Polydatin ameliorates experimental diabetes-induced fibronectin through inhibiting the activation of NF-κB signaling pathway in rat glomerular mesangial cells

Potential of Polydatin Against Ischemia-Reperfusion Injury: New Insights from Pharmacological-Pathological Mechanism Associations

Ischemia-reperfusion injury is a multi-tissue/organ susceptible and highly destructive disease. The complex pathological mechanisms of ischemia-reperfusion injury make its prevention and treatment highly challenging, and the development of novel drugs with pharmacological pleiotropy that can target multiple pathological mechanisms has become the focus of current drug research. Polydatin is a traditional Chinese medicine monomer with pleiotropic pharmacological effects, and existing research evidence suggests that polydatin has strong protective potential against ischemia-reperfusion injury. However, the mechanism of polydatin against ischemia-reperfusion injury is still unclear. In this review, the extensive pharmacological-pathological mechanism associations between polydatin and ischemia-reperfusion injury have been described from the perspectives of inflammatory response, oxidative stress, apoptosis, autophagy, ferroptosis, and cellular pyroptosis, which will provide references to the basic and applied research of polydatin in the field of ischemia-reperfusion injury.

Improved bioavailability of polydatin and its protective effect against cisplatin induced nephrotoxicity through self-assembled fucoidan and carboxymethyl chitosan delivery system

Cisplatin induced acute kidney injury (AKI) is clinically prevalent, with a complex pathogenesis and a lack of effective therapeutic drugs. Polydatin (Po) has excellent biological activity, but its low solubility and bioavailability limit its application. In this study, fucoidan (Fu) and carboxymethyl chitosan (Cs) self-assembled into nanoparticles through electrostatic interactions/hydrogen bonding and loaded Po (Fu/Cs Po NPs). In vitro studies found that Fu/Cs Po NPs protected human renal tubular epithelial (HK-2) cells from cisplatin induced damage and accumulation of reactive oxygen species (ROS). Mechanistic studies showed that Fu/Cs Po NPs inhibited cisplatin induced DNA damage and activation of cyclic guanosine monophosphate synthase (cGAS) and intron gene stimulator (STING) pathways. In vivo studies showed that Fu/Cs Po NPs treatment alleviated cisplatin induced AKI symptoms, including elevated blood urea nitrogen (BUN) and serum creatinine (SCr), as well as pathological damage to kidney tissues. In vivo mechanism studies also showed that Fu/Cs Po NPs treatment inhibited cisplatin induced DNA damage and activation of the cGAS-STING pathway. The pharmacokinetic and tissue distribution results demonstrated that the Fu/Cs delivery system enhanced the bioavailability and kidney accumulation of Po in vivo. In summary, our study provided potential drugs for the treatment of cisplatin induced AKI.

Resveratrol and piceid enhance efferocytosis by increasing the secretion of MFG-E8 in human THP-1 macrophages

The process of apoptotic cell clearance by phagocytes, known as efferocytosis, plays an essential role in maintaining homeostasis. Defects in efferocytosis can lead to inflammatory diseases such as atherosclerosis and autoimmune disorders. Therefore, the maintenance and promotion of efferocytosis are considered crucial for preventing these diseases. In this study, we observed that resveratrol, a representative functional food ingredient, and its glycoside, piceid, promoted efferocytosis in both human THP-1 macrophages differentiated with phorbol 12-myristate 13-acetate and peritoneal macrophages from thioglycolate-elicited mice. Resveratrol and piceid significantly increased mRNA expression and protein secretion of MFG-E8 in THP-1 macrophages. Furthermore, the activation of efferocytosis and the increment in MFG-E8 protein secretion caused by resveratrol or piceid treatment were canceled by MFG-E8 knockdown in THP-1 macrophages. In conclusion, we have demonstrated for the first time that resveratrol and piceid promote efferocytosis through the upregulation of MFG-E8 excretion in human THP-1 macrophages.

Polydatin attenuates diabetic renal inflammatory fibrosis via the inhibition of STING pathway

Diabetic nephropathy (DN) is a complication of diabetes and is mainly characterized by renal fibrosis, which could be attributed to chronic kidney inflammation. Stimulator of interferon genes (STING), a linker between immunity and metabolism, could ameliorate various metabolic and inflammatory diseases. However, the regulatory role of STING in DN remains largely unexplored. In this study, knockdown of STING decreased extracellular matrix (ECM), pro-inflammatory, and fibrotic factors in high glucose (HG)-induced glomerular mesangial cells (GMCs), whereas overexpression of STING triggered the inflammatory fibrosis process, suggesting that STING was a potential target for DN. Polydatin (PD) is a glucoside of resveratrol and has been reported to ameliorate DN by inhibiting inflammatory responses. Nevertheless, whether PD improved DN via STING remains unclear. Here, transcriptomic profiling implied that the STING/NF-κB pathway might be an important target for PD. We further found that PD decreased the protein expression of STING, and subsequently suppressed the activation of downstream targets including TBK1 phosphorylation and NF-κB nuclear translocation, and eventually inhibited the production of ECM, pro-inflammatory and fibrotic factors in HG-induced GMCs. Notably, results of molecular docking, molecular dynamic simulations, surface plasmon resonance, cellular thermal shift assay and Co-immunoprecipitation assay indicated that PD directly bound to STING and restored the declined proteasome-mediated degradation of STING induced by HG. In diabetic mice, PD also inhibited the STING pathway and improved the pathological changes of renal inflammatory fibrosis. Our study elucidated the regulatory role of STING in DN, and the novel mechanism of PD treating DN via inhibiting STING expression.

Polydatin improves vascular endothelial function by maintaining mitochondrial homeostasis under high glucose conditions

Previous studies have shown that polydatin (Poly) confer cardioprotective effects. However, its underlying mechanisms remain elusive. This study showed that Poly (10 µM) treatment reversed the high glucose (HG)-induced decrease in acetylcholine-elicited vasodilation in aortas. Poly also improved the acetylcholine-induced vasodilation of aortic vessels isolated from diabetic rats. Meanwhile, Poly ameliorated the morphological damage of the thoracic aorta and improved the viability of HUVECs under HG conditions. Furthermore, analysis of the vasoprotective effect of Poly under HG conditions by transmission electron microscopy, Western blotting, and qPCR revealed that Poly improved endothelial pyroptosis through the NLRP3/Caspase/1-IL-1β pathway, enhanced dynamin-related protein 1-mediated mitochondrial fission, and increased the mitochondrial membrane potential under HG conditions. In conclusion, Poly restored acetylcholine-induced vasodilation impaired by HG incubation, which was associated with reduced oxidation, inflammation, and pyroptosis, the recovery of the mitochondrial membrane potential and maintenance of mitochondrial dynamic homeostasis of endothelial cells in the aortas.

The association between circulatory, local pancreatic PCSK9 and type 2 diabetes mellitus: The effects of antidiabetic drugs on PCSK9

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a potent modulator of cholesterol metabolism and plays a crucial role in the normal functioning of pancreatic islets and the progression of diabetes. Islet autocrine PCSK9 deficiency can lead to the enrichment of low-density lipoprotein (LDL) receptor (LDLR) and excessive LDL cholesterol (LDL-C) uptake, subsequently impairing the insulin secretion in β-cells. Circulatory PCSK9 levels are primarily attributed to hepatocyte secretion. Notably, anti-PCSK9 strategies proposed for individuals with hypercholesterolemia chiefly target liver-derived PCSK9; however, these anti-PCSK9 strategies have been associated with the risk of new-onset diabetes mellitus (NODM). In the current review, we highlight a new direction in PCSK9 inhibition therapy strategies: screening candidates for anti-PCSK9 from the drugs used in type 2 diabetes mellitus (T2DM) treatment. We explored the association between circulating, local pancreatic PCSK9 and T2DM, as well as the relationship between PCSK9 monoclonal antibodies and NODM. We discussed the emergence of artificial and natural drugs in recent years, exhibiting dual benefits of antidiabetic activity and PCSK9 reduction, confirming that the diverse effects of these drugs may potentially impact the progression of diabetes and associated disorders, thereby introducing novel avenues and methodologies to enhance disease prognosis.

