Asiaticoside Attenuates Cell Growth Inhibition and Apoptosis Induced by Aβ1-42 via Inhibiting the TLR4/NF-κB Signaling Pathway in Human Brain Microvascular Endothelial Cells

Asiaticoside Attenuates Blood-Spinal Cord Barrier Disruption by Inhibiting Endoplasmic Reticulum Stress in Pericytes After Spinal Cord Injury

The blood-spinal cord barrier (BSCB) plays a vital role in the recovery of spinal cord function after spinal cord injury (SCI). Pericytes, pluripotent members of the neurovascular unit (NVU), receive signals from neighboring cells and are critical for maintaining CNS function. Therapeutic targets for the BSCB include endothelial cells (ECs) and glial cells, but few drugs target pericytes. This study was designed to explore whether asiaticoside has a positively effect on pericytes and the integrity of the BSCB. In this study, we found that asiaticoside could inhibit the loss of junction proteins just 1 day after SCI in vivo, but our in vitro study showed no significant differences in the expression of endothelial junction proteins between the control and asiaticoside treatment groups. We also found that asiaticoside could inhibit endoplasmic reticulum (ER) stress and pericyte apoptosis, which might be associated with the inhibition of junction protein reduction in ECs. Thus, we investigated the interactions between pericytes and ECs. Our results showed that asiaticoside could decrease the release of matrix metalloproteinase (MMP)-9 in pericytes and therefore upregulate the expression of junction proteins in ECs. Furthermore, the protective effect of asiaticoside on pericytes is related to the inhibition of ER stress via the MAPK signaling pathway. Taken together, our results demonstrate that asiaticoside treatment inhibits BSCB disruption and enhances functional recovery after SCI.

The Standardized Extract of Centella asiatica and Its Fractions Exert Antioxidative and Anti-Neuroinflammatory Effects on Microglial Cells and Regulate the Nrf2/HO-1 Signaling Pathway

Background

Neuroinflammation and oxidative stress can aggravate the progression of Alzheimer's disease (AD). Centella asiatica has been traditionally consumed for memory and cognition. The triterpenes (asiaticoside, madecassoside, asiatic acid, madecassic acid) have been standardized in the ethanolic extract of Centella asiatica (SECA). The bioactivity of the triterpenes in different solvent polarities of SECA is still unknown.

Objective

In this study, the antioxidative and anti-neuroinflammatory effects of SECA and its fractions were explored on lipopolysaccharides (LPS)-induced microglial cells.

Methods

HPLC measured the four triterpenes in SECA and its fractions. SECA and its fractions were tested for cytotoxicity on microglial cells using MTT assay. NO, pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), ROS, and MDA (lipid peroxidation) produced by LPS-induced microglial cells were measured by colorimetric assays and ELISA. Nrf2 and HO-1 protein expressions were measured using western blotting.

Results

The SECA and its fractions were non-toxic to BV2 microglial cells at tested concentrations. The levels of NO, TNF-α, IL-6, ROS, and lipid peroxidation in LPS-induced BV2 microglial cells were significantly reduced (p < 0.001) by SECA and its fractions. SECA and some of its fractions can activate the Nrf2/HO-1 signaling pathway by significantly enhancing (p < 0.05) the Nrf2 and HO-1 protein expressions.

Conclusions

This study suggests that the inhibitory activity of SECA and its fractions on pro-inflammatory and oxidative stress events may be the result of the activation of antioxidant defense systems. The potential of SECA and its fractions in reducing neuroinflammation and oxidative stress can be further studied as a potential therapeutic strategy for AD.

Neurotropin alleviates cognitive impairment by inhibiting TLR4/MyD88/NF-κB inflammation signaling pathway in mice with vascular dementia

Vascular dementia (VD) is the second most common cause of dementia after Alzheimer's disease. Neuroinflammation contributes to pathogenesis of VD. Neurotropin (NTP) is an analgesic that has been shown to suppress inflammation and neural repair. But its effects on VD are still unclear. Therefore, this study aimed to investigate the therapeutic effects and potential mechanisms of NTP in the VD model mice established by bilateral common carotid artery stenosis method. In VD mice, we found that NTP treatment increased cerebral blood flow by Laser speckle imaging, reduced neuron loss by Nissl, HE and immunochemistry staining, attenuated white matter damage by magnetic resonance imaging and ultrastructural damage by transmission electron microscope, improved cognitive functions by new object recognition test and three-chamber test, Y maze test and Morris water maze test, inhibited significantly glial activation by immunofluorescence methods, reduced the expression of TLR4, down-regulated expression of MyD88 and phosphorylation of NF-κB P65, decreased the levels of pro-inflammatory cytokines IL-1β, IL-6 and TNFα. Further, we showed that administration of a TLR4 inhibitor TAK242 had a similar effect to NTP, while the TLR4 agonist CRX-527 attenuated the effect of NTP in the VD mice. Collectively, our study suggested that NTP alleviates cognitive impairment by inhibiting TLR4/MyD88/NF-κB inflammation signaling pathway in the VD mice. Thus, NTP may be a promising therapeutic approach and a potential TLR4 inhibitor for VD.

Neurovascular glial unit: A target of phytotherapy for cognitive impairments

BACKGROUND

Neurovascular glial unit (NVGU) dysfunction has been reported to be an early and critical event in the pathophysiology of Alzheimer's disease (AD) and vascular dementia (VD). Although herbal medicines, with their favorable safety profiles and low adverse effects, have been suggested to be useful for the treatment of cognitive impairment, the potential role of the NVGU as the target of the effects of herbal medicines is still unclear.

PURPOSE

This review aimed to retrieve evidence from experimental studies of phytopharmaceuticals targeting the NVGU for the treatment of cognitive impairment in AD and VD, and discussed the potential of phytopharmaceuticals to improve cognitive impairment from the perspective of the NVGU.

STUDY DESIGN AND METHODS

We systematically searched PubMed, Google Scholar, Web of Science, and CNKI. The keywords used for searching information on the NVGU in the treatment of cognitive impairments included "Alzheimer's disease," "Vascular dementia," "Herbal medicines," "Natural products," "Neurovascular," "Adverse reaction," and "Toxicity, etc." We selected studies on the basis of predefined eligibility criteria.

RESULTS

NVGU mainly consists of endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes, and neurons, and damage to these cells can induce cognitive impairment by impairing the blood-brain barrier (BBB) and cerebral blood flow (CBF) as well as neuronal function. The active components of herbal medicines, including Ginkgo biloba L., Ginseng Radix et Rhizoma, Epimedium Folium, Chuanxiong Rhizoma, Carthami flos, and Acorus tatarinowii Schott, as well as traditional Chinese medicine prescriptions have shown the potential to improve BBB function and increase CBF to prevent cognitive impairment by inhibiting astrocyte and microglia activation, protecting oligodendrocyte myelin function, reducing neuronal apoptosis, and promoting angiogenesis.

CONCLUSIONS

Herbal medicines demonstrate great potential to prevent cognitive impairment. Multiple components from herbal medicines may function through different signaling pathways to target the NVGU. Future studies using novel drug-carrier or delivery systems targeting the NVGU will certainly facilitate the development of phytopharmaceuticals for AD and VD.

Asiaticoside Mitigates Alzheimer's Disease Pathology by Attenuating Inflammation and Enhancing Synaptic Function

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder, hallmarked by the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles. Due to the uncertainty of the pathogenesis of AD, strategies aimed at suppressing neuroinflammation and fostering synaptic repair are eagerly sought. Asiaticoside (AS), a natural triterpenoid derivative derived from Centella asiatica, is known for its anti-inflammatory, antioxidant, and wound-healing properties; however, its neuroprotective function in AD remains unclear. Our current study reveals that AS, when administered (40 mg/kg) in vivo, can mitigate cognitive dysfunction and attenuate neuroinflammation by inhibiting the activation of microglia and proinflammatory factors in Aβ1-42-induced AD mice. Further mechanistic investigation suggests that AS may ameliorate cognitive impairment by inhibiting the activation of the p38 MAPK pathway and promoting synaptic repair. Our findings propose that AS could be a promising candidate for AD treatment, offering neuroinflammation inhibition and enhancement of synaptic function.

