Curcumin Inhibits TLR2/4-NF-κB Signaling Pathway and Attenuates Brain Damage in Permanent Focal Cerebral Ischemia in Rats

Exploring Chinese herbal medicine for ischemic stroke: insights into microglia and signaling pathways

Ischemic stroke is a prevalent clinical condition affecting the central nervous system, characterized by a high mortality and disability rate. Its incidence is progressively rising, particularly among younger individuals, posing a significant threat to human well-being. The activation and polarization of microglia, leading to pro-inflammatory and anti-inflammatory responses, are widely recognized as pivotal factors in the pathogenesis of cerebral ischemia and reperfusion injury. Traditional Chinese herbal medicines (TCHMs) boasts a rich historical background, notable efficacy, and minimal adverse effects. It exerts its effects by modulating microglia activation and polarization, suppressing inflammatory responses, and ameliorating nerve injury through the mediation of microglia and various associated pathways (such as NF-κB signaling pathway, Toll-like signaling pathway, Notch signaling pathway, AMPK signaling pathway, MAPK signaling pathway, among others). Consequently, this article focuses on microglia as a therapeutic target, reviewing relevant pathway of literature on TCHMs to mitigate neuroinflammation and mediate IS injury, while also exploring research on drug delivery of TCHMs. The ultimate goal is to provide new insights that can contribute to the clinical management of IS using TCHMs.

Role of curcumin and its nanoformulations in the treatment of neurological diseases through the effects on stem cells

Curcumin from turmeric is a natural phenolic compound with a promising potential to regulate fundamental processes involved in neurological diseases, including inflammation, oxidative stress, protein aggregation, and apoptosis at the molecular level. In this regard, employing nanoformulation can improve curcumin efficiency by reducing its limitations, such as low bioavailability. Besides curcumin, growing data suggest that stem cells are a noteworthy candidate for neurodegenerative disorders therapy due to their anti-inflammatory, anti-oxidative, and neuronal-differentiation properties, which result in neuroprotection. Curcumin and stem cells have similar neurogenic features and can be co-administered in a cell-drug delivery system to achieve better combination therapeutic outcomes for neurological diseases. Based on the evidence, curcumin can induce the neuroprotective activity of stem cells by modulating their related signalling pathways. The present review is about the role of curcumin and its nanoformulations in the improvement of neurological diseases alone and through the effect on different categories of stem cells by discussing the underlying mechanisms to provide a roadmap for future investigations.

MiR-19b-3p Inhibits Hypoxia-Ischemia Encephalopathy by Inhibiting SOX6 Expression via Activating Wnt/β-catenin Pathway

Hypoxic-ischemic encephalopathy (HIE) is a detrimental factor in infant death and chronic disease. The specific pathogenesis is not entirely clear. Therefore, exploring the pathogenesis of HIE is critical. The expression of miR-19b-3p and SOX6 in umbilical blood of HIE patients was detected by qRT-PCR assay. HT22 cells were triggered with oxygen-glucose deprivation/reoxygenation (OGD/R) to construct the HIE cell model. Cell Counting Kit-8 (CCK-8) assay was used to estimate viability. SOD and MDA levels were detected by enzyme linked immunosorbent assay. Flow cytometry was implemented to ascertain neurocyte apoptosis. Cellular β-catenin immunofluorescence staining was used to detect the expression and distribution of β-catenin protein. Wnt signaling pathway activation was detected by TOPFlash/FOPFlash luciferase reporter assay. The targeting correlation of SOX6 and miR-19b-3p was corroborated by dual-luciferase reporter gene assay and RNA pull-down assay. MiR-19b-3p expression was once down-regulated, whilst SOX6 expression was up-regulated in HIE patients. MiR-19b-3p overexpression promoted cell proliferation, repressed cell apoptosis, oxidative stress response, and Wnt/β-catenin pathway activation in OGD/R-triggered HT22 cells. MiR-19b-3p negatively regulated SOX6 expression. SOX6 knockdown improved OGD/R-triggered HT22 cells injury via Wnt/β-catenin pathway activation. MiR-19b-3p overexpression suppressed OGD/R-triggered HT22 cell injury via inhibiting SOX6 expression via activating Wnt/β-catenin pathway.

A Review on Therapeutic Potential of Natural Phytocompounds for Stroke

Stroke is a serious condition that results from an occlusion of blood vessels that leads to brain damage. Globally, it is the second highest cause of death, and deaths from strokes are higher in older people than in the young. There is a higher rate of cases in urban areas compared to rural due to lifestyle, food, and pollution. There is no effective single medicine for the treatment of stroke due to the multiple causes of strokes. Thrombolytic agents, such as alteplase, are the main treatment for thrombolysis, while multiple types of surgeries, such ascraniotomy, thrombectomy, carotid endarterectomy, and hydrocephalus, can be performed for various forms of stroke. In this review, we discuss some promising phytocompounds, such as flavone C-glycoside (apigenin-8-C-β-D-glucopyranoside), eriodictyol, rosamirinic acid, 6″-O-succinylapigenin, and allicin, that show effectiveness against stroke. Future study paths are given, as well as suggestions for expanding the use of medicinal plants and their formulations for stroke prevention.

The action of curcumin against damage resulting from cerebral stroke: a systematic review

Stroke is the second leading cause of morbidity and mortality globally. Treatments for stroke are limited, and preventive treatments are scarce. Curcumin (CUR) has several biological effects, as described in the literature, which highlight its antioxidant and neuroprotective effects. Therefore, this qualitative systematic review aimed to investigate the effects of CUR on damage caused by stroke in rodent models. A systematic search was performed on three databases PubMed, Scopus, and Web of Science. In addition, the risk-of-bias and quality of the studies were assessed using SYRCLE and Collaborative Approach for Meta-Analysis and Review of Animal Data from Experimental Studies, respectively. The selection, inclusion, and exclusion criteria were established by the authors. At the end of our systematic search of the three databases, we found a total of 728 articles. After excluding duplicates and triplicates and reading the abstracts, keywords, and full texts, 53 articles were finally included in this systematic review. CUR exerts several beneficial effects against the damage caused by both ischemic and hemorrhagic stroke, via different pathways. However, because of its low bioavailability, Free-form CUR only exerted significant effects when it was administered at high concentrations. In contrast, when CUR was administered using nanostructured systems, positive responses were observed even at low concentrations. The mechanisms of action of CUR, free or in nanostructure, are extremely important for the recovery of injured brain tissue after a stroke; CUR has neuroprotective, antioxidant, anti-inflammatory, and anti-apoptotic effects and helps to maintain the integrity of the blood-brain barrier. Finally, we concluded that CUR presents an extremely important and significant response profile against the damage caused by stroke, making it a possible therapeutic candidate for individuals affected by this disease.

Mechanisms Underlying Curcumin-Induced Neuroprotection in Cerebral Ischemia

Ischemic stroke is the leading cause of death and disability worldwide, and restoring the blood flow to ischemic brain tissues is currently the main therapeutic strategy. However, reperfusion after brain ischemia leads to excessive reactive oxygen species production, inflammatory cell recruitment, the release of inflammatory mediators, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, and blood-brain barrier damage; these pathological mechanisms will further aggravate brain tissue injury, ultimately affecting the recovery of neurological functions. It has attracted the attention of researchers to develop drugs with multitarget intervention effects for individuals with cerebral ischemia. A large number of studies have established that curcumin plays a significant neuroprotective role in cerebral ischemia via various mechanisms, including antioxidation, anti-inflammation, anti-apoptosis, protection of the blood-brain barrier, and restoration of mitochondrial function and structure, restoring cerebral circulation, reducing infarct volume, improving brain edema, promoting blood-brain barrier repair, and improving the neurological functions. Therefore, summarizing the results from the latest literature and identifying the potential mechanisms of action of curcumin in cerebral ischemia will serve as a basis and guidance for the clinical applications of curcumin in the future.