Stilbenes, a Versatile Class of Natural Metabolites for Inflammation-An Overview

Stilbenes are polyphenolic allelochemicals synthesized by plants, especially grapes, peanuts, rhubarb, berries, etc., to defend themselves under stressful conditions. They are now exploited in medicine for their antioxidant, anti-proliferative and anti-inflammatory properties. Inflammation is the immune system's response to invading bacteria, toxic chemicals or even nutrient-deprived conditions. It is characterized by the release of cytokines which can wreak havoc on healthy tissues, worsening the disease condition. Stilbenes modulate NF-κB, MAPK and JAK/STAT pathways, and reduce the transcription of inflammatory factors which result in maintenance of homeostatic conditions. Resveratrol, the most studied stilbene, lowers the Michaelis constant of SIRT1, and occupies the substrate binding pocket. Gigantol interferes with the complement system. Besides these, oxyresveratrol, pterostilbene, polydatin, viniferins, etc., are front runners as drug candidates due to their diverse effects from different functional groups that affect bioavailability and molecular interactions. However, they each have different thresholds for toxicity to various cells of the human body, and thus a careful review of their properties must be conducted. In animal models of autoinflammatory diseases, the mode of application of stilbenes is important to their absorption and curative effects, as seen with topical and microemulsion gel methods. This review covers the diversity seen among stilbenes in the plant kingdom and their mechanism of action on the different inflammatory pathways. In detail, macrophages' contribution to inflamed conditions in the liver, the cardiac, connective and neural tissues, in the nephrons, intestine, lungs and in myriad other body cells is explored, along with detailed explanation on how stilbenes alleviate the symptoms specific to body site. A section on the bioavailability of stilbenes is included for understanding the limitations of the natural compounds as directly used drugs due to their rapid metabolism. Current delivery mechanisms include sulphonamides, or using specially designed synthetic drugs. It is hoped that further research may be fueled by this comprehensive work that makes a compelling argument for the exploitation of these compounds in medicine.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

Inhibiting apoptosis of Schwann cell under the high-glucose condition: A promising approach to treat diabetic peripheral neuropathy using Chinese herbal medicine

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes. Glycemic control and lifestyle alterations cannot prevent the development of DPN; therefore, investigating effective treatments for DPN is crucial. Schwann cells (SCs) maintain the physiological function of peripheral nerves and promote the repair and regeneration of injured nerves. Inhibiting the apoptosis of SCs through various pathological pathways in a high-glucose environment plays an important role in developing DPN. Therefore, inhibiting the apoptosis of SCs can be a novel treatment strategy for DPN. Previous studies have indicated the potential of Chinese herbal medicine (CHM) in treating DPN. In this study, we have reviewed the effects of CHM (both monomers and extracts) on the apoptosis of SCs by interfering with the production of advanced glycation end products, oxidative stress, and endoplasmic reticulum stress pathological pathways. This review will demonstrate the potentialities of CHM in inhibiting apoptosis in SCs, providing new insights and perspectives for treating DPN.

Uncovering the Anticancer Potential of Polydatin: A Mechanistic Insight

Polydatin or 3-O-β-d-resveratrol-glucopyranoside (PD), a stilbenoid component of Polygonum cuspicadum (Polygonaceae), has a variety of biological roles. In traditional Chinese medicine, P. cuspicadum extracts are used for the treatment of infections, inflammation, and cardiovascular disorders. Polydatin possesses a broad range of biological activities including antioxidant, anti-inflammatory, anticancer, and hepatoprotective, neuroprotective, and immunostimulatory effects. Currently, a major proportion of the population is victimized with cervical lung cancer, ovarian cancer and breast cancer. PD has been recognized as a potent anticancer agent. PD could effectively inhibit the migration and proliferation of ovarian cancer cells, as well as the expression of the PI3K protein. The malignancy of lung cancer cells was reduced after PD treatments via targeting caspase 3, arresting cancer cells at the S phase and inhibiting NLRP3 inflammasome by downregulation of the NF-κB pathway. This ceases cell cycle, inhibits VEGF, and counteracts ROS in breast cancer. It also prevents cervical cancer by regulating epithelial-to-mesenchymal transition (EMT), apoptosis, and the C-Myc gene. The objective of this review is thus to unveil the polydatin anticancer potential for the treatment of various tumors, as well as to examine the mechanisms of action of this compound.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

Pharmacological effects of polydatin in the treatment of metabolic diseases: A review

BACKGROUND

Metabolic diseases (MDs), a series of chronic disorders, severely decreases the quality of life for patients but also cause a heavy economic burden. Emerging evidence suggests that Polydatin (PD), an important glucoside of resveratrol, is widely distributed in many plants and has shown good therapeutic potential in metabolic diseases.

PURPOSE

To review the PD discovered before 2021 and their potential to treat metabolic diseases. The activities against diabetes, Obesity, atherosclerosis, NAFLD, NASH, hyperlipidemia, and gout with special emphasis on pharmacology, pharmacokinetics, mechanisms of action, possible roles in current medicine, and future perspectives are discussed.

METHODS

A comprehensive search of published literature was conducted to locate original publications pertaining to polydatin and MDs through the end of 2021 using MEDLINE, Elsevier, Springer, PubMed, Scholar, and CNKI databases. The main inquiry used was for the presence of the following keywords in various combinations in the abstracts: 'Polydatin', 'Metabolic diseases', 'Pharmacology', 'Toxicology', 'Pharmacokinetics', 'Diabetes', 'Obesity', 'Atherosclerosis', 'Non-alcoholic fatty liver disease', 'Non-alcoholic steatohepatitis', 'Hyperlipidemia', and 'Gout'.

RESULTS

The search yielded 987 articles, of which 33 articles were included in this review. Studies have revealed that PD can promote insulin secretion, alleviate insulin resistance, regulate glucose and lipid metabolism, reduce liver lipid deposition, inhibit inflammation, oxidative stress, and decrease uric acid deposition in preclinical experiments. The underlying mechanisms of PD in treatment MDs may be attributed to the regulation of multiple signaling pathways, including. NF-κB, AGEs/RAGE, MAPK/ERK, AMPK/LDLR, IRS1/PI3K/AKT, LKB1/AMPK, PPARβ-NO, SIRT1-PGC-1α-SOD2, PKC, etc., The pharmacokinetic profiles of PD provide valuable information on therapeutic efficacy in treating metabolic diseases.

CONCLUSION

This review summarizes the available reports and evidence which support the use of PD as a potential candidate in the treatment of MDs and provides an overview of the modulatory effects of PD in metabolic diseases and cell signaling pathways, which may have important implications in its future clinical use.

Polydatin as a therapeutic alternative for central nervous system disorders: A systematic review of animal studies

Polydatin, or piceid, is a natural stilbene found in grapes, peanuts, and wines. Polydatin presents pharmacological activities, including neuroprotective properties, exerting preventive and/or therapeutic effects in central nervous system (CNS) disorders. In the present study, we summarize and discuss the neuroprotective effects of polydatin in CNS disorders and related pathological conditions in preclinical animal studies. A systematic review was performed by searching online databases, returning a total of 110 records, where 27 articles were selected and discussed here. The included studies showed neuroprotective effects of polydatin in experimental models of neurological disorders, including cerebrovascular disorders, Parkinson's disease, traumatic brain injuries, diabetic neuropathy, glioblastoma, and neurotoxicity induced by chemical agents. Most studies were focused on stroke (22.2%) and conducted in male rodents. The intervention protocol with polydatin was mainly acute (66.7%), with postdamage induction treatment being the most commonly used regimen (55.2%). Overall, polydatin ameliorated behavioral dysfunctions and/or promoted neurological function by virtue of its antioxidant and antiinflammatory properties. In summary, this review offers important scientific evidence for the neuroprotective effects and distinct pharmacological mechanisms of polydatin that not only enhances the present understanding but is also useful for the development of future preclinical and clinical investigations.