Oestrogen ameliorates blood-brain barrier damage after experimental subarachnoid haemorrhage via the SHH pathway in male rats

BACKGROUND

Sex differences affect the occurrence, progression and regression of subarachnoid haemorrhage (SAH). Oestrogen plays a protective role in alleviating the vasospasm and neuronal apoptosis induced by SAH. However, whether oestrogen affects blood‒brain barrier (BBB) integrity has not been fully studied. Oestrogen has been found to regulate the sonic hedgehog (SHH) signalling pathway through the oestrogen receptor in gastric cancer and adrenal glands, and the SHH signalling pathway has an important role in maintaining the BBB by upregulating the expression of tight junction proteins. In this study, we investigated the relationship between oestrogen and the SHH signalling pathway using clinical data and established an experimental SAH model to explore whether oestrogen could ameliorate BBB damage after SAH through the SHH pathway.

METHODS

Correlations between oestrogen and the SHH pathway were analysed by patients' cerebrospinal fluid (CSF) samples and the Genotype-Tissue Expression database (GTEx). Then, an experimental rat SAH model was established using the endovascular perforation method and treated with oestrogen, oestrogen inhibitors and SHH signalling pathway inhibitors. Then, the effects of oestrogen on BBB damage were analysed by western blot, immunofluorescence and neurobehavioural experiments.

RESULTS

ESLIA detection and correlation analysis showed that oestrogen levels in patients' CSF were positively correlated with the SHH pathway, which was further verified by GTEx gene-correlation analysis. SHH was found to be mainly expressed in neurons and astrocytes in rats under physiological conditions and was upregulated by oestrogen pretreatment. In the SAH model, oestrogen pretreatment was found to reverse SAH-induced decreases in the SHH pathway, which were counteracted by oestrogen receptor inhibitors. Furthermore, oestrogen pretreatment reduced SAH-induced BBB damage, brain oedema and neurological dysfunction, which were eliminated by SHH pathway inhibitors.

CONCLUSION

In conclusion, we demonstrate here that oestrogen pretreatment ameliorates brain injury after SAH, at least in part through SHH pathway-mediated BBB protection.

Mitochondrial oxidative stress in brain microvascular endothelial cells: Triggering blood-brain barrier disruption

Blood-brain barrier disruption plays an important role in central nervous system diseases. This review provides information on the role of mitochondrial oxidative stress in brain microvascular endothelial cells in cellular dysfunction, the disruption of intercellular junctions, transporter dysfunction, abnormal angiogenesis, neurovascular decoupling, and the involvement and aggravation of vascular inflammation and illustrates related molecular mechanisms. In addition, recent drug and nondrug therapies targeting cerebral vascular endothelial cell mitochondria to repair the blood-brain barrier are discussed. This review shows that mitochondrial oxidative stress disorder in brain microvascular endothelial cells plays a key role in the occurrence and development of blood-brain barrier damage and may be critical in various pathological mechanisms of blood-brain barrier damage. These new findings suggest a potential new strategy for the treatment of central nervous system diseases through mitochondrial modulation of cerebral vascular endothelial cells.

A review of pharmacokinetic and pharmacological properties of asiaticoside, a major active constituent of Centella asiatica (L.) Urb

ETHNOPHARMACOLOGICAL RELEVANCE

Centella asiatica (L.) Urb., a potential medicinal plant, is widely used in orient traditional medicine. Its major active constituents include asiaticoside (AS), madecassoside (MS), asiatic acid and madecassic acid. Thereinto, AS is a pentacyclic triterpenoid saponin with a variety of pharmacological effects including antitumor, neuroprotective and wound healing effects.

AIM OF THE STUDY

In this review, we summarize the pharmacokinetics, safety and pharmacological properties of AS.

MATERIALS AND METHODS

We gathered information about AS from articles published up to 2022 and listed in Google scholar, PubMed, Web of Science, Elsevier, and similar databases. The keywords used in our search included "asiaticoside", "Centella asiatica", "pharmacokinetics", "nerve", "cancer", "skin", etc. RESULTS: AS appeared to degrade through a first-order reaction and had low biotoxicity. However, the pharmacokinetic properties of AS differed according to species. AS is highly blood-brain-barrier permeable without any harmful side effect. It has a variety of pharmacological effects including anti-neural inflammation and anti-cancer properties, as well as protective properties for the skin, cardiovascular system, and pulmonary system.

CONCLUSION

This review comprehensively summarized current information regarding the pharmacokinetic and pharmacological properties of AS, and supported the pharmaceutical value of this compound. Future research should focus on improving bioavailability of AS and conducting clinical assessment.

Acupoint catgut embedding improves learning and memory impairment in vascular dementia rats

Background

Vascular dementia (VD) is a disease that affects brain function through cerebrovascular disease. Due to its complex pathogenesis, there is no effective drug treatment for VD. The present study aimed to evaluate the role of acupoint catgut embedding in the treatment of rats with VD and its possible molecular mechanism.

Methods

A modified 4 vessel occlusion (4-VO) method was used to establish a VD model rat, and spatial learning and memory ability was assessed using the Morris water maze (MWM) test. The protein expression levels were detected by Western blot. Hematoxylin and eosin (HE) staining was used for histological analysis and enzyme-linked immunosorbent assay (ELISA) was applied for analysis of serum inflammatory factors.

Results

We successfully constructed VD model rats with spatial learning and memory impairment, hippocampus injury, and high inflammatory response. Treatment of VD rats with acupoint catgut embedding significantly reduced escape latency and increased the time in the target quadrant and platform crossing times. VD-mediated hippocampal tissue damage and inflammatory reaction [down-regulating interleukin-1β (IL-1β), interleukin-6 (IL-6)] were significantly alleviated by acupoint catgut embedding treatment. In addition, further mechanism exploration found that acupoint catgut embedding treatment could improve the activity of the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway. In summary, acupoint catgut embedding treatment improved spatial learning and memory loss, alleviated pathological damage of the hippocampus, and inhibited inflammation response in VD rats, which was probably related to the inhibition of the TLR4/MyD88/NF-κB signaling pathway.

Conclusions

Acupoint catgut embedding may warrant further study as an adjuvant therapy for the treatment of VD.

Ginsenoside Rd protects transgenic Caenorhabditis elegans from β-amyloid toxicity by activating oxidative resistant

Alzheimer's disease (AD) is a serious public health issue but few drugs are currently available for the disease, and these only target the symptoms. It is well established that oxidative stress plays a crucial role in AD, and there is compelling evidence linking oxidative stress to β-amyloid (Aβ). An exciting source of potential new AD therapeutic medication possibilities is medicinal plants. Ginsenoside Rd (GS-Rd) is one of the main bioactive substances in ginseng extracts. In our study, we used a network pharmacology analysis to identify overlapping GS-Rd (therapeutic) and AD (disease)-relevant protein targets, gene ontology (GO) and bio-process annotation, and the KEGG pathway analysis data predicted that GS-Rd impacts multiple targets and pathways, such as the MAPK signal pathway and the JAT-STAT3 signaling pathway. We then assessed the role of GS-Rd in C. elegans and found that GS-Rd prolongs lifespan, improves resistance to heat stress, delays physical paralysis and increases oxidative stress responses. Overall, these results suggest that GS-Rd protects against the toxicity of Aβ. The RNA-seq analysis revealed that GS-Rd achieves its effects by regulating gene expressions like daf-16 and skn-1, as well as by participating in many AD-related pathways like the MAPK signaling pathway. In addition, in CL4176 worms, GS-Rd decreased reactive oxygen species (ROS) levels and increased SOD activity. Additional research with transgenic worms showed that GS-Rd aided in the movement of DAF-16 from the cytoplasm to the nucleus. Taken together, the results indicate that GS-Rd significantly reduces Aβ aggregation by targeting the MAPK signal pathway, induces nuclear translocation of DAF-16 to activate downstream signaling pathways and increases resistance to oxidative stress in C. elegans to protect against Aβ-induced toxicity.

