2,3,4',5-TETRAHYDROXYSTILBENE-2-O-β-d-GLUCOSIDE SUPPRESSES MATRIX METALLOPROTEINASE EXPRESSION AND INFLAMMATION IN ATHEROSCLEROTIC RATS

Anti-atherosclerotic effect of tetrahydroxy stilbene glucoside via dual-targeting of hepatic lipid metabolisms and aortic M2 macrophage polarization in ApoE-/- mice

Tetrahydroxy stilbene glucoside (TSG) is a water-soluble natural product that has shown potential in treating atherosclerosis (AS). However, its underlying mechanisms remain unclear. Here, we demonstrate that an 8-week TSG treatment (100 mg/kg/d) significantly reduces atherosclerotic lesions and alleviates dyslipidemia symptoms in ApoE-/- mice. 1H nuclear magnetic resonance metabolomic analysis reveals differences in both lipid components and water-soluble metabolites in the livers of AS mice compared to control groups, and TSG treatment shifts the metabolic profiles of AS mice towards a normal state. At the transcriptional level, TSG significantly restores the expression of fatty acid metabolism-related genes (Srepb-1c, Fasn, Scd1, Gpat1, Dgat1, Pparα and Cpt1α), and regulates the expression levels of disturbed cholesterol metabolism-related genes (Srebp2, Hmgcr, Ldlr, Acat1, Acat2 and Cyp7a1) associated with lipid metabolism. Furthermore, at the cellular level, TSG remarkably polarizes aortic macrophages to their M2 phenotype. Our data demonstrate that TSG alleviates arthrosclerosis by dual-targeting to hepatic lipid metabolism and aortic M2 macrophage polarization in ApoE-/- mice, with significant implications for translational medicine and the treatment of AS using natural products.

Natural drugs targeting inflammation pathways can be used to treat atherosclerosis

Atherosclerosis (AS) is the chronic gradual degradation of arteries in combination with inflammation. Currently, the main research focus has been on interactions between inflammatory cells, inflammatory mediators, and immune mechanisms, while some studies have reported natural drugs were exerting a critical role against AS, whereas the usage of natural drugs was always limited by various factors such as poor penetration across biological barriers, low bioavailability, and unclear mechanisms. Herein, we reviewed the potential targets for inflammation against AS, discussed the underlying mechanisms of natural drugs for AS, particularly highlighted the dilemma of current research, and finally, offered perspectives in this field.

2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucoside Attenuates Reactive Oxygen Species-Dependent Inflammation and Apoptosis in Porphyromonas gingivalis-Infected Brain Endothelial Cells

We recently reported that the periodontopathic bacteria Porphyromonas gingivalis (P. gingivalis) initiates an inflammatory cascade that disrupts the balance of reactive oxygen species (ROS), resulting in apoptotic cell death in brain endothelial cells. An extract from Polygonum multiflorum Thunb., 2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucoside (THSG) has been well-reported to diminish the inflammation in many disease models. However, the effects of THSG in the area of the brain–oral axis is unknown. In this study, we examined the effects of THSG in P. gingivalis-stimulated inflammatory response and apoptotic cell death in brain endothelial cells. THSG treatment remarkably lessened the upregulation of IL-1β and TNF-α proteins in bEnd.3 cells infected with P. gingivalis. Treatment of THSG further ameliorated brain endothelial cell death, including apoptosis caused by P. gingivalis. Moreover, the present study showed that the inhibitory effects on NF-κB p65 and antiapoptotic properties of THSG is through inhibiting the ROS pathway. Importantly, the ROS inhibitory potency of THSG is similar to a ROS scavenger N-Acetyl-L-Cysteine (NAC) and NADPH oxidase inhibitor apocynin. Furthermore, the protective effect of THSG from P. gingivalis infection was further confirmed in primary mouse brain endothelial cells. Taken together, this study indicates that THSG attenuates an ROS-dependent inflammatory response and cell apoptosis in P. gingivalis-infected brain endothelial cells. Our results also suggest that THSG could be a potential herbal medicine to prevent the risk of developing cerebrovascular diseases from infection of periodontal bacteria.

