Effects of berberine on hippocampal neuronal damage and matrix metalloproteinase-9 activity following transient global cerebral ischemia

Current development and structure-activity relationship study of berberine derivatives

Berberine is a quaternary ammonium isoquinoline alkaloid derived from traditional Chinese medicines Coptis chinensis and Phellodendron chinense. It has many pharmacological activities such as hypoglycemic, hypolipidemic, anti-tumor, antimicrobial and anti-inflammatory. Through structural modifications at various sites of berberine, the introduction of different groups can change berberine's physical and chemical properties, thereby improving the biological activity and clinical efficacy, and expanding the scope of application. This paper reviews the research progress and structure-activity relationships of berberine in recent years, aiming to provide valuable insights for the exploration of novel berberine derivatives.

Effect of berberine on the hippocampal structure, biochemical factors, memory, and blood-brain barrier in rat model of transient global cerebral ischemia

Global cerebral ischemia (GCI) results in damage to the neurons and leads to cognitive impairments. Berberine (BBR) is known for its neuroprotective qualities. This study aimed to investigate the effects of BBR on memory, Blood-brain barrier (BBB) permeability, biochemical factors, and neuronal structure. Sixty-three adult male Wistar rats were divided randomly into Sham (21), GCI (21), and GCI + BBR (21) groups. The GCI + BBR group received 50 mg/kg of BBR for 7 days before and 6 h after 20 min of GCI induction. After 24 h, assessments included hippocampal neuronal structure, catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GPX) levels, memory performance, and BBB permeability. The GCI + BBR group reduced volume loss in the CA1 and its sublayers (oriens, pyramidal, and radiatum) compared to the GCI group (p < 0.0001, p < 0.001, p < 0.01 and p < 0.001, respectively). Additionally, the GCI + BBR group showed higher pyramidal neuron density (p < 0.0001) and number (p < 0.0001) compared to the GCI group. BBR also decreased MDA levels (p < 0.0001) and increased CAT activity (p < 0.0001) in the GCI + BBR group compared to the GCI group, with GPX and SOD activity approaching Sham levels (p < 0.0001, both). BBR demonstrated significant improvements in short and long-term memory compared to the GCI group (p < 0.01, p < 0.0001, respectively). Furthermore, BBB permeability in the GCI + BBR group was significantly reduced compared to the GCI group (p < 0.0001). These findings demonstrated BBR's potential to protect the neurons in the CA1 and BBB structures, enhance antioxidant activity, and alleviate GCI-induced memory impairments.

Neuroprotective Properties of Berberine: Molecular Mechanisms and Clinical Implications

Berberine (BBR), an isoquinoline alkaloid natural product, is isolated primarily from Coptis chinensis and other Berberis plants. BBR possesses various bioactivities, including antioxidant, anti-inflammation, anticancer, immune-regulation, and antimicrobial activities. Growing scientific evidence underscores BBR's substantial neuroprotective potential, prompting increased interest and scrutiny. In this comprehensive review, we elucidate the neuroprotective attributes of BBR, delineate the underlying molecular mechanisms, and assess its clinical safety and efficacy. The multifaceted molecular mechanisms responsible for BBR's neuroprotection encompass the attenuation of oxidative stress, mitigation of inflammatory responses, inhibition of apoptotic pathways, facilitation of autophagic processes, and modulation of CYP450 enzyme activities, neurotransmitter levels, and gut microbiota composition. Furthermore, BBR engages numerous signaling pathways, including the PI3K/Akt, NF-κB, AMPK, CREB, Nrf2, and MAPK pathways, to confer its neuroprotective effects. This comprehensive review aims to provide a substantial knowledge base, stimulate broader scientific discourse, and facilitate advancements in the application of BBR for neuroprotection.