Systematic Review of the Therapeutic Role of Apoptotic Inhibitors in Neurodegeneration and Their Potential Use in Schizophrenia

Schizophrenia (SZ) is a deleterious brain disorder affecting cognition, emotion and reality perception. The most widely accepted neurochemical-hypothesis is the imbalance of neurotransmitter-systems. Depleted GABAergic-inhibitory function might produce a regionally-located dopaminergic and glutamatergic-storm in the brain. The dopaminergic-release may underlie the positive psychotic-symptoms while the glutamatergic-release could prompt the primary negative symptoms/cognitive deficits. This may occur due to excessive synaptic-pruning during the neurodevelopmental stages of adolescence/early adulthood. Thus, although SZ is not a neurodegenerative disease, it has been suggested that exaggerated dendritic-apoptosis could explain the limited neuroprogression around its onset. This apoptotic nature of SZ highlights the potential therapeutic action of anti-apoptotic drugs, especially at prodromal stages. If dysregulation of apoptotic mechanisms underlies the molecular basis of SZ, then anti-apoptotic molecules could be a prodromal therapeutic option to halt or prevent SZ. In fact, risk alleles related in apoptotic genes have been recently associated to SZ and shared molecular apoptotic changes are common in the main neurodegenerative disorders and SZ. PRISMA-guidelines were considered. Anti-apoptotic drugs are commonly applied in classic neurodegenerative disorders with promising results. Despite both the apoptotic-hallmarks of SZ and the widespread use of anti-apoptotic targets in neurodegeneration, there is a strikingly scarce number of studies investigating anti-apoptotic approaches in SZ. We analyzed the anti-apoptotic approaches conducted in neurodegeneration and the potential applications of such anti-apoptotic therapies as a promising novel therapeutic strategy, especially during early stages.

γ-Glutamylcysteine attenuates amyloid-β oligomers-induced neuroinflammation in microglia via blocking NF-κB signaling pathway

Alzheimer's disease (AD) is the most prevalent neurogenerative disease, characterized by progressive memory loss and cognitive deficits. Intracellular neurofibrillary tangles (NFTs) and amyloid-β (Aβ)-formed neuritic plaques are major pathological features of AD. Aβ evokes activation of microglia to release inflammatory mediators and ROS to induce neurotoxicity, leading to neurodegeneration. γ-Glutamylcysteine (γ-GC), an intermediate dipeptide of the GSH-synthesis pathway and possessing anti-inflammatory and anti-oxidative properties, represents a relatively unexplored option for AD treatment. In the present study, we investigated the anti-inflammatory effect of γ-GC on Aβ oligomer (AβO)-induced neuroinflammation and the associated molecular mechanism in microglia. The results showed that γ-GC reduced AβO-induced release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and nitric oxide (NO), and the expression of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2). γ-GC decreased ROS and MDA production and increased the GSH level, GSH/GSSG ratio, and SOD activity in AβO-treated microglia. Mechanistically, γ-GC inhibited activation of nuclear factor kappa B (NF-κB), and upregulated the nuclear receptor-related 1 (Nurr1) protein expression to suppress the transcriptional effect of NF-κB on the inflammatory genes. Besides, γ-GC suppressed the AβO-induced neuroinflammation in mice. These findings suggested that γ-GC might represent a potential therapeutic agent for anti-neuroinflammation.

MXenes-integrated microneedle combined with asiaticoside to penetrate the cuticle for treatment of diabetic foot ulcer

Patients with diabetic foot ulcers usually suffer from inefficient epithelisation and angiogenesis accompanied by chronic wound healing. Diabetic foot ulcers remain a major challenge in clinical medicine; however, traditional treatments are incapable of transdermal drug delivery, resulting in a low drug delivery rate. We report the development of Ti2C3 MXenes-integrated poly-γ-glutamic acid (γ-PGA) hydrogel microneedles to release asiaticoside (MN-MXenes-AS). Asiaticoside was loaded into PGA-MXenes hydrogel to facilitate cell proliferation while regulating angiogenesis. The characterisation and mechanical strength of the microneedles were investigated in vitro, and the wound-healing efficacy of the microneedles was confirmed in diabetic mice. MXenes significantly improved the mechanical strength of microneedles, while γ-PGA hydrogels provided a moist microenvironment for wound healing. Mice treated with MN-MXenes-AS demonstrated obvious improvements in wound healing process. We successfully fabricated an MXenes-integrated microneedle that possesses sufficient rigidity to penetrate the cuticle for subcutaneous drug delivery, thereby accelerating diabetic wound healing. We demonstrated that MN-MXenes-AS is effective in promoting growth both in vivo and in vitro. Collectively, our data show that MN-MXenes-AS accelerated the healing of diabetic foot ulcers, supporting the use of these microneedles in the treatment of chronic wounds.

Graphical Abstract

Progress in the correlation of postoperative cognitive dysfunction and Alzheimer's disease and the potential therapeutic drug exploration

Postoperative cognitive dysfunction (POCD) is a decrease in mental capacity that can occur days to weeks after a medical procedure and may become permanent and rarely lasts for a longer period of time. With the continuous development of research, various viewpoints in academic circles have undergone subtle changes, and the role of anesthesia depth and anesthesia type seems to be gradually weakened; Alzheimer's disease (AD) is a latent and progressive neurodegenerative disease in the elderly. The protein hypothesis and the synaptic hypothesis are well-known reasons. These changes will also lead to the occurrence of an inflammatory cascade. The exact etiology and pathogenesis need to be studied. The reasonable biological mechanism affecting brain protein deposition, neuroinflammation, and acetylcholine-like effect has a certain relationship between AD and POCD. Whereas there is still further uncertainty about the mechanism and treatment, and it is elusive whether POCD is a link in the continuous progress of AD or a separate entity, which has doubts about the diagnosis and treatment of the disease. Therefore, this review is based on the current common clinical characteristics of AD and POCD, and pathophysiological research, to search for their common points and explore the direction and new strategies for future treatment.

URB597 and Andrographolide Improve Brain Microvascular Endothelial Cell Permeability and Apoptosis by Reducing Oxidative Stress and Inflammation Associated with Activation of Nrf2 Signaling in Oxygen-Glucose Deprivation

Ischemic stroke, a cerebrovascular disease worldwide, triggers a cascade of pathophysiological events, including blood-brain barrier (BBB) breakdown. Brain microvascular endothelial cells (BMECs) play a vital role in maintaining BBB function. The injury of BMECs may worsen neurovascular dysfunction and patients' prognosis. Therefore, uncover the principal molecular mechanisms involved in BBB disruption in stroke becomes pressing. The endocannabinoid system (ECS) has been implicated in increasingly physiological functions, both in neurometabolism and cerebrovascular regulation. Modulating its activities by the fatty acid amide hydrolase (FAAH) shows anti-inflammatory characteristics. Andrographolide (AG), one Chinese herbal ingredient, has also attracted attention for its role in immunomodulatory and as a therapeutic target in BBB disorders. Recently, the FAAH inhibitor URB597 and AG have important regulatory effects on neuronal and vascular cells in ischemia. However, the effects of URB597 and AG on BMEC permeability and apoptosis in oxygen-glucose deprivation (OGD) and the underlying mechanisms remain unclear. To address these issues, cultured BMECs (bEnd.3 cells) were exposed to OGD. The cell viability, permeability, tube formation, and apoptosis were assessed following treatment with URB597, AG, and cotreatment. Mitochondrial membrane potential (MMP), reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), proinflammatory factors, tight junction (TJ) proteins, and oxidative stress-mediated Nrf2 signaling were also investigated. Results revealed that OGD broke the endothelial barrier, cell viability, MMP, and tube formation, which was reversed by URB597 and AG. OGD-induced enhancement of ROS, MDA, and apoptosis was reduced after drug interventions. URB597 and AG exhibited antioxidant/anti-inflammatory and mitochondrial protective effects by activating Nrf2 signaling. These findings indicated that URB597 and AG protect BMECs against OGD-induced endothelial permeability impairment and apoptosis by reducing mitochondrial oxidative stress and inflammation associated with activation of Nrf2 signaling. URB597 and AG showing the vascular protection may have therapeutic potential for the BBB damage in ischemic cerebrovascular diseases.