A Review of Pharmacology, Toxicity and Pharmacokinetics of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside

Polygonum multiflorum Thunb. (He-shou-wu in Chinese), a Chinese botanical drug with a long history, is widely used to treat a variety of chronic diseases in clinic, and has been given the reputation of “rejuvenating and prolonging life” in many places. 2,3,4′,5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG, C₂₀H₂₂O₉) is the main and unique active ingredient isolated from Polygonum multiflorum Thunb., which has extensive pharmacological activities. Modern pharmacological studies have confirmed that TSG exhibits significant activities in treating various diseases, including inflammatory diseases, neurodegenerative diseases, cardiovascular diseases, hepatic steatosis, osteoporosis, depression and diabetic nephropathy. Therefore, this review comprehensively summarizes the pharmacological and pharmacokinetic properties of TSG up to 2021 by searching the databases of Web of Science, PubMed, ScienceDirect and CNKI. According to the data, TSG shows remarkable anti-inflammation, antioxidation, neuroprotection, cardiovascular protection, hepatoprotection, anti-osteoporosis, enhancement of memory and anti-aging activities through regulating multiple molecular mechanisms, such as NF-κB, AMPK, PI3K-AKT, JNK, ROS-NO, Bcl-2/Bax/Caspase-3, ERK1/2, TGF-β/Smad, Nrf2, eNOS/NO and SIRT1. In addition, the toxicity and pharmacokinetics of TSG are also discussed in this review, which provided direction and basis for the further development and clinical application of TSG.

Nephroprotective activity of natural products against chemical toxicants: The role of Nrf2/ARE signaling pathway

Nephropathy can occur following exposure of the kidneys to oxidative stress. Oxidative stress is the result of reactive oxygen species (ROS) formation due to intracellular catabolism or exogenous toxicant exposure. Many natural products (NPs) with antioxidant properties have been used to demonstrate that oxidative damage-induced nephrotoxicity can be ameliorated or at least reduced through stimulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Nrf2 is a basic leucine zipper (bZip) transcription factor that regulates gene expression of the antioxidant response elements (ARE). Nrf2 is involved in the cellular antioxidant-detoxification machinery. Nrf2 activation is a major mechanism of nephroprotective activity for these NPs, which facilitates its entry into the nucleus, primarily by inhibiting Kelch like-ECH-associated protein 1 (Keap1). The purpose of this article was to review the peer-reviewed literature of NPs that have shown mitigating effects on renal disorder by stimulating Nrf2 and thereby suggesting potential new therapeutic or prophylactic strategies against kidney-damaging xenobiotics.

Polygonum multiflorum: Recent updates on newly isolated compounds, potential hepatotoxic compounds and their mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum multiflorum Thunb.(PM), (known as Heshouwu () in China) is one of the most important and well mentioned Chinese medicinal herbs in the literature for its use in blackening hair, nourishing liver and kidney, anti-aging, anti-hyperlipidemia, antioxidant, anti-inflammatory, anticancer, hepatoprotection, cardio-protection and improving age-related cognitive dysfunction. The purpose of this review is to give a comprehensive and recent update on PM: new compounds or isolated for the first time, potential hepatotoxic compounds and their mechanisms. Moreover, future perspectives and challenges in the future study of this plant are conversed which will make a new base for further study on PM.

MATERIALS AND METHODS

A comprehensive review of relevant published literature on PM using the scientific databases SCOPUS, PubMed, and Science Direct was done.

RESULTS

PM is broadly produced in many provinces of China and well known in other Eastern Asian Countries for its ethno-medical uses. Previous phytochemical investigation of PM had led to the isolation of more than 175 compounds including recently isolated 70 new compounds. Most of the new compounds isolated after 2015 are majorly dianthrone glycosides and stilbene glycosides. Processing has also a significant effect on chemical composition, pharmacological activities, and toxicity of PM. PM-induced liver injury is increasing after the first report in Hong Kong in 1996. Hepatotoxicity of PM was constantly reported in Japan, Korea, China, Australia, Britain, Italy, and other countries although its toxicity is related to idiosyncratic hepatotoxicity. More interestingly, although there is indispensable interest to predict idiosyncratic hepatotoxicity of PM and understand its mechanisms, the responsible hepatotoxic compounds and mechanisms of liver damage induced by PM are still not clear. There is a big controversy on the identification of the most responsible constituent. Anthraquinone and stilbene compounds in PM, mainly emodine and TSG are mentioned in the literature to be the main responsible hepatotoxic compounds. However, comparing the two compounds, which one is the more critical toxic agent for PM-induced hepatotoxicity is not well answered. Affecting different physiological and metabolic pathways such as oxidative phosphorylation and TCA cycle pathway, metabolic pathways, bile acid excretion pathway and genetic polymorphisms are among the mechanisms of hepatotoxicity of PM.

CONCLUSION

Deeper and effective high throughput experimental studies are still research hotspots to know the most responsible constituent and the mechanism of PM-induced hepatotoxicity.

