and nighttime sleep disturbance. Oxidative stress and inflammation downstream of stress hormone signaling and dysregulated circadian rhythms are identified as major disease-relevant pathomechanistic drivers. We discuss the role of reactive oxygen species and present results from antioxidant interventions. Lastly, we provide an overview of oxidative stress markers and adverse redox processes reported for noise-exposed animals and humans. This position paper summarizes all available epidemiological, clinical, and preclinical evidence of transportation noise as an important environmental risk factor for public health and discusses its implications on the population level.

Noise and Air Pollution as Risk Factors for Hypertension: Part II-Pathophysiologic Insight

Traffic noise and air pollution are environmental stressors found to increase risk for cardiovascular events. The burden of disease attributable to environmental stressors and cardiovascular disease globally is substantial, with a need to better understand the contribution of specific risk factors that may underlie these effects. Epidemiological observations and experimental evidence from animal models and human controlled exposure studies suggest an essential role for common mediating pathways. These include sympathovagal imbalance, endothelial dysfunction, vascular inflammation, increased circulating cytokines, activation of central stress responses, including hypothalamic and limbic pathways, and circadian disruption. Evidence also suggests that cessation of air pollution or noise through directed interventions alleviates increases in blood pressure and intermediate surrogate pathways, supporting a causal link. In the second part of this review, we discuss the current understanding of mechanisms underlying and current gaps in knowledge and opportunities for new research.

The alkaloids of Corydalis hendersonii Hemsl. contribute to the cardioprotective effect against ischemic injury in mice by attenuating cardiomyocyte apoptosis via p38 MAPK signaling pathway

BACKGROUND

There is a characteristic Tibetan folk medicine in China named Corydalis hendersonii Hemsl. (CH) has been used for treatment of cardiovascular related diseases, called "plethora" in Tibetan medicine. Previous studies demonstrated that ethanol extract of CH showed anti-acute myocardial infarction (AMI) effect through inhibiting fibrosis and inflammation. Rich alkaloids fraction (RAF) is isolated from CH, but whether RAF possessing an equivalent effect with the CH ethanol extract and by which mechanism it protects against AMI has not yet reported. The paper aimed to study the potential role of RAF on myocardial injured mice and its underlying mechanism.

MATERIALS AND METHODS

Liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) was used to analyze the chemical profile and isolate pure compounds. The ligation of left anterior descending (LAD) of coronary artery in mice was used to evaluate the in vivo anti-AMI effect, by dividing into eight groups: Sham, Model, Fosinopril (10 mg/kg, i.g.), total extract (TE, 400 mg/kg, i.g.), poor alkaloids fraction  (PAF, 300 mg/kg, i.g.), and RAF (25, 50, and 100 mg/kg, respectively, i.g.) groups. Echocardiography was used to evaluate mice heart function through the index of left ventricular end-systolic  diameter (LVEDs), left ventricular end-diastolic diameter (LVEDd), fractional shortening (FS) and ejection fraction (EF). We detected the lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in the serum and the plasma level of angiotensin II (AngII). The apoptosis of mice myocardial tissue was verified by TUNEL assay. The expression of p38 mitogen-activated protein kinases (p38 MAPK), Bcl-2 and Bcl-2-associated X protein (Bax) were detected through immunofluorescence staining, qRT-PCR and western blot in mice heart tissue and H9c2 cells.

RESULTS

Echocardiography data indicated that the values of LVEDd and LVEDs were reduced and the values of FS and EF were improved by TE and RAF significantly. RAF also decreased the levels of LDH, CK-MB and AngII and significantly inhibited inflammatory cells in the marginal zone of myocardial infarction. The TUNEL assay results showed that RAF significantly attenuated cell apoptosis. Immunofluorescence and qRT-PCR assay showed that RAF inhibited p38 MAPK, Bax, and Bcl-2 proteins in mice myocardium. Western blot results validated that the expressions of key proteins were inhibited by RAF. Also, the apoptotic cells and apoptosis-related proteins were dramatically reduced by RAF in vivo and in vitro. Besides, RAF and PAF were analyzed by LCMS-IT-TOF to identify the main compounds and to demonstrate the difference between them. The results showed that a total of 14 alkaloids were identified, which indicated that the isoquinoline alkaloids were the main ingredients in RAF may contributing to the cardioprotective effect in mice.