Healthy Serum-Derived Exosomes Improve Neurological Outcomes and Protect Blood–Brain Barrier by Inhibiting Endothelial Cell Apoptosis and Reversing Autophagy-Mediated Tight Junction Protein Reduction in Rat Stroke Model

Blood–brain barrier (BBB) dysfunction causing edema and hemorrhagic transformation is one of the pathophysiological characteristics of stroke. Protection of BBB integrity has shown great potential in improving stroke outcome. Here, we assessed the efficacy of exosomes extracted from healthy rat serum in protection against ischemic stroke in vivo and in vitro. Exosomes were isolated by gradient centrifugation and ultracentrifugation and exosomes were characterized by transmission electron microscopy (TEM) and nanoparticle tracking video microscope. Exosomes were applied to middle cerebral artery occlusion (MCAO) rats or brain microvascular endothelial cell line (bEnd.3) subjected to oxygen-glucose deprivation (OGD) injury. Serum-derived exosomes were injected intravenously into adult male rats 2 h after transient MCAO. Infarct volume and gross cognitive function were assessed 24 h after reperfusion. Poststroke rats treated with serum-derived exosomes exhibited significantly reduced infarct volumes and enhanced neurological function. Apoptosis was assessed via terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining and the expression of B-cell lymphoma-2 (Bcl-2), Bax, and cleaved caspase-3 24 h after injury. Our data showed that serum exosomes treatment strikingly decreased TUNEL⁺ cells in the striatum, enhanced the ratio of Bcl-2 to Bax, and inhibited cleaved caspase-3 production in MCAO rats and OGD/reoxygenation insulted bEnd.3 cells. Under the consistent treatment, the expression of microtubule-associated protein 1 light chain 3B-II (LC3B-II), LC3B-I, and Sequestosome-1 (SQSTM1)/p62 was detected by Western blotting. Autolysosomes were observed via TEM. We found that serum exosomes reversed the ratio of LC3B-II to LC3B-I, prevented SQSTM1/p62 degradation, autolysosome formation, and autophagic flux. Together, these results indicated that exosomes isolated from healthy serum provided neuroprotection against experimental stroke partially via inhibition of endothelial cell apoptosis and autophagy-mediated BBB breakdown. Intravenous serum-derived exosome treatment may, therefore, provide a novel clinical therapeutic strategy for ischemic stroke.

Pharmacological Effects of Centella asiatica on Skin Diseases: Evidence and Possible Mechanisms

The medicinal herb Centella asiatica (L.) Urban known as gotu kola has been reported to exhibit a wide range of pharmacological activities. In particular, a significant body of scientific research exists on the therapeutic properties of preparations of C. asiatica or its triterpenes in the treatment of skin diseases. The present study is aimed to provide a comprehensive overview of the beneficial effects of C. asiatica on skin diseases. Peer-reviewed articles on the potent dermatological effects of C. asiatica were acquired from PubMed, Web of Science, Scopus, ScienceDirect, and SciFinder. This review provides an understanding of pharmacological studies which confirm the potent dermatological effects and underlying molecular mechanisms of C. asiatica. This medicinal plant and its triterpenes include asiaticoside, madecassoside, and their aglycones, asiatic acid and madecassic acid. These compounds exert therapeutic effects on dermatological diseases such as acne, burns, atopic dermatitis, and wounds via NF-κB, TGF-β/Smad, MAPK, Wnt/β-catenin, and STAT signaling in in vitro and in vivo studies. However, additional rigorously controlled long-term clinical trials will be necessary to confirm the full potential of C. asiatica as a therapeutic agent.

Hypoxia-Induced Neuroinflammation in Alzheimer's Disease: Potential Neuroprotective Effects of Centella asiatica

Alzheimer's disease (AD) is a neurodegenerative disorder that is characterised by the presence of extracellular beta-amyloid fibrillary plaques and intraneuronal neurofibrillary tau tangles in the brain. Recurring failures of drug candidates targeting these pathways have prompted research in AD multifactorial pathogenesis, including the role of neuroinflammation. Triggered by various factors, such as hypoxia, neuroinflammation is strongly linked to AD susceptibility and/or progression to dementia. Chronic hypoxia induces neuroinflammation by activating microglia, the resident immune cells in the brain, along with an increased in reactive oxygen species and pro-inflammatory cytokines, features that are common to many degenerative central nervous system (CNS) disorders. Hence, interests are emerging on therapeutic agents and plant derivatives for AD that target the hypoxia-neuroinflammation pathway. Centella asiatica is one of the natural products reported to show neuroprotective effects in various models of CNS diseases. Here, we review the complex hypoxia-induced neuroinflammation in the pathogenesis of AD and the potential application of Centella asiatica as a therapeutic agent in AD or dementia.

Actions and Therapeutic Potential of Madecassoside and Other Major Constituents of Centella asiatica: A Review

Centella asiatica is a popular herb well-known for its wide range of therapeutic effects and its use as a folk medicine for many years. Its therapeutic properties have been well correlated with the presence of asiaticoside, madecassoside, asiatic and madecassic acids, the pentacyclic triterpenes. The herb has been extensively known to treat skin conditions; nevertheless, several pre-clinical and clinical studies have scientifically demonstrated its effectiveness in other disorders. Among the active constituents that have been identified in Centella asiatica, madecassoside has been the subject of only a relatively small number of scientific reports. Therefore, this review, while including other major constituents of this plant, focuses on the therapeutic potential, pharmacokinetics and toxicity of madecassoside.

CEACAM1 Inhibited IκB-α/NF-κB Signal Pathway Via Targeting MMP-9/TIMP-1 Axis in Diabetic Atherosclerosis

Atherosclerosis (AS) is the most common and serious complication in type 2 diabetes mellitus (T2DM). Recent studies have emphasized that inflammation is the main cause of atherosclerosis. Studies have shown that carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) regulates the expression of matrix metallopeptidase 9 (MMP-9) after ischemic stroke to reduce inflammation. The aim of this study was to elucidate potential molecular mechanism of CEACAM1 on the inflammatory response in atherosclerosis. The serum levels of CEACAM1, MMP-9, and tissue inhibitors of metalloproteinase 1 (TIMP-1) in T2DM patients and healthy control was detected. The results showed that the levels of CEACAM1 and TIMP-1 were significantly decreased, and the levels of MMP-9 were significantly higher than those in the control group. Moreover, we also observed the effect of CEACAM1 on atherosclerosis in T2DM rats. Hematoxylin & eosin (HE) staining and oil red staining showed that CEACAM1 recombinant protein reduced intima-media thickness and the area of atherosclerotic plaques. To further explore the molecular mechanism of CEACAM1 regulating MMP-9/TIMP-1, we conducted experiments in rat aorta vascular endothelial cells and rat aorta smooth muscle cells. The result showed that CEACAM1 inhibits inflammatory response via MMP-9/TIMP-1 axis. Taken together, CEACAM1 attenuates diabetic atherosclerosis by inhibition of IκB/NF-κB signal pathway via MMP-9/TIMP-1 axis, which indicate that CEACAM1 is potentially amenable to therapeutic manipulation for clinical application in atherosclerosis in T2DM.