Polyphenols and Their Metabolites in Renal Diseases: An Overview

Kidney diseases constitute a worldwide public health problem, contributing to morbidity and mortality. The present study aimed to provide an overview of the published data regarding the potential beneficial effects of polyphenols on major kidney diseases, namely acute kidney injury, chronic kidney disease, diabetic nephropathy, renal cancer, and drug-induced nephrotoxicity. This study consists of a bibliographical review including in vitro and in vivo studies dealing with the effects of individual compounds. An analysis of the polyphenol metabolome in human urine was also conducted to estimate those compounds that are most likely to be responsible for the kidney protective effects of polyphenols. The biological effects of polyphenols can be highly attributed to the modulation of specific signaling cascades including those involved in oxidative stress responses, anti-inflammation processes, and apoptosis. There is increasing evidence that polyphenols afford great potential in renal disease protection. However, this evidence (especially when in vitro studies are involved) should be considered with caution before its clinical translation, particularly due to the unfavorable pharmacokinetics and extensive metabolization that polyphenols undergo in the human body. Future research should consider polyphenols and their metabolites that indeed reach kidney tissues.

Dexmedetomidine Protects Against Kidney Fibrosis in Diabetic Mice by Targeting miR-101-3p-Mediated EndMT

Objective: Our main purpose is to explore the effect and mechanism of Dexmedetomidine (DEX)  in diabetic nephropathy fibrosis.

Methods: Diabetic model was established by intraperitoneal injection of streptozotocin (STZ) treated CD-1 mice and high glucose cultured human dermal microvascular endothelial cells (HMVECs). Immunofluorescence was used to detect renal endothelial-mesenchymal transition (EndMT); Hematoxylin and Eosin (HE) staining and Masson’s Trichrome Staining (MTS) was used to analyze renal fibrosis; CCK-8 was used to evaluate cell viability; Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to assess the expression of miR-101-3p; Western blots were utilized to judge the protein expression levels of EndMT, extracellular matrix and TGF-β1/Smad3 signal pathway.

Results: In this study, we first found that the protective effect of DEX on DN was related to EndMT. DEX alleviated kidney fibrosis by inhibiting EndMT in diabetic CD-1 mice. DEX could also inhibit high glucose-induced HMVECs EndMT. Then, we confirmed that miR-101-3p was the regulatory target of DEX. The expression of miR-101-3p was decreased in diabetic CD-1 mice and high glucose-induced HMVECs. After DEX treatment, the miR-101-3p increased, and the inhibition of miR-101-3p could counteract the protective effect of DEX and aggravate the EndMT. Finally, we found that the TGF- β1/Smad3 signal pathway was involved in the protective effect of DEX on DN. DEX inhibited the activation of TGF-β1/Smad3 signal pathway. On the contrary, inhibiting miR-101-3p promoted the expression of TGF-β1/Smad3.

Conclusion: DEX protects kidney fibrosis in diabetic mice by targeting miR-101-3p-mediated EndMT.

Polydatin Attenuates Cisplatin-Induced Acute Kidney Injury by Inhibiting Ferroptosis

Cisplatin is widely used in the treatment of solid tumors, but its application is greatly limited due to its nephrotoxicity; thus, there is still no effective medicine for the treatment of cisplatin-induced acute kidney injury (Cis-AKI). We previously identified that polydatin (PD) exerts nephroprotective effects by antioxidative stress in AKI models. Recent evidence suggests that oxidative stress-induced molecular events overlap with the process of ferroptosis and that there are common molecular targets, such as glutathione (GSH) depletion and lipid peroxidation. Nevertheless, whether the nephroprotective effect of PD is related to anti-ferroptosis remains unclear. In this study, the inhibitory effect of PD on ferroptosis was observed in both cisplatin-treated HK-2 cells (20 μM) in vitro and a Cis-AKI mouse model (20 mg/kg, intraperitoneally) in vivo, characterized by the reversion of excessive intracellular free iron accumulation and reactive oxygen species (ROS) generation, a decrease in malondialdehyde (MDA) content and GSH depletion, and an increase in glutathione peroxidase-4 (GPx4) activity. Remarkably, PD dose-dependently alleviated cell death induced by the system Xc⁻ inhibitor erastin (10 μM), and the effect of the 40 μM dose of PD was more obvious than that of ferrostatin-1 (1 μM) and deferoxamine (DFO, 100 μM), classical ferroptosis inhibitors. Our results provide insight into nephroprotection with PD in Cis-AKI by inhibiting ferroptosis via maintenance of the system Xc⁻-GSH-GPx4 axis and iron metabolism.

Polydatin Alleviates Diabetes-Induced Hyposalivation through Anti-Glycation Activity in db/db Mouse

Polydatin (resveratrol-3-O-β-mono-D-glucoside) is a polyphenol that can be easily accessed from peanuts, grapes, and red wine, and is known to have antiglycation, antioxidant, and anti-inflammatory effects. Diabetes mellitus is a very common disease, and diabetic complications are very common complications. The dry mouth symptom is one of the most common oral complaints in patients with diabetes mellitus. Diabetes mellitus is thought to promote hyposalivation. In this study, we aimed to investigate the improvement effect of polydatin on diabetes-induced hyposalivation in db/db mouse model of type 2 diabetes. We examined salivary flow rate, TUNEL assay, PAS staining, and immunohistochemical staining for AGEs, RAGE, HMGB1, 8-OHdG, and AQP5 to evaluate the efficacy of polydatin in the submandibular salivary gland. Diabetic db/db mice had a decreased salivary flow rate and salivary gland weight. The salivary gland of the vehicle-treated db/db mice showed an increased apoptotic cell injury. The AGEs were highly accumulated, and its receptor, RAGE expression was also enhanced. Expressions of HMGB1, an oxidative cell damage marker, and 8-OHdG, an oxidative DNA damage marker, increased greatly. However, polydatin ameliorated this hypofunction of the salivary gland and inhibited diabetes-related salivary cell injury. Furthermore, polydatin improved mucin accumulation, which is used as a damage marker for salivary gland acinar cells, and decreased expression of water channel AQP5 was improved by polydatin. In conclusion, polydatin has a potent protective effect on diabetes-related salivary gland hypofunction through its antioxidant and anti-glycation activities, and its AQP5 upregulation. This result suggests the possibility of the use of polydatin as a therapeutic drug to improve hyposalivation caused by diabetes.

Therapeutic potential of resveratrol in diabetic nephropathy according to molecular signaling

BACKGROUND

Diabetic nephropathy (DN) as a severe complication of diabetes mellitus (DM), is a crucial menace for human health and survival and remarkably elevates the healthcare systems' costs. Therefore, it is worth noting to identify novel preventive and therapeutic strategies to alleviate the disease conditions. Resveratrol, as a well-defined anti-diabetic/ antioxidant agent has capabilities to counteract diabetic complications. It has been predicted that resveratrol will be a fantastic natural polyphenol for diabetes therapy in the next few years.

OBJECTIVE

Accordingly, the current review aims to depict the role of resveratrol in the regulation of different signaling pathways that are involved in the reactive oxygen species (ROS) production, inflammatory processes, autophagy, and mitochondrial dysfunction, as critical contributors to DN pathophysiology.