CONCLUSIONS

RAF improves cardiac function by inhibiting apoptosis via p38 MAPK signaling pathway, and RAF contributes to the effect against myocardial ischemic injury of TE in mice, which provides a substantial reference for the clinical application against ischemia heart disease and quality control of CH.

Modified rougan decoction alleviates lipopolysaccharide-enrofloxacin-induced hepatotoxicity via activating the Nrf2/ARE pathway in chicken

Liver injury plays a heavy burden on the chicken industry. Although modified rougan decoction is a prescription for the treatment of liver disease based on the classical prescription of rougan decoction (containing peony and licorice). However, the effect and mechanism of modified rougan decoction on the liver remain unclear. In this study, the effects of the water extracts (MRGD) and the alcohol precipitates of water extracts (MRGDE) against lipopolysaccharide-enrofloxacin (LPS-ENR)-induced hepatotoxicity were discussed in vivo and in vitro. The isolated hepatocytes and 128 one-day-old Hyline chickens were considered research objects. The indices of liver injury and oxidative stress were evaluated by hematoxylin and eosin (H&E) stained and the assay kits, and the nuclear erythroid 2-related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway was detected by the RT-PCR, western blot, and immunofluorescence tests. All data were analyzed using the IBM SPSS 20.0 software. In vivo, the structural integrity of the liver was maintained, AST, ALT, and MDA levels were decreased, and antioxidant enzymes were increased, confirming that the oxidative stress was reduced and liver injury was alleviated. Correspondingly, MRGD and MRGDE were observed to improve cell viability and decrease lactate dehydrogenase (LDH) in vitro, and the cell oxidative damage was reduced. In addition, the nuclear translocation of Nrf2 was improved significantly, and the mRNA and protein expression levels of the related genes were upregulated. In conclusion, MRGD and MRGDE can exert a protective effect against LPS-ENR-induced hepatotoxicity by activating the Nrf2/ARE pathway, which might be a potential therapeutic prescription for preventing or treating liver injury. Notably, no significant difference was found between the 2 extracts, suggesting that a depth extraction method did not always improve the efficacy of natural medicine. Our results provided new insights into finding effective hepatoprotective medicine.

The Neurobiological Links between Stress and Traumatic Brain Injury: A Review of Research to Date

Neurological dysfunctions commonly occur after mild or moderate traumatic brain injury (TBI). Although most TBI patients recover from such a dysfunction in a short period of time, some present with persistent neurological deficits. Stress is a potential factor that is involved in recovery from neurological dysfunction after TBI. However, there has been limited research on the effects and mechanisms of stress on neurological dysfunctions due to TBI. In this review, we first investigate the effects of TBI and stress on neurological dysfunctions and different brain regions, such as the prefrontal cortex, hippocampus, amygdala, and hypothalamus. We then explore the neurobiological links and mechanisms between stress and TBI. Finally, we summarize the findings related to stress biomarkers and probe the possible diagnostic and therapeutic significance of stress combined with mild or moderate TBI.

Chemical Composition and Potential Properties in Mental Illness (Anxiety, Depression and Insomnia) of Agarwood Essential Oil: A Review

As a valuable medicinal herb and spice, agarwood is widely used in the fields of daily chemistry, traditional medicine, religion and literary collection. It mainly contains sesquiterpenes and 2-(2-phenylethyl)chromones, which are often used to soothe the body and mind, relieve anxiety, act as an antidepressant and treat insomnia and other mental disorders, presenting a good calming effect. This paper reviews the chemical composition of the essential oils of different sources of agarwood, as well as the progress of research on the sedative and tranquilizing pharmacological activity and mechanism of action of agarwood essential oil (AEO), and then analyzes the current problems of AEO research and its application prospects in the treatment of mental diseases.

