Tetrahydroxy stilbene glucoside reduces the cognitive impairment and overexpression of amyloid precursor protein induced by aluminum exposure

Preclinical Evidence and Underlying Mechanisms of Polygonum multiflorum and Its Chemical Constituents Against Cognitive Impairments and Alzheimer's Disease

Objectives

Cognitive impairments, ranging from mild to severe, adversely affect daily functioning, quality of life, and work capacity. Despite significant efforts in the past decade, more than 200 promising drug candidates have failed in clinical trials. Herbal remedies are gaining interest as potential treatments for dementia due to their long history and safety, making them valuable for drug development. This review aimed to examine the mechanisms behind the effect of Polygonum multiflorum on cognitive function.

Methods

This study focused primarily on the effects of Polygonum multiflorum and its chemical constituents on cognitive behavioral outcomes including the Morris water maze, the passive avoidance test, and the Y maze, as well as pathogenic targets of cognitive impairment and Alzheimer's disease (AD) like amyloid deposition, amyloid precursor protein, tau hyperphosphorylation, and cognitive decline. Additionally, a thorough evaluation of the mechanisms behind Polygonum multiflorum's impact on cognitive function was conducted. We reviewed the most recent data from preclinical research done on experimental models, particularly looking at Polygonum multiflorum's effects on cognitive decline and AD.

Results

According to recent research, Poligonum multiflorum and its bioactive components, stilbene, and emodin, influence cognitive behavioral results and regulate the pathological target of cognitive impairment and AD. Their mechanisms of action include reducing oxidative and mitochondrial damage, regulating neuroinflammation, halting apoptosis, and promoting increased neurogenesis and synaptogenesis.

Conclusion

This review serves as a comprehensive compilation of current experiments on AD and other cognitive impairment models related to the therapeutic effects of Polygonum multiflorum. We believe that these findings can serve as a basis for future clinical trials and have potential applications in the treatment of human neurological disorders.

Pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN), a sterile inflammatory disease, is a serious complication of diabetes mellitus. However, recent evidence indicates that pyroptosis, a new term for pro-inflammatory cell death featured by gasdermin D (GSDMD)-stimulated plasma membrane pore generation, cell expansion and rapid lysis with the extensive secretion of pro-inflammatory factors, including interleukin-1β (IL-1β) and -18 (IL-18) may be involved in DN. Caspase-1-induced canonical and caspase-4/5/11-induced non-canonical inflammasome-signaling pathways are mainly believed to participate in pyroptosis-mediated cell death. Further research has uncovered that activation of the caspase-3/8 signaling pathway may also activate pyroptosis. Accumulating evidence has shown that NLRP3 inflammasome activation plays a critical role in promoting the pathogenesis of DN. In addition, current studies have suggested that pyroptosis-induced cell death promotes several diabetic complications that include DN. Our present study briefs the cellular mechanisms of pyroptosis-related signaling pathways and their impact on the promotion of DN. In this review, several investigational compounds suppressing pyroptosis-mediated cell death are explored as promising therapeutics in DN.

Tetrahydroxystilbene Glucoside Ameliorates Infrasound-Induced Central Nervous System (CNS) Injury by Improving Antioxidant and Anti-Inflammatory Capacity

Background

Infrasound is a major threat to global health by causing injuries of the central nervous system (CNS). However, there remains no effective therapeutic agent for preventing infrasound-caused CNS injury. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glycoside (THSG) exerts protective function against CNS injuries and may have beneficial effects on infrasound-induced CNS impairment.

Methods

A mouse model with CNS (oxidative stress-induced inflammation and neuronal apoptosis) injuries was established when the mouse was exposed to the infrasound of 16 Hz at 130 dB for 2 h each day and the duration of treatment was 8 d. The mice were divided into the control (CG, healthy mice), the model (MG, model mice), and the THSG (EG, experimental group, model mice treated with THSG) groups. The learning and memory impairments caused by infrasound were examined using a Morris water maze test. Lipid profiles, antioxidant biomarkers, and inflammatory cytokines in hippocampus tissue were measured by using corresponding ELISA kits. Meanwhile, BCL-2/BAX/caspase-3 signaling pathway was measured in the hippocampi and prefrontal cortex of the mouse brain using real-time qPCR and Western blot. Nissl's stain was used to measure neuronal necrosis in the hippocampi and prefrontal cortex of the mouse brain.