RESULTS

The pathogenesis of DN can be multifactorial; hyperglycemia is one of the prominent risk factors of DN development that is closely related to oxidative stress. Resveratrol, as a well-defined polyphenol, has various biological and medicinal properties, including anti-diabetic, anti-inflammatory, and anti-oxidative effects.

CONCLUSION

Resveratrol prevents kidney damages that are caused by oxidative stress, enhances antioxidant capacity, and attenuates the inflammatory and fibrotic responses. For this reason, resveratrol is considered an interesting target in DN research due to its therapeutic possibilities during diabetic disorders and renal protection.

Mechanisms and Efficacy of Chinese Herbal Medicines in Chronic Kidney Disease

As the current treatment of chronic kidney disease (CKD) is limited, it is necessary to seek more effective and safer treatment methods, such as Chinese herbal medicines (CHMs). In order to clarify the modern theoretical basis and molecular mechanisms of CHMs, we reviewed the knowledge based on publications in peer-reviewed English-language journals, focusing on the anti-inflammatory, antioxidative, anti-apoptotic, autophagy-mediated and antifibrotic effects of CHMs commonly used in kidney disease. We also discussed recently published clinical trials and meta-analyses in this field. Based on recent studies regarding the mechanisms of kidney disease in vivo and in vitro, CHMs have anti-inflammatory, antioxidative, anti-apoptotic, autophagy-mediated, and antifibrotic effects. Several well-designed randomized controlled trials (RCTs) and meta-analyses demonstrated that the use of CHMs as an adjuvant to conventional medicines may benefit patients with CKD. Unknown active ingredients, low quality and small sample sizes of some clinical trials, and the safety of CHMs have restricted the development of CHMs. CHMs is a potential method in the treatment of CKD. Further study on the mechanism and well-conducted RCTs are urgently needed to evaluate the efficacy and safety of CHMs.

Polydatin-loaded chitosan nanoparticles ameliorates early diabetic nephropathy by attenuating oxidative stress and inflammatory responses in streptozotocin-induced diabetic rat

In various developed countries, diabetic nephropathy (DN) is the principal cause of end-stage kidney disease and a main reason of injury and mortality in individuals with renal morbidity worldwide. Polydatin (POL) has been evaluated as a potential antioxidant, anti-inflammatory and a nephroprotective agent. In spite of this, the possible benefits and protective effects of POL on early diabetic nephropathy are not quite clarified. For the effective clearance from the body besides safe drug delivery, biodegradable nanoparticles have interesting attraction. This work was designed to evaluate the positive effect and possible mechanisms of Polydatin-loaded Chitosan-Nanoparticles (POL-NPs) on early DN in streptozotocin-induced diabetic rats. Followed the induction of diabetes, rats classified into four groups, diabetic control and diabetic rats treated daily and orally with; POL, Polydatin-loaded chitosan-Nanoparticles (POL-NPs), plus normal control rats. Our findings showed that diabetic group presented a significant high level of the blood glucose, blood glycosylated hemoglobin (HbA1c), serum insulin, renal function related parameters, renal Advanced glycation-end products (AGEs) and lipid peroxidation level compared to normal control rats, while serum albumin level and the activities of renal antioxidant enzymes were significantly decreased. Moreover, in the kidney of diabetic rat mRNA expression of nuclear factor-kappa B (NF-κB) and cyclooxygenase-2 (Cox-2) were up-regulated. Besides, increase in serum levels of pro-inflammatory cytokines (TNF-α, IL-6 and IL-18) and decrease in anti-inflammatory cytokine (IL-10). POL and POL-NPs supplementation were significantly attenuate the above-mention results and returned the normal equilibrium between pro- and anti-inflammatory cytokines. In conclusion, POL and POL-NPs have antidiabetic effect, suppresses oxidative stress and mitigates renal inflammation through inhibition of NF-κB in diabetic kidney in early progressive DN.

Dissecting Efficacy and Metabolic Characteristic Mechanism of Taxifolin on Renal Fibrosis by Multivariate Approach and Ultra-Performance Liquid Chromatography Coupled With Mass Spectrometry-Based Metabolomics Strategy

Taxifolin (TFN) is an important natural compound with antifibrotic activity; however, its pharmacological mechanism is not clear. In this study, our aim is to gain insight into the effects of TFN and its potential mechanisms in unilateral ureteral obstruction (UUO) animal model using metabolomics approach to identify the metabolic biomarkers and perturbed pathways. Serum metabolomics analysis by UPLC-Q-TOF/MS was carried out to discover the changes in the metabolic profile. It showed that TFN has a significant protective effect on UUO-induced renal fibrosis and a total of 32 potential biomarkers were identified and related to RF progression. Of note, 27 biomarkers were regulated by TFN treatment, which participate in eight metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, and phenylalanine metabolism. It also showed that metabolomics was a promising strategy to better dissect metabolic characteristics and pharmacological mechanisms of natural compounds by multivariate approach and ultra-performance liquid chromatography coupled with mass spectrometry.

Control over Polymorph Formation of Polydatin in Binary Solvent System and Structural Characterization

Polydatin is a natural product used for anti-oxidant, anti-inflammatory and anti-tumor purposes, and often added in medicine, nutraceutical, cosmetics, and dietary supplement. Polymorphism is a key feature of solid-state pharmaceutical products. Polymorphic modifications may exhibit different physical and chemical properties. Here we report two different polymorphs, and the amorphous form of Polydatin. Polymorphs were prepared in binary solvent system. The crystal structures of the two forms were revealed for the first time. The structure and 3D packing were determined with single crystal X-ray diffraction analysis. The batch consistency and stability were identified with Powder X-ray diffraction analysis. Various functional groups present in the polymorphs were analyzed with fourier transform infrared spectroscopic method. The thermal properties were investigated with DSC and TGA. HPLC-MS was used for the pharmacokinetic study. Results show that form B has the faster absorption, and can be maintained in animal bodies for a longer time than form A.

Polydatin attenuates hepatic stellate cell proliferation and liver fibrosis by suppressing sphingosine kinase 1

Sphingosine kinase 1 (SphK1) plays critical roles in the activation of hepatic stellate cells (HSCs) and liver fibrosis. Our previous study found that polydatin ameliorates chronic liver injury and fibrosis by inhibiting oxidative stress. However, whether polydatin exerts an anti-fibrotic effect on liver fibrosis dependent on SphK1 signaling is unknown. We aimed to investigate the role of polydatin in SphK1, which mediates HSC activation and liver fibrosis. C57BL/6 mice were induced using CCl₄ 5 μL g^-1 i.p. twice a week for 6 weeks and treated with or without polydatin. Human immortalized HSC line (LX-2) was induced using platelet-derived growth factor-BB (PDGF-BB) or adenovirus-SphK1 and treated with polydatin. Hepatic macrophage filtration, collagen deposition, expression of α-smooth muscle, active caspase-3, and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells were markedly increased in mice induced by CCl₄ for 6 weeks. In contrast, polydatin attenuated collagen synthesis and hepatocyte apoptosis. Furthermore, polydatin exhibited significant anti-proliferative activity against PDGF-BB-induced activated hepatic stellate cells (HSCs). SphK1 was strongly induced in mice exposed to CCl₄, whereas its expression and activity were inhibited by polydatin treatment. Finally, SphK1 overexpression in LX-2 cells promoted proliferation of activated HSCs, which could not be reversed by polydatin treatment. These results demonstrate that polydatin attenuates HSC proliferation and activation through inhibition of SphK1 signaling, contributing to the suppression of liver fibrosis.

