Protective effect of polydatin on learning and memory impairments in neonatal rats with hypoxic‑ischemic brain injury by up‑regulating brain‑derived neurotrophic factor

Resveratrol Reduces Neuroinflammation and Hippocampal Microglia Activation and Protects Against Impairment of Memory and Anxiety-Like Behavior in Experimental Cerebral Palsy

Cerebral palsy (CP) is a neurodevelopmental disorder characterized by motor and postural impairments. However, early brain injury can promote deleterious effects on the hippocampus, impairing memory. This study aims to investigate the effects of resveratrol treatment on memory, anxiety-like behavior, and neuroinflammation markers in rats with CP. Male Wistar rats were subjected to perinatal anoxia (P0-P1) and sensory-motor restriction (P2-P28). They were treated with resveratrol (10 mg/kg, 0.1 ml/100 g) or saline from P3-P21, being divided into four experimental groups: CS (n = 15), CR (n = 15), CPS (n = 15), and CPR (n = 15). They were evaluated in the tests of novel object recognition (NORT), T-Maze, Light-Dark Box (LDB), and Elevated Plus Maze (EPM). Compared to the CS group, the CPS group has demonstrated a reduced discrimination index on the NORT (p < 0.0001) and alternation on the T-Maze (p < 0.01). In addition, the CPS group showed an increase in permanence time on the dark side in LDB (p < 0.0001) and on the close arms of the EPM (p < 0.001). The CPR group demonstrated an increase in the object discrimination index (p < 0.001), on the alternation (p < 0.001), on the permanence time on the light side (p < 0.0001), and on the open arms (p < 0.001). The CPR group showed a reduction in gene expression of IL-6 (p = 0.0175) and TNF-α (p = 0.0007) and an increase in Creb-1 levels (p = 0.0020). The CPS group showed an increase in the activated microglia and a reduction in cell proliferation in the hippocampus, while CPR animals showed a reduction of activated microglia and an increase in cell proliferation. These results demonstrate promising effects of resveratrol in cerebral palsy behavior impairment through reduced neuroinflammation in the hippocampus.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

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.

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.

The Neuroprotective Role of Polydatin: Neuropharmacological Mechanisms, Molecular Targets, Therapeutic Potentials, and Clinical Perspective

Neurodegenerative diseases (NDDs) are one of the leading causes of death and disability in humans. From a mechanistic perspective, the complexity of pathophysiological mechanisms contributes to NDDs. Therefore, there is an urgency to provide novel multi-target agents towards the simultaneous modulation of dysregulated pathways against NDDs. Besides, their lack of effectiveness and associated side effects have contributed to the lack of conventional therapies as suitable therapeutic agents. Prevailing reports have introduced plant secondary metabolites as promising multi-target agents in combating NDDs. Polydatin is a natural phenolic compound, employing potential mechanisms in fighting NDDs. It is considered an auspicious phytochemical in modulating neuroinflammatory/apoptotic/autophagy/oxidative stress signaling mediators such as nuclear factor-κB (NF-κB), NF-E2–related factor 2 (Nrf2)/antioxidant response elements (ARE), matrix metalloproteinase (MMPs), interleukins (ILs), phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), and the extracellular regulated kinase (ERK)/mitogen-activated protein kinase (MAPK). Accordingly, polydatin potentially counteracts Alzheimer’s disease, cognition/memory dysfunction, Parkinson’s disease, brain/spinal cord injuries, ischemic stroke, and miscellaneous neuronal dysfunctionalities. The present study provides all of the neuroprotective mechanisms of polydatin in various NDDs. Additionally, the novel delivery systems of polydatin are provided regarding increasing its safety, solubility, bioavailability, and efficacy, as well as developing a long-lasting therapeutic concentration of polydatin in the central nervous system, possessing fewer side effects.