Results

THSG significantly ameliorated the learning and memory impairments caused by infrasound. On the other hand, THSG improved lipid profiles, increased antioxidant properties by affecting the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA), and displayed anti-inflammatory action via the downregulation of IL- (interleukin-) 6, IL-8, IL-10, TNF- (tumor necrosis factor-) α, and hs-CRP (high-sensitivity C-reactive protein) in the hippocampal tissues of the mouse model (P < 0.05). Additionally, Nissl's stain showed that THSG inhibited infrasound-induced neuronal necrosis in the hippocampi and prefrontal cortex. Besides, THSG exerted antiapoptosis function by upregulating the level of Bcl-2 and downregulating the levels of BAX and caspase-3 in the hippocampi.

Conclusion

THSG may be an effective anti-infrasound drug against CNS injury by improving antioxidant, anti-inflammatory, antiapoptosis, and antinecrosis capacities. Further research is still needed to confirm the exact molecular mechanism.

Resveratrol derivative excited postsynaptic potentiation specifically via PKCβ-NMDA receptor mediation

Several decades have passed since resveratrol (RSV) was first identified in red wine. Researchers have reported the pleiotropic anti-oxidant, anti-inflammatory, anti-cancer, anti-aging, and neuronal protective effects of resveratrol and its glycosylated derivative. However, few studies have distinguished the minute differences in the properties between resveratrol and its glycosylated derivative in terms of synaptic plasticity. As an abundant natural product of glycosylated resveratrol, the derivative 2,3,4',5-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) has been determined to be a better option for long-term potentiation (LTP) in the hippocampus under physiological and pathological conditions than resveratrol. TSG, as well as its parent molecule RSV, could elicit early-LTP and recover fast excitatory postsynaptic potentials (EPSPs) in the hippocampus. Using various modalities, including pre- and post-whole-cell patch clamping techniques in the calyx of Held, pharmacological inhibition of the N-methyl-d-aspartic acid receptor (NMDAr) and the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAr) as well as protein kinase C (PKC) activation, we demonstrated that TSG, unlike RSV, could merely promote NMDA-mediated EPSC via PKCβ cascade. Our results provide new knowledge that glycosylation of resveratrol could significantly improve its specificity in promoting sole NMDAr mediation of EPSPs, in addition to improving solubility and resistance against oxidation in vivo. These observations could contribute to further exploration of pharmaceutical evaluation of glycosylated stilbene in the future.

Tetrahydroxystilbene glycoside antagonizes β-amyloid-induced inflammatory injury in microglia cells by regulating PU.1 expression

Inhibiting β-amyloid (Aβ)-induced microglial activation is proposed as an effective strategy for the treatment of Alzheimer’s disease. Tetrahydroxystilbene glycoside (TSG) is the main active ingredient of Polygonum multiflorum and has a wide range of biological properties, including antiinflammation. Here, we focused on the function and regulatory mechanism of TSG in Aβ-induced N9 and BV2 cells. The results showed that Aβ treatment induced the activation of microglia cells and the production of inflammatory molecules, including inducible nitric oxide synthase, nitric oxide, cyclooxygenase 2, and prostaglandin E2, which were significantly inhibited by TSG pretreatment. Furthermore, we found Aβ exposure increased the levels of microglial M1 markers, interleukin (IL)-1β, IL-6, and tumor necrosis factor α, and the pretreatment of TSG suppressed the increase of M1 markers and enhanced the levels of M2 markers, including IL-10, brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, and arginase-1. PU.1 overexpression was found to eradicate the anti-inflammatory effects of TSG in Aβ-induced microglial cells. Taken together, these findings indicate that TSG attenuates Aβ-induced microglial activation and polarizes microglia towards M2 phenotype, which may be closely associated with the regulation of PU.1.

Tetrahydroxy stilbene glucoside alleviates palmitic acid-induced inflammation and apoptosis in cardiomyocytes by regulating miR-129-3p/Smad3 signaling

Objective

Tetrahydroxy stilbene glucoside (TSG) has been reported to exert a cytoprotective effect against various toxicants. However, the function and mechanism of TSG in palmitic acid (PA)-induced inflammation and apoptosis in cardiomyocytes are still unknown. The present study was designed to investigate the post-transcriptional mechanism in TSG-treated cardiomyocytes’ inflammation and apoptosis induced by PA.