Microglia in depression: an overview of microglia in the pathogenesis and treatment of depression

Major depressive disorder is a highly debilitating psychiatric disorder involving the dysfunction of different cell types in the brain. Microglia are the predominant resident immune cells in the brain and exhibit a critical role in depression. Recent studies have suggested that depression can be regarded as a microglial disease. Microglia regulate inflammation, synaptic plasticity, and the formation of neural networks, all of which affect depression. In this review, we highlighted the role of microglia in the pathology of depression. First, we described microglial activation in animal models and clinically depressed patients. Second, we emphasized the possible mechanisms by which microglia recognize depression-associated stress and regulate conditions. Third, we described how antidepressants (clinical medicines and natural products) affect microglial activation. Thus, this review aimed to objectively analyze the role of microglia in depression and focus on potential antidepressants. These data suggested that regulation of microglial actions might be a novel therapeutic strategy to counteract the adverse effects of devastating mental disorders.

Aquilaria Species (Thymelaeaceae) Distribution, Volatile and Non-Volatile Phytochemicals, Pharmacological Uses, Agarwood Grading System, and Induction Methods

Agarwood is a highly valuable fragrant wood of Aquilaria spp. (Thymelaeaceae) which has been widely utilized in traditional medicine, religious rites, and cultural activities. This study summarizes a review on the identification of Aquilaria cultivars, volatile and non-volatile phytochemicals, pharmacological uses, and agarwood grading system to determine its quality, and different agarwood induction methods. Due to the highly demanding and depleted natural resources, the research on agarwood is still insufficient, and it has broad research and development prospects in many industries. However, due to the significant scientific nature of agarwood application, developing high-quality products and drugs from agarwood have become highly important, while no one has discussed in detail the phytochemicals uses and provided a summary until now. The main phytochemicals of agarwood include terpenoids, dominated by sesquiterpenes. For centuries, terpenoids have been used in traditional Chinese medicine and have been shown to possess various pharmacological properties, including bacteriostatic, antibacterial, sedation, analgesia, anti-inflammation, anti-asthmatic, hypoglycemic, antidepressant, and many others. Alongside biological activity screening, phytochemical advances and pharmacological research have also made certain progress. Therefore, this review discusses the research progress of agarwood in recent years and provides a reference basis for further study of Aquilaria plants and agarwood.

Transportation noise pollution and cardiovascular disease

Epidemiological studies have found that transportation noise increases the risk of cardiovascular morbidity and mortality, with high-quality evidence for ischaemic heart disease. According to the WHO, ≥1.6 million healthy life-years are lost annually from traffic-related noise in Western Europe. Traffic noise at night causes fragmentation and shortening of sleep, elevation of stress hormone levels, and increased oxidative stress in the vasculature and the brain. These factors can promote vascular dysfunction, inflammation and hypertension, thereby elevating the risk of cardiovascular disease. In this Review, we focus on the indirect, non-auditory cardiovascular health effects of transportation noise. We provide an updated overview of epidemiological research on the effects of transportation noise on cardiovascular risk factors and disease, discuss the mechanistic insights from the latest clinical and experimental studies, and propose new risk markers to address noise-induced cardiovascular effects in the general population. We also explain, in detail, the potential effects of noise on alterations of gene networks, epigenetic pathways, gut microbiota, circadian rhythm, signal transduction along the neuronal-cardiovascular axis, oxidative stress, inflammation and metabolism. Lastly, we describe current and future noise-mitigation strategies and evaluate the status of the existing evidence on noise as a cardiovascular risk factor.

Melatonin ameliorates diabetes-induced brain injury in rats

Diabetic brain is a serious complication of diabetes, and it is associated with oxidative stress and neuronal injury. This study investigated the protective effect of melatonin (MLT) on diabetes-induced brain injury. A rat model of type 2 diabetes mellitus was produced by intraperitoneal injection of nicotinamide 100 mg/kg, followed by intraperitoneal injection of streptozotocin 55 mg/kg. The diabetic rats were orally administered MLT 10 mg/kg of body weight for 15 days. MLT remarkably downregulated serum glucose levels. It also improved levels of the lipid peroxidation product 4-hydroxynonenal, improved levels of antioxidants including glutathione, glutathione peroxidase and glutathione reductase in the brains of the diabetic rats, and this is indicative of the antioxidant potential of MLT. MLT also prevented increase in homocysteine, amyloid-β42 and tau levels in diabetic rats, and this suggests that it can reduce the risk of dementia. This is associated with reduction in the levels of the dopamine, serotonin, and glutamate and is indicative of the regulatory effect of MLT on neurotransmitters. Treatment with MLT improved diabetes-induced structural alteration in the hippocampus and cerebral cortex. MLT significantly reduced caspase-3 and Bax as well as significantly increase Bcl-2 protein and GFAP-positive astrocytes indicating its anti-apoptotic effect. MLT showed remarkable ameliorative effect against biochemical and molecular alterations in the brains of diabetic rats most likely through its antioxidant property.