Suppression of apoptosis in vascular endothelial cell, the promising way for natural medicines to treat atherosclerosis

Atherosclerosis, a chronic multifactorial disease, is closely related to the development of cardiovascular diseases and is one of the predominant causes of death worldwide. Normal vascular endothelial cells play an important role in maintaining vascular homeostasis and inhibiting atherosclerosis by regulating vascular tension, preventing thrombosis and regulating inflammation. Currently, accumulating evidence has revealed that endothelial cell apoptosis is the first step of atherosclerosis. Excess apoptosis of endothelial cells induced by risk factors for atherosclerosis is a preliminary event in atherosclerosis development and might be a target for preventing and treating atherosclerosis. Interestingly, accumulating evidence shows that natural medicines have great potential to treat atherosclerosis by inhibiting endothelial cell apoptosis. Therefore, this paper reviewed current studies on the inhibitory effect of natural medicines on endothelial cell apoptosis and summarized the risk factors that may induce endothelial cell apoptosis, including oxidized low-density lipoprotein (ox-LDL), reactive oxygen species (ROS), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α), homocysteine (Hcy) and lipopolysaccharide (LPS). We expect this review to highlight the importance of natural medicines, including extracts and monomers, in the treatment of atherosclerosis by inhibiting endothelial cell apoptosis and provide a foundation for the development of potential antiatherosclerotic drugs from natural medicines.

Otoprotective Effect of 2,3,4',5-Tetrahydroxystilbene-2-O-β-d-Glucoside on Gentamicin-Induced Apoptosis in Mouse Cochlear UB/OC-2 Cells

Excessive levels of reactive oxygen species (ROS) lead to mitochondrial damage and apoptotic cell death in gentamicin-induced ototoxicity. 2,3,4',5-Tetrahydroxystilbene-2-O-β-d-glucoside (THSG), a bioactive constituent, isolated from Polygonum multiflorum Thunb., exhibits numerous biological benefits in treating aging-related diseases by suppressing oxidative damage. However, its protective effect on gentamicin-induced ototoxicity remains unexplored. Therefore, here, we aimed to investigate the otoprotective effect of THSG on gentamicin-induced apoptosis in mouse cochlear UB/OC-2 cells. We evaluated the effect of gentamicin and THSG on the ROS level, superoxide dismutase (SOD) activity, mitochondrial membrane potential, nuclear condensation, and lactate dehydrogenase (LDH) release, and the expression of apoptosis-related proteins was assessed to understand the molecular mechanisms underlying its preventive effects. The findings demonstrated that gentamicin increased ROS generation, LDH release, and promoted apoptotic cell death in UB/OC-2 cells. However, THSG treatment reversed these effects by suppressing ROS production and downregulating the mitochondrial-dependent apoptotic pathway. Additionally, it increased the SOD activity, decreased the expression of apoptosis-related proteins, alleviated the levels of the apoptotic cells, and impaired cytotoxicity. To the best of our knowledge, this is the first study to demonstrate that THSG could be a potential therapeutic option to attenuate gentamicin-induced ototoxicity.

A Candidate Drug for Nonalcoholic Fatty Liver Disease: A Review of Pharmacological Activities of Polygoni Multiflori Radix

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients' compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

Biological Effects of Tetrahydroxystilbene Glucoside: An Active Component of a Rhizome Extracted from Polygonum multiflorum

Polygonum multiflorum Thunb. (PM), a traditional Chinese medicinal herb, has been widely used in the Orient as a tonic and antiaging agent. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG, C20H22O9, FW = 406.38928) is one of the active components extracted from PM. TSG is an antioxidant agent, which exhibits remarkable antioxidative activities in vivo and in vitro. The antioxidant effect of TSG is achieved by its radical-scavenging effects. TSG can inhibit apoptosis and protect neuronal cells against injury through multifunctional cytoprotective pathways. TSG performs prophylactic and therapeutic activities against Alzheimer's disease, Parkinson's disease, and cerebral ischemia/reperfusion injury. It is also antiatherosclerotic and anti-inflammatory. However, the mechanisms underlying these pharmacological activities are unclear. This study aimed at reviewing experimental studies and describing the effectiveness and possible mechanisms of TSG.