Multifaceted role of polyphenols in the treatment and management of neurodegenerative diseases

Neurodegenerative diseases (NDDs) are conditions that cause neuron structure and/or function to deteriorate over time. Genetic alterations may be responsible for several NDDs. However, a multitude of physiological systems can trigger neurodegeneration. Several NDDs, such as Huntington's, Parkinson's, and Alzheimer's, are assigned to oxidative stress (OS). Low concentrations of reactive oxygen and nitrogen species are crucial for maintaining normal brain activities, as their increasing concentrations can promote neural apoptosis. OS-mediated neurodegeneration has been linked to several factors, including notable dysfunction of mitochondria, excitotoxicity, and Ca2+ stress. However, synthetic drugs are commonly utilized to treat most NDDs, and these treatments have been known to have side effects during treatment. According to providing empirical evidence, studies have discovered many occurring natural components in plants used to treat NDDs. Polyphenols are often safer and have lesser side effects. As, epigallocatechin-3-gallate, resveratrol, curcumin, quercetin, celastrol, berberine, genistein, and luteolin have p-values less than 0.05, so they are typically considered to be statistically significant. These polyphenols could be a choice of interest as therapeutics for NDDs. This review highlighted to discusses the putative effectiveness of polyphenols against the most prevalent NDDs.

Demethyleneberberine, a potential therapeutic agent in neurodegenerative disorders: a proposed mechanistic insight

INTRODUCTION

Neurodegenerative disorders are a diverse variety of diseases that can be distinguished from developing degeneration of neurons in the CNS. Several alkaloids have shown mounting effects in neurodegenerative disorders, and berberine is one of them. Demethyleneberberine is a metabolite of berberine that has better blood-brain barrier crossing capacity. Demethyleneberberine possesses anti-inflammatory, anti-oxidant, and mitochondrial targeting properties. However, neither the pharmacological action nor the molecular mechanism of action of demethyleneberberine on neurodegenerative disorders has been explored yet.

MATERIALS AND METHODS

A systematic literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elseveier) databases was carried out with the help of keywords like "Demethyleneberberine; neuroinflammation; oxidative stress; Neuroprotective; Neurodegenerative disorders" till date.

CONCLUSION

This review focus on the neuroprotective potential of demethyleneberberine in neurodegenerative disorders by attenuating different pathways, i.e., NF-κB, MAPK, and AMPK signalling.

Berberine: A Comprehensive Review on its Isolation, Biosynthesis, Chemistry and Pharmacology

The isoquinoline compounds from alkaloidal class have been excellent source of important phytoconstituents having wide range of pharmacological activities. Berberine is a protoberberine alkaloidal compound obtained from Berberis genus plants which belongs to family Barberidaceae. Due to its unique structural properties, berberine and its derivatives has been exploited extensively for its potential uses in various pharmacological targets such as cancer, inflammation, diabetes, gastrointestinal disorder, viral and microbial infections, neurological disorder like Alzheimer, anxiety, schizophrenia, depression, etc. This review illustrates the updated information on berberine with respect to its isolation, biosynthesis, chemical synthesis, structural modification and pharmacological activities. An extensive literature search were carried out in various search engine like PubMed, Google Scholars, Research Gate and SCOPUS by using keywords like Berberine, protoberberine alkaloids, isoquinoline derivatives, pharmacological effects, etc. Prephenic acid is the starting material for biosynthesis of berberine. Structural modifications lead to generation of various potential derivatives, which earn patents by researchers. Besides toxicities, the complications of low solubility and bioavailability should be eliminated. To improve its safety, efficacy and selectivity the berberine should be carefully derivatized.

Berberine: A Plant-derived Alkaloid with Therapeutic Potential to Combat Alzheimer's disease

Berberine (a protoberberine isoquinoline alkaloid) has shown promising pharmacological activities, including analgesic, anti-inflammatory, anticancer, antidiabetic, anti-hyperlipidemic, cardioprotective, memory enhancement, antidepressant, antioxidant, anti-nociceptive, antimicrobial, anti- HIV and cholesterol-lowering effects. It is used in the treatment of the neurodegenerative disorder. It has strong evidence to serve as a potent phytoconstituent in the treatment of various neurodegenerative disorders such as AD. It limits the extracellular amyloid plaques and intracellular neurofibrillary tangles. It has also lipid-glucose lowering ability, hence can be used as a protective agent in atherosclerosis and AD. However, more detailed investigations along with safety assessment of berberine are warranted to clarify its role in limiting various risk factors and AD-related pathologies. This review highlights the pharmacological basis to control oxidative stress, neuroinflammation and protective effect of berberine in AD, which will benefit to the biological scientists in understanding and exploring the new vistas of berberine in combating Alzheimer's disease.