Aquilariae Lignum Methylene Chloride Fraction Attenuates IL-1β-Driven Neuroinflammation in BV2 Microglial Cells

Microglial hyperactivation and neuroinflammation are known to induce neuronal death, which is one of the main causes of neurodegenerative disorders. We previously found that Aquilariae Lignum extract attenuated both neuronal excitotoxicity and neuroinflammation in vivo and in vitro. For further analysis, we extracted the methylene chloride fraction of Aquilariae Lignum to determine the bioactive compounds. In this study, we investigated the anti-neuroinflammatory effects and underlying mechanisms of the Aquilariae Lignum fraction (ALF) using lipopolysaccharide (LPS)-stimulated BV2 microglial cells. BV2 cells were pretreated with ALF (0.5, 1, and 2.5 μg/mL) before treatment with LPS (1 μg/mL). Pretreatment with ALF significantly attenuated the LPS-induced overproductions of nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and interleukin (IL)-1β. These anti-inflammatory effects were supported by ALF-mediated modulation of the nuclear factor-kappa B (NF-κB) pathway. Furthermore, ALF exerted strong anti-inflammasome effects, as shown by IL-1β-specific inhibitory activity, but not activity against tumor necrosis factor (TNF)-α, along with inhibition of caspase-1 activity and NACHT, LRR, and PYD domain-containing protein 3 (NLRP3)-related molecules. These results indicate the potent anti-neuroinflammatory activity of ALF and that its underlying mechanism may involve the regulation of NLRP3 inflammasome-derived neuroinflammation in microglial cells.

DUOX2, a common modulator in preventive effects of monoamine-based antidepressants on water immersion restraint stress- and indomethacin- induced gastric mucosal damage

Multiple kinds of monoamine-based antidepressants have been shown prophylactic effects in experimentally induced gastric ulcer. The loss of redox homeostasis plays a principle role in the development of peptic mucosal damage. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are one of the most important sources of reactive oxygen species within the gastrointestinal tract. It is unclear whether there are some common NADPH oxidases modulated by monoamine-based antidepressants in different gastric mucosal damage models. We explored the effects of selective serotonin-norepinephrine reuptake inhibitor (SNRI) duloxetine on the reactive oxygen species production and antioxidant capacity in the gastric mucosa of water immersion restraint (WIRS) or indomethacin treated rats, and examined the role of NADPH oxidases in the protective effects. Pretreated duloxetine prevented the increase of gastric mucosal NADPH oxidase activity and NADPH oxidase inhibitor apocynin dose-dependently protected gastric mucosa from damage by the two factors. Furthermore, dual oxidase 2 (DUOX2) and NADPH oxidase4 (NOX4) are involved in the protective effects of duloxetine in both models. We then examined NADPH oxidases expression modulated by the other monoamine-based antidepressants including selective serotonin reuptake inhibitor (SSRIs) fluoxetine, tricyclic agent (TCAs) amitriptyline and monoamine oxidase inhibitor (MAOs) moclobemide in the two models, and all the three antidepressants reduced the DUOX2 expression in the gastric mucosa. So DUOX2 was a common modulator in the preventive effects of all the monoamine-based antidepressants on WIRS- and indomethacin-induced gastric lesion. Our work provided a peripheral joint molecular target for monoamine modulatory antidepressants, which may be helpful to reveal the mechanisms of this kind of drugs more than monoamine regulation.