Methods

The mRNA and protein levels were assayed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. The targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. Cell proliferation was analyzed by CCK-8 assay. Annexin V-fluorescein isothiocyanate/polyimide (annexin V-FITC/PI) staining was used to evaluate apoptosis using flow cytometry.

Results

TSG restricted the detrimental effects, including the activated inflammatory response and apoptosis, of PA in cardiomyocytes, as well as the up-regulation of miR-129-3p and down-regulation of p-Smad3 expression. In addition, bioinformatics and experimental analysis suggested that Smad3 was a direct target of miR-129-3p, which could inhibit or enhance the expression of p-Smad by transfection with miR-129-3p mimics or inhibitors, respectively. Furthermore, our results demonstrated that overexpression of Smad3 reversed the inhibition of inflammation and apoptosis by overexpression of miR-129-3p in PA-stimulated cardiomyocytes.

Conclusion

TSG targeted to miR-129-3p/Smad3 signaling inhibited PA-induced inflammation and apoptosis in cardiomyocytes.

EGCG Nanoparticles Attenuate Aluminum Chloride Induced Neurobehavioral Deficits, Beta Amyloid and Tau Pathology in a Rat Model of Alzheimer's Disease

Rational: Alzheimer's disease (AD) is a neurodegenerative pathology characterized by the presence of neuritic plaques and neurofibrillary tangles. Aluminum has been reported to play an important role in the etiology and pathogenesis of this disease. Hence, the present study aimed to evaluate the neuroprotective role of epigallocatechin-gallate (EGCG) loaded nanoparticles (nanoEGCG) against aluminum chloride (AlCl3) induced neurobehavioral and pathological changes in AD induced rats. Method: 100 mg/kg body weight AlCl3 was administered orally for 60 days, which was followed by 10 mg/kg body weight free EGCG and nanoEGCG treatment for 30 days. Morris water maze, open field and novel object recognition tests were employed for neurobehavioral assessment of the rats. This was followed by histopathological assessment of the cortex and the hippocampus in the rat brain. For further validation biochemical, immunohistochemistry and western blot assays were carried out. Result: Aluminum exposure reduced the exploratory and locomotor activities in open field and significantly reduced the memory and learning curve of rats in Morris water maze and novel object recognition tests. These neurobehavioral impairments were significantly attenuated in nanoEGCG treated rats. Histopathological assessment of the cortex and hippocampus of AlCl3 induced rat brains showed the presence of both neuritic plaques and neurofibrillary tangles. In nanoEGCG treated rats this pathology was absent. Significant increase in biochemical, immunohistochemical and protein levels was noted in AlCl3 induced rats. While these levels were greatly reduced in nanoEGCG treated rats. Conclusion: In conclusion, this study strengthens the hypothesis that EGCG nanoparticles can reverse memory loss, neuritic plaque and neurofibrillary tangles formation.

Dual modulation on glial cells by tetrahydroxystilbene glucoside protects against dopamine neuronal loss

Background

Microglia-mediated neuroinflammation is recognized to mainly contribute to the pathogenesis of Parkinson’s disease (PD). Tetrahydroxystilbene glucoside (TSG) has been proved to be beneficial for health with a great number of pharmacological properties. We examined the effects of TSG against dopamine (DA) neuronal loss towards development of a PD treatment strategy.

Methods

Substantia nigral stereotaxic single injection of lipopolysaccharide (LPS)-induced rat DA neuronal damage was employed to investigate TSG-produced neuroprotection. In addition, primary rat midbrain neuron-glia co-cultures were performed to explore the underlying mechanisms.

Results

Daily intraperitoneal injection of TSG for seven consecutive days significantly attenuated LPS-induced loss of DA neurons in the substantia nigra. In addition, glia-dependent mechanisms were responsible for TSG-mediated neuroprotection. First, TSG ameliorated microglia-mediated neuroinflammation and the subsequent production of various pro-inflammatory and neurotoxic factors. Second, astroglial neurotrophic factor neutralization weakened TSG-mediated neuroprotection, showing that TSG was protective in part via increasing astroglia-derived neurotrophic factor secretion.

Conclusions

TSG protects DA neurons against LPS-induced neurotoxicity through dual modulation on glial cells by attenuating microglia-mediated neuroinflammation and enhancing astroglia-derived neurotrophic effects. These findings might open new alternative avenues for PD treatment.