Mitoprotective Effects of Centella asiatica (L.) Urb.: Anti-Inflammatory and Neuroprotective Opportunities in Neurodegenerative Disease

Natural products remain a crucial source of drug discovery for accessible and affordable solutions for healthy aging. Centella asiatica (L.) Urb. (CA) is an important medicinal plant with a wide range of ethnomedicinal uses. Past in vivo and in vitro studies have shown that the plant extract and its key components, such as asiatic acid, asiaticoside, madecassic acid and madecassoside, exhibit a range of anti-inflammatory, neuroprotective, and cognitive benefits mechanistically linked to mitoprotective and antioxidant properties of the plant. Mitochondrial dysfunction and oxidative stress are key drivers of aging and neurodegenerative disease, including Alzheimer’s disease and Parkinson’s disease. Here we appraise the growing body of evidence that the mitoprotective and antioxidative effects of CA may potentially be harnessed for the treatment of brain aging and neurodegenerative disease.

Asiaticoside and polylysine-releasing collagen complex for effectively reducing initial inflammatory response using inflamed induced in vitro model

Inflammation is a significant clinical problem that can arise from full-thickness wounds or burn injuries or microbial disease. Although topical wound healing substances could promote rapid wound healing by preventing or reducing the consequences of inflammation, there still remains a need for the development of novel substances that can effectively reduce infection and inflammation in initial wound healing phase. In this study, collagen was combined with asiaticoside (AS) and ε-poly-l-lysine (εPLL). This complex was then applied to in vitro models of infection and inflammation. Collagen-AS coatings inhibited the initial inflammatory response to LPS through a sustained release of AS, and a bilayer coating-εPLL showed a notable antimicrobial effect using microbial infection test. In this study, we determined whether asiaticoside and εPLL have anti-inflammatory and antibacterial effects through different mechanisms. Collectively, the collagen-AS/εPLL complex indicated great therapeutic potentials for accelerate wound healing and the complex may be considered as a artificial scaffold substitute product to full-thickness wound healing.

In vivo Therapeutic Effects and Mechanisms of Hydroxyasiaticoside Combined With Praziquantel in the Treatment of Schistosomiasis Induced Hepatic Fibrosis

Schistosomiasis has been a fatal obstinate disease that threatens global human health, resulting in the granulomatous inflammation and liver fibrosis. Objective:The aim of this study was to evaluate the therapeutic effects and mechanisms of hydroxyasiaticoside combined with praziquantel in the treatment of schistosomiasis-induced liver fibrosis. Methods:Mice were randomly distributed into four experimental groups: normal control group, model group, praziquantel group, praziquantel + hydroxyasiaticoside group. Except for the normal control group, they were infected with Schistosomia cercariae through the abdominal skin to induce liver fibrosis. In the intervention group, mice were administered with the respective drugs by gavage after 8 weeks of infection. At the end of the treatment, mice were sacrificed to collect blood for the determination of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum levels. Moreover, the liver was excised, weighed, and liver indices were calculated. Histopathological examination was performed to assess liver morphology. Besides, the expression of collagen type I and III in liver was determined; the mRNA expression levels of IL-6 and TNF-α in liver tissues were measured using Real-time PCR while ELISA and western blotting were performed on liver tissue homogenate to determine the protein expression of IL-6 and TNF-α. Results:The combination of praziquantel and hydroxyasiaticoside lowered the pathological scores of schistosomiasis-induced hepatic fibrosis, the liver indice, serum AST and ALT levels, improved liver morphology, downregulated the expression levels of hepatic type I and III collagen, inhibited the mRNA expression levels of pro-inflammatory factors (IL-6 and TNF-α) in the liver of mice relative to the praziquantel alone. Conclusion:The combination of hydroxyasiaticoside and praziquantel is a potential therapeutic option for schistosomiasis-induced hepatic fibrosis. Notably, this combination noticeably suppresses the protein and mRNA expression levels of pro-inflammatory factors (TNF-α and IL-6) in the liver.

Pinoresinol diglucoside attenuates neuroinflammation, apoptosis and oxidative stress in a mice model with Alzheimer's disease

For Alzheimer's disease (AD), there is still no effective treatment strategy. Pinoresinol diglucoside (PDG) is one of the major lignans isolated from Eucommia ulmoides. It is endowed with multiple pharmacological activities, including anti-inflammatory, antioxidant and anticancer activities. In this study, we investigated the potential neuroprotective functions of PDG in AD. Mice model with AD was established adopting stereotactic hippocampal injection of Aβ1-42 (410 pmol/mouse), and 3 days later, mice were administrated with 5 and 10 mg/kg PDG by intragastric administration every day for 3 weeks. Morris water maze and Y-maze tests demonstrated that PDG treatment could markedly reverse Aβ1-42-induced memory impairment in mice. It is found that PDG restrained the release of proinflammatory cytokines (tumor necrosis factor α and interleukin 1β), reactive oxygen species and malondialdehyde, and promoted the activity of the antioxidant enzyme (superoxide dismutase and catalase) by quantitative real-time-PCR, colorimetric method and ELISA assay. Western blot assay results have shown that PDG could also upregulate the ratio of Bcl-2/Bax and downregulate cytochrome c and cleaved caspase-3 expressions, thereby inhibiting neuronal apoptosis. Furthermore, PDG also significantly reduced the expression of Toll-like receptor 4 (TLR4) and the activation of nuclear factor-κB (NF-κB) p65, and promoted nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expressions. In conclusion, PDG can attenuate neuroinflammation, neuronal apoptosis and oxidative stress through the TLR4/NF-κB and Nrf2/HO-1 pathways, and ameliorate memory dysfunction induced by Aβ1-42 in mice.

Use of medicinal plants for headache, and their potential implication in medication-overuse headache: Evidence from a population-based study in Nepal

Background

In Nepal, traditional treatment using medicinal plants is popular. Whereas medication-overuse headache is, by definition, caused by excessive use of acute headache medication, we hypothesized that medicinal plants, being pharmacologically active, were as likely a cause.

Methods

We used data from a cross-sectional, nationwide population-based study, which enquired into headache and use of medicinal plants and allopathic medications. We searched the literature for pharmacodynamic actions of the medicinal plants.

Results

Of 2100 participants, 1794 (85.4%) reported headache in the preceding year; 161 (7.7%) reported headache on ≥15 days/month, of whom 28 (17.4%) had used medicinal plants and 117 (72.7%) allopathic medication(s). Of 46 with probable medication-overuse headache, 87.0% (40/46) were using allopathic medication(s) and 13.0% (6/46) medicinal plants, a ratio of 6.7:1, higher than the overall ratio among those with headache of 4.9:1 (912/185). Of 60 plant species identified, 49 were pharmacodynamically active on the central nervous system, with various effects of likely relevance in medication-overuse headache causation.

Conclusions

MPs are potentially a cause of medication-overuse headache, and not to be seen as innocent in this regard. Numbers presumptively affected in Nepal are low but not negligible. This pioneering project provides a starting point for further research to provide needed guidance on use of medicinal plants for headache.

Platycodin D Inhibits β-Amyloid-Induced Inflammation and Oxidative Stress in BV-2 Cells Via Suppressing TLR4/NF-κB Signaling Pathway and Activating Nrf2/HO-1 Signaling Pathway

Alzheimer's disease (AD) is a common neurodegenerative disease associated with deposition of β-amyloid peptide (Aβ). Platycodin D (PLD), a triterpenesaponin, may possess neuro-protective effect. In the current study, we aimed to explore the effects of PLD on Aβ-induced inflammation and oxidative stress in microglial BV-2 cells. Our study showed that PLD treatment improved cell viability in Aβ-induced BV-2 cells. PLD attenuated Aβ-induced inflammation with deceased production of TNF-α, IL-1β and IL-6 in Aβ-induced BV-2 cells. PLD also mitigated the oxidative stress in Aβ-induced BV-2 cells, as evidenced by deceased production of ROS and MDA, and increased SOD activity. Furthermore, the increased expression levels of TLR4 and p-p65 and decreased IκBα expression in the Aβ-stimulated BV-2 cells were attenuated by PLD treatment. Overexpression of TLR4 reversed the anti-inflammatory effect of PLD in Aβ-stimulated BV-2 cells. In addition, PLD treatment enhanced the Aβ-stimulated increase in the expression levels of Nrf2, HO-1, and NQO1 in BV-2 cells. Knockdown of Nrf2 abrogated the anti-oxidative effect of PLD in Aβ-stimulated BV-2 cells. In conclusion, these findings indicated that PLD protected BV-2 cells from Aβ-induced oxidative stress and inflammation via regulating the TLR4/NF-κB and Nrf2/HO-1 signaling pathways. Thus, PLD may be a potential candidate for the treatment of AD.