Oxidative stress and inflammation contribute to traffic noise-induced vascular and cerebral dysfunction via uncoupling of nitric oxide synthases

Environmental pollution and non-chemical stressors such as mental stress or traffic noise exposure are increasingly accepted as health risk factors with substantial contribution to chronic noncommunicable diseases (e.g. cardiovascular, metabolic and mental). Whereas the mechanisms of air pollution-mediated adverse health effects are well characterized, the mechanisms of traffic noise exposure are not completely understood, despite convincing clinical and epidemiological evidence for a significant contribution of environmental noise to overall mortality and disability. The initial mechanism of noise-induced cardiovascular, metabolic and mental disease is well defined by the „noise reaction model“ and consists of neuronal activation involving the hypothalamic-pituitary-adrenal (HPA) axis as well as the sympathetic nervous system, followed by a classical stress response via cortisol and catecholamines. Stress pathways are initiated by noise-induced annoyance and sleep deprivation/fragmentation. This review highlights the down-stream pathophysiology of noise-induced mental stress, which is based on an induction of inflammation and oxidative stress. We highlight the sources of reactive oxygen species (ROS) involved and the known targets for noise-induced oxidative damage. Part of the review emphasizes noise-triggered uncoupling/dysregulation of endothelial and neuronal nitric oxide synthase (eNOS and nNOS) and its central role for vascular dysfunction.

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Exposure to (traffic) noise causes non-auditory (indirect) cardiovascular and cerebral health harms via neuronal activation.

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Noise activates the HPA axis and sympathetic nervous system increasing levels of stress hormones, vasoconstrictors and ROS.

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Noise induces inflammation and stimulates several ROS sources leading to cerebral and cardiovascular oxidative damage.

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Noise leads to eNOS and nNOS uncoupling contributing to cardiometabolic disease and cognitive impairment.

Stress-induced blood brain barrier disruption: Molecular mechanisms and signaling pathways

Stress is a nonspecific response to a threat or noxious stimuli with resultant damaging consequences. Stress is believed to be an underlying process that can trigger central nervous system disorders such as depression, anxiety, and post-traumatic stress disorder. Though the pathophysiological basis is not completely understood, data have consistently shown a pivotal role of inflammatory mediators and hypothalamo-pituitary-adrenal (HPA) axis activation in stress induced disorders. Indeed emerging experimental evidences indicate a concurrent activation of inflammatory signaling pathways and not only the HPA axis, but also, peripheral and central renin-angiotensin system (RAS). Furthermore, recent experimental data indicate that the HPA and RAS are coupled to the signaling of a range of central neuro-transmitter, -mediator and -peptide molecules that are also regulated, at least in part, by inflammatory signaling cascades and vice versa. More recently, experimental evidences suggest a critical role of stress in disruption of the blood brain barrier (BBB), a neurovascular unit that regulates the movement of substances and blood-borne immune cells into the brain parenchyma, and prevents peripheral injury to the brain substance. However, the mechanisms underlying stress-induced BBB disruption are not exactly known. In this review, we summarize studies conducted on the effects of stress on the BBB and integrate recent data that suggest possible molecular mechanisms and signaling pathways underlying stress-induced BBB disruption. Key molecular targets and pharmacological candidates for treatment of stress and related illnesses are also summarized.

Activation of MIP-2 and MCP-5 Expression in Methylmercury-Exposed Mice and Their Suppression by N-Acetyl-L-Cysteine

Methylmercury (MeHg) is a well-known neurotoxin of the central nervous system (CNS). Neuroinflammation is one of the main pathways of MeHg-induced CNS impairment. This study aims to investigate the expressions of IL-6, MIP-2, and MCP-5, as biomarkers in relation with MeHg-induced CNS impairment and N-acetyl-L-cysteine (NAC) treatment in mice, as well as histopathological changes of brain tissue and clinical symptom such as ataxia. Twenty male Balb/c mice, aged 8-9 weeks, were divided into 4 groups and treated with saline (control), NAC [150 mg/kg body weight (BW) day], MeHg (4 mg Hg/kg BW), or a combination of MeHg and NAC for 17 days. MeHg induced the expression of IL-6, MIP-2, and MCP-5 in the serum, with median values (those in controls) of 55.06 (9.44), 15.94 (9.30), and 458.91 (239.91) mg/dl, respectively, and a statistical significance was observed only in IL-6 expression (p < 0.05). MIP-2 and MCP-5 expressions tended to increase in the cerebrum of MeHg-treated group compared with controls; however, the difference was not statistically significant. MeHg treatment also increased IL-6 expression in the cerebellum (7.73 and 4.81 mg/dl in MeHg-treated group and controls, respectively), with a marginal significance. NAC significantly suppressed MeHg-induced IL-6 and MIP-2 expressions in the serum (p < 0.05 for both), and slightly reduced MCP-5 expression in the cerebrum. Ataxia was observed in all MeHg-treated mice after 9-day exposure as well as the decrease of intact Purkinje cells in brain tissue (p < 0.05). These findings suggest that MeHg induced neurotoxicity by elevating the expression of IL-6, MIP-2, and MCP-5 and causing ataxia symptoms, and NAC reduced MeHg-mediated effects on the CNS.