A Review of Plant Extracts and Plant-Derived Natural Compounds in the Prevention/Treatment of Neonatal Hypoxic-Ischemic Brain Injury

Neonatal hypoxic-ischemic (HI) brain injury is one of the major drawbacks of mortality and causes significant short/long-term neurological dysfunction in newborn infants worldwide. To date, due to multifunctional complex mechanisms of brain injury, there is no well-established effective strategy to completely provide neuroprotection. Although therapeutic hypothermia is the proven treatment for hypoxic-ischemic encephalopathy (HIE), it does not completely chang outcomes in severe forms of HIE. Therefore, there is a critical need for reviewing the effective therapeutic strategies to explore the protective agents and methods. In recent years, it is widely believed that there are neuroprotective possibilities of natural compounds extracted from plants against HIE. These natural agents with the anti-inflammatory, anti-oxidative, anti-apoptotic, and neurofunctional regulatory properties exhibit preventive or therapeutic effects against experimental neonatal HI brain damage. In this study, it was aimed to review the literature in scientific databases that investigate the neuroprotective effects of plant extracts/plant-derived compounds in experimental animal models of neonatal HI brain damage and their possible underlying molecular mechanisms of action.

Protective Effects of Polydatin Against Dementia-Related Disorders

Dementia is a collection of symptoms affecting a person's cognition. Dementia is debilitating, and therefore, finding an effective treatment is of utmost importance. Resveratrol, which exhibits neuroprotective effects, has low bioavailability. However, its glucoside polydatin is more bioavailable. Here, the evidence that supports the protective role of polydatin against dementia- related diseases such as Alzheimer's disease, vascular dementia, alcohol-related dementia, and Lewy body dementias is presented. The beneficial effects of polydatin from a mechanistic perspective are specifically emphasized in this review. Future directions in this area of research are also discussed.

Neuroprotective Effects of Medicinal Plants in Cerebral Hypoxia and Anoxia: A Systematic Review

Background:

Hypoxia and anoxia are dangerous and sometimes irreversible complications in the central nervous system (CNS), which in some cases lead to death.

Objective:

The aim of this review was to investigate the neuroprotective effects of medicinal plants in cerebral hypoxia and anoxia.

Methods:

The word hypox*, in combination with some herbal terms such as medicinal plant, phyto* and herb*, was used to search for relevant publications indexed in the Institute for Scientific Information (ISI) and PubMed from 2000-2019.

Results:

Certain medicinal plants and herbal derivatives can exert their protective effects in several ways. The most important mechanisms are the inhibition of inducible nitric oxide synthase (iNOS), production of NO, inhibition of both hypoxia-inducible factor 1α and tumor necrosis factor-alpha activation, and reduction of extracellular glutamate, N-Methyl-D-aspartic and intracellular Ca (2+). In addition, they have an antioxidant activity and can adjust the expression of genes related to oxidant generation or antioxidant capacity. These plants can also inhibit lipid peroxidation, up-regulate superoxide dismutase activity and inhibit the content of malondialdehyde and lactate dehydrogenase. Moreover, they also have protective effects against cytotoxicity through down-regulation of the proteins that causes apoptosis, anti-excitatory activity, inhibition of apoptosis signaling pathway, reduction of pro-apoptotic proteins, and endoplasmic reticulum stress that causes apoptosis during hypoxia, increasing anti-apoptotic protein, inhibition of protein tyrosine kinase activation, decreasing proteases activity and DNA fragmentation, and upregulation of mitochondrial cytochrome oxidase.

Conclusion:

The results indicated that medicinal plants and their compounds mainly exert their neuroprotective effects in hypoxia via regulating proteins that are related to antioxidant, anti-apoptosis and anti-inflammatory activities.

MicroRNA-9 mediated the protective effect of ferulic acid on hypoxic-ischemic brain damage in neonatal rats

Neonatal hypoxic-ischemic brain damage (HIBD) is prone to cognitive and memory impairments, and there is no effective clinical treatment until now. Ferulic acid (FA) is found within members of the genus Angelica, reportedly shows protective effects on neuronal damage. However, the protective effects of FA on HIBD remains unclear. In this study, using the Morris water maze task, we herein found that the impairment of spatial memory formation in adult rats exposed to HIBD was significantly reversed by FA treatment and the administration of LNA-miR-9. The expression of miRNA-9 was detected by RT-PCR analyses, and the results shown that miRNA-9 was significantly increased in the hippocampus of neonatal rats following HIBD and in the PC12 cells following hypoxic-ischemic injury, while FA and LNA-miR-9 both inhibited the expression of miRNA-9, suggesting that the therapeutic effect of FA was mainly attributed to the inhibition of miRNA-9 expression. Indeed, the silencing of miR-9 by LNA-miR-9 or FA similarly attenuated neuronal damage and cerebral atrophy in the rat hippocampus after HIBD, which was consistent with the restored expression levels of brain-derived neurotrophic factor (BDNF). Therefore, our findings indicate that FA treatment may protect against neuronal death through the inhibition of miRNA-9 induction in the rat hippocampus following hypoxic-ischemic damage.