Tetrahydroxystilbene Glucoside Produces Neuroprotection against 6-OHDA-Induced Dopamine Neurotoxicity

Parkinson's disease (PD) was one of the most common neurodegenerative diseases with a slow and progressive loss of dopamine (DA) neurons in the midbrain substantia nigra (SN). Neuroinflammation was identified to be an important contributor to PD pathogenesis with the hallmark of microglia activation. Tetrahydroxystilbene glucoside (TSG) was the main active component extracted from Polygonum multiflorum and held amounts of pharmacological activities including antioxidant, free radical-scavenging, anti-inflammation, and cardioprotective properties. Recent studies demonstrated that TSG exerted neuroprotection from several neurodegenerative disease models. However, the underlying mechanisms were not completely elucidated. In the present study, rat nigral stereotaxic injection of 6-hydroxydopamine- (6-OHDA-) elicited DA neuronal injury was performed to investigate TSG-mediated neuroprotection on DA neurons. In addition, primary rat midbrain neuron-glia cocultures were applied to explore the mechanisms underlying TSG-exerted neuroprotection. Results showed that daily intraperitoneal injection of TSG for 14 consecutive days significantly protected DA neurons from 6-OHDA-induced neurotoxicity and suppressed microglia activation. Similar neuroprotection was shown in primary neuron-glia cocultures. In vitro studies further demonstrated that TSG inhibited microglia activation and subsequent release of proinflammatory factors. Moreover, TSG-mediated neuroprotection was closely related with the inactivation of mitogen-activated protein kinase (MAPK) signaling pathway. Together, TSG protects DA neurons from 6-OHDA-induced neurotoxicity via the inhibition of microglia-elicited neuroinflammation. These findings suggest that TSG might hold potential therapeutic effects on PD.

The natural compound 2,3,5,4'-tetrahydroxystilbene-2-O-β-d glucoside protects against adriamycin-induced nephropathy through activating the Nrf2-Keap1 antioxidant pathway

2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (THSG) is an active compound extracted from Polygonum multiflorum Thunb. This herb and radix Polygoni Multiflori preparata have been used to treat arteriosclerosis, hyperlipidemia, hypercholesterolemia, and diabetes for thousands of years. This study aimed to investigate the protective effects of THSG in an Adriamycin (AD)-induced focal segmental glomerulosclerosis (FSGS) mouse model and the underlying mechanisms in an in vitro system. Mice were treated with THSG (2.5 and 10 mg/kg, oral gavage) for 24 consecutive days. On the third day, mice were intravenously given a single dose of AD (10 mg/kg). At the end of the experiment, plasma and kidney samples were harvested to evaluate the therapeutic effects of THSG. The potential mechanisms of THSG in protecting against AD-induced cytotoxicity were examined using a real-time polymerase chain reaction, immunoblots, lactate dehydrogenase assay, and a cellular oxidized-thiol detection system in a mouse mesangial cell line. In this study, THSG showed concentration-dependent protective effects in ameliorating the progression of AD-induced FSGS. THSG suppressed albuminuria and hypercholesterolemia and reduced the status of lipid peroxidation in urine, plasma, and kidney tissue samples. Furthermore, THSG protected against podocyte damage, reduced renal fibrotic gene expressions, and alleviated the severity of glomerulosclerosis. Treatment of mouse mesangial cells with THSG induced nuclear factor erythroid-derived 2-like 2 (Nrf2) nuclear translocation, increased heme oxygenase-1 and NAD(P)H:quinone oxidoreductase (NQO)-1 gene expressions, and reduced cellular thiol oxidation and resistance to AD-induced cytotoxicity. Silencing Nrf2 and its repressor protein, Kelch-like ECH-associated protein 1 (Keap1), abolished these protective effects of THSG. In conclusion, THSG can play a protective role in ameliorating the progression of FSGS in a mouse model through activation of the Nrf2-Keap1 antioxidant pathway. Although a well-designed therapeutic study is needed, THSG may be applied to manage chronic kidney disease.

2,3,4′,5-tetrahydroxystilbene-2-O-β-d-glycoside attenuates atherosclerosis in apolipoprotein E-deficient mice: role of reverse cholesterol transport

The aim of this study was to evaluate the potential effects of 2,3,4′,5-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) on the development of atherosclerotic plaque in ApoE−/− mice, and explore the mechanisms involved. Our data showed that after 8 weeks of treatment, TSG ameliorated serum levels of total cholesterol, triglyceride, and low density lipoprotein cholesterol, and increased serum levels of high density lipoprotein cholesterol in ApoE−/− mice. TSG suppressed hepatic steatosis, the formation of atherosclerotic lesions, and the formation of macrophage foam cells in ApoE−/− mice. Moreover, TSG improved the expressions of hepatic SR-BI, ABCG5, and CYP7A1, and up-regulated the protein expressions of aortic ABCA1 and ABCG1. An in-vitro study showed that TSG promoted macrophage cholesterol efflux and increased the protein expressions of ABCA1 and ABCG1. Our findings provide evidence for a positive role of TSG in preventing atherosclerosis by promoting reverse cholesterol transport. These effects may be achieved by stimulating cholesterol efflux through ABCA1 and ABCG1, promoting SR-BI-mediated cholesterol uptake in the liver, increasing secretion of cholesterol into bile by ABCG5, and improving cholesterol metabolism by the CYP7A1 pathway. In addition, antioxidative and anti-inflammatory effects of TSG may also contribute to its inhibitory effects on atherosclerosis. Further study is needed to investigate whether other potential mechanisms are involved in TSG-mediated atheroprotection.