Preliminary research on the effects and mechanisms of umbilical cord‑derived mesenchymal stem cells in streptozotocin‑induced diabetic retinopathy

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes, and a common cause of blindness in working‑age individuals. Mesenchymal stem cell (MSC) transplantation has been considered a promising intervention therapy for DR, wherein the differentiation of MSCs into nerve cells plays an essential role. However, research into the role of MSCs in DR treatment remains incomplete, and the mechanisms of retinal repair at the molecular level have yet to be clarified. In the present study, all‑trans retinoic acid (ATRA) was used to promote the proliferation of rat umbilical cord (UC)‑derived MSCs and their differentiation into nerve cells. Furthermore, the effects and mechanisms of UC‑MSCs with or without ATRA treatment were investigated in rats subjected to streptozocin (STZ)‑induced DR. The results demonstrated that the transplantation of UC‑MSCs treated with or without ATRA attenuated DR in rats, and alleviated retinal tissue damage and apoptosis. In addition, the transplantation of UC‑MSCs treated with or without ATRA attenuated angiogenesis and inflammation in the retina by regulating the levels of relevant cytokines. UC‑MSCs treated with ATRA exerted a more prominent therapeutic effect than the untreated UC‑MSCs. On the whole, these findings indicate that UC‑MSCs alleviate STZ‑induced DR in rats by regulating angiogenesis and the inflammatory response at the molecular level. Thus, the findings of the present study may provide a theoretical basis for the application of MSCs in the treatment of DR.

Dietary polyphenols as antidiabetic agents: Advances and opportunities

Dietary polyphenols have been widely investigated as antidiabetic agents in cell, animals, human study, and clinical trial. The number of publication (Indexed by Web of Science) on “polyphenols and diabetes” significantly increased since 2010. This review highlights the advances and opportunities of dietary polyphenols as antidiabetic agents. Dietary polyphenols prevent and manage Type 2 diabetes mellitus via the insulin‐dependent approaches, for instance, protection of pancreatic islet β‐cell, reduction of β‐cell apoptosis, promotion of β‐cell proliferation, attenuation of oxidative stress, activation of insulin signaling, and stimulation of pancreas to secrete insulin, as well as the insulin‐independent approaches including inhibition of glucose absorption, inhibition of digestive enzymes, regulation of intestinal microbiota, modification of inflammation response, and inhibition of the formation of advanced glycation end products. Moreover, dietary polyphenols ameliorate diabetic complications, such as vascular dysfunction, nephropathy, retinopathy, neuropathy, cardiomyopathy, coronary diseases, renal failure, and so on. The structure–activity relationship of polyphenols as antidiabetic agents is still not clear. The individual flavonoid or isoflavone has no therapeutic effect on diabetic patients, although the clinical data are very limited. Resveratrol, curcumin, and anthocyanins showed antidiabetic activity in human study. How hyperglycemia influences the bioavailability and bioactivity of dietary polyphenols is not well understood. An understanding of how diabetes alters the bioavailability and bioactivity of dietary polyphenols will lead to an improvement in their benefits and clinical outcomes.

Fucoxanthin Alleviates Oxidative Stress through Akt/Sirt1/FoxO3α Signaling to Inhibit HG-Induced Renal Fibrosis in GMCs

As one of the main marine carotenoids, fucoxanthin has strong antioxidant activity. FoxO3α, a member of the forkhead box O family of transcription factors, plays an important role in DN by regulating oxidative stress. The activity of FoxO3α is related to its phosphorylation and acetylation status, regulated by Akt and Sirt1, a lysine deacetylase. Our study aimed to investigate whether fucoxanthin could alleviate oxidative stress and fibrosis via FoxO3α in DN and whether Akt and Sirt1 were involved. We found that in GMCs cultured in HG, fucoxanthin treatment significantly reduced the expression of FN and collagen IV, as well as reactive oxygen species generation, suggesting that fucoxanthin is beneficial to alleviate both fibrosis and oxidative stress in DN. In addition, we found that fucoxanthin decreased the phosphorylation and acetylation level of FoxO3α, reversed the protein level of FoxO3α inhibited by HG, and then promoted the nuclear transport of FoxO3α. Besides, fucoxanthin promoted the expression of manganese superoxide dismutase, a downstream target of FoxO3α. Furthermore, we found that fucoxanthin reversed the activation of Akt and inhibition of Sirt1. However, the enhancement of fucoxanthin in FoxO3α expression and nuclear transport was significantly decreased by pretreatment with Akt activator SC79 or Sirt1 inhibitor EX527. In summary, our study explored fucoxanthin alleviated oxidative stress and fibrosis induced by HG through Akt/Sirt1/FoxO3α signaling in GMCs, suggesting fucoxanthin is a potential therapeutic strategy for DN.

Novel polydatin-loaded chitosan nanoparticles for safe and efficient type 2 diabetes therapy: In silico, in vitro and in vivo approaches

Polydatin (PD) has many pharmacological activities; however, its bioavailability is still a critical cornerstone issue. The present investigation aimed to develop a novel oral formula of polydatin-loaded chitosan nanoparticles (PD-CSNPs) to improve PD therapeutic potential against type 2 diabetes. The interaction mechanism between PD and CSNPs was studied via Monte Carlo and molecular dynamics simulations. The formula was prepared and characterized by FTIR, XRD, TEM, and dynamic light scattering. The release profile of PD was studied in vitro, as well as the cytotoxicity effect versus Vero cell line and antidiabetic activity in type 2 diabetic rats were investigated. The practical results verified the formation of PD-CSNPs with entrapment efficiency of about 96.74 ± 0.39%, size average 144.25 ± 3.37 nm, and the prolonged release pattern was less than 20% after 12 hrs. The cytotoxicity study confirmed the safety of the formula at low and high doses. Moreover, the in vivo study revealed that PD-CSNPs exhibited highly significant antidiabetic efficacy in diabetic rats compared to free PD. To conclude, the current investigation proved that CSNPs are promising nanocarriers for nontoxic and effective PD delivery against type 2 diabetes.

Effects of Dexmedetomidine on the RhoA /ROCK/ Nox4 Signaling Pathway in Renal Fibrosis of Diabetic Rats

Objective

To investigate the effects and mechanisms of dexmedetomidine (Dex) on model rats of diabetic nephropathy (DN).

Methods

Rats were divided into NC, model, Dex-L (1μg/ kg), Dex-M (5μg/kg) and Dex-H (10μg/kg) groups. Rats in all groups except in the NC group were injected with streptozotocin (STZ) combined with right nephrectomy. Rats in Dex (1, 5 and 10μg/kg) groups received gavage with Dex (1, 5 and 10μg/kg). After 4 weeks, rats were sacrificed and kidneys were collected. HE staining was performed for a renal injury. Masson staining was applied to detect the fibrotic accumulation in rat kidney. Radioimmunoassay was used to test the renal function. Immunohistochemical method was used to detect protein expressions of RhoA, p-MYPT and Nox4 in rat kidney.

Results

Compared with the NC group, the levels of urine microalbumin in protein, α1-MG and β2-MG, renal fibrotic accumulation, RhoA, p-MYPT, Nox4 and α-SMA in model group increased significantly (P＜0.001, respectively). Compared with the model group, Dex low, medium and high groups improved the deposition of renal fiber in rats, inhibited the expression levels of microalbumin, α1-MG and β2-MG in urine and decreased expression of RhoA, p-MYPT, Nox4 and α-SMA proteins (P＜0.05, P＜0.01).

Conclusion

Dex is possible to inhibit the expression of α-SMA and renal fibrous substance deposition in rat kidney via RhoA/ROCK/Nox4 signaling pathway, thereby reducing early kidney damage in model rats.