Kleeb Bua Daeng, a Thai Traditional Herbal Formula, Ameliorated Unpredictable Chronic Mild Stress-Induced Cognitive Impairment in ICR Mice

Thai traditional herbal formula ''Kleeb Bua Daeng (KBD)''consists of a 1:1:1 ratio (dry weight) of three medicinal plants: Piper nigrum fruit, the aerial part of Centella asiatica and the petals of Nelumbo nucifera. Oral administration of KBD to unpredictable chronic mild stress (UCMS) mice significantly improved their cognitive function caused by chronic mild stress. Daily administration of KBD significantly decreased the serum corticosterone (CORT) and malondialdehyde (MDA) levels but increased the catalase and superoxide dismutase activities in both frontal cortex and hippocampus. The effects of KBD were similar to those caused by oral administration of vitamin E. HPLC analysis of the KBD extract revealed the presence of piperine, madecassoside, asiaticoside, luteolin-7-O-glucoside, rutin, kaempferol-3-glucoside, quercetin, kaempferol and ferulic acid as major constituents.

Electroacupuncture reduces astrocyte number and oxidative stress in aged rats with surgery-induced cognitive dysfunction

Objectives

To investigate the effects of electroacupuncture in regulating astrocytes and oxidative stress in a rat model of postoperative cognitive dysfunction (POCD).

Methods

Male aged Sprague-Dawley rats were randomized to undergo left hepatic lobe resection to induce POCD, followed by either electroacupuncture or no treatment; or similar surgery without left lobe resection or electroacupuncture (sham). Postsurgical cognitive function, hippocampal astrocyte number and oxidative stress indicators were measured.

Results

At days 1, 3 and 7 following surgery, escape latency was significantly shorter and platform crossing frequency was increased with electroacupuncture versus other groups. At postoperative day 1, the electroacupuncture group showed significantly fewer glial fibrillary acidic protein (GFAP)-positive hippocampal astrocytes versus the POCD model group. In POCD rats, electroacupuncture significantly decreased serum S100 calcium binding protein B and neuron-specific enolase levels, and increased brain-derived neurotrophic factor and glial cell-derived neurotrophic factor levels, at days 1, 3 and 7. Electroacupuncture significantly attenuated the hippocampal POCD-induced increase in malondialdehyde and decreased superoxide dismutase levels at day 1 following surgery.

Conclusion

Electroacupuncture may improve cognitive function in rats with POCD by reducing hippocampal GFAP-positive astrocyte number and suppressing oxidative stress.

Aquilariae Lignum extract attenuates glutamate-induced neuroexcitotoxicity in HT22 hippocampal cells

An imbalance between excitatory and inhibitory neurotransmitters is known to induce neuronal excitotoxicity which is a major cause of neurodegenerative disorders. Excessive glutamate concentration leads to the neuronal death by increasing oxidative stress and affecting the apoptotic signaling pathway. We investigated the anti-excitotoxic effects and associated working mechanisms of 30% ethanol extract of Aquilariae Lignum (ALE) against hippocampal neuronal death by glutamate. HT22 cells were treated with glutamate (20 mM) for 24 h following pretreatment with ALE (5, 10, 25 μg/mL). Cell viability, biochemical analysis, flow chemistry, and Western blotting assays were performed. Glutamate treatment substantially increased the intracellular level of reactive oxygen species (ROS) and Ca2+ influx into the cell, which were followed by apoptosis. ALE pretreatment, however, significantly attenuated these excitotoxicity-related features according to the results of Annexin V analysis and the lactate dehydrogenase assay, in which the calpain pathway (in a caspase 3-independent manner) may be involved. ALE pretreatment also significantly attenuated the glutamate-induced activation of both inflammation-associated molecules (extracellular signal-regulated kinase, c-Jun N-terminal kinases and p38) and death-related molecules (p53, apoptosis-inducing factor). The inactivation of brain-derived neurotrophic factor (BDNF) was restored by ALE pretreatment. Our results verified that A. Lignum has potential neuroprotective effects on glutamate-induced excitotoxicity in hippocampal neuron cells, and its underlying mechanism may involve the regulation of ROS-mediated cell death pathways.