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.

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.

TSG attenuates LPC-induced endothelial cells inflammatory damage through notch signaling inhibition

Lysophosphatidylcholine (LPC) induces inflammation in endothelial cells (ECs) but the mechanism is not fully understood. The Notch signaling pathway is involved in chronic EC inflammation, but its functions in LPC-induced endothelial inflammatory damage and 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside's (TSG) protective effect during LPC-induced inflammatory damage in human umbilical vein endothelial cells (HUVECs) is largely unknown. We report that Notch signaling activation contributed to LPC-induced injury in HUVECs, and that TSG protected HUVECs from LPC-induced injury by antagonizing Notch signaling activation by LPC. γ-secretase inhibitor (DAPT), a specific inhibitor of the Notch signaling pathway, and Notch1 siRNA were used to inhibit Notch activity. HUVECs were exposed to LPC in the presence or absence of TSG, DAPT, and Notch1 siRNA. LPC treatment of HUVECs resulted in reduced cell viability, and Notch1 and Hes1 upregulation. Either silencing of Notch1 by siRNA or pharmacological inhibition of Notch signaling by DAPT prevented the loss of cell viability, and induction of apoptosis, and enhanced expression Notch1, Hes1 and MCP-1 by LPC in HUVECs. Similarly, TSG reduced LPC stimulation of Notch1, Hes1, and MCP-1 expression, prevented the release of IL-6 and CRP and rescued HUVECs from LPC-induced cell damage. Our data indicate that the Notch signaling pathway is a crucial mediator of endothelial inflammatory damage and that TSG protects against endothelial inflammatory damage by inhibiting the Notch signaling pathway. Our findings suggest that targeting Notch signaling by natural products such as TSG is a promising strategy for the prevention and treatment of chronic inflammation associated diseases, including atherosclerosis. © 2015 IUBMB Life, 68(1):37-50, 2016.

Tetrahydroxystilbene glucoside inhibits TNF-α-induced migration of vascular smooth muscle cells via suppression of vimentin

Vascular smooth muscle cell (VSMC) migration triggered by TNF-α is an important event that occurs during the development of atherosclerosis. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (TSG) has been proven to exhibit significant anti-atherosclerotic activity. Herein we investigate the inhibitory effect of TSG on TNF-α-induced VSMC migration and explore the underlying mechanisms. TSG pretreatment markedly inhibited TNF-α-induced cell migration. The inhibition of vimentin redistribution and expression was involved in the inhibitory effect of TSG on VSMC migration. The suppression of vimentin expression by shRNA in VSMCs significantly inhibited TNF-α-induced cell migration. Furthermore, TSG inhibited the TNF-α-induced expression of TGFβ1 and TGFβR1, and phosphorylation of TGFβR1 and Smad2/3. TSG also suppressed the nuclear translocation of Smad4 induced by TNF-α. These results suggest that TSG inhibits VSMC migration induced by TNF-α through inhibiting vimentin rearrangement and expression. The interruption of TGFβ/Smad pathway appears to be responsible for the suppression of TSG on vimentin expression.

Tetrahydroxystilbene Glucoside Improves TNF-α-Induced Endothelial Dysfunction: Involvement of TGFβ/Smad Pathway and Inhibition of Vimentin Expression

Endothelial dysfunction plays an important role in the pathogenesis of atherogenesis. 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum (PM), exhibits significant anti-atherosclerotic activity. Here, we used human umbilical vein endothelial cells (HUVECs) induced by tumor necrosis factor-α (TNF-α) in vitro to investigate the cytoprotective effects of TSG on TNF-α-induced endothelial injury and the related mechanisms. Pretreatment with 50 and 100 μM TSG markedly attenuated TNF-α-induced loss of cell viability and release of lactate dehydrogenase (LDH) and inhibited TNF-α-induced cell apoptosis. The inhibition of vimentin expression was involved in the cytoprotection afforded by TSG. Using inhibitors for PI3K and TGFβ or siRNA for Akt and Smad2, we found that vimentin production in HUVECs is regulated by TGFβ/Smad signaling, but not by PI3K–Akt–mTOR signaling. Meanwhile, TSG inhibited both the expression of TGFβ1 and the phosphorylation of Smad2 and Smad3, and TSG suppressed the nuclear translocation of Smad4 induced by TNF-α. These results suggest that TSG protects HUVECs against TNF-α-induced cell damage by inhibiting vimentin expression via the interruption of the TGFβ/Smad signaling pathway.