Curcumin Suppresses Colon Cancer In Vitro and In Vivo

Objective: To discuss In Vitro and In Vivo the effects of curcumin on colon cancer. Material and Methods: SW620 cell and nude mice with tumor were respectively divided into 3 groups: NC, low, middle, high and 5-Fu groups. Measuring the cell activity by MTT, the cell cycle and cell apoptosis using flow cytometry and relative proteins by WB assay in cell experiment. Evaluating tumor volume and weight, cell apoptosis rate by TUNEL assay and relative proteins by Immunohistochemistry (IHC). Results: Compared with NC group, the SW620 cell activity was significantly depressed with cell apoptosis and G1 phase rates increasing and PI3K, AKT and P53 proteins expression were significantly differences in curcumin treated groups with dose-dependent by WB assay; In Vivo study, the tumor volume and size were significantly suppressed and positive cell number were significantly up-regulation in curcumin treated groups with dose-dependent, and PI3K, AKT and P53 proteins expression were significantly differences in curcumin treated groups with dose-dependent by IHC. Conclusions: Curcumin had anti-tumor effects to colon cancer via regulation PI3K/AKT/P53 pathway In Vivo and vitro study.

Effect of Curcumin in Experimental Pulmonary Tuberculosis: Antimycobacterial Activity in the Lungs and Anti-Inflammatory Effect in the Brain

Tuberculosis (TB) is one of the ten leading causes of death worldwide. Patients with TB have been observed to suffer from depression and anxiety linked to social variables. Previous experiments found that the substantial pulmonary inflammation associated with TB causes neuroinflammation, neuronal death, and behavioral impairments in the absence of brain infection. Curcumin (CUR) is a natural product with antioxidant, anti-inflammatory and antibacterial activities. In this work, we evaluated the CUR effect on the growth control of mycobacteria in the lungs and the anti-inflammatory effect in the brain using a model of progressive pulmonary TB in BALB/c mice infected with drug-sensitive mycobacteria (strain H37Rv). The results have shown that CUR decreased lung bacilli load and pneumonia of infected animals. Finally, CUR significantly decreased neuroinflammation (expression of TNFα, IFNγ and IL12) and slightly increased the levels of nuclear factor erythroid 2-related to factor 2 (Nrf2) and the brain-derived neurotrophic factor (BDNF) levels, improving behavioral status. These results suggest that CUR has a bactericidal effect and can control pulmonary mycobacterial infection and reduce neuroinflammation. It seems that CUR has a promising potential as adjuvant therapy in TB treatment.

Curcumin suppress inflammatory response in traumatic brain injury via p38/MAPK signaling pathway

Traumatic brain injury (TBI) is a common disease worldwide with a high mortality and disability rate and is closely related to the inflammatory response. However, the molecular mechanisms during the pathophysiological responses are not completely understood. This study was conducted to investigate the protective effect of curcumin on TBI and the molecular mechanisms of the p38/MAPK signal pathway. We found that curcumin remarkably ameliorated secondary brain injury after TBI, including effects on the neurological severity score and inflammation. After injection of curcumin, the neurological function score of mice decreased significantly. Curcumin exhibited antiinflammatory pharmacological effects, as reflected by inhibition of inflammatory factors (e.g., interleukin [IL]-1β, IL-6, and tumor necrosis factor [TNF]-α). Additionally, curcumin notably reduced the expression of p-p38 according to western blotting and immunohistochemical analyses. In conclusion, curcumin remarkably alleviated posttraumatic inflammation and thus shows potential for treating inflammation associated with TBI.

The natural (poly)phenols as modulators of microglia polarization via TLR4/NF-κB pathway exert anti-inflammatory activity in ischemic stroke

Increasing evidences suggest that inflammation plays a key role in the pathogenesis of stroke, a devastating disease second only to cardiac ischemia as a cause of death worldwide. Microglia are the first non-neuronal cells on the scene during the innate immune response to acute ischemic stroke. Microglia respond to acute brain injury by activating and developing classic M1-like (pro-inflammatory) or alternative M2-like (anti-inflammatory) phenotypes. M1 microglia produce pro-inflammatory cytokines to exacerbate neural death, astrocyte apoptosis, and blood brain barrier (BBB) disruption, while M2 microglia play the opposite role. NF-κB, a central regulator of the inflammatory response, was responsible for microglia M1 and M2 polarization. NF-κB p65 and p50 form a heterodimer to initiate a pro-inflammatory cytokine response, which enhances M1 activation and impair M2 response of microglia. TLR4, expressed on the surface of microglia, plays an important role in activating NF-κB, ultimately causing the M1 response of microglia. Therefore, modulation of microglial phenotypes via TLR4/NF-κB signaling pathway may be a promising therapeutic approach for ischemic stroke. Dietary (poly)phenols are present in various foods, which have shown promising protective effects on ischemic stroke. In vivo studies strongly suggest that many (poly)phenols have a pronounced impact on ischemic stroke, as demonstrated by lower neuroinflammation. Thus, this review focuses on the anti-inflammatory properties of dietary (poly)phenols and discusses their effects on the polarization of microglia through modulating TLR4/NF-κB signaling pathway in the ischemic stroke.

Oxidative Stress in the Brain: Basic Concepts and Treatment Strategies in Stroke

The production of free radicals is inevitably associated with metabolism and other enzymatic processes. Under physiological conditions, however, free radicals are effectively eliminated by numerous antioxidant mechanisms. Oxidative stress occurs due to an imbalance between the production and elimination of free radicals under pathological conditions. Oxidative stress is also associated with ageing. The brain is prone to oxidative damage because of its high metabolic activity and high vulnerability to ischemic damage. Oxidative stress, thus, plays a major role in the pathophysiology of both acute and chronic pathologies in the brain, such as stroke, traumatic brain injury or neurodegenerative diseases. The goal of this article is to summarize the basic concepts of oxidative stress and its significance in brain pathologies, as well as to discuss treatment strategies for dealing with oxidative stress in stroke.

Intestinal Barrier Dysfunction Exacerbates Neuroinflammation via the TLR4 Pathway in Mice With Heart Failure

Aims

The present study aimed to investigate alterations in neuroinflammation after heart failure (HF) and explore the potential mechanisms.

Methods

Male wild-type (WT) and Toll-like receptor 4 (TLR4)-knockout (KO) mice were subjected to sham operation or ligation of the left anterior descending coronary artery to induce HF. 8 weeks later, cardiac functions were analyzed by echocardiography, and intestinal barrier functions were examined by measuring tight junction protein expression, intestinal permeability and plasma metabolite levels. Alterations in neuroinflammation in the brain were examined by measuring microglial activation, inflammatory cytokine levels and the proinflammatory signaling pathway. The intestinal barrier protector intestinal alkaline phosphatase (IAP) and intestinal homeostasis inhibitor L-phenylalanine (L-Phe) were used to examine the relationship between intestinal barrier dysfunction and neuroinflammation in mice with HF.

Results

Eight weeks later, WT mice with HF displayed obvious increases in intestinal permeability and plasma lipopolysaccharide (LPS) levels, which were accompanied by elevated expression of TLR4 in the brain and enhanced neuroinflammation. Treatment with the intestinal barrier protector IAP significantly attenuated neuroinflammation after HF while effectively increasing plasma LPS levels. TLR4-KO mice showed significant improvements in HF-induced neuroinflammation, which was not markedly affected by intestinal barrier inhibitors or protectors.

Conclusion

HF could induce intestinal barrier dysfunction and increase gut-to-blood translocation of LPS, which could further promote neuroinflammation through the TLR4 pathway.