Neuroprotective effects of N-acetylcysteine via inhibition of matrix metalloproteinase in a mouse model of transient global cerebral ischemia

N-acetylcysteine (NAC) is known to serve many biological functions including acting as an antioxidant, and electing antiinflammatory effects. Previous reports have revealed that NAC may have neuroprotective effects against the deleterious effects of brain ischemia. Despite of this, the mechanism by which NAC prevents neuronal damage after brain ischemia remains unclear. The current study aimed to investigate this mechanism in a mouse model of transient global brain ischemia. In the present study, mice were subjected to 20 min of transient global brain ischemia, proceeded by intraperitoneal administration of NAC (150 mg/kg) in one group. The mice were then euthanized 72 h after this ischemic insult for collection of experimental tissues. The effect of NAC on neuronal damage and matrix metalloproteinase (MMP)-9 activity were assessed and immunofluorescence, and hippocampal terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay experiments were conducted and results compared between NAC- and vehicle-treated groups. Neuronal damage was primarily observed in the hippocampal CA1 and CA2 regions. In NAC-treated mice, neuronal damage was significantly reduced after ischemia when compared to vehicle-treated animals. NAC also inhibited increased MMP-9 activity after global brain ischemia. NAC increased laminin and NeuN expression and inhibited increases in TUNEL-positive cells, all in the hippocampus. These results suggest that NAC reduces hippocampal neuronal damage following transient global ischemia, potentially via reductions in MMP-9 activity.

Neuroprotective Role of Phytochemicals

Neurodegenerative diseases are normally distinguished as disorders with loss of neurons. Various compounds are being tested to treat neurodegenerative diseases (NDs) but they possess solitary symptomatic advantages with numerous side effects. Accumulative studies have been conducted to validate the benefit of phytochemicals to treat neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). In this present review we explored the potential efficacy of phytochemicals such as epigallocatechin-3-galate, berberin, curcumin, resveratrol, quercetin and limonoids against the most common NDs, including Alzheimer's disease (AD) and Parkinson's disease (PD). The beneficial potentials of these phytochemicals have been demonstrated by evidence-based but more extensive investigation needs to be conducted for reducing the progression of AD and PD.

Berberine Protects Secondary Injury in Mice with Traumatic Brain Injury Through Anti-oxidative and Anti-inflammatory Modulation

Traumatic brain injury (TBI) is one of the major causes of death and disability worldwide. Novel and effective therapy is needed to prevent the secondary spread of damage beyond the initial injury. The aim of this study was to investigate whether berberine has a neuroprotective effect on secondary injury post-TBI, and to explore its potential mechanism in this protection. The mice were randomly divided into Sham-saline, TBI-saline and TBI-Berberine (50 mg/kg). TBI was induced by Feeney's weight-drop technique. Saline or berberine was administered via oral gavage starting 1 h post-TBI and continuously for 21 days. Motor coordination, spatial learning and memory were assessed using beam-walking test and Morris water maze test, respectively. Brain sections were processed for lesion volume assessment, and expression of neuronal nuclei (NeuN), cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), 8-hydroxy-2-deoxyguanosine (8-OHdG), ionized calcium-binding adapter molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP) were detected via immunohistochemistry and immunofluorescence. There were statistically significant improvement in motor coordination, spatial learning and memory in the TBI-Berberine group, compared to the TBI-saline group. Treatment with berberine significantly reduced cortical lesion volume, neuronal loss, COX-2, iNOS and 8-OHdG expression in both the cortical lesion border zone (LBZ) and ipsilateral hippocampal CA1 region (CA1), compared to TBI-saline. Berberine treatment also significantly decreased Iba1- and GFAP-positive cell number in both the cortical LBZ and ipsilateral CA1, relative to saline controls. These results indicated that berberine exerted neuroprotective effects on secondary injury in mice with TBI probably through anti-oxidative and anti-inflammatory properties.