Tetrahydroxy Stilbene Glucoside Alleviates High Glucose-Induced MPC5 Podocytes Injury Through Suppression of NLRP3 Inflammasome

BACKGROUND

Tetrahydroxy stilbene glucoside (TSG) is an active ingredient of Heshouwu and is an antioxidant. The underlying mechanisms of the renoprotective effect of TSG in diabetic nephropathy have not been previously reported. In this study, we investigated the mechanisms of TSG in preventing podocytes injury in high glucose (HG) condition.

METHODS

Cultured mouse podocytes (MPC5) were incubated in HG (30mmol/L) plus various concentration of TSG (0.1, 1 and 10μM) for 48 hours. Reactive oxygen species (ROS) production, malondialdehyde (MDA) levels, terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP-biotin nick end-labeling (TUNEL) fluorescence intensity, caspase-3 activity and the mRNA expression of nephrin in cultured podocytes were determined. The protein expression of Nod-like receptor protein 3 (NLRP3) inflammsome, interleukin-1β (IL-1β) and nephrin was detected by Western blot.

RESULTS

When the podocytes were incubated with various concentrations of TSG under HG conditions for 48 hours, TSG decreased ROS production, MDA levels, TUNEL fluorescence intensity and caspase-3 activity, but increased cell viability and the expression of nephrin in HG-induced podocytes in a dose-dependent manner. Subsequently, the podocytes treated with TSG at 10 μΜ decreased the expression of NLRP3 inflammasome and IL-1β compared with that of control. Furthermore, the podocytes transfected with NLRP3- small interfering RNA (siRNA) exhibited a significant decrease in the expression of caspase-1 and IL-1β, but exhibited a significant increase in the expression of nephrin. Eventually, TSG significantly increased the expression of nephrin in IL-1β-treated podocytes.

CONCLUSIONS

TSG attenuates high glucose-induced cell apoptosis in vitro partly through the suppression of NLRP3 inflammasome signaling.

Tetrahydroxy stilbene glucoside ameliorates H2O2-induced human brain microvascular endothelial cell dysfunction in vitro by inhibiting oxidative stress and inflammatory responses

Tetrahydroxy stilbene glucoside (TSG) is one of the main active ingredients of Polygonum multiflorum and performs various types of biological activity, particularly anti-inflammatory and anti-oxidative activities. However, the beneficial effect of TSG in H₂O₂-induced human brain microvascular endothelial cell (HBMEC) dysfunction has not been fully elucidated. In the present study, H₂O₂-induced oxidative stress and inflammatory responses, and the pharmacological effect of TSG were investigated. The results demonstrated that H₂O₂ appeared to exert a cytotoxic effect on HBMECs, as the cell viability was significantly inhibited in H₂O₂-treated HBMECs. Conversely, TSG did not exert a toxic effect on HBMECs, and TSG inhibited H₂O₂-induced HBMEC cytotoxicity in a dose-dependent manner. Furthermore, the findings indicated that TSG restricted the oxidative stress caused by H₂O₂ via inhibition of malondialdehyde and reactive oxygen species, and upregulation of superoxide dismutase and glutathione. H₂O₂-induced injury was associated with enhancing the levels of inflammatory cytokines, tumor necrosis factor-α, interleukin (IL)-6 and IL-1β in the cultured HBMECs, which were attenuated by TSG treatment. Furthermore, the findings demonstrated that TSG inhibited necrosis factor-κB protein expression levels, which, as an upstream transcription factor, may regulate inflammatory responses. Thus, TSG protected HBMECs from H₂O₂-induced dysfunction by inhibiting oxidative stress and inflammatory responses.

Current pharmacological developments in 2,3,4',5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG)

2,3,4',5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG), a resveratrol analog with glucoside, is purified from a traditional Chinese herbal medicine polygonum multiflorum. It has been extensively studied in last decade and known to exert strong anti-inflammatory, anti-oxidative, anti-apoptotic, and free radical scavenging activities, and therefore has been listed as a potential agent for disease therapies. Recent studies extend well-beyond effects of TSG on the injury of neurons, cardiomyocytes and endothelial cells, and report important functions of TSG in a lot of pathophysiological conditions. For example, TSG has been shown to prevent the production of pro-inflammatory cytokines in microglia and macrophages in vitro, and ameliorate pro-inflammatory responses in animal models with neurodegeneration, atherosclerosis, and rat paw or ear oedema. TSG can prevent the proliferation of vascular smooth cells, gastrointestinal dysfunctions, platelet aggregation, osteoblastic injury, diabetic nephropathy and melanogenesis. TSG is also indicated to facilitate long-term potentiation and learning and memory in both normal and pathological conditions. These effects to some extent enrich the understanding about the role of TSG in disease prevention and therapy. However, to date, we still have no outlined knowledges about the pharmacological effects of TSG, though the role of TSG in aging and Alzheimer's disease has been reviewed in recent years. Here, we summarize the current pharmacological developments of TSG as well as its possible mechanisms in disease prevention and therapy, aiming to push the understanding about the protective role of TSG as well as its preclinical assessment of novel applications.