Antiallergic drug desloratadine as a selective antagonist of 5HT2A receptor ameliorates pathology of Alzheimer's disease model mice by improving microglial dysfunction

Alzheimer's disease (AD) is a progressively neurodegenerative disease characterized by cognitive deficits and alteration of personality and behavior. As yet, there is no efficient treatment for AD. 5HT_2A receptor (5HT_2A R) is a subtype of 5HT₂ receptor belonging to the serotonin receptor family, and its antagonists have been clinically used as antipsychotics to relieve psychopathy. Here, we discovered that clinically first-line antiallergic drug desloratadine (DLT) functioned as a selective antagonist of 5HT_2A R and efficiently ameliorated pathology of APP/PS1 mice. The underlying mechanism has been intensively investigated by assay against APP/PS1 mice with selective 5HT_2A R knockdown in the brain treated by adeno-associated virus (AAV)-ePHP-si-5HT_2A R. DLT reduced amyloid plaque deposition by promoting microglial Aβ phagocytosis and degradation, and ameliorated innate immune response by polarizing microglia to an anti-inflammatory phenotype. It stimulated autophagy process and repressed neuroinflammation through 5HT_2A R/cAMP/PKA/CREB/Sirt1 pathway, and activated glucocorticoid receptor (GR) nuclear translocation to upregulate the transcriptions of phagocytic receptors TLR2 and TLR4 in response to microglial phagocytosis stimulation. Together, our work has highly supported that 5HT_2A R antagonism might be a promising therapeutic strategy for AD and highlighted the potential of DLT in the treatment of this disease.

Asiaticoside ameliorates acinar cell necrosis in acute pancreatitis via toll-like receptor 4 pathway

Acinar cell necrosis is one of the most prominent pathophysiological changes of acute pancreatitis (AP). Asiaticoside (AS) is a triterpene compound with confirmed apoptosis-and necrosis-related activities. However, the specific effects of AS on AP have not been determined. In this study, we aimed to investigate the protective effect of AS on AP using two mouse models. In the caerulein-induced mild acute pancreatitis (MAP) model, We found that AS administration reduced serum amylase levels and alleviated the histopathological manifestations of pancreatic tissue in a dose-dependent manner. And the levels of toll-like receptor 4 (TLR4) and necrotic related proteins (RIP3 and p-MLKL) of pancreatic tissue were reduced after AS administration. In addition, TLR4 deficiency eliminated the protective effect of AS on AP induced by caerulein in mice. Correspondingly, we elucidated the effect of AS in vitro and found that AS protected against pancreatic acinar cells necrosis and TAK-242 counteracted this protective effect. Meanwhile, we found that AS ameliorated the severity of pancreatic tissue injury and pancreatitis-associated lung injury in a severe acute pancreatitis model induced by l-arginine. Furthermore, Molecular docking results revealed interaction between AS and TLR4. Taken together, our data for the first time confirmed the protective effects of AS on AP in mice via TLR4 pathway.

Tetracyclic and Pentacyclic Triterpenes with High Therapeutic Efficiency in Wound Healing Approaches

Wounds are among the most common skin conditions, displaying a large etiological diversity and being characterized by different degrees of severity. Wound healing is a complex process that involves multiple steps such as inflammation, proliferation and maturation and ends with scar formation. Since ancient times, a widely used option for treating skin wounds are plant- based treatments which currently have become the subject of modern pharmaceutical formulations. Triterpenes with tetracyclic and pentacyclic structure are extensively studied for their implication in wound healing as well as to determine their molecular mechanisms of action. The current review aims to summarize the main results of in vitro, in vivo and clinical studies conducted on lupane, ursane, oleanane, dammarane, lanostane and cycloartane type triterpenes as potential wound healing treatments.

Blood-Brain Barrier Permeability of Asiaticoside, Madecassoside and Asiatic Acid in Porcine Brain Endothelial Cell Model

Neurotherapeutic potentials of Centella asiatica and its reputation to boost memory, prevent cognitive deficits and improve brain functions are widely acknowledged. The plant's bioactive compounds, i.e. asiaticoside, madecassoside and asiatic acid were reported to have central nervous system (CNS) actions, particularly in protecting the brain against neurodegenerative disorders. Hence, it is important for these compounds to cross the blood-brain barrier (BBB) to be clinically effective therapeutics. This study aimed to explore the capability of asiaticoside, madecassoside and asiatic acid to cross the BBB using in vitro BBB model from primary porcine brain endothelial cells (PBECs). Our findings showed that asiaticoside, madecassoside and asiatic acid are highly BBB permeable with apparent permeability (P_app) of 70.61 ± 6.60, 53.31 ± 12.55 and 50.94 ± 10.91 × 10^-6 cm/s respectively. No evidence of cytotoxicity and tight junction disruption of the PBECs were observed in the presence of these compounds. Asiatic acid showed cytoprotective effect towards the PBECs against oxidative stress. This study reported for the first time that Centella asiatica compounds demonstrated high capability to cross the BBB, comparable to central nervous system drugs, and therefore warrant further development as therapeutics for the treatment of neurodegenerative diseases.

Therapeutic Potential of Centella asiatica and Its Triterpenes: A Review

Centella asiatica (also known as Centella asiatica (L.) Urb. or Gotu kola) is a traditional Chinese medicine with extensive medicinal value, which is commonly used in Southeast Asian countries. This study aimed to summarize the effects of C. asiatica and its main components on neurological diseases, endocrine diseases, skin diseases, cardiovascular diseases, gastrointestinal diseases, immune diseases, and gynecological diseases, as well as potential molecular mechanisms, to study the pathological mechanism of these diseases based on the changes at the molecular level. The results showed that C. asiatica and its triterpenoids had extensive beneficial effects on neurological and skin diseases, which were confirmed through clinical studies. They exhibited anti-inflammatory, anti-oxidative stress, anti-apoptotic effects, and improvement in mitochondrial function. However, further clinical studies are urgently required due to the low level of evidence and lack of patients.

New mechanism of nerve injury in Alzheimer's disease: β-amyloid-induced neuronal pyroptosis