Jiao-Tai-Wan Improves Cognitive Dysfunctions through Cholinergic Pathway in Scopolamine-Treated Mice

Cognitive dysfunction is characterized as the gradual loss of learning ability and cognitive function, as well as memory impairment. Jiao-tai-wan (JTW), a Chinese medicine prescription including Coptis chinensis and cinnamon, is mainly used for the treatment of insomnia, while the effect of JTW in improving cognitive function has not been reported. In this study, we employed a scopolamine- (SCOP-) treated learning and memory deficit model to explore whether JTW could alleviate cognitive dysfunction. In behavioral experiments, Morris water maze, Y-maze, fearing condition test, and novel object discrimination test were conducted. Results showed that oral administration of JTW (2.1 g/kg, 4.2 g/kg, and 8.4 g/kg) can effectively promote the ability of spatial recognition, learning and memory, and the memory ability of fresh things of SCOP-treated mice. In addition, the activity of acetylcholinesterase (AChE) was effectively decreased; the activity of choline acetyltransferase (ChAT) and concentration of acetylcholine (Ach) were improved after JTW treatment in both hippocampus and cortex of SCOP-treated mice. JTW effectively ameliorated oxidative stress because of decreased the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) and increased the activities of superoxide dismutase (SOD) and catalase (CAT) in hippocampus and cortex. Furthermore, JTW promotes the expressions of neurotrophic factors including postsynaptic density protein 95 (PSD95) and synaptophysin (SYN) and brain-derived neurotrophic factor (BDNF) in both hippocampus and cortex. Nissl's staining shows that the neuroprotective effect of JTW was very effective. To sum up, JTW might be a promising candidate for the treatment of cognitive dysfunction.

Berberis Vulgaris and Berberine: An Update Review

Berberine is an isoquinoline alkaloid present in several plants, including Coptis sp. and Berberis sp. Berberine is a customary component in Chinese medicine, and is characterized by a diversity of pharmacological effects. An extensive search in electronic databases (PubMed, Scopus, Ovid, Wiley, ProQuest, ISI, and Science Direct) were used to identify the pharmacological and clinical studies on Berberis vulgaris and berberine, during 2008 to 2015, using 'berberine' and 'Berberis vulgaris' as search words. We found more than 1200 new article studying the properties and clinical uses of berberine and B. vulgaris, for treating tumor, diabetes, cardiovascular disease, hyperlipidemia, inflammation, bacterial and viral infections, cerebral ischemia trauma, mental disease, Alzheimer disease, osteoporosis, and so on. In this article, we have updated the pharmacological effects of B. vulgaris and its active constituent, berberine. Copyright © 2016 John Wiley & Sons, Ltd.

Protection of Gastrointestinal Mucosa from Acute Heavy Alcohol Consumption: The Effect of Berberine and Its Correlation with TLR2, 4/IL1β-TNFα Signaling

The purpose of the present study is to confirm the protective effect of berberine (BBR) on gastrointestinal injury caused by acute heavy alcohol exposure, an effect that has not been reported previously. Our research details how BBR protects against gastrointestinal injuries from acute alcohol exposure using both in vivo and in vitro experiments. Acute high alcohol concentrations lead to obvious damage to the gastrointestinal mucosa, resulting in necrosis of the intestinal mucosa. Oral administration of BBR was able to significantly reduce this alcohol-induced damage, inhibit increases of alcohol-induced TNFα and IL-1β expression in gastrointestinal mucosa as well as their upstream signals TLR2 and TLR4, and regulate cytokines that modulate tight junctions. Alcohol consumption is a popular human social behavior worldwide, and the present study reports a comprehensive mechanism by which BBR protects against gastrointestinal injuries from alcohol stress, providing people with a novel application of BBR.