Metal ions influx is a double edged sword for the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is a common form of dementia in aged people, which is defined by two pathological characteristics: β-amyloid protein (Aβ) deposition and tau hyperphosphorylation. Although the mechanisms of AD development are still being debated, a series of evidence supports the idea that metals, such as copper, iron, zinc, magnesium and aluminium, are involved in the pathogenesis of the disease. In particular, the processes of Aβ deposition in senile plaques (SP) and the inclusion of phosphorylated tau in neurofibrillary tangles (NFTs) are markedly influenced by alterations in the homeostasis of the aforementioned metal ions. Moreover, the mechanisms of oxidative stress, synaptic plasticity, neurotoxicity, autophagy and apoptosis mediate the effects of metal ions-induced the aggregation state of Aβ and phosphorylated tau on AD development. More importantly, imbalance of these mechanisms finally caused cognitive decline in different experiment models. Collectively, reconstructing the signaling network that regulates AD progression by metal ions may provide novel insights for developing chelators specific for metal ions to combat AD.

Neuroprotective effects of 2,3,5,4'-tetrahydoxystilbene-2-O-β-D-glucoside from Polygonum multiflorum against glutamate-induced oxidative toxicity in HT22 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Since ancient times, Polygonum multiflorum Thunb. has been used to treat premature grey hair, dizziness, and blurred vision in East Asia. A major bioactive constituent of this medicinal herb, 2,3,5,4'-tetrahydoxystilbene-2-O-β-D-glucoside (THSG), has antioxidant activity and exerts beneficial effects on cognition and memory.

AIM OF THE STUDY

The purpose of the current study was to determine if THSG affects hippocampal neuronal cell death and mitochondrial function following exposure to oxidative stress.

MATERIALS AND METHODS

HT22 hippocampal cells with or without THSG pretreatment were exposed to glutamate, and the effects on cell viability and expression of molecules related to apoptotic cell death were examined using biochemical techniques, flow cytometry, western immunoblotting, and real-time polymerase chain reaction.

RESULTS

Pretreatment with THSG significantly attenuated glutamate-induced loss of cell viability and release of lactate dehydrogenase as well as apoptotic cell death. THSG inhibited generation of reactive oxygen species (ROS), expression of heme oxygenase-1, and activation of caspase-3 and calpain-1 proteases, all of which were increased by glutamate. THSG inhibited glutamate-induced disruption of mitochondrial membrane potential (MMP) and voltage-dependent anion channel-1. It also regulated the ratio of Bax to Bcl-2.

CONCLUSIONS

These results indicate that THSG has a marked neuroprotective effect against glutamate-induced hippocampal damage by decreasing ROS production and stabilizing MMP. These findings suggest the potential of THSG as a new therapeutic agent for the treatment of cognitive disorders.

Impact of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-D-glucoside on cognitive deficits in animal models of Alzheimer's disease: a systematic review

BACKGROUND

The efficacy of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) treatment on cognitive decline in individuals with Alzheimer's disease (AD) has not been investigated. Therefore, we systematically reviewed the effect of TSG on cognitive deficits in a rodent model of AD.

METHODS

We identified eligible studies published from January 1980 to April 2015 by searching seven electronic databases. We assessed the study quality, evaluated the efficacy of TSG treatment, and performed a stratified meta-analysis and meta-regression analysis to assess the influence of study design on TSG efficacy.

RESULTS

Among a total of 381 publications, 18 fulfilled our inclusion criteria. The overall methodological quality of these studies was poor. The meta-analysis revealed a statistically significant benefit of TSG on acquisition memory (standardized mean difference [SMD] = -1.46 (95 % CI: -1.81 to -1.10, P < 0.0001) and retention memory (SMD =1.93 (95 % CI: 1.40 to 2.46, P < 0.0001) in experimental models of AD. The stratified analysis revealed a significantly higher effect size for both acquisition and retention memory in studies that used mixed sex models and a significantly higher effect size for acquisition memory in studies that used transgenic models.