Neuroprotective Effects of Curcumin in Cerebral Ischemia: Cellular and Molecular Mechanisms

Despite being a major global health concern, cerebral ischemia/stroke has limited therapeutic options. Tissue plasminogen activator (tPA) is the only available medication to manage acute ischemic stroke, but this medication is associated with adverse effects and has a narrow therapeutic time window. Curcumin, a polyphenol that is abundantly present in the rhizome of the turmeric plant (Curcuma longa), has shown promising neuroprotective effects in animal models of neurodegenerative diseases, including cerebral ischemia. In the central nervous system (CNS), neuroprotective effects of curcumin have been experimentally validated in Alzheimer's disease, Parkinson's disease, multiple sclerosis, and cerebral ischemia. Curcumin can exert pleiotropic effects in the postischemic brain including antioxidant, anti-inflammatory, antiapoptotic, vasculoprotective, and direct neuroprotective efficacies. Importantly, neuroprotective effects of curcumin has been reported in both ischemic and hemorrhagic stroke models. A broad-spectrum neuroprotective efficacy of curcumin suggested that curcumin can be an appealing therapeutic strategy to treat cerebral ischemia. In this review, we aimed to address the pharmacotherapeutic potential of curcumin in cerebral ischemia including its cellular and molecular mechanisms of neuroprotection revealing curcumin as an appealing therapeutic candidate for cerebral ischemia.

The Roles of Nitric Oxide Synthase/Nitric Oxide Pathway in the Pathology of Vascular Dementia and Related Therapeutic Approaches

Vascular dementia (VaD) is the second most common form of dementia worldwide. It is caused by cerebrovascular disease, and patients often show severe impairments of advanced cognitive abilities. Nitric oxide synthase (NOS) and nitric oxide (NO) play vital roles in the pathogenesis of VaD. The functions of NO are determined by its concentration and bioavailability, which are regulated by NOS activity. The activities of different NOS subtypes in the brain are partitioned. Pathologically, endothelial NOS is inactivated, which causes insufficient NO production and aggravates oxidative stress before inducing cerebrovascular endothelial dysfunction, while neuronal NOS is overactive and can produce excessive NO to cause neurotoxicity. Meanwhile, inflammation stimulates the massive expression of inducible NOS, which also produces excessive NO and then induces neuroinflammation. The vicious circle of these kinds of damage having impacts on each other finally leads to VaD. This review summarizes the roles of the NOS/NO pathway in the pathology of VaD and also proposes some potential therapeutic methods that target this pathway in the hope of inspiring novel ideas for VaD therapeutic approaches.

Curcumin attenuates spatial memory impairment by anti-oxidative, anti-apoptosis, and anti-inflammatory mechanism against methamphetamine neurotoxicity in male Wistar rats: Histological and biochemical changes

OBJECTIVE

Methamphetamine is used extensively around the world as a psychostimulant. The complications related to methamphetamine include methamphetamine-induced neurotoxicity, mainly involving intraneuronal processes, such as oxidative stress and excitotoxicity. Curcumin is effective against neuronal injury due to its antioxidant, anti-inflammatory effects. In this study, we examined the protective effects of curcumin against methamphetamine neurotoxicity.

METHODS

Sixty male Wistar rats were divided into the following groups: control (n = 12), DMSO (n = 12), methamphetamine (n = 12), and methamphetamine + curcumin (100 and 200 mg/kg, respectively, intraperitoneal [IP]; n = 12). Neurotoxicity was induced by 40 mg/kg of methamphetamine administrated through 4 injections (4 × 10 mg/kg, q2h, IP). Curcumin (100 and 200 mg/kg) was administered at 7 days after the last methamphetamine injection. By using a Morris water maze task, the hippocampus-dependent memory and spatial learning were evaluated 1 day after the last curcumin injection. Then, the animal brains were isolated for biochemical measurements, as well as glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor protein-1(Iba-1) and caspase-3 immunohistochemical staining.

RESULTS

The current study demonstrated that administration of curcumin significantly attenuates spatial memory impairment (P < 0.01) following methamphetamine neurotoxicity. Curcumin caused a significant increase in the levels of superoxide dismutase and glutathione peroxidase (P < 0.05). However, it decreased tumor necrosis factor (TNF-α) (P < 0.05) and malondialdehyde (P < 0.01) levels as compared to the methamphetamine group. Also, curcumin significantly reduced Iba-1 (P < 0. 01), GFAP and caspase-3 positive cells in the hippocampus (P < 0.001).

CONCLUSION

Curcumin exerted neuroprotective effects on methamphetamine neurotoxicity because of its antioxidant and anti-inflammatory effect.

Effects of Medicinal Plants and Flavonoids on Parkinson's Disease: A Review on Basic and Clinical Evidences

Parkinson’s disease (PD) is a neurodegenerative disorder which is characterized by typical symptoms including gradual progressive muscle rigidity, tremor and loss of motor skills. Although there is no definitive cure for PD, the extract of some medicinal plants and their ingredients have been suggested to relieve its symptoms and to prevent disability in patients. This review is focused on therapeutic effects of some medicinal plants and their ingredients on PD. The findings presented in this review were collected from experimental and clinical studies in databases including PubMed, Web of Science and Google Scholar until the end of May 2019. The keywords "neurotoxicity " or "Parkinson’s disease" or "neuroprotective" and "Medicinal plants" and "Flavonoids" were searched. Based on the results of animal and clinical studies, the extract of medicinal plants and their components which are discussed in this review have neuro-protective effects against PD. These protective properties mainly are mediated through inhibition of dopamine metabolizing enzymes, reduction oxidant markers, increase of antioxidant agents and suppression of neuro-inflammation.

Protective effects of maternal administration of curcumin and hesperidin in the rat offspring following repeated febrile seizure: Role of inflammation and TLR4

Neuroinflammation has a key role in seizure generation and perpetuation in the neonatal period, and toll-like receptor 4 (TLR4) pathway has a prominent role in neuroinflammatory diseases. Administration of antioxidants and targeting TLR4 in the embryonic period may protect rat offspring against the next incidence of febrile seizure and its harmful effects. Curcumin and hesperidin are natural compounds with anti-inflammatory and antioxidant properties and have an inhibitory action on TLR4 receptors. We evaluated the effect of maternal administration of curcumin and hesperidin on infantile febrile seizure and subsequent memory dysfunction in adulthood. Hyperthermia febrile seizure was induced on postnatal days 9-11 on male rat pups with 24 h intervals, in a Plexiglas box that was heated to ~45 °C by a heat lamp. We used enzyme-linked immunosorbent assay, Western blotting, malondialdehyde (MDA), and glutathione (GSH) assessment for evaluation of inflammatory cytokine levels, TLR4 protein expression, and oxidative responses in the hippocampal tissues. For assessing working memory and long-term potentiation, the double Y-maze test and Schaffer collateral-CA1 in vivo electrophysiological recording were performed, respectively Our results showed that curcumin and hesperidin decreased TNF-α, IL-10, and TLR4 protein expression and reversed memory dysfunction. However, they did not provoke a significant effect on GSH content or amplitude and slope of recorded fEPSPs in the hippocampus. In addition, curcumin, but not hesperidin, decreased interleukin-1β (IL-1β) and MDA levels. These findings imply that curcumin and hesperidin induced significant protective effects on febrile seizures, possibly via their anti-inflammatory and antioxidant properties and downregulation of TLR4.

Neuroprotective effect of Umbelliferone against Cerebral ischemia/Reperfusion induced neurological deficits: in-vivo and in-silico studies

Inflammatory pathway is the significant marker of neuro-inflammation and plays a significant role in the expansion of cerebral ischemia/reperfusion injury. Umbelliferone (UF), 7-hydroxy coumarin, has been already proved for its anti-inflammatory and anti-oxidative effects against ischemic brain injury in the rodent model, but its underlying pharmacological mechanism for neuro-protection remain unclear. In this study, we try to explore the neuro-protective effect of umbelliferone against ischemia/Reperfusion induced neurological deficits in rats and explore the underlying mechanism. Inserting thread into the middle cerebral artery was used to induce the ischemic stroke model. The rats were treated with the umbelliferone (5, 10 and 20 mg/kg) for 14 days prior to the ischemic stroke. At the end of the experimental study, brain infarction volume, neurological score, brain edema, pro-inflammatory cytokines, inflammatory mediator were estimated in the region of brain and serum. The mRNA expression of Toll-like receptor-4 (TLR4), myeloid differentiation factor 88 (MyD88), Fas and FasL were also estimated at the end of the study. Dose dependently treatment of umbelliferone down-regulated the neurological score, brain infarction, inflammatory mediator (TNF-α, IL-1β, IL-6, COX-2, NF-kB and PGE₂) in the serum and brain tissue as compared to I/R induced control group rats. Umbelliferone also reduced the expression of TRL4, MyD88, Fas and FasL as compared to I/R control group rats. Umbelliferone also decreased the level of nuclear factor kappa B (NF-kB) compared to MACO control group rats. Collectively, the obtained result showed that the umbelliferone protected the brain against the ischemic injury in the rats through the inhibition of inflammatory pathway.Communicated by Ramaswamy H. Sarma.