Therapeutic potential of berberine against neurodegenerative diseases

Berberine (BBR) is an organic small molecule isolated from various plants that have been used in traditional Chinese medicine. Isolation of this compound was its induction into modern medicine, and its usefulness became quickly apparent as seen in its ability to combat bacterial diarrhea, type 2 diabetes, hypercholesterolemia, inflammation, heart diseases, and more. However, BBR’s effects on neurodegenerative diseases remained relatively unexplored until its ability to stunt Alzheimer’s disease (AD) progression was characterized. In this review, we will delve into the multi-faceted defensive capabilities and bio-molecular pathways of BBR against AD, Parkinson’s disease (PD), and trauma-induced neurodegeneration. The multiple effects of BBR, some of which enhance neuro-protective factors/pathways and others counteract targets that induce neurodegeneration, suggest that there are many more branches to the diverse capabilities of BBR that have yet to be uncovered. The promising results seen provide a convincing and substantial basis to support further scientific exploration and development of the therapeutic potential of BBR against neurodegenerative diseases.

Herbal medicines for ischemic stroke: combating inflammation as therapeutic targets

Stroke is a debilitating disease for which limited therapeutic approaches are available currently. Thus, there is an urgent need for developing novel therapies for stroke. Astrocytes, endothelial cells and pericytes constitute a neurovascular network for metabolic requirement of neurons. During ischemic stroke, these cells contribute to post-ischemic inflammation at multiple stages of ischemic cascades. Upon ischemia onset, activated resident microglia and astrocytes, and infiltrated immune cells release multiple inflammation factors including cytokines, chemokines, enzymes, free radicals and other small molecules, not only inducing brain damage but affecting brain repair. Recent progress indicates that anti-inflammation is an important therapeutic strategy for stroke. Given a long history with direct experience in the treatment of human subjects, Traditional Chinese Medicine and its related natural compounds are recognized as important sources for drug discovery. Last decade, a great progress has been made to identify active compounds from herbal medicines with the properties of modulating post-ischemic inflammation for neuroprotection. Herein, we discuss the inflammatory pathway in early stage and secondary response to injured tissues after stroke from initial artery occlusion to brain repair, and review the active ingredients from natural products with anti-inflammation and neuroprotection effects as therapeutic agents for ischemic stroke. Further studies on the post-ischemic inflammatory mechanisms and corresponding drug candidates from herbal medicine may lead to the development of novel therapeutic strategies in stroke treatment.

Berberine exerts an anticonvulsant effect and ameliorates memory impairment and oxidative stress in a pilocarpine-induced epilepsy model in the rat

Though new antiepileptic drugs are emerging, approximately a third of epileptic patients still suffer from recurrent convulsions and cognitive dysfunction. Therefore, we tested whether berberine (Ber), a vegetable drug, has an anticonvulsant property and attenuates memory impairment in a pilocarpine (Pilo)-induced epilepsy model in rats. The rats were injected with 400 mg/kg Pilo to induce convulsions, and Ber 25, 50, and 100 mg/kg were administrated by the intragastric route once daily 7 days before Pilo injection until the experiment was over. Convulsions were observed after Pilo injection. For the rats that developed status epilepticus (SE), malondialdehyde, glutathione levels, superoxide dismutase, and catalase activity in the hippocampus were measured 24 hours after SE. The rats received the Morris water-maze test 2 weeks after SE, and then were killed for fluoro-jade B staining to detect the degenerating neurons. We found Ber delayed latency to the first seizure and the time to develop SE in a dose-dependent manner. Malondialdehyde levels were decreased, while glutathione and catalase activity were strengthened in Ber-injected SE rats. In the Morris water-maze test, Ber decreased escape latency compared to saline-treated SE rats. Additionally, Ber reduced the number of fluoro-jade B-positive cells in the hippocampal CA1 region. Our data suggest that Ber exerts anticonvulsant and neuroprotective effects on Pilo-induced epilepsy in rats. Simultaneously, Ber attenuates memory impairment. The beneficial effect may be partly due to mitigation of the oxidative stress burden.