CONCLUSIONS

Our meta-analysis highlights a significantly better treatment effect in rodent AD models that received TSG that in those that did not. These findings indicate a potential therapeutic role of TSG in AD therapy. However, additional well-designed and detailed experimental studies are needed to evaluate the safety of TSG.

Biological Activities of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside in Antiaging and Antiaging-Related Disease Treatments

2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG) is active component of the Chinese medicinal plant Polygonum multiflorum Thunb. (THSG). Pharmacological studies have demonstrated that THSG exhibits numerous biological functions in treating atherosclerosis, lipid metabolism, vascular and cardiac remodeling, vascular fibrosis, cardiac-cerebral ischemia, learning and memory disorders, neuroinflammation, Alzheimer and Parkinson diseases, diabetic complications, hair growth problems, and numerous other conditions. This review focuses on the biological effects of THSG in antiaging and antiaging-related disease treatments and discusses its molecular mechanisms.

The History, Status, Gaps, and Future Directions of Neurotoxicology in China

BACKGROUND

Rapid economic development in China has produced serious ecological, environmental, and health problems. Neurotoxicity has been recognized as a major public health problem. The Chinese government, research institutes, and scientists conducted extensive studies concerning the source, characteristics, and mechanisms of neurotoxicants.

OBJECTIVES

This paper presents, for the first time, a comprehensive history and review of major sources of neurotoxicants, national bodies/legislation engaged, and major neurotoxicology research in China.

METHODS

Peer-reviewed research and pollution studies by Chinese scientists from 1991 to 2015 were examined. PubMed, Web of Science and Chinese National Knowledge Infrastructure (CNKI) were the major search tools.

RESULTS

The central problem is an increased exposure to neurotoxicants from air and water, food contamination, e-waste recycling, and manufacturing of household products. China formulated an institutional framework and standards system for management of major neurotoxicants. Basic and applied research was initiated, and international cooperation was achieved. The annual number of peer-reviewed neurotoxicology papers from Chinese authors increased almost 30-fold since 2001.

CONCLUSIONS

Despite extensive efforts, neurotoxicity remains a significant public health problem. This provides great challenges and opportunities. We identified 10 significant areas that require major educational, environmental, governmental, and research efforts, as well as attention to public awareness. For example, there is a need to increase efforts to utilize new in vivo and in vitro models, determine the potential neurotoxicity and mechanisms involved in newly emerging pollutants, and examine the effects and mechanisms of mixtures. In the future, we anticipate working with scientists worldwide to accomplish these goals and eliminate, prevent and treat neurotoxicity.

CITATION

Cai T, Luo W, Ruan D, Wu YJ, Fox DA, Chen J. 2016. The history, status, gaps, and future directions of neurotoxicology in China. Environ Health Perspect 124:722-732; http://dx.doi.org/10.1289/ehp.1409566.

Protective effect of tetrahydroxy stilbene glucoside on learning and memory by regulating synaptic plasticity

Damage to synaptic plasticity induced by neurotoxicity of amyloid-beta is regarded to be one of the pathological mechanisms of learning and memory disabilities in Alzheimer's disease patients. This study assumed that the damage of amyloid-beta to learning and memory abilities was strongly associated with the changes in the Fyn/N-methyl-D-aspartate receptor 2B (NR2B) expression. An APP695V7171 transgenic mouse model of Alzheimer's disease was used and treatment with tetrahydroxy-stilbene glucoside was administered intragastrically. Results showed that intragastric administration of tetrahydroxy-stilbene glucoside improved the learning and memory abilities of the transgenic mice through increasing NR2B receptors and Fyn expression. It also reversed parameters for synaptic interface structure of gray type I. These findings indicate that tetrahydroxy stilbene glucoside has protective effects on the brain, and has prospects for its clinical application to improve the learning and memory abilities and treat Alzheimer's disease.