Polydatin Inhibits Adipose Tissue Inflammation and Ameliorates Lipid Metabolism in High-Fat-Fed Mice

Polydatin (PD), an active component of Chinese herbs, is reported to have many biological functions, such as cardioprotective actions, anti-inflammatory activities, and antitumor effects. In this study, we investigated the effects of PD on body weight control, glucose and lipid metabolic regulation, and anti-inflammation in a high-fat-diet- (HFD-) induced obese mice model. After treatment of PD (100 mg/kg/d for 4 weeks), HFD mice reduced body weight, retroperitoneal fat mass, and adipose cell sizes; significantly lowered serum total cholesterol triglyceride (TG) and low-density lipoprotein (LDL) levels; and increased high-density lipoprotein (HDL) levels compared with the HFD control mice. Further studies showed that PD downregulated the mRNA and protein expressions of peroxisome proliferator-activated receptor gamma (PPARγ), a transcription factor involving in the regulation of adipocyte differentiation, in the retroperitoneal fat of HFD mice. Additionally, PD significantly upregulated the mRNA and protein expressions of leptin, an adipocyte-derived anorexic hormone that regulates food intake and energy expenditure, in the adipose tissues of HFD mice. Moreover, PD reduced the expression levels of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-α) in the retroperitoneal and epididymal tissues of HFD mice, suggesting that PD prevented adipose tissue inflammation. In conclusion, PD may serve as a pharmaceutic candidate for obesity-related lipid metabolism, anti-inflammation, and body weight loss.

Polydatin Inhibits NLRP3 Inflammasome in Dry Eye Disease by Attenuating Oxidative Stress and Inhibiting the NF-κB Pathway

Polydatin (also named pieceid, (E)-piceid, (E)-polydatin, trans-polydatin, or 3,5,4'-trihydroxystilbene-3-b-D-glucoside) is a monocrystalline compound isolated from the root and rhizome of Polygonum cuspidatum Sieb. et Zucc. (Polygonaceae). A previous study showed that polydatin has antioxidant and anti-inflammatory effects. However, the effect of polydatin in dry eye disease (DED) has not been elucidated. DED rat models were induced by exorbital lacrimal gland-excision. In vivo, the present study showed that the excision of lacrimal glands induced changes such as reduced tear fluid, severe corneal irregularity, damage, tear film break, and goblet cell loss as well as increased inflammation cytokine and NLRP3 expression in conjunctival tissue. However, these changes were restored by polydatin eye dropping. In vitro, polydatin inhibited hyperosmolar stress-induced inflammation through attenuation of the translocation of NF-κB to the nucleus and the mRNA expression of TNF-α, IL-6, IL-1β, and MMP9. In addition, the hyperosmolar stress-induced NLRP3 inflammasome pathway and ROS production were inhibited by polydatin. Our findings provided insight into the effect of polydatin as a candidate reagent for the treatment of DED.

Targeting the ROS/PI3K/AKT/HIF-1α/HK2 axis of breast cancer cells: Combined administration of Polydatin and 2-Deoxy-d-glucose

It is well established that cancer cells depend upon aerobic glycolysis to provide the energy they need to survive and proliferate. However, anti-glycolytic agents have yielded few positive results in human patients, in part due to dose-limiting side effects. Here, we discovered the unexpected anti-cancer efficacy of Polydatin (PD) combined with 2-deoxy-D-glucose (2-DG), which is a compound that inhibits glycolysis. We demonstrated in two breast cell lines (MCF-7 and 4T1) that combination treatment with PD and 2-DG induced cell apoptosis and inhibited cell proliferation, migration and invasion. Furthermore, we determined the mechanism of PD in synergy with 2-DG, which decreased the intracellular reactive oxygen (ROS) levels and suppressed the PI3K/AKT pathway. In addition, the combined treatment inhibited the glycolytic phenotype through reducing the expression of HK2. HK2 deletion in breast cancer cells thus improved the anti-cancer activity of 2-DG. The combination treatment also resulted in significant tumour regression in the absence of significant morphologic changes in the heart, liver or kidney in vivo. In summary, our study demonstrates that PD synergised with 2-DG to enhance its anti-cancer efficacy by inhibiting the ROS/PI3K/AKT/HIF-1α/HK2 signalling axis, providing a potential anti-cancer strategy.

Polydatin attenuates spinal cord injury in rats by inhibiting oxidative stress and microglia apoptosis via Nrf2/HO-1 pathway

AIMS

Spinal cord injury (SCI) is one of the most devastating central lesions, resulting in serious locomotor deficit. Polydatin is a glucoside of resveratrol with proven anti-cardiovascular, anti-inflammatory and anti-oxidative properties. The main purpose of this study was to investigate whether polydatin could alleviate SCI in rats and explore the underlying mechanisms.

MATERIALS AND METHODS

SCI rats induced by a weight-drop device were treated with intraperitoneal injection of 20 or 40 mg/kg polydatin. Then the locomotor function of SCI rats was evaluated by the Basso, Beattie and Bresnahan locomotor rating scale, spinal cord edema was measured by the wet/dry weight method, oxidative stress markers were detected by commercial kits and cell apoptosis status was measured by TUNEL staining. In addition, reactive oxygen species (ROS) generation, lactate dehydrogenase (LDH) production and apoptosis status were detected in murine microglia BV2 cells treated with 100 ng/ml lipopolysaccharides (LPS) and 4.0 μM polydatin. The expression of apoptosis-related proteins involved in nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway was measured by western blot.

KEY FINDINGS

Our data showed that polydatin treatment improved locomotor performance of SCI rats, as well as reduced oxidative stress and inhibited apoptosis by enhancing Nrf2/HO-1 signaling. In addition, polydatin was found to up-regulate Nrf2 activity and the inhibitory effects of polydatin on oxidative stress and apoptosis in LPS-stimulated BV2 microglia was neutralized by silencing Nrf2 using specific siRNA.

SIGNIFICANCE

We demonstrate that polydatin may protect the spinal cord from SCI by suppression of oxidative stress and apoptosis via improving Nrf2/HO-1 signaling in microglia.

Inhibiting the urokinase-type plasminogen activator receptor system recovers STZ-induced diabetic nephropathy

The urokinase-type plasminogen activator (uPA) receptor (uPAR) participates to the mechanisms causing renal damage in response to hyperglycaemia. The main function of uPAR in podocytes (as well as soluble uPAR -(s)uPAR- from circulation) is to regulate podocyte function through αvβ3 integrin/Rac-1. We addressed the question of whether blocking the uPAR pathway with the small peptide UPARANT, which inhibits uPAR binding to the formyl peptide receptors (FPRs) can improve kidney lesions in a rat model of streptozotocin (STZ)-induced diabetes. The concentration of systemically administered UPARANT was measured in the plasma, in kidney and liver extracts and UPARANT effects on dysregulated uPAR pathway, αvβ3 integrin/Rac-1 activity, renal fibrosis and kidney morphology were determined. UPARANT was found to revert STZ-induced up-regulation of uPA levels and activity, while uPAR on podocytes and (s)uPAR were unaffected. In glomeruli, UPARANT inhibited FPR2 expression suggesting that the drug may act downstream uPAR, and recovered the increased activity of the αvβ3 integrin/Rac-1 pathway indicating a major role of uPAR in regulating podocyte function. At the functional level, UPARANT was shown to ameliorate: (a) the standard renal parameters, (b) the vascular permeability, (c) the renal inflammation, (d) the renal fibrosis including dysregulated plasminogen-plasmin system, extracellular matrix accumulation and glomerular fibrotic areas and (e) morphological alterations of the glomerulus including diseased filtration barrier. These results provide the first demonstration that blocking the uPAR pathway can improve diabetic kidney lesion in the STZ model, thus suggesting the uPA/uPAR system as a promising target for the development of novel uPAR-targeting approaches.