Berberine rescues D-galactose-induced synaptic/memory impairment by regulating the levels of Arc

Synaptic communication forms the basis of learning and memory. Disruptions of synaptic function and memory have been widely reported in many neurological diseases, such as dementia. Thus, restoration of impaired synaptic communication is a potential therapeutic approach for these diseases. In this study, we demonstrated that supplementation with berberine, a plant alkaloid with a long history of medicinal usage in Chinese medicine, effectively reverses the synaptic deficits induced by D-galactose. We also found that berberine rescued D-galactose-induced memory impairment and additionally rescued the mRNA and protein levels of Arc/Arg3.1, an important immediate early gene that is crucial for maintaining normal synaptic plasticity. Our study provides the first piece of evidence supporting the potential use of berberine in the treatment of neural diseases with synaptic/memory impairments.

Protective effect of melatonin against transient global cerebral ischemia-induced neuronal cell damage via inhibition of matrix metalloproteinase-9

AIMS

Melatonin possesses various pharmacological effects including neuroprotective effects against brain ischemia. Post-ischemic increases in matrix metalloproteinase-9 (MMP-9) expression and activity mainly contribute to neuronal damage by degradation of the extracellular matrix. This study was designed to examine whether melatonin has a neuroprotective effect and an influence on MMP-9 in transient global brain ischemia.

MAIN METHODS

Mice were subjected to 20 min of global brain ischemia and sacrificed 72h later. Melatonin (30 mg/kg) was administered 30 min before and 2h after ischemia as well as once daily until sacrifice.

KEY FINDINGS

Hippocampal pyramidal cell damage after ischemia was significantly decreased by melatonin. As observed by zymography, melatonin inhibited the increase of MMP-9 activity after ischemia. In the brain sections, the increased gelatinase activity was mainly observed in the hippocampus after ischemia and melatonin also reduced gelatinase activity. The laminin and NeuN expression levels were reduced in the hippocampal CA1 and CA2 regions after ischemia, and melatonin reduced laminin degradation and neuronal loss. A TUNEL assay demonstrated that there were TUNEL-positive cells in the hippocampus and the number of TUNEL-positive cells was significantly decreased by melatonin. There was no difference in the ischemia-induced hippocampal neuronal damage between the vehicle- and melatonin-treated groups of MMP-9 knock-out mice.

SIGNIFICANCE

These data demonstrate that melatonin suppressed the occurrence of neuronal injury, which might be partly due to its inhibitory effects on MMP-9 in addition to its anti-oxidative effects. MMP-9 may be an important key target of melatonin in neuroprotection against global ischemia.

The protective effect of berberine against neuronal damage by inhibiting matrix metalloproteinase-9 and laminin degradation in experimental autoimmune encephalomyelitis

OBJECTIVE

This study aims to assess the protective effect of berberine against neuronal damage in the brain parenchyma of mice with experimental autoimmune encephalomyelitis (EAE).

METHODS

EAE was induced in female C57 BL/6 mice with myelin oligodendrocyte glycoprotein 35-55 amino acid peptide. The berberine treatment was initiated on the day of disease onset and administered daily until the mice were sacrificed. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, gelatin gel, and gelatin in situ zymography were analysed in this study.

RESULTS

Berberine reduced the TUNEL-positive neuronal cells of EAE mice. Gelatin gel and gelatin in situ zymography showed up-regulation of gelatinase activity, which was mainly located in neurons and colocalized with remarkable laminin degradation in EAE mice. Berberine significantly inhibited gelatinase activity and reduced the laminin degradation in EAE mice.

DISCUSSION

Our data suggest that berberine could provide protection against neuronal damage in EAE by inhibiting gelatinase activity and reducing laminin degradation. These findings provide further support that berberine can be a potential therapeutic agent for multiple sclerosis.