The present study was designed to investigate the role of β-amyloid (Aβ1-42 ) in inducing neuronal pyroptosis and its mechanism. Mice cortical neurons (MCNs) were used in this study, LPS + Nigericin was used to induce pyroptosis in MCNs (positive control group), and Aβ1-42 was used to interfere with MCNs. In addition, propidium iodide (PI) staining was used to examine cell permeability, lactate dehydrogenase (LDH) release assay was employed to detect cytotoxicity, immunofluorescence (IF) staining was used to investigate the expression level of the key protein GSDMD, Western blot was performed to detect the expression levels of key proteins, and enzyme-linked immunosorbent assay (ELISA) was utilized to determine the expression levels of inflammatory factors in culture medium, including IL-1β, IL-18 and TNF-α. Small interfering RNA (siRNA) was used to silence the mRNA expression of caspase-1 and GSDMD, and Aβ1-42 was used to induce pyroptosis, followed by investigation of the role of caspase-1-mediated GSDMD cleavage in pyroptosis. In addition, necrosulfonamide (NSA), an inhibitor of GSDMD oligomerization, was used for pre-treatment, and Aβ1-42 was subsequently used to observe the pyroptosis in MCNs. Finally, AAV9-siRNA-caspase-1 was injected into the tail vein of APP/PS1 double transgenic mice (Alzheimer's disease mice) for caspase-1 mRNA inhibition, followed by observation of behavioural changes in mice and measurement of the expression of inflammatory factors and pyroptosis-related protein. As results, Aβ1-42 could induce pyroptosis in MCNs, increase cell permeability and enhance LDH release, which were similar to the LPS + Nigericin-induced pyroptosis. Meanwhile, the expression levels of cellular GSDMD and p30-GSDMD were up-regulated, the levels of NLRP3 inflammasome and GSDMD-cleaved protein caspase-1 were up-regulated, and the levels of inflammatory factors in the medium were also up-regulated. siRNA intervention in caspase-1 or GSDMD inhibited Aβ1-42 -induced pyroptosis, and NSA pre-treatment also caused the similar inhibitory effects. The behavioural ability of Alzheimer's disease (AD) mice was relieved after the injection of AAV9-siRNA-caspase-1, and the expression of pyroptosis-related protein in the cortex and hippocampus was down-regulated. In conclusion, Aβ1-42 could induce pyroptosis by GSDMD protein, and NLRP3-caspase-1 signalling was an important signal to mediate GSDMD cleavage, which plays an important role in Aβ1-42 -induced pyroptosis in neurons. Therefore, GSDMD is expected to be a novel therapeutic target for AD.

Asiaticoside attenuates neonatal hypoxic-ischemic brain damage through inhibiting TLR4/NF-κB/STAT3 pathway

Background

Neonatal hypoxic ischemic encephalopathy (HIE) is currently a leading cause of neonatal death. Asiaticoside (AT), a bioactive constituent isolated from Centella asiatica, possesses numerous biological properties. For instance, previous studies showed that AT could protect ischemia hypoxia neurons by mediating BCL-2 protein. However, the roles and underlying mechanisms of AT in neonatal HIE have not been clarified.

Methods

Rice-Vannucci was applied to construct a hypoxic-ischemic brain damage (HIBD) model. Pathological damage of brain neuron tissue was determined by hematoxylin-eosin (HE) staining, while apoptosis was evaluated by terminal-deoxynucleoitidyl transferase nick end labeling (TUNEL) staining. Western blot and immunohistochemistry were applied to monitor related proteins levels. Enzyme-linked immunosorbent assay (ELISA) was conducted to measure the expression levels of inflammatory cytokines.

Results

The present study indicated that AT dose-dependently ameliorated histologic damage and inhibited apoptosis induced by hypoxic ischemia (HI) (P<0.01). AT also dose-dependently alleviated oxidative damage and reduced the levels of proinflammatory cytokines (ICAM-1, IL-18, and IL-1β) and TLR4 level. In terms of mechanism, decrease of TLR and IL-18 suppressed NF-κB phosphorylation and reduced the levels of TNFα, IL-6, and p-STAT3, leading to the inactivation of NF-κB/STAT3 pathway. Interestingly, with the addition of lipopolysaccharide (LPS), the increase of TLR4 activated NF-κB/STAT3 pathway again.

Conclusions

Collectively, the data provide insight into a novel mechanism by which AT may be an effective agent for HIE via the TLR4/NF-κB/STAT3 pathway.

Protective Effect of Asiaticoside on Radiation-induced Proliferation Inhibition and DNA Damage of Fibroblasts and Mice Death

Background

Radiation-induced injuries (RII) mainly result from reactive oxygen species (ROS), which are harmful compounds that can damage DNA. Asiaticoside (AC), one of the main functional components extracted from Centella asiatica, has potent pharmacological effects such as anti-inflammatory and anti-oxidant activity. However, its role in RII remains unclear.

Purpose

The purpose of the current study is to investigate whether AC can mitigate RII in vitro and in vivo.

Material and Methods

Cell model of RII was successfully established by 5J/m₂ radiation in vitro. For the in vivo RII model, mice were irradiated with 5 Gy to the thorax. The degree of damage to cells or mouse tissue was determined by measuring the numbers of DNA double-strand breaks (DSBs), oxidative stress, and mouse survival rates.

Results

In the in vitro assay, AC administration significantly reduced radiation-induced growth inhibition of Escherichia coli and fibroblasts, DSBs and apoptosis of fibroblasts; in the in vivo study, AC could decrease antioxidant capacity (T-AOC) of plasma and protect mice from RII, thereby improving the survival rates of mice after radiation.

Conclusions

These novel data indicate that AC is able to prevent radiation-initiated genotoxicity by mitigating DNA damage, and might serve as a safe and effective radio-protective agent.

Toward a better understanding of metabolic and pharmacokinetic characteristics of low-solubility, low-permeability natural medicines

Today, it is very challenging to develop new active pharmaceutical ingredients. Developing good preparations of well-recognized natural medicines is certainly a practical and economic strategy. Low-solubility, low-permeability natural medicines (LLNMs) possess valuable advantages such as effectiveness, relative low cost and low toxicity, which is shown by the presence of popular products on the market. Understanding the in vivo metabolic and pharmacokinetic characteristics of LLNMs contributes to overcoming their associated problems, such as low absorption and low bioavailability. In this review, the structure-based metabolic reactions of LLNMs and related enzymatic systems, cellular and bodily pharmacological effects and metabolic influences, drug-drug interactions involved in metabolism and microenvironmental changes, and pharmacokinetics and dose-dependent/linear pharmacokinetic models are comprehensively evaluated. This review suggests that better pharmacological activity and pharmacokinetic behaviors may be achieved by modifying the metabolism through using nanotechnology and nanosystem in combination with the suitable administration route and dosage. It is noteworthy that novel nanosystems, such as triggered-release liposomes, nucleic acid polymer nanosystems and PEGylated dendrimers, in addition to prodrug and intestinal penetration enhancer, demonstrate encouraging performance. Insights into the metabolic and pharmacokinetic characteristics of LLNMs may help pharmacists to identify new LLNM formulations with high bioavailability and amazing efficacy and help physicians carry out LLNM-based precision medicine and individualized therapies.

Sevoflurane attenuates brain damage through inhibiting autophagy and apoptosis in cerebral ischemia‑reperfusion rats

The present study aimed to investigate the effects of sevoflurane post-conditioning in a rat brain cerebral ischemia-reperfusion (I/R) model and examine its possible mechanism. Rats were randomly divided into six groups: Sham control group (Sham), I/R group, sevoflurane group (Se), Toll-like receptor-4 (TLR4) inhibitor group (Tak-242), nuclear factor (NF)-κB inhibitor group (QNZ) and Sevoflurane post-conditioning combined with TLR4-NF-κB signaling pathway inhibitor group (Se + Tak-242). Morris water maze test and tetrazolium chloride staining were used to investigate the I/R injury. The nerve cell apoptosis and autophagy in cortical tissue were detected by TUNEL and transmission electron microscopy, respectively. The expression of TLR4 protein in cortical tissue was observed by immunohistochemical staining. The expression of autophagy and apoptotic associated proteins in cortical tissues and the activity of TLR4-NF-κB signaling pathway were assayed by western blot analysis. Sevoflurane post-conditioning improved the learning and memory dysfunction caused by cerebral I/R injury. The cerebral infarction area, nerve cell apoptosis and formation of autophagic vacuoles were reduced after sevoflurane administration. The expression of light chain 3II/I, Beclin-1, Bad and Cleaved-Caspase-3 proteins were inhibited and the expression of Bcl-2 protein was upregulated after sevoflurane administration. Sevoflurane post-conditioning also inhibited the TLR4 protein and NF-κB phosphorylation, and increased inhibitor of kBα phosphorylation. The treatment effect of Tak-242 and QNZ groups were not significantly different compared with the Se group (P>0.05), and the Se + Tak-242 group had the best results. The present study demonstrated that sevoflurane post-conditioning could protect middle cerebral artery occlusion-induced brain injury rats by inhibiting autophagy and apoptosis, and that its mechanism is related to the TLR4-NF-κB signaling pathway.