Protective mechanisms of resveratrol derivatives against TNF-α-induced inflammatory responses in rat mesangial cells

INTRODUCTION

Resveratrol has been reported to alleviate inflammatory responses and oxidative stress in mesangial cells and in several types of renal injury in animal models. Previously, the active resveratrol derivatives from the roots of Vitis thunbergii Sieb. & Zucc. (Vitaceae) were shown to have significant anti-platelet and anti-oxidative activities. However, the anti-inflammatory mechanisms of these resveratrol derivatives in rat mesangial cells (RMCs) have not been clarified fully.

METHODS

The protective mechanisms of resveratrol derivatives involved in tumor necrosis factor-α (TNF-α)-induced inflammatory responses were assessed by Western blot analysis, real-time PCR, and RT-PCR. The involvement of various signaling molecules in these responses was investigated using selective pharmacological inhibitors.

RESULTS

Nontoxic concentrations of the resveratrol derivatives significantly attenuated cytosolic phospholipase A₂ (cPLA₂) and cyclooxygenase 2 (COX-2) expression in RMCs challenged by TNF-α. These resveratrol derivatives inhibited TNF-α-activated ERK1/2 and JNK1/2 without affecting p38 phosphorylation. Next, we demonstrated that TNF-α induced NF-κB activation, translocation, and promoter activity, which was inhibited by pretreatment with resveratrol derivatives in RMCs.

CONCLUSION

The protective mechanisms of resveratrol derivatives against TNF-α-stimulated inflammatory responses via cPLA₂/COX-2/PGE₂ inhibition was caused by the attenuation of the JNK1/2, ERK1/2, and NF-κB signaling pathways in RMCs.

In vivo assessment of polydatin, a natural polyphenol compound, on arsenic-induced free radical overproduction, gene expression, and genotoxicity

Arsenic (As) is a well-known contaminant of global groundwater. Its exposure causes several hazardous effects on animals and human via oxidative stress. The present study examined the effect of polydatin (PD) on free radical overproduction in rats exposed to As. Thirty-five male rats randomly allocated into five equal groups. To the control group, physiological saline was given orally and to the second group only 100 mg/L As was given by drinking water for 60 days. The other groups were treated with As (100 mg/L) and PD orally at 50, 100, and 200 mg/kg/day, respectively. Treatment with As enhanced malondialdehyde level but decreased glutathione level in blood, liver, kidney, brain, lung, and heart of rats. Also, As decreased superoxide dismutase and catalase activities of erythrocyte, liver, kidney, brain, lung, and heart in rats. Furthermore, As treatment gave rise to increased DNA damage and gene expressions of interleukin 1 beta (IL-1β), nuclear factor kappa beta (NFκB), p53, and tumor necrosis factor-α (TNF-α) in the lung, brain, kidney, and liver. However, treatment of PD ameliorated As-exposed lipid peroxidation, antioxidant enzymes activities, DNA damage, gene expressions, and histopathological changes in tissues. In conclusion, PD has a dose-dependent protective effect on lipid peroxidation and antioxidant defense mechanism in rats against As exposure.

Photostability and antioxidant activity studies on the inclusion complexes of trans-polydatin with β-cyclodextrin and derivatives

The inclusion complexes of trans-polydatin and three cyclodextrins (CDs), namely β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD) and (2-hydroxy) propyl-β-cyclodextrin (HP-β-CD) were prepared.

CAPE-pNO2 ameliorated diabetic nephropathy through regulating the Akt/NF-κB/ iNOS pathway in STZ-induced diabetic mice

Diabetic nephropathy (DN) is one of the most severe complications of diabetes mellitus. This study aimed to determine the effects and potential mechanism of caffeic acid para-nitro phenethyl ester (CAPE-pNO₂), a derivative of caffeic acid phenethyl ester (CAPE), on DN; In vivo, intraperitoneal injections of streptozotocin (STZ) were used to induce diabetes in mice; then, the mice were intraperitoneally injected daily with CAPE or CAPE-pNO₂ for 8 weeks. The mice were sacrificed, and blood samples and kidney tissues were collected to measure biological indexes. The results showed that CAPE and CAPE-pNO₂ could lower serum creatinine, blood urea nitrogen, 24-h albumin excretion, malondialdehyde and myeloperoxidase levels and increase superoxide dismutase activity in diabetic mice. According to HE, PAS and Masson staining, these two compounds ameliorated structural changes and fibrosis in the kidneys. In addition, the immunohistochemical and western blot results showed that CAPE and CAPE-pNO₂ inhibited inflammation through the Akt/NF-κB pathway and prevented renal fibrosis through the TGF-β/Smad pathway. In vitro, CAPE and CAPE-pNO₂ inhibited glomerular mesangial cell (GMC) proliferation, arrested cell cycle progression and suppressed ROS generation. These compounds also inhibited ECM accumulation via regulating the TGF-β1, which was a similar effect to that of the NF-κB inhibitor PDTC. More importantly, CAPE and CAPE-pNO₂ could up-regulate nitric oxide synthase expression in STZ-induced diabetic mice and HG-induced GMCs. CAPE-pNO₂ had stronger effects than CAPE both in vivo and in vitro. These data suggest that CAPE-pNO₂ ameliorated DN by suppressing oxidative stress, inflammation, and fibrosis via the Akt/NF-κB/ iNOS pathway.

Impacts of the serum containing total flavonoids of Ajuga on rat glomerular mesangial cells

The aim of the current study was to investigate the impacts and possible mechanisms of total flavonoids of Ajuga (TFA) on glomerular mesangial cells (GMC) through in vitro observations of the impacts of TFA‑containing serum on GMC proliferation and extracellular matrix (ECM) secretion in lipopolysaccharides (LPS)‑induced rats. Rat GMC was cultured in vitro, using LPS to stimulate the proliferation of GMC and the secretion of ECM; meanwhile, TFA‑containing serum (TFA‑S) was used for the intervention. Methyl thiazolyl tetrazolium (MTT) assay was performed to test the proliferation of GMC; enzyme‑linked immunosorbent assay (ELISA) was used to detect the expressions of fibronectin (FN) and collagen IV (Col‑IV) in cell supernatant, flow cytometry was performed to detect the cell cycle, and reverse transcription-polymerase chain reaction was performed to detect the expression levels of matrix metalloproteinase 9 (MMP‑9) mRNA and transforming growth factor β1 (TGF‑β1) mRNA. The GMC proliferation and the expressions of FN and Col‑IV in cell supernatant were significantly reduced after 24 and 48 h TFA‑S intervention (P<0.05 or 0.01). A total of 48 h subsequent to the intervention, the proportion of GMC in the G1 phase and the relative expression of MMP‑9 mRNA were significantly increased (P<0.05 or 0.01), however the proportion of GMC in S phase and the relative expression of TGF‑β1 mRNA were significantly reduced (P<0.05 or 0.01). TFA‑S can inhibit LPS‑induced GMC proliferation and ECM accumulation, and its roles are associated with regulating the cell cycle and the expression levels of TGF‑β1 and MMP‑9.

Regulation of PCSK9 by nutraceuticals

PCSK9 (proprotein convertase subtilisin kexin type 9) is a liver secretory enzyme that regulates plasma low-density lipoprotein (LDL) cholesterol (LDL-C) levels through modulation of LDL receptor (LDLR) density on the surface of hepatocytes. Inhibition of PCSK9 using monoclonal antibodies can efficiently lower plasma LDL-C, non-high-density lipoprotein cholesterol and lipoprotein (a). PCSK9 inhibition is also an effective adjunct to statin therapy; however, the cost-effectiveness of currently available PCSK9 inhibitors is under question. Nutraceuticals offer a safe and cost-effective option for PCSK9 inhibition. Several nutraceuticals have been reported to modulate PCSK9 levels and exert LDL-lowering activity. Mechanistically, those nutraceuticals that inhibit PCSK9 through a SREBP (sterol-responsive element binding protein)-independent pathway can be more effective in lowering plasma LDL-C levels compared with those inhibiting PCSK9 through the SREBP pathway. The present review aims to collect available data on the nutraceuticals with PCSK9-inhibitory effect and the underlying mechanisms.