Most appropriate animal models to study the efficacy of statins: a systematic review

BACKGROUND

In animal models and clinical trials, statins are reported as effective in reducing cholesterol levels and lowering the risk of cardiovascular diseases. We have aggregated the findings in animal models - mice, rats and rabbits - using the technique of systematic review and meta-analysis to highlight differences in the efficacy of statins.

MATERIALS AND METHODS

We searched Medline and Embase. After examining all eligible articles, we extracted results about total cholesterol and other blood parameters, blood pressure, myocardial infarction and survival. Weighted and standard mean difference random effects meta-analysis was used to measure overall efficacy in prespecified species, strains and subgroups.

RESULTS

We included in systematic review 161 animal studies and we analysed 120 studies, accounting for 2432 animals. Statins lowered the total cholesterol across all species, although with large differences in the effect size: -30% in rabbits, -20% in mice and -10% in rats. The reduction was larger in animals fed on a high-cholesterol diet. Statins reduced infarct volume but did not consistently reduce the blood pressure or effect the overall survival. Few studies considered strains at high risk of cardiovascular diseases or hard outcomes.

CONCLUSIONS

Although statins showed substantial efficacy in animal models, few preclinical data considered conditions mimicking human pathologies for which the drugs are clinically indicated and utilized. The empirical finding that statins are more effective in lowering cholesterol derived from an external source (i.e. diet) conflicts with statin's supposed primary mechanism of action.

Inhibitory effects of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside on angiotensin II-induced proliferation of vascular smooth muscle cells

OBJECTIVE

To investigate the effect of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the root of Polygonum multiflorum, on angiotensin II (Ang II)-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs) and to identify the potential mechanism.

METHODS

Cell proliferation and cell cycle were determined by cell counting, 5-bromo-2'-deoxyuridine incorporation assay, proliferating cell nuclear antigen protein expression and flow cytometry. Levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), mitogenic extracellular kinase 1/2 (MEK1/2) and Src in VSMCs were measured by Western blot. The expression of c-fos, c-jun and c-myc mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). Intracellular reactive oxygen species (ROS) was measured by fluorescence assay.

RESULTS

TSG significantly inhibited Ang II-induced VSMCs proliferation and arrested cells in the G /S checkpoint (P<0.05 or P<0.01). TSG decreased the levels of phosphorylated ERK1/2, MEK1/2 and Src in VSMCs (P<0.05 or P<0.01). TSG also suppressed c-fos, c-jun and c-myc mRNA expression <0.05 or P<0.01). In addition, the intracellular ROS was reduced by TSG (P<0.01).

CONCLUSIONS

TSG inhibited Ang II-induced VSMCs proliferation. Its antiproliferative effect might be associated with down-regulation of intracellular ROS, followed by the suppression of the Src-MEK1/2-ERK1/2 signal pathway, and hence, blocking cell cycle progression.

2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside suppresses expression of adhesion molecules in aortic wall of dietary atherosclerotic rats and promonocytic U937 cells

We sought to investigate whether TSG suppressed the ICAM-1/VCAM-1 expression in dietary atherosclerotic rats and in Ox-LDL-induced U937 cells. For this purpose, 60 male Sprague-Dawley rats were randomly-and-equally divided into six groups. Atherosclerosis was induced by feeding rats a hyperlipidemic diet. TSG (120, 60 or 30 mg/kg/day) was administered by oral gavage. Simvastatin (2 mg/kg/day) was administered as positive control whereas physiological saline (0.9% NaCl) served as untreated control. After 12 weeks, rats were euthanized by ethyl carbonate (1,200 mg/kg) and aortic wall samples were collected. Besides, U937 cells were stimulated for 48 h by Ox-LDL (80 μg/mL) with and without TSG (120, 60, 30 μg/L) or simvastatin (100 μg/L). ICAM-1/VCAM-1 mRNA expression was determined by RT-PCR and protein expression was detected by immunohistochemistry and/or western blotting. The data show that ICAM-1/VCAM-1 mRNA/protein expression was significantly enhanced in atherosclerotic aortas compared with normal diet group. Ox-LDL-induced ICAM-1/VCAM-1 mRNA/protein expression in U937 cells. Importantly, TSG significantly inhibited ICAM-1/VCAM-1 expression in atherosclerotic aortas in a dose-dependent manner. TSG-pretreatment also inhibited ICAM-1/VCAM-1 expression in Ox-LDL-induced U937 cells. Therefore, we concluded that TSG suppressed the expression of adhesion (ICAM-1/VCAM-1) molecules both in vivo (in aortic wall of dietary atherosclerotic rats) and in vitro (U937 cells).