Dexmedetomidine Ameliorates Acute Stress-Induced Kidney Injury by Attenuating Oxidative Stress and Apoptosis through Inhibition of the ROS/JNK Signaling Pathway

Acute stress induces tissue damage through excessive oxidative stress. Dexmedetomidine (DEX) reportedly has an antioxidant effect. However, protective roles and related potential molecular mechanisms of DEX against kidney injury induced by acute stress are unknown. Herein, rats were forced to swim 15 min followed by restraint stress for 3 h with/without DEX (30 μg/kg). Successful model establishment was validated by an open-field test. Assessment of renal function (creatinine, urea nitrogen), histopathology, oxidative stress (malondialdehyde, glutathione, and superoxide dismutase), and apoptosis (transferase-mediated dUTP nick end labeling) was performed. Localization of apoptosis was determined by immunohistochemistry of cleaved caspase 3 protein. In addition, key proteins of the death receptor-mediated pathway, mitochondrial pathway, endoplasmic reticulum stress (ERS) pathway, and ROS/JNK signaling pathway were measured by Western blot. We found that DEX significantly improved renal dysfunction, ameliorated kidney injury, reduced oxidative stress, and alleviated apoptosis. DEX also inhibited the release of norepinephrine (NE), decreased the production of reactive oxygen species (ROS), and inhibited JNK phosphorylation. Additionally, DEX downregulated the expression of Bax, cytochrome C, cleaved caspase 9, and cleaved caspase 3 proteins in mitochondria-dependent pathways. In summary, DEX protects against acute stress-induced kidney injury in rats by reducing oxidative stress and apoptosis via inhibition of the ROS/JNK pathway.

Polygonum aviculare L. extract reduces fatigue by inhibiting neuroinflammation in restraint-stressed mice

BACKGROUND

Chronic fatigue patients experience various neuropsychological symptoms, including fatigue behaviors, chronic pain, and depression. They also display immune system dysregulation. Polygonum aviculare L. extract (PAE) is a traditional herbal medicine used to treat inflammatory diseases by reportedly decreasing pro-inflammatory cytokine production.

HYPOTHESIS/PURPOSE

We hypothesized that the anti-inflammatory properties of PAE would attenuate fatigue symptoms in a mouse model of restraint stress.

STUDY DESIGN

We evaluated the effects of PAE on fatigue using three experimental groups: unstressed, vehicle-treated stressed, and PAE-treated stressed mice. This restraint stress paradigm, comprised of restraint for 3 h daily for 15 days, was used to model chronic fatigue.

METHODS

We compared lethargy-like behavior between our experimental groups using forced-swim, sucrose preference, and open-field tests once per week on days 7 and 14 of restraint stress. We also used histology and western blotting to evaluate pro-inflammatory cytokine expression in the brain and serum, and microglial activation in the brain. Finally, we used liquid chromatography/mass spectroscopy (LC/MS) to identify individual components of PAE, and applied cell culture techniques to test the effects of these components on neuronal cells in vitro.

RESULTS

In restraint-stressed mice, PAE treatment decreased lethargy-like behavior relative to vehicle-treated animals. PAE treatment also reduced expression of fatigue-related factors such as corticosterone, serotonin, and catecholamines (adrenaline and noradrenaline) in the brain and serum, and decreased expression of CD68, Ibal-1, and the inflammatory cytokines TNF-α, IL-6, and IL-1β in the brain. Together, these data indicate that PAE reduced fatigue and is anti-inflammatory. Furthermore, histopathological analyses indicated that PAE treatment recovered atrophic volumes and hepatic injuries. Finally, LC/MS analysis of PAE identified four individual chemicals: myricitrin, isoquercitrin, avicularin, and quercitrin. In neuronal cell cultures, treatment with these PAE components inhibited TNF-α production, confirming that PAE treatment reduces neuroinflammation.

CONCLUSIONS

PAE treatment may reduce fatigue by suppressing neuroinflammation and the expression of fatigue-related hormones.