Polydatin reduces Staphylococcus aureus lipoteichoic acid-induced injury by attenuating reactive oxygen species generation and TLR2-NFκB signalling

Staphylococcus aureus (S. aureus) causes severe inflammation in various infectious diseases, leading to high mortality. The clinical application of antibiotics has gained a significant curative effect. However, it has led to the emergence of various resistant bacteria. Therefore, in this study, we investigated the protective effect of polydatin (PD), a traditional Chinese medicine extract, on S. aureus lipoteichoic acid (LTA)-induced injury in vitro and in vivo. First, a significant improvement in the pathological conditions of PD in vivo was observed, suggesting that PD had a certain protective effect on LTA-induced injury in a mouse model. To further explore the underlying mechanisms of this protective effect of PD, LTA-induced murine macrophages were used in this study. The results have shown that PD could reduce the NF-κB p65, and IκBα phosphorylation levels increased by LTA, resulting in a decrease in the transcription of pro-inflammatory factors, such as TNF-α, IL-1β and IL-6. However, LTA can not only activate NF-κB through the recognition of TLR2 but also increase the level of intracellular reactive oxygen species (ROS), thereby activating NF-κB signalling. We also detected high levels of ROS that activate caspases 9 and 3 to induce apoptosis. In addition, using a specific NF-κB inhibitor that could attenuate apoptosis, namely NF-κB p65, acted as a pro-apoptotic transcription factor in LTA-induced murine macrophages. However, PD could inhibit the generation of ROS and NF-κB p65 activation, suggesting that PD suppressed LTA-induced injury by attenuating ROS generation and TLR2-NFκB signalling.

Protein kinase CK2α catalytic subunit ameliorates diabetic renal inflammatory fibrosis via NF-κB signaling pathway

Activation of casein kinase 2 (CK2) is closely linked to the body disturbance of carbohydrate metabolism and inflammatory reaction. The renal chronic inflammatory reaction in the setting of diabetes is one of the important hallmarks of diabetic renal fibrosis. However, it remains unknown whether CK2 influences the process of diabetic renal fibrosis. The current study is aimed to investigate if CK2α ameliorates renal inflammatory fibrosis in diabetes via NF-κB pathway. To explore potential regulatory mechanism of CK2α, the expression and activity of CK2α, which were studied by plasmid transfection, selective inhibitor, small-interfering RNA (siRNA) and adenovirus infection in vitro or in vivo, were analyzed by means of western blotting (WB), dual luciferase reporter assay and electrophoretic mobility shift assay (EMSA). The following findings were observed: (1) Expression of CK2α was upregulated in kidneys of db/db and KKAy diabetic mice; (2) Inhibition of CK2α kinase activity or knockdown of CK2α protein expression suppressed high glucose-induced expressions of FN and ICAM-1 in glomerular mesangial cells (GMCs); (3) Inhibition of CK2α kinase activity or knockdown of CK2α protein expression not only restrained IκB degradation, but also suppressed HG-induced nuclear accumulation, transcriptional activity and DNA binding activity of NF-κB in GMCs; (4) Treatment of TBB or CK2α RNAi adenovirus infection ameliorated renal fibrosis in diabetic animals; (5) Treatment of TBB or CK2α RNAi adenovirus infection suppressed IκB degradation and NF-κB nuclear accumulation in glomeruli of diabetic animals. This study indicates the essential role of CK2α in regulating the diabetic renal pathological process of inflammatory fibrosis via NF-κB pathway, and inhibition of CK2α may serve as a promising therapeutic strategy for diabetic nephropathy.

Polydatin promotes Nrf2-ARE anti-oxidative pathway through activating CKIP-1 to resist HG-induced up-regulation of FN and ICAM-1 in GMCs and diabetic mice kidneys

Our previous study indicated that Casein kinase 2 interacting protein-1 (CKIP-1) could promote the activation of the nuclear factor E2-related factor 2 (Nrf2)/ antioxidant response element (ARE) pathway, playing a significant role in inhibiting the fibrosis of diabetic nephropathy (DN). Polydatin (PD) has been shown to possess strong resistance effects on renal fibrosis which is closely related to activating the Nrf2/ARE pathway, too. Whereas, whether PD could resist DN through regulating CKIP-1 and consequently promoting the activation of Nrf2-ARE pathway needs further investigation. Here, we found that PD significantly reversed the down-regulation of CKIP-1 and attenuated fibronectin (FN) and intercellular cell adhesion molecule-1 (ICAM-1) in glomerular mesangial cells (GMCs) exposed to high glucose (HG). Moreover, PD could decrease Keap1 expression and promote the nuclear content, ARE-binding ability, and transcriptional activity of Nrf2. The activation of Nrf2-ARE pathway by PD eventually led to the quenching of hydrogen peroxide (H2O2) and superoxide overproduction boosted by HG. Depletion of CKIP-1 blocked the Nrf2-ARE pathway activation and reversed FN and ICAM-1 down-regulation induced by PD in GMCs challenged with HG. PD increased CKIP-1 and Nrf2 levels in the kidney tissues as well as improved the anti-oxidative effect and renal dysfunction of diabetic mice, which eventually reversed the up-regulation of FN and ICAM-1. Experiments above suggested that PD could increase the CKIP-1-Nrf2-ARE pathway activation to prevent the OSS-induced insult in GMCs and diabetic mice which effectively postpone the diabetic renal fibrosis and the up-regulation of CKIP-1 is probably a novel mechanism in this process.

Polydatin improves the developmental competence of bovine embryos in vitro via induction of sirtuin 1 (Sirt1)

The aim of the present study was to investigate the beneficial effect of polydatin (PD), the glycoside form of resveratrol, on embryo development in vitro. Oocytes were aspirated from ovaries of Korean Hanwoo cows and cultured until Day 8 in a humidified atmosphere of 5% CO2 in air at 38.5°C. Protein and gene expression levels were determined through confocal microscopy and reverse transcription–polymerase chain reaction respectively, whereas the number of total and apoptotic cells in Day 8 blastocysts was determined using Hoechst 33342 staining and terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling. Of the different concentrations of PD (0.5, 1.0 and 2.0 µM) added to the IVM medium, only 1.0 µM PD significantly improved blastocyst development. Immunofluorescence analysis confirmed that protein levels of sirtuin 1 (Sirt1) increased significantly (P < 0.05) after PD treatment, whereas levels of reactive oxygen species (ROS) were significantly (P < 0.05) decreased, as evidenced by reductions in 8-oxoguanine immunoreactivity. Similarly, protein levels of nuclear factor (NF)-κB and cyclo-oxygenase (COX)-2  were significantly (P < 0.05) lower in the PD-treated group than in the control group. Treatment with 1.0 µM PD reduced gene expression of BCL2-associated X protein, inducible nitric oxide synthase, COX2 and Nfkb, but increased the expression of Sirt1, supporting the immunofluorescence data. PD possesses antioxidant activity and is useful for embryo development in vitro. We conclude that supplementation of IVM medium with PD improves embryo developmental competence via Sirt1.

Polydatin attenuates potassium oxonate-induced hyperuricemia and kidney inflammation by inhibiting NF-κB/NLRP3 inflammasome activation via the AMPK/SIRT1 pathway

This study was designed to investigate the effects of polydatin (PLD) on potassium oxonate-induced hyperuricemic rats.