Neuroprotective Effects of Ginsenoside Rf on Amyloid-β-Induced Neurotoxicity in vitro and in vivo

Alzheimer's disease (AD) is a neurodegenerative disease characterized by the deposition of amyloid-β peptides (Aβ). Aβ accumulation leads to the formation of neurofibrillary tangles, inflammation, axonal injury, synapse loss, and neuronal apoptosis. Thus, reducing Aβ levels should exert a neuroprotective effect against AD. Ginsenoside Rf, an extract from Panax notoginseng, has potent anti-fatigue, anti-nociception, anti-oxidation, and anti-inflammation properties. However, it is unclear whether ginsenoside Rf is effective in the treatment of AD. Here, we reported that ginsenoside Rf could significantly attenuate Aβ-induced apoptosis in N2A cells, as reflected by a dramatic increase in mitochondrial membrane potential and decrease in Ca2 + concentration, reactive oxygen species, and active caspase-3 expression. Meanwhile, ginsenoside Rf could alleviate the Aβ-induced inflammation reaction, such as the decrease of interferon-gamma (IFN-γ) and active caspase-1 expression and the increase of interleukin-13. Furthermore, we also found that Rf is able to accelerate Aβ clearance and subsequently reduces Aβ level in N2A cells stably transfected with human Swedish mutant APP695 (N2A-APP). More importantly, daily Rf treatment (20 mg/kg, i.p.) throughout the experiment dramatically improved spatial learning and memory in Aβ42-induced mouse model of AD. Taken together, these results indicate that ginsenoside Rf may decrease Aβ-induced neurotoxicity and memory decline via anti-inflammatory response during AD development, suggesting that Rf may be a potential therapeutic agent for treating AD.

Baicalein administered in the subacute phase ameliorates ischemia-reperfusion-induced brain injury by reducing neuroinflammation and neuronal damage

Ischemic stroke is a cerebrovascular disease with high morbidity, high mortality, and high disability, representing a serious threat to human life and health. Clinically, the extensive injury caused by ischemic stroke results from ischemia-reperfusion (I/R) injury thrombolytic treatment. However, there are few reports on the use of medications in the subacute stage of cerebral I/R. Baicalein (5,6,7-trihydroxyflavone) is a biologically active ingredient extracted from the root of Scutellaria baicalensis Georgi. In the present study, we investigated the therapeutic effect of baicalein administered in the subacute phase of cerebral I/R injury in a rat model of ischemia induced by occlusion of the middle cerebral artery (MCA). Rats were treated daily with baicalein (200 mg/kg, i.g.) in the subacute phase (24 h after reperfusion) for 7 days. The results showed that baicalein significantly reduced neurobehavioral deficits and decreased brain infarct volume from 18.99% to 7.41%. Immunofluorescence analysis of the ischemic penumbra showed that baicalein significantly reduced expression of the M1 marker, cluster of differentiation (CD) 16 and CD86, and increased expression of the M2 marker, CD 163 and CD206, indicating that baicalein inhibited M1 transformation and promoted M2 transformation of microglia/macrophage to inhibit neuroinflammation. Moreover, baicalein suppressed NF-κB signaling by reducing IκBα phosphorylation and nuclear translocation of NF-κB/p65, which decreased the release of the pro-inflammatory factors IL-6, IL-18, and TNF-α. In addition, baicalein reduced phosphorylation of JNK, ERK and p38, which are involved modulation of microglia/macrophage M1/M2 polarization. Western blot analysis of apoptosis- and autophagy-related proteins showed that baicalein increased the Bcl-2/Bax ratio and reduced caspase-3 expression to decrease neuronal apoptosis and ameliorate neuronal loss. Baicalein also decreased the LC3-II/LC3-I ratio and promoted phosphorylation of the PI3K/Akt/mTOR signaling pathway which implied inhibition of autophagy. These observations suggest that baicalein exerts neuroprotective effects by reducing neuroinflammation, apoptosis and autophagy, and protects against cerebral I/R injury in the subacute phase in vivo.

FGF21 Protects Against Hypoxia Injury Through Inducing HSP72 in Cerebral Microvascular Endothelial Cells

Background: Fibroblast growth factor 21 (FGF21), a member of a family of atypical FGFs, functions as cytokine to control endocrinology and metabolism. Recently, the roles of FGF21 in cardio-cerebral-vascular diseases have been gradually uncovered. In the present study, we investigated the effect of FGF21 on bEnd.3 cerebral microvascular endothelial cells (CMECs) upon hypoxia stress.

Methods and Results: CMECs were cultured in the condition of 1% O₂ for 8 h to induce hypoxia stimuli. For FGF21 treatment, recombinant FGF21 (50 nM) was added into the culture medium. Various biomedical assays were used to evaluate the hypoxia-induced injury in CMECs. Under normoxia condition, FGF21 had no obvious effect on cell viability and did not cause any cytotoxicity on CMECs. Under hypoxia condition, FGF21 significantly attenuated the hypoxia-induced injury, evidenced by the influences of FGF21 on CMEC viability and LDH release. TUNEL staining assay and immunoblotting of caspase-3 showed that FGF21 reduced hypoxia-induced apoptosis in CMECs. Mechanistically, FGF21 treatment compromised the hypoxia-induced changes of reactive oxygen species, malondialdehyde, total antioxidant activity, and total superoxide dismutase levels. FGF21 administration decreased hypoxia-induced matrix metalloprotein 3 and matrix metalloprotein 2/9 activity in CMECs. Activities of cyclooxygenase-2 and NF-κB-p65, two pro-inflammatory factors, were also upregulated by hypoxia but suppressed by FGF21. At last, we found that FGF21 increased heat shock protein family A member 1A (HSP72) mRNA and protein expression. Blockade of HSP72 by a pharmacological inhibitor VER155008 or specific siRNA-mediated knockdown abrogated the protection of FGF21 against hypoxia in CMECs.

Conclusion: These data demonstrate that FGF21 protects against hypoxia stress-induced injury in CMECs by inducing HSP72 expression, suggesting a therapeutic value of FGF21 in hypoxia-related brain diseases such as ischemic stroke and acute mountain sickness.

Effects of Betaine on LPS-Stimulated Activation of Microglial M1/M2 Phenotypes by Suppressing TLR4/NF-κB Pathways in N9 Cells

Microglia mediate multiple facets of neuroinflammation. They can be phenotypically divided into a classical phenotype (pro-inflammatory, M1) or an alternative phenotype (anti-inflammatory, M2) with different physiological characteristics and biological functions in the inflammatory process. Betaine has been shown to exert anti-inflammatory effects. In this study, we aimed to verify the anti-inflammatory effects of betaine and elucidate its possible molecular mechanisms of action in vitro. Lipopolysaccharide (LPS)-activated microglial cells were used as an inflammatory model to study the anti-inflammatory efficacy of betaine and explore its mechanism of regulating microglial polarisation by investigating the morphological changes and associated inflammatory changes. Cytokine and inflammatory mediator expression was also measured by ELISA, flow cytometry, immunofluorescence, and western blot analysis. Toll-like receptor (TLR)-myeloid differentiation factor 88 (Myd88)-nuclear factor-kappa B (NF-κB) p65, p-NF-κB p65, IκB, p-IκB, IκB kinase (IKK), and p-IKK expression was determined by western blot analysis. Betaine significantly mitigated the production of pro-inflammatory cytokines and increased the release of anti-inflammatory cytokines. It promoted the conversion of the microglia from M1 to M2 phenotype by decreasing the expression of inducible nitric oxide synthase and CD16/32 and by increasing that of CD206 and arginase-1. Betaine treatment inhibited the TLR4/NF-κB pathways by attenuating the expression of TLR4-Myd88 and blocking the phosphorylation of IκB and IKK. In conclusion, betaine could significantly alleviate LPS-induced inflammation by regulating the polarisation of microglial phenotype; thus, it might be an effective therapeutic agent for neurological disorders.