Berberine Inhibits the Release of Glutamate in Nerve Terminals from Rat Cerebral Cortex

Berberine, an isoquinoline plant alkaloid, protects neurons against neurotoxicity. An excessive release of glutamate is considered to be one of the molecular mechanisms of neuronal damage in several neurological diseases. In this study, we investigated whether berberine could affect endogenous glutamate release in nerve terminals of rat cerebral cortex (synaptosomes) and explored the possible mechanism. Berberine inhibited the release of glutamate evoked by the K⁺ channel blocker 4-aminopyridine (4-AP), and this phenomenon was prevented by the chelating extracellular Ca²⁺ ions and the vesicular transporter inhibitor bafilomycin A1, but was insensitive to the glutamate transporter inhibitor DL-threo-beta-benzyl-oxyaspartate. Inhibition of glutamate release by berberine was not due to it decreasing synaptosomal excitability, because berberine did not alter 4-AP-mediated depolarization. The inhibitory effect of berberine on glutamate release was associated with a reduction in the depolarization-induced increase in cytosolic free Ca²⁺ concentration. Involvement of the Ca_v2.1 (P/Q-type) channels in the berberine action was confirmed by blockade of the berberine-mediated inhibition of glutamate release by the Ca_v2.1 (P/Q-type) channel blocker ω-agatoxin IVA. In addition, the inhibitory effect of berberine on evoked glutamate release was prevented by the mitogen-activated/extracellular signal-regulated kinase kinase (MEK) inhibitors. Berberine decreased the 4-AP-induced phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and synapsin I, the main presynaptic target of ERK; this decrease was also blocked by the MEK inhibition. Moreover, the inhibitory effect of berberine on evoked glutamate release was prevented in nerve terminals from mice lacking synapsin I. Together, these results indicated that berberine inhibits glutamate release from rats cortical synaptosomes, through the suppression of presynaptic Cav2.1 channels and ERK/synapsin I signaling cascade. This finding may provide further understanding of the mode of berberine action in the brain and highlights the therapeutic potential of this compound in the treatment of a wide range of neurological disorders.

Neuroprotection of early and short-time applying berberine in the acute phase of cerebral ischemia: up-regulated pAkt, pGSK and pCREB, down-regulated NF-κB expression, ameliorated BBB permeability

BACKGROUND

Berberine (BBR) has gained attention for its vast beneficial biological effects through immunomodulation, anti-inflammatory and anti-apoptosis properties. Inflammatory and apoptosis damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The aim of this study was to explore BBR's effect in ischemic injury and the role of the Akt/GSK (glycogen synthase kinase) signaling cascade in mediating the anti-apoptosis and anti-inflammatory effects in the rat brain of permanent middle cerebral artery occlusion (pMCAO). Male Sprague-Dawley rats were subjected to pMCAO and randomly assigned into four groups: Sham (sham-operated) group, pMCAO (pMCAO+0.9% saline) group, BBR-L (pMCAO+BBR 10 mg/kg) and BBR-H (pMCAO+BBR 40 mg/kg) group. BBR was administered immediately after pMCAO and the neuroprotection was detected. Phospho-Akt (pAkt), phospho-glycogen synthase kinase 3-β (pGSK3β), phospho-cAMP response element binding protein (pCREB), nuclear factor-kappa B (NF-κB) and claudin-5 in ischemic cerebral cortex were detected by immunohistochemistry, reverse transcription-polymerase chain reaction and western blotting. Compared with pMCAO group, BBR dramatically lessened neurological deficits scores, brain water contents and infarct sizes, upregulated the expression of pAkt, pGSK3β, pCREB and claudin-5, and decreased the nuclear accumulation of NF-κB (P<0.05) in ischemic brain. The results showed that BBR reduced ischemic brain injury after pMACO, and this effect may be via the increasing the activation of Akt/GSK signaling and claudin-5, and decreasing NF-κB expression.