Liposomal Encapsulated Curcumin Effectively Attenuates Neuroinflammatory and Reactive Astrogliosis Reactions in Glia Cells and Organotypic Brain Slices

Introduction

The polyphenolic spice and food coloring ingredient curcumin has beneficial effects in a broad variety of inflammatory diseases. Amongst them, curcumin has been shown to attenuate microglia reaction and prevent from glial scar formation in spinal cord and brain injuries.

Methods

We developed a protocol for the efficient encapsulation of curcumin as a model for anti-inflammatory drugs yielding long-term stable, non-toxic liposomes with favorable physicochemical properties. Subsequently, we evaluate the effects of liposomal curcumin in experimental models for neuroinflammation and reactive astrogliosis.

Results

We could show that liposomal curcumin can efficiently reduce the reactivity of human microglia and astrocytes and preserve tissue integrity of murine organotypic cortex slices.

Discussion and Perspective

In perspective, we want to administer this curcumin formulation in brain implant coatings to prevent neuroinflammation and glial scar formation as foreign body responses of the brain towards implanted materials.

Curcumin suppresses glioblastoma cell proliferation by p-AKT/mTOR pathway and increases the PTEN expression

BACKGROUND

Glioblastoma (GB) is the most common neoplasm in the brain. Curcumin, as a known polyphenolic compound extracted from turmeric, is a chemotherapy used in some cancer treatments in China. However, the effect of curcumin on the survivability of GB cells remains to be elucidated.

METHODS

We performed a CCK8 assay to detect the viability of GB cells following treatments with curcumin and examined the migration and invasion the ability of these cells using the wound-healing and transwell invasion assays. The cell proliferation and apoptotic proteins were detected by Western blot analyses. We utilized a glioblastoma-xenograft mouse model to assess cell proliferation following curcumin treatment.

RESULTS

We found that curcumin inhibited the proliferation, migration, and invasion of U251 and U87 GB cells. We detected that curcumin decreased p-AKT and p-mTOR protein expression, and promoted the apoptosis of U251 and U87 GB cells. Further, we found that curcumin promoted the PTEN and p53 expression, as the tumor suppressor genes. In addition, we administered curcumin to nude mice and found that curcumin decreased the tumor volume, caused necrosis of tumor tissue, and significantly enhanced the PTEN and p53 expression in vivo.

CONCLUSIONS

These results indicated that curcumin inhibited proliferation by decreasing the p-AKT/p-mTOR pathway and promoted apoptosis by increasing the PTEN and p53 expression. Our study provided the molecular mechanisms by which curcumin inhibited glioblastoma and its targeted interventions.

Targeting Myeloperoxidase (MPO) Mediated Oxidative Stress and Inflammation for Reducing Brain Ischemia Injury: Potential Application of Natural Compounds

Oxidative stress and inflammation are two critical pathological processes of cerebral ischemia-reperfusion injury. Myeloperoxidase (MPO) is a critical inflammatory enzyme and therapeutic target triggering both oxidative stress and neuroinflammation in the pathological process of cerebral ischemia-reperfusion injury. MPO is presented in infiltrated neutrophils, activated microglial cells, neurons, and astrocytes in the ischemic brain. Activation of MPO can catalyze the reaction of chloride and H2O2 to produce HOCl. MPO also mediates oxidative stress by promoting the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), modulating the polarization and inflammation-related signaling pathways in microglia and neutrophils. MPO can be a therapeutic target for attenuating oxidative damage and neuroinflammation in ischemic stroke. Targeting MPO with inhibitors or gene deficiency significantly reduced brain infarction and improved neurological outcomes. This article discusses the important roles of MPO in mediating oxidative stress and neuroinflammation during cerebral ischemia-reperfusion injury and reviews the current understanding of the underlying mechanisms. Furthermore, we summarize the active compounds from medicinal herbs with potential as MPO inhibitors for anti-oxidative stress and anti-inflammation to attenuate cerebral ischemia-reperfusion injury, and as adjunct therapeutic agents for extending the window of thrombolytic treatment. We highlight that targeting MPO could be a promising strategy for alleviating ischemic brain injury, which merits further translational study.

Phenolic Compounds Exerting Lipid-Regulatory, Anti-Inflammatory and Epigenetic Effects as Complementary Treatments in Cardiovascular Diseases

Atherosclerosis is the main process behind cardiovascular diseases (CVD), maladies which continue to be responsible for up to 70% of death worldwide. Despite the ongoing development of new and potent drugs, their incomplete efficacy, partial intolerance and numerous side effects make the search for new alternatives worthwhile. The focus of the scientific world turned to the potential of natural active compounds to prevent and treat CVD. Essential for effective prevention or treatment based on phytochemicals is to know their mechanisms of action according to their bioavailability and dosage. The present review is focused on the latest data about phenolic compounds and aims to collect and correlate the reliable existing knowledge concerning their molecular mechanisms of action to counteract important risk factors that contribute to the initiation and development of atherosclerosis: dyslipidemia, and oxidative and inflammatory-stress. The selection of phenolic compounds was made to prove their multiple benefic effects and endorse them as CVD remedies, complementary to allopathic drugs. The review also highlights some aspects that still need clear scientific explanations and draws up some new molecular approaches to validate phenolic compounds for CVD complementary therapy in the near future.

Role of curcumin and its nanoformulations in neurotherapeutics: A comprehensive review

Curcumin, a dietary polyphenol and major constituent of Curcuma longa (Zingiberaceae), is extensively used as a spice in Asian countries. For ages, turmeric has been used in traditional medicine systems to treat various diseases, which was possible because of its anti-inflammatory, antioxidant, anticancerous, antiepileptic, antidepressant, immunomodulatory, neuroprotective, antiapoptotic, and antiproliferative effects. Curcumin has potent antioxidant, anti-inflammatory, antiapoptotic, neurotrophic activities, which support its plausible neuroprotective effects in neurodegenerative disease. However, there is limited information available regarding the clinical efficacy of curcumin in neurodegenerative cases. The low oral bioavailability of curcumin may be speculated as a plausible factor that limits its effects in humans. Therefore, utilization of several approaches for the enhancement of bioavailability may improve clinical outcomes. Furthermore, the use of nanotechnology and a targeted drug delivery system may improve the bioavailability of curcumin. The present review is designed to summarize the molecular mechanisms pertaining to the neuroprotective effects of curcumin and its nanoformulations.

Protective Effect of Stachydrine Against Cerebral Ischemia-Reperfusion Injury by Reducing Inflammation and Apoptosis Through P65 and JAK2/STAT3 Signaling Pathway

Stachydrine, a constituent of Leonurus japonicus Houtt which also called Japanese motherwort has been shown to improve vascular microcirculation and ameliorate endothelial dysfunction. This study investigated the neuroprotective effect of stachydrine. Male Sprague-Dawley (SD) rats were randomly divided into sham, control, and stachydrine groups. The neurological deficit score was evaluated and the infarct size of the brain was measured using 2,3,5-triphenyltetra-zolium (TTC) chloride staining assay, and the pathological changes in the brain tissues were examined by HE staining. Nissl and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) staining were performed to assess the numbers of Nissl bodies and the levels of apoptosis in the neurons. The activities of superoxide dismutase (SOD) and the levels of malondialdehyde (MDA) were also measured. The release of inflammatory factors IL-1β and TNF-α were detected by Enzyme-linked immunosorbent assay (ELISA). Compared with the control group, the stachydrine group showed a significant prevention of neurological deficit, as indicated by the reduced infarct volume in the brain. Moreover, the stachydrine treatment reduced the activities of SOD, the levels of MDA and decreased the amount of IL-1β, and TNF-α, indicating that it could function to decrease the level of inflammation, thus reducing brain damage. The ischemic stroke model of PC12 cells was prepared via oxygen-glucose deprivation (OGD) protocol for 6 h. The expression of P65 and JAK2/STAT3 signaling pathway related proteins was measured by western blot. The treatment group was found to have the survival rate of PC12 cells improved and the release of inflammatory factors reduced when compared with the OGD group. This study demonstrated that stachydrine could improve nerve function by inhibiting the phosphorylation of P65/JAK2 and STAT3.