Neuroprotective effect of hesperidin on aluminium chloride induced Alzheimer's disease in Wistar rats

The present study was aimed to evaluate the protective effect of hesperidin (Hes) on aluminium chloride (AlCl3) induced neurobehavioral and pathological changes in Alzheimeric rats. Intraperitonial injection of AlCl3 (100 mg/kg body weight) for 60 days significantly elevated the levels of aluminium (Al), activity of acetylcholinesterase (AChE) and protein expressions of amyloid precursor protein (APP), β amyloid (Aβ 1-42), β and γ secretases as compared to control group in hippocampus and cortex of rat brain. Hes administration orally along with AlCl3 injection for 60 days, significantly revert the Al concentration, AChE activity and Aβ synthesis-related molecules in the studied brain regions. Our results showed that aluminum exposure was significantly reduced the spontaneous locomotor and exploratory activities in open field test and enhanced the learning and memory impairments in morris water maze test. The behavioral impairments caused by aluminum were significantly attenuated by Hes. The histopathological studies in the hippocampus and cortex of rat brain also supported that Hes (100 mg/kg) markedly reduced the toxicity of AlCl3 and preserved the normal histoarchitecture pattern of the hippocampus and cortex. From these results, it is concluded that hesperidin can reverse memory loss caused by aluminum intoxication through attenuating AChE activity and amyloidogenic pathway.

Monitoring trace elements generated by automobiles: air pollutants with possible health impacts

Major transformations in the environmental composition are principally attributable to the combustion of fuels by automobiles. Motorized gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas (CNG)-powered four-stroke auto-rickshaws (FSA) are potential source of air pollution in south Asia and produce toxic amount of particulate matter (PM) to the environment. In this study, we attempted to characterize elemental pollutants from the PM of TSA and FSA using proton-induced X-ray emission (PIXE) analysis. The observations of the existing investigation recognized significant increase in Al (P < 0.05), P (P < 0.01), and Zn (P < 0.01) from the PM samples of FSA. In addition, the concentrations of Cu, Fe, K, Mg, Na and S were also observed exceeding the recommended National Institute for Environmental Studies limits. On the contrary, increased concentration of Sr and V were observed in the PM samples from TSA. It is generally believed that FSA generates smaller amount of PM but data obtained from FSA are clearly describing that emissions from FSA comprised potentially more toxic substances than TSA. The current research is specific to metropolitan population and has evidently revealed an inconsistent burden of exposure to air pollutants engendered by FSA in urban communities, which could lead to the disruption of several biological activities and may cause severe damage to entire ecological system.

Bioactive cis-stilbenoids from the tubers of Scirpus yagara

Two new cis-stilbenoids, sciryagarol I (1) and II (2) were isolated from the EtOAc extract of the tubers of Scirpus yagara, together with four known compounds. The structures of all compounds were determined by comprehensive analyses of their spectroscopic data and comparison with literature information. The compounds 3, 4 and 6 were isolated for the first time from this genus. Some compounds were tested for their cytotoxicity against human tumor cell lines and antimicrobial activity. Compounds 1-4 showed significant cytotoxicity against the Hela cell lines with IC(50) values ranging from 7.21 to 61.21μM. 1 and 2 exhibited some antimicrobial activity against Staphylococcus aureus and Candida albicans with uniform MICs of 79.3μl/ml for 2, and 152μl/ml for 1, respectively.

Protective effect of tetrahydroxystilbene glucoside on 6-OHDA-induced apoptosis in PC12 cells through the ROS-NO pathway

Oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases, such as Parkinson's disease. The molecule, 2,3,5,4'-tetrahydr- oxystilbene-2-O-β-D-glucoside (TSG), is a potent antioxidant derived from the Chinese herb, Polygonum multiflorum Thunb. In this study, we investigated the protective effect of TSG against 6-hydroxydopamine-induced apoptosis in rat adrenal pheochromocytoma PC12 cells and the possible mechanisms. Our data demonstrated that TSG significantly reversed the 6-hydroxydopamine-induced decrease in cell viability, prevented 6-hydroxydopamine-induced changes in condensed nuclei and decreased the percentage of apoptotic cells in a dose-dependent manner. In addition, TSG slowed the accumulation of intracellular reactive oxygen species and nitric oxide, counteracted the overexpression of inducible nitric oxide syntheses as well as neuronal nitric oxide syntheses, and also reduced the level of protein-bound 3-nitrotyrosine. These results demonstrate that the protective effects of TSG on rat adrenal pheochromocytoma PC12 cells are mediated, at least in part, by the ROS-NO pathway. Our results indicate that TSG may be effective in providing protection against neurodegenerative diseases associated with oxidative stress.