Tetrahydroxystilbene glucoside attenuates neuroinflammation through the inhibition of microglia activation

Neuroinflammation is closely implicated in the pathogenesis of neurological diseases. The hallmark of neuroinflammation is the microglia activation. Upon activation, microglia are capable of producing various proinflammatory factors and the accumulation of these factors contribute to the neuronal damage. Therefore, inhibition of microglia-mediated neuroinflammation might hold potential therapy for neurological disorders. 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from Polygonum multiflorum, is reported to be beneficial for human health with a great number of pharmacological properties including antioxidant, free radical-scavenging, anti-inflammation, antilipemia, and cardioprotective effects. Recently, TSG-mediated neuroprotective effects have been well demonstrated. However, the neuroprotective actions of TSG on microglia-induced neuroinflammation are not known. In the present study, microglia BV2 cell lines were applied to investigate the anti-neuroinflammatory effects of TSG. Results showed that TSG reduced LPS-induced microglia-derived release of proinflammatory factors such as TNFα, IL-1β, and NO. Moreover, TSG attenuated LPS-induced NADPH oxidase activation and subsequent reactive oxygen species (ROS) production. Further studies indicated that TSG inhibited LPS-induced NF-κB signaling pathway activation. Together, TSG exerted neuroprotection against microglia-mediated neuroinflammation, suggesting that TSG might present a promising benefit for neurological disorders treatment.

The effect of 2,3,4',5-tetrahydroxystilbene-2-0-β-D glucoside on neointima formation in a rat artery balloon injury model and its possible mechanisms

2,3,4',5-tetrahydroxystilbene-2-0-β-D glucoside (TSG) has been recognized to suppress the proliferation of vascular smooth muscle cells (VSMCs). The aim of the present study was to determine whether TSG inhibits neointimal hyperplasia in a rat carotid arterial balloon injury model. Balloon injury was induced in the left common carotid artery of rats. TSG (30, 60, 120 mg/kg/day) was treated from 3 days prior to, until 14 days after the induction of balloon injury. The ratio of intima-to-media was significantly reduced in the TSG-treated rats at 14 days after the induction of injury, which was associated with reduced expressions of proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA) and platelet-derived growth factor-BB (PDGF-BB), as markers of VSMCs proliferation and migration. Additionally, TSG significantly inhibited PDGF-BB induced cell migration in cultured VSMCs. Furthermore, we explored the underlying mechanisms for such effects of TSG. The result showed that TSG markedly reduced balloon injury-induced AKT, extracellular signal-regulated kinase (ERK1/2) and nuclear factor kappaB (NF-κB) activation as well as mRNA expressions of c-myc, c-fos and c-jun, which is important signal pathway for VSMCs proliferation. And in both vivo and vitro model, TSG markedly regulated matrix metalloproteinase-2, 9 expressions and collagen I, III expressions, which are key factors in extracellular matrix for VSMCs migration. These results suggest that the anti-proliferative and anti-migrative effects of TSG on VSMCs could help to explain the beneficial effects of TSG on neointima hyperplasia induced by balloon injury.

Proteomic analysis for anti-atherosclerotic effect of tetrahydroxystilbene glucoside in rats

2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) extracted from Polygonum multiflorum (a traditional Chinese medicinal herb) has been proved to exhibit significant anti-atherosclerotic activity. In this study, we firstly used proteomic analyses to investigate the molecular events occurring in the atherosclerotic rats after TSG treatment. Aortic samples were collected from the atherosclerotic rat group and the TSG-treated group, and its proteome was analyzed by two-dimensional gel electrophoresis (2-DE). Proteins showing significant changes in expression were identified and analyzed by matrix-assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). As a result, 21 protein spots were found with significant differential expression after the treatment with TSG. A total of 18 spots were identified by database searching, and 17 spots matched with known proteins. Among these proteins (11 proteins up-regulated and six proteins down-regulated), five proteins were mainly involved in inflammation, cholesterol transport, cell apoptosis and adhesion. TSG treatment enhanced the expression of HSP 70, lipocortin 1 and Apo A-I, and inhibited the expression of calreticulin, vimentin. Furthermore, we randomly selected four proteins and confirmed the results of proteomic analysis by RT-PCR and western blotting. In conclusion, TSG treatment suppresses atherosclerosis by altering the expression of different proteins. Calreticulin, vimentin, HSP 70, lipocortin 1, and Apo A-I, are key proteins that may be novel molecular targets responsible for atherogenesis suppression induced by TSG treatment.