Low n-6/n-3 PUFA ratio improves inflammation and myocardial ischemic reperfusion injury

This study investigated the potential effect of n-6/n-3 polyunsaturated fatty acids (PUFA) on inflammation and myocardial ischemic reperfusion injury (MIRI) in rats, together with the underlying protective mechanisms, and screen out most effective ratio of n-6/n-3 within limits. The rats with pre-infarct treatment were distributed among 5 groups according to the n-6/n-3 ratio (36:1; 1:1, 5:1, 10:1, 50:1); for the post-infarct treatment, the rats were distributed among 6 groups, including the control group (36:1) which was subjected to a sham procedure; the model group (36:1); and 4 test groups (n-6/n-3 ratio: 1:1, 5:1, 10:1, 50:1). All of the rats were fed a purple perilla seed oil and safflower oil-based fatty emulsion. The serum levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were determined using enzyme-linked immunosorbent assay. Staining with triphenyl tetrazolium chloride, hematoxylin and eosin, or Masson's trichrome was performed for histological examination. Cardiomyocyte apoptosis was examined by TUNEL assay. Western blotting was performed to examine the expression levels of apoptosis-related proteins and signaling pathway proteins. Our data indicate that in both the pre-infarct treatment and post-infarct treatment, low ratios of n-6/n-3 PUFAs significantly inhibited the levels of serum inflammatory factors, the infarct size of MIRI rats, number of cardiomyocytes undergoing apoptosis, and the expression levels of caspase-3, Bcl-2, and Bax in the MIRI group. Thus a low ratio of n-6/n-3 PUFAs ameliorates inflammation and myocardial ischemic reperfusion injury.

Curcumin Effects on Memory Impairment and Restoration of Irregular Neuronal Distribution in the Hippocampal CA1 Region After Global Cerebral Ischemia in Male Rats

Introduction:

Global Cerebral Ischemia (GCI) causes neuronal damage with subsequent neurological and cognitive impairments. Curcumin has anti-inflammatory, antioxidant, and neuroprotective properties, which makes it a potential candidate for improving GCI-induced impairments. This study aimed to investigate the effects of curcumin on the neurological and memory deficits, as well as spatial neuronal distribution in the Cornu Ammonis 1 region after GCI in rats.

Methods:

56 Sprague-Dawley male rats were randomly assigned into 4 groups of sham (n=14), control (n=14), curcumin 50 mg/kg (n=14), and curcumin 100 mg/kg (n=14). Each group was divided into the two subgroups of short-term (7 days) and long-term (28 days) treatment periods. The Neurological Severity Score (NSS), passive avoidance task, and the traction test were performed at postoperative days of 0, 1, 2, 3, 7, 14, 21, and 28. The novel object recognition test and Voronoi tessellation were carried out on days 7 and 28 after GCI.

Results:

Curcumin 100 mg/kg significantly decreased neurological severity score on postoperative days of 7 and 28 compared with the control (P<0.001) and curcumin 50 mg/kg groups (P<0.05–P<0.001), respectively. Also, curcumin 100 mg/kg significantly increased step-through latency times on postoperative days of 3–28 and 14–28 compared with the control (P<0.05–P<0.001) and curcumin 50 mg/kg groups (P<0.01–P<0.001). Moreover, it increased the novelty preference index during the novel object recognition test in the 28-day treatment subgroup after GCI. Curcumin (100 mg/kg) could maintain the neuronal aggregation in the CA1 region after GCI at a level near to what is generally observed in normal rats.

Conclusion:

Curcumin could improve memory and neurological deficits and restore irregular neuronal distribution in the CA1 region after GCI in a time-dependent manner, and its higher dose was more effective than its lower dose. Curcumin may have beneficial effects on reducing brain complications after ischemia.

[Collateral circulation and Toll-like receptor 4 levels in patients with acute cerebral infarction after intravenous thrombolysis]

OBJECTIVE

To investigate the relationship between Toll-like receptor 4 (TLR4) and collateral circulation in patients with acute cerebral infarction (AIS) after thrombolytic therapy.

METHODS

This retrospective, observational cohort study was conducted among 65 patients with AIS receiving thrombolytic therapy, who were divided according to findings by computed tomographic angiography (CTA) into good collateral circulation (group A, n = 34) and poor collateral circulation (group B, n = 31). Serum samples were collected from all the patients and the levels of TLR4 were measured with ELISA.

RESULTS

The patients in group A had significantly better outcomes than those in group B. The NIHSS scores at 24 h and 30 days after thrombolytic therapy, mRS scores at 90 days and serum TLR4 levels were significantly lower in group A than in group B (P &lt; 0.05); the percentages of patients with symptomatic intracerebral hemorrhage were comparable between the two groups. The serum levels of TLR4 were negatively correlated with the rMLC score (P &lt; 0.05). Multivariate logistic regression analysis showed that a high level of TLR4 was associated with a poor collateral circulation after thrombolysis.

CONCLUSIONS

Good collateral circulation can increase the benefit of intravenous thrombolysis in patients with ACI, and the level of TLR4 is a predictive factor for the compensation of collateral circulation following ACI.

Neuroprotective potency of some spice herbs, a literature review

In recent years, growing attention has been given to traditional medicine. In traditional medicine a large number of plants have been used to cure neurodegenerative diseases such as Alzheimer's disease (AD) and other memory related disorders. Crocus sativus (C. sativus), Nigella sativa (N. sativa), Coriandrum sativum (C. sativum), Ferula assafoetida (F. assafoetida), Thymus vulgaris (T. vulgaris), Zataria multiflora (Z. multiflora) and Curcuma longa (C. longa) were used traditionally for dietary, food additive, spice and various medicinal purposes. The Major components of these herbs are carotenoids, monoterpenes and poly phenol compounds which enhanced the neural functions. These medicinal plants increased anti-oxidant, decreased oxidant levels and inhibited acetylcholinesterase activity in the neural system. Furthermore, neuroprotective of plants occur via reduced pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α and total nitrite generation. Therefore, the effects of the above mentioned medicinal and their active constituents improved neurodegenerative diseases which indicate their therapeutic potential in disorders associated with neuro-inflammation and neurotransmitter deficiency such as AD and depression.

Cerebrovascular inflammation: A critical trigger for neurovascular injury?

The cerebrovascular system is not only inert bystandard that support the metabolic demands of the brain but also elicit the barrier functions against risk factors mediated neurovascular injury. The onsets of cerebrovascular inflammation are considered as stimuli that can provoke the host defense system and trigger the development of neurological disorders. Homeostasis of the brain function is regulated by the movement of endothelial, glial, and neuronal cells within the neurovascular unit (NVU), which acts as a "platform" for the coordinated action of anti- and pro-inflammatory mechanisms. The cerebrovascular system plays an integral role in the inflammatory response by either producing or expressing a variety of cytokines, adhesion molecules, metalloproteinases, and serine proteases. Excessive inflammatory cytokine production can further be affecting the blood-brain barrier (BBB) integrity and lead to brain tissue damage. In this review, we summarize the more recent evidence highlighting the importance of cerebrovascular injury in terms of risk prediction, and the mechanisms mediating the upregulation of inflammatory mediators in cerebrovascular dysfunction and neurodegeneration.

Resveratrol downregulates the TLR4 signaling pathway to reduce brain damage in a rat model of focal cerebral ischemia

Previous studies have demonstrated that inflammation and disruption of the blood-brain barrier (BBB) are important pathological processes during focal cerebral ischemia. Therefore, the present study evaluated the neuroprotective effects of resveratrol against brain damage, inflammation and BBB disruption in rats with focal cerebral ischemia and assessed the potential underlying molecular mechanisms. Sprague-Dawley rats underwent cerebral ischemia/reperfusion (IR) and then received intraperitoneal resveratrol (10 and 100 mg/kg) 2 h following the onset of ischemia. Following 24 h of ischemia, neurological deficit scores, cerebral infarctions, morphological characteristics, cerebral water content, myeloperoxidase (MPO) activity and Evans blue extravasation were assessed. Additionally, the protein expression levels of Toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB p65 were detected using western blot analyses, the mRNA expression levels of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) were examined by reverse-transcription polymerase chain reaction, and tumor necrosis factor (TNF)-α and interleukin (IL)-1β blood levels were determined by ELISA. Resveratrol significantly reduced neurological deficit scores, cerebral infarct sizes, neuronal injury, MPO activity and EB content. Cerebral ischemia increased the expression levels of TLR4, NF-κB p65, COX-2, MMP-9, TNF-α and IL-1β, but all of these factors were reduced by resveratrol. In conclusion, the present data suggest that resveratrol reduces inflammation, BBB disruption and brain damage in rats following focal cerebral ischemia. Additionally, the neuroprotective effects of resveratrol against cerebral ischemia may be associated with downregulation of the TLR4 pathway.

Impact of curcumin on toll-like receptors

Toll-like receptors (TLRs) have a pivotal role in the activation of innate immune response and inflammation. TLRs can be divided into two subgroups including extracellular TLRs that recognize microbial membrane components (TLR1, 2, 4, 5, 6, and 10), and intracellular TLRs that recognize microbial nucleic acids (TLR3, 7, 8, and 9). Curcumin is a dietary polyphenol from Curcuma longa L. that is reputed to have diverse biological and pharmacological effects. Extensive research has defined the molecular mechanisms through which curcumin mediates its therapeutic effects. One newly defined and important target of curcumin is the TLR, where it exerts an inhibitory effect. In the current study, we focus upon the TLR antagonistic effect of curcumin and curcumin's therapeutic effect as mediated via TLR inhibition. The available evidence indicates that curcumin inhibits the extracellular TLR 2 and 4 and intracellular TLR9 and thereby exerts a therapeutic effect in diseases such as cancer, inflammation, infection, autoimmune, and ischemic disease. Curcumin effectively modulates the TLR response and thereby exerts its potent therapeutic effects.

The protective effect of melatonin on brain ischemia and reperfusion in rats and humans: In vivo assessment and a randomized controlled trial

Carotid endarterectomy (CEA) is the treatment of choice for carotid stenosis. Some patients develop ischemia and reperfusion (I/R) injury after CEA. This study was designed to investigate the neuroprotective effects of melatonin on I/R injury in both rats and humans. To this end, 36 male rats were evaluated, and a double-blind randomized controlled trial (RCT) including 60 patients was performed. A rat model of middle cerebral artery occlusion was used to mimic cerebral I/R. After 2 hour of occlusion and 24 hour of reperfusion, blood samples and brain tissues were harvested for further assessments. Compared with the vehicle treatment, melatonin decreased the expression of nuclear factor κ light-chain-enhancer of activated B cells (NF-κB) and S100 calcium-binding protein β (S100β) (P < 0.05) and markedly increased the expression of nuclear erythroid 2-related factor 2 (Nrf2), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) (P < 0.05). The participants in the RCT took 6 mg/d melatonin orally from 3 days before surgery to 3 days after surgery. Blood samples were drawn at the following times: baseline; pre-anesthesia; carotid reconstruction completion; and 6, 24, and 72 hour after CEA. Compared with the oral placebo treatment, melatonin decreased the expression of NF-κB, tumor necrosis factor-α, interleukin-6 (IL-6), and S100β (P < 0.05) and increased the expression of Nrf2, SOD, CAT, and GPx (P < 0.05) in patients after CEA. Our findings suggested that melatonin could ameliorate brain I/R injury after CEA and that this outcome was essentially due to the antioxidant and anti-inflammatory effects of melatonin.

Mangiferin Potentiates Neuroprotection by Isoflurane in Neonatal Hypoxic Brain Injury by Reducing Oxidative Stress and Activation of Phosphatidylinositol-3-Kinase/Akt/Mammalian Target of Rapamycin (PI3K/Akt/mTOR) Signaling

Background

Hypoxic-ischemic brain injury in the perinatal period is a main cause of perinatal mortality and neurologic complications in neonates and children. Recent studies have focused on the neuroprotective effect of anesthetic drugs. The volatile anesthetic isoflurane has been shown to exert neuroprotective effects in cerebral ischemia. Mangiferin is a natural polyphenol with various pharmacological properties, including antioxidant and ant-tumor effects. This study aimed to determine whether mangiferin potentiates the neuroprotective effects of isoflurane and also if mangiferin when administered alone exerts neuroprotective effects following hypoxic-ischemic brain injury.

Material/Methods

Sprague-Dawley rats were subjected to cerebral hypoxic ischemia on postnatal day 10 (P10). Mangiferin (50, 100, or 200 mg/kg b.w.) was intragastrically administered from P3 to P12 and 1 h prior to insult on the day of ischemic induction. At 3 h after hypoxia-ischemia (HI) insult, separate groups of rat pups were exposed to isoflurane (1.5%) for 6 h. Following 48 h of HI, the rats were sacrificed and brain tissues were used for analysis.

Results

Mangiferin treatment attenuated neuronal apoptosis and reduced cerebral infarct volume. The expression of cleaved caspase-3 and apoptotic cascade proteins were regulated. The levels of reactive oxygen species (ROS) and malondialdehyde were reduced by mangiferin and/or isoflurane exposure. The levels of antioxidant glutathione were considerably raised under HI injury, which was modulated by mangiferin and isoflurane exposure. The PI3K/Akt signaling pathway, which was downregulated following HI insult, was activated by mangiferin and/or isoflurane.

Conclusions

This study reveals the potent neuroprotective efficacy of mangiferin against HI-induced brain injury via effectively modulating apoptotic pathways, ROS levels, and PI3K/Akt cascades while potentiating protective effects of isoflurane.

Potential Medications or Compounds Acting on Toll-like Receptors in Cerebral Ischemia

Background:

Toll-like receptors play an integral role in the process of inflammatory response after ischemic in-jury. The therapeutic potential acting on TLRs is worth of evaluations. The aim of this review was to introduce readers some potential medications or compounds which could alleviate the ischemic damage via TLRs.

Methods:

Research articles online on TLRs were reviewed. Categorizations were listed according to the follows, methods acting on TLRs directly, modulations of MyD88 or TRIF signaling pathway, and the ischemic tolerance induced by the pre-conditioning or postconditioning with TLR ligands or minor cerebral ischemia via acting on TLRs.

Results:

There are only a few studies concerning on direct effects. Anti-TLR4 or anti-TLR2 therapies may serve as promis-ing strategies in acute events. Approaches targeting on inhibiting NF-κB signaling pathway and enhancing interferon regu-latory factor dependent signaling have attracted great interests. Not only drugs but compounds extracted from traditional Chinese medicine have been used to identify their neuroprotective effects against cerebral ischemia. In addition, many re-searchers have reported the positive therapeutic effects of preconditioning with agonists of TLR2, 3, 4, 7 and 9. Several trails have also explored the potential of postconditioning, which provide a new idea in ischemic treatments. Considering all the evidence above, many drugs and new compounds may have great potential to reduce ischemic insults.

Conclusion:

This review will focus on promising therapies which exerting neuroprotective effects against ischemic injury by acting on TLRs.