2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside inhibits proliferation of vascular smooth muscle cells: involvement of NO/cGMP/PKG pathway

The proliferation of vascular smooth muscle cells (VSMCs) induced by injury to the intima of arteries is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis. 2,3,4',5-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from Polygonum multiflorum, has been found to have an antiatherosclerotic effect. The aim of this study was to investigate the effects of TSG on platelet derived growth factor (PDGF)-BB induced VSMCs proliferation and to explore the possible mechanisms of such effects. Pretreatment of VSMCs with TSG significantly inhibited PDGF-BB-induced cell proliferation in a concentration-dependent but not time-dependent manner. In addition, flow cytometry analysis of the DNA content revealed blocking of the PDGF-BB-inducible cell cycle progression by TSG. On the contrary, an inhibitory effect of TSG on VSMCs proliferation and expression of cell cycle regulators were markedly attenuated by addition of an nitric oxide (NO) synthase inhibitor, a soluble guanylate cyclase inhibitor and a cyclic GMP (cGMP)-dependent protein kinase (PKG) inhibitor: N(G)-nitro-L-arginine methyl ester (L-NAME), 1H-[1,2,4] oxadiazolo [4,3-α] quinoxalin-1-one (ODQ) and KT5823, respectively. It was also demonstrated that TSG enhanced NO and cGMP formation through up-regulating endothelial NO synthase expression in VSMCs. The findings indicate that TSG inhibited VSMCs proliferation induced by PDGF-BB may involve the NO/cGMP/PKG signal pathway.

Beneficial effects of THSG on acetic acid-induced experimental colitis: involvement of upregulation of PPAR-γ and inhibition of the Nf-Κb inflammatory pathway

The polyphenolic compound 2,3,5,4′-tetrahydroxystilbene-2-O-beta-D-glucoside (THSG) has been shown to possess anti-inflammatory effects. Here, we examined the effects of THSG on experimental mice with colitis induced by acetic acid and whether the underlying mechanisms were associated with the PPAR-γ and NF-κB pathways. Mice were randomized into six equal groups: normal, colitis model, THSG (10, 30, 60 mg·kg⁻¹) and mesalazine. The mice were administered 10, 30, 60 mg·kg⁻¹ THSG or 100 mg·kg⁻¹ mesalazine or saline once daily by intragastric administration for 7 days after induction of colitis by acetic acid irrigation. THSG dramatically attenuated acetic acid-induced colon lesions, including reversing the body weight loss and improving histopathological changes. THSG apparently decreased the increase of malondialdehyde (MDA) which is a marker of lipid peroxidation. THSG appears to exert its beneficial effects on acetic acid-induced experimental colitis through upregulation of PPAR-γ mRNA and protein levels and inhibition of the NF-κB pathway, which in turn decreases the protein overexpression of the downstream inflammatory mediators TNF-α, IL-6 and COX-2. The effect of THSG 60 mg·kg⁻¹ on PPAR-γ mRNA expression was higher than that of mesalazine. THSG may thus be a promising new candidate or lead compound for the treatment of IBD.

Montelukast inhibits matrix metalloproteinases expression in atherosclerotic rabbits

BACKGROUND

Matrix metalloproteinases (MMPs) play important roles in the development and destabilization of atherosclerotic plaques. It is known that montelukast inhibits neointimal hyperplasia. However, the underlying mechanisms for the inhibitory effects of montelukast on neointimal formation have been poorly defined.

METHODS

Thirty-six male New Zealand White rabbits were randomized as normal control, placebo (0.9% NaCl, 1.5 ml/kg/day, via intraperitoneal injection), atorvastatin (atorvastatin, 1.5 mg/kg/day, orally) and montelukast groups (montelukast, 1.5 mg/kg/day, via intraperitoneal injection). Atherosclerosis was induced by balloon-injury and high-cholesterol (HC) diet. Serum lipids were measured at 0, 8 and 12 weeks. After 12 weeks, the rabbits were sacrificed and histopathological changes examined. Immunohistochemistry and reverse transcription-polymerase chain reaction were used to measure the expression of MMP-2 and MMP-9 in the plaques.

RESULTS

It was found that montelukast reduced neointimal formation, decreased macrophage accumulation, and increased smooth muscle cells. It also attenuated the expression of MMP-2 and MMP-9 in atherosclerotic plaques, but it had no effect on plasma lipid levels.

CONCLUSION

These data indicate that montelukast inhibits neointimal hyperplasia in association with decreased expression of MMP-2 and MMP-9 independent of plasma lipid levels in atherosclerotic plaques after vascular injury in hyperlipidemic rabbits.