Pure mechanistic analysis of additive neuroprotective effects between baicalin and jasminoidin in ischemic stroke mice

Both baicalin (BA) and jasminoidin (JA) are active ingredients in Chinese herb medicine Scutellaria baicalensis and Fructus gardeniae, respectively. They have been shown to exert additive neuroprotective action in ischemic stroke models. In this study we used transcriptome analysis to explore the pure therapeutic mechanisms of BA, JA and their combination (BJ) contributing to phenotype variation and reversal of pathological processes. Mice with middle cerebral artery obstruction were treated with BA, JA, their combination (BJ), or concha margaritifera (CM). Cerebral infarct volume was examined to determine the effect of these compounds on phenotype. Using the hippocampus microarray and ingenuity pathway analysis (IPA) software, we exacted the differentially expressed genes, networks, pathways, and functions in positive-phenotype groups (BA, JA and BJ) by comparing with the negative-phenotype group (CM). In the BA, JA, and BJ groups, a total of 7, 4, and 11 specific target molecules, 1, 1, and 4 networks, 51, 59, and 18 canonical pathways and 70, 53, and 64 biological functions, respectively, were identified. Pure therapeutic mechanisms of BA and JA were mainly overlapped in specific target molecules, functions and pathways, which were related to the nervous system, inflammation and immune response. The specific mechanisms of BA and JA were associated with apoptosis and cancer-related signaling and endocrine and hormone regulation, respectively. In the BJ group, novel target profiles distinct from mono-therapies were revealed, including 11 specific target molecules, 10 functions, and 10 pathways, the majority of which were related to a virus-mediated immune response. The pure additive effects between BA and JA were based on enhanced action in virus-mediated immune response. This pure mechanistic analysis may provide a clearer outline of the target profiles of multi-target compounds and combination therapies.

Effect of acupuncture on the TLR2/4-NF-κB signalling pathway in a rat model of traumatic brain injury

Objective

To study the effect of acupuncture on the TLR2/4-NF-κB signalling pathway in the cortex of Sprague-Dawley rats following traumatic brain injury (TBI), and investigate the possible mechanism underlying the effects of acupuncture on scar repair.

Methods

TBI was established using Feeney’s free-falling epidural percussion model. In total, 108 rats were randomly divided into a normal group (n=18), untreated TBI model group (TBI group, n=36) and manual acupuncture-treated TBI group (TBI+MA, n=36). Each group of rats was subdivided into three time groups: 3-day (3d), 7-day (7d) and 14-day (14d). No treatment was given to rats in the normal and TBI groups. The TBI+MA group received manual acupuncture at GV20, GV26, GV16 through GV15, and bilateral LI4. mRNA expression of TLR2, TLR4, NF-κB and protein in the rat cortices was quantified using real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blot analyses.

Results

The modified neurological severity score (mNSS) scores of the TBI+MA group were improved compared with baseline scores 12 hours after modelling, and improved at 7d and 14d compared with the TBI group (P<0.05), while the score of the TBI group did not improve until 14d compared to baseline. mRNA and protein expression of TLR2, TLR4 and NF-κB in the TBI group were higher than the normal group at 3d (P<0.05), reached a peak at 7d, then began to decrease at 14d. mRNA and protein expression of TLR2, TLR4 and NF-κB were higher in the TBI+MA group compared with the TBI group at 3d (P<0.05), were significantly down-regulated at 7d (P<0.01), and decreased to normal levels at 14d.

Conclusions

Acupuncture has a bidirectional regulatory effect on the TLR2/4-NF-κB signalling pathway-related genes TLR2, TLR4 and NF-κB in the TBI rat cortex, promoting their expression in the early stage and inhibiting it in the later stage.

Neuroprotective Effect of Curcumin Against Cerebral Ischemia-Reperfusion Via Mediating Autophagy and Inflammation

Curcumin, a polyphenolic compound extracted from Curcuma longa, has drawn attention for its effective bioactivities against ischemia-induced injury. This study aimed to evaluate the neuroprotective effect of curcumin and investigate the underlying mechanism that mediates autophagy and inflammation in an animal model of middle cerebral artery occlusion (MCAO) in rats. Curcumin was delivered to Sprague Dawley male rats at a dose of 200 mg/kg curcumin by intraperitoneal injection 30 min after ischemia-reperfusion (I/R). LY294002, a specific inhibitor of the PI3K/Akt/mTOR pathway, as well as anisomycin, an activator of TLR4/p38/MAPK, was administered by ventricle injection 30 min before MCAO. The same volume of saline was given as a control. Brain infarction and neurological function were determined 24 h post-MCAO. Immunoblotting and immunofluorescence were used to detect alterations in autophagy-relevant proteins Akt, p-Akt, mTOR, p-mTOR, LC3-II, and LC3-I, and inflammation-related proteins TLR4, p-38, p-p38, and IL-1 in the ipsilateral hemisphere. Cerebral I/R injury resulted in significant alterations of LC3-II/LC3-I, IL-1, TLR4, and p-p38. Curcumin in MCAO rats significantly improved brain damage and neurological function by upregulating p-Akt and p-mTOR and downregulating LC3-II/LC3-I, IL-1, TLR4, p-38, and p-p38. However, these protective effects against ischemia could be suppressed when LY294002 or anisomycin was included. Curcumin exerts neuroprotective effects by attenuating autophagic activities through mediating the PI3K/Akt/mTOR pathway, while also suppressing an inflammatory reaction by regulating the TLR4/p38/MAPK pathway. Furthermore, this study indicates that curcumin could be an effective therapy for patients afflicted with ischemia.

Surface functionalized exosomes as targeted drug delivery vehicles for cerebral ischemia therapy

The safe and effective delivery of drugs is a major obstacle in the treatment of ischemic stroke. Exosomes hold great promise as an endogenous drug delivery nanosystem for the treatment of cerebral ischemia given their unique properties, including low immunogenicity, innate stability, high delivery efficiency, and ability to cross the blood-brain barrier (BBB). However, exosome insufficient targeting capability limits their clinical applications. In this study, the c(RGDyK) peptide has been conjugated to the exosome surface by an easy, rapid, and bio-orthogonal chemistry. In the transient middle cerebral artery occlusion (MCAO) mice model, The engineered c(RGDyK)-conjugated exosomes (cRGD-Exo) target the lesion region of the ischemic brain after intravenous administration. Furthermore, curcumin has been loaded onto the cRGD-Exo, and administration of these exosomes has resulted in a strong suppression of the inflammatory response and cellular apoptosis in the lesion region. The results suggest a targeting delivery vehicle for ischemic brain based on exosomes and provide a strategy for the rapid and large-scale production of functionalized exosomes.

Interleukin-10 release from astrocytes suppresses neuronal apoptosis via the TLR2/NFκB pathway in a neonatal rat model of hypoxic-ischemic brain damage

The biological function of interleukin-10 (IL-10) and the relationship between IL-10 secretion and the Toll-like receptor 2 (TLR2) expression levels in the central nervous system following hypoxic-ischemic brain damage (HIBD) are poorly understood. Here, we intend to elucidate the biological function and mechanism of IL-10 secretion following HIBD. In this study, we used a neonatal rat model of HIBD and found that rats injected with adeno-associated virus-IL-10-shRNA (short hairpin RNA) exhibited partially impaired learning and memory function compared to rats administered adeno-associated virus-control-shRNA. In vitro oxygen-glucose deprivation (OGD) induced IL-10 release from astrocytes but not from neurons. Pretreatment with exogenous recombinant IL-10 alleviated OGD-mediated apoptosis of neurons but not astrocytes. In addition, we also observed that hypoxic injury induced a marked increase in IL-10 expression in astrocytes as a result of activation of the TLR2/phosphorylated nuclear factor kappa B (p-NFκB) p65 signaling cascade; furthermore, this effect disappeared upon small interfering RNA targeting rat TLR2 gene (siTLR2) treatment. Pyrrolidinedithiocarbamate, an inhibitor of NFκB activation, reduced the IL-10 expression levels in both OGD-injured astrocytes in vitro and the hippocampi of HIBD rats in vivo but did not significantly affect TLR2 expression. Furthermore, a luciferase assay revealed that p-NFκB p65 could bind the -1700/-1000 bp proximal region of the IL-10 gene promoter to regulate IL-10 secretion from astrocytes and that this interaction could be controlled by OGD treatment. These data suggest that HIBD induces IL-10 secretion from astrocytes to exert a paracrine-induced anti-apoptotic effect on injured neurons via the TLR2/NFκB signaling pathway, which may improve learning and memory dysfunction after ischemic injury.

Curcumin prevents reperfusion injury following ischemic stroke in rats via inhibition of NF‑κB, ICAM-1, MMP-9 and caspase-3 expression

Reperfusion is the only approved therapy for acute ischemic stroke; however, it can cause excessive inflammation responses and aggravate brain damage. Therefore, supplementary treatment against inflammation caused by reperfusion is required. In a previous study from our group, curcumin was demonstrated to decrease infarction volume, brain edema and blood-brain barrier (BBB) disruption against cerebral ischemia/reperfusion (I/R) injury. However, the underlying mechanisms remain unclear. The present study was conducted to understand whether curcumin protects against cerebral I/R injury through anti-inflammatory and antiapoptotic properties. Ischemia for 1 h was induced in vivo in Wistar rats by middle cerebral artery occlusion (MCAO), followed by reperfusion for 24 h, and curcumin was injected intraperitoneally at 30 min prior to reperfusion. Immunohistochemistry was performed to analyze the expression levels of nuclear factor (NF)-κB, intercellular adhesion molecule (ICAM)-1, matrix metalloproteinase (MMP)-9 and caspase-3. The findings revealed that inflammation (NF-κB, ICAM-1 and MMP-9) and apoptosis (caspase-3)-related markers were significantly downregulated in the curcumin-treated MCAO group compared with the vehicle-treated MCAO group. Furthermore, brain infarction size, brain edema and neurological dysfunction were attenuated in the curcumin-treated MCAO group compared with the vehicle-treated MCAO group. Taken together, the present results provided evidence that the protective effect of curcumin against cerebral I/R injury might be mediated by anti-inflammatory and anti-apoptotic properties. Therefore, curcumin may be a promising supplementary agent against cerebral I/R injury in the future.

Potential therapeutic and protective effect of curcumin against stroke in the male albino stroke-induced model rats

AIMS

The present study was carried out to understand the therapeutic effect of curcumin (CUR) against stroke in the experimental animal model. The study investigates the healing effect of CUR on mitochondrial dysfunction and inflammation.

MATERIALS AND METHODS

Male albino, Wistar strain rats were used for the induction of middle cerebral artery occlusion (MCAO), and reperfusion. Enzyme-linked immunosorbent assay (ELISA) was used for the determination of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) in the brain region. Western blot analysis was used to determine the protein expression levels of Bax, Bcl-2, p53, and Sirt1.

KEY FINDINGS

The water level was determined in brain region by using standard method. Experimental results indicated that the use of CUR significantly reduced brain edema and water content. IL-6 and TNF-α were significantly reduced in the brain region following use of CUR. Mitochondrial membrane potential (MMP) also reduced significantly after CUR treatment. Protein expression of p53 and Bax were significantly reduced, whereas Bcl-2 and Sirt1 were increased following CUR treatment.

SIGNIFICANCE

Taking all these data together, it is suggested that the use of CUR may be a potential therapeutic agent for the treatment of stroke.

Nobiletin improves propofol-induced neuroprotection via regulating Akt/mTOR and TLR 4/NF-κB signaling in ischemic brain injury in rats

BACKGROUND

Stroke is regarded as one of the main health concerns globally, presenting with high mortality and morbidity rates. Cerebral ischemic damage and infarction are critically associated with stroke. Various mechanisms related to inflammation, oxidative stress and excitotoxicity are found to be involved in ischemic damage. Very short time period for treatment has necessitated in development of more effective neuroprotective agents. Study aimed in investigated the effects of nobiletin on experimentally induced ischemic brain injury and also to assess whether nobiletin potentiated the neuroprotective effects of propofol.

METHODS

Male Sprague-Dawley rats were subjected to ischemia/reperfusion (I/R) injury. Induction of cerebral infarction and I/R was done by middle cerebral artery occlusion (MCAO). Nobiletin (100 or 200mg/kg b.wt.) was intragastrically administered to rats for 9 days before ischemia induction and on the day of induction nobiletin was administered an hour prior. Separate group of rats were post-conditioned with propofol (50mg/kg/h; i.v.) for 30min following 24h of reperfusion.

RESULTS

Propofol post-conditioning either with or without administration of nobiletin prior I/R injury attenuated pulmonary edema, neuronal apoptosis and reduced cerebral infarct volume. Overproduction of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and nitric oxide following I/R were reduced. Propofol either alone or with prior nobiletin treatment had down-regulated TLR4 and TLR4-mediated NF-κB signaling and caused activation of Akt/mTOR cascade.

CONCLUSION

Propofol post-conditioning either with nobiletin prior I/R injury was found to be more effective than propofol alone, suggesting the positive effects of nobiletin on propofol-mediated anti-inflammatory and neuroprotective effects.

Plumbagin inhibits neuronal apoptosis, intimal hyperplasia and also suppresses TNF-α/NF-κB pathway induced inflammation and matrix metalloproteinase-2/9 expression in rat cerebral ischemia

Cerebral ischemic damage and infarction are well documented in stroke, which is presenting a foremost health concern globally with very high mortality and morbidity rates. Mechanisms that are associated with excitotoxicity, inflammation and oxidative stress are found to be critically involved in ischemic damage. Adverse effects of current therapies are imposing the need in development of neuroprotective agents that are very effective. To explore this we experimentally induced ischemic brain injury and investigated the effects of plumbagin. Induction of cerebral infarction and ischemia-reperfusion (I/R) was done by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Plumbagin (50, 100 or 200 mg/kg b.wt) was intragastrically administered for 9 days before ischemia induction and an hour prior on the day of ischemic insult. Plumbagin treatment attenuated pulmonary edema, neuronal apoptosis and reduced cerebral infarct volume. Cleaved caspase-3 and apoptotic cascade protein expressions were regulated. Overproduction of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and nitric oxide (NO) following I/R were reduced. Prior plumbagin administration had down-regulated NF-κB signalling and MMP-2 and MMP-9 expression. Overall, the results reveal the potent neuroprotective efficacy of plumbagin against I/R-induced brain injury via effectively modulating apoptotic pathways, MMPs and neuro-inflammatory cascades.

Up-regulated fractalkine (FKN) and its receptor CX3CR1 are involved in fructose-induced neuroinflammation: Suppression by curcumin

Recent studies suggest that diet-induced fractalkine (FKN) stimulates neuroinflammation in animal models of obesity, yet how it occurs is unclear. This study investigated the role of FKN and it receptor, CX3CR1, in fructose-induced neuroinflammation, and examined curcumin's beneficial effect. Fructose feeding was found to induce hippocampal microglia activation with neuroinflammation through the activation of the Toll-like receptor 4 (TLR4)/nuclear transcription factor κB (NF-κB) signaling, resulting in the reduction of neurogenesis in the dentate gyrus (DG) of mice. Serum FKN levels, as well as hypothalamic FKN and CX3CR1 gene expression, were significantly increased in fructose-fed mice with hypothalamic microglia activation. Hippocampal gene expression of FKN and CX3CR1 was also up-regulated at 14d and normalized at 56d in mice fed with fructose, which were consistent with the change of GFAP. Furthermore, immunostaining showed that GFAP and FKN expression was increased in cornu amonis 1, but decreased in DG in fructose-fed mice. In vitro studies showed that GFAP and FKN expression was stimulated in astrocytes, and suppressed in mixed glial cells exposed to 48h-fructose, with the continual increase of pro-inflammatory cytokines. Thus, increased FKN and CX3CR1 may cause a cross-talk between activated glial cells and neurons, playing an important role in the development of neuroinflammation in fructose-fed mice. Curcumin protected against neuronal damage in hippocampal DG of fructose-fed mice by inhibiting microglia activation and suppressed FKN/CX3CR1 up-regulation in the neuronal network. These results suggest a new therapeutic approach to protect against neuronal damage associated with dietary obesity-associated neuroinflammation.