Protection of the Geum japonicum Thunb. var. chinense extracts against oxygen-glucose deprivation and re-oxygenation induced astrocytes injury via BDNF/PI3K/Akt/CREB pathway

Geum japonicum Tunb. var. chinense (GJ) is a traditional Chinese medicine usually used for the alleviation of dizziness and headache. Previous studies have reported that the GJ extracts could alleviate cerebral I/R injury by reducing apoptosis in vivo. To further elucidate the positive role and underlying mechanism of the GJ extracts in cerebral I/R injury, the current study investigated the effects of the GJ extracts on oxygen-glucose deprivation and re-oxygenation (OGD/R)-induced astrocytes injury in light of BDNF/PI3K/Akt/CREB signaling pathway with seropharmacological method. In the present study, the LC-MS profiling of the GJ extracts, obtain by reflux extraction, led to the identification of three possible active components were 5-desgalloylstachyurin, tellimagrandin II (TG II) and 3,4,5-Trihydroxybenzaldehyde (THBA). Drug-containing serum was collected from rats given different doses of the GJ extracts (0, 1.75 g/kg, 7 g/kg). Data indicated that the GJ extracts could increase the cell viability and decrease apoptosis and the expression of glial fibrillary acidic protein (GFAP) in OGD/R-induced astrocytes. In addition, the detection of apoptosis-related factors showed that the GJ extracts could obviously increase the expression of Bcl-2 and reduce the expression of Bax, Caspase-3 and cleaved-Caspase-3. Furthermore, the GJ extracts markedly increased the expression of BDNF, TrkB, PI3K, p-Akt and p-CREB. All these effects of the GJ extracts could be significantly reversed by LY294002, an inhibitor of PI3K. These data indicated that the GJ extracts could protect astrocytes against OGD/R-induced injury by inhibiting astrocytes reactivity and apoptosis, owing to the activation of the BDNF/PI3K/Akt/CREB pathway. The results support the application of the GJ extracts in the treatment of ischemic stroke and other ischemic encephalopathy.

KLF2 protects BV2 microglial cells against oxygen and glucose deprivation injury by modulating BDNF/TrkB pathway

Cerebral ischemia injury is common in cerebral ischemic disease, and treatment options remain limited. Krueppel-like factor 2 (KLF2) is reported to negatively regulate inflammation in several ischemic diseases. Our study aimed to investigate the effects and underlying mechanism of KLF2 in BV2 microglial cells exposed to oxygen and glucose deprivation (OGD). We first found decreased KLF2 and toll-like receptor 2 (TLR2)/TLR4 in these cells. OGD also led to decrease in cell viability and increase in LDH release, apoptosis, the Bax/Bcl-2 ratio, and caspase3/9 expression, as well as production of inflammatory cytokines (e.g., TNFα, IL-1β and IL-6), reactive oxygen species (ROS), and TLR2/TLR4. To examine KLF2's effects on these OGD effects, we infected BV2 microglial cells with an ad-KLF2 or negative control vector, and we found that KLF2 reversed all of the effects of OGD exposure. Furthermore, KLF2 significantly increased levels of BDNF and TrkB in these cells, but these effects were blocked by K252a, a BDNF/TrkB inhibitor. K252a also decreased cell viability and increased apoptosis, inflammatory factors, ROS production, and TLR2/TLR4 expression in OGD-exposed BV2 cells that were treated with KLF2, were implying that K252a could reverse the effects of KLF2 on these cells. Taken together, our study results indicate that KLF2 may protect BV2 microglial cells against OGD injury by activating the BDNF/TrkB pathway.

Polydatin Attenuates Neuronal Loss via Reducing Neuroinflammation and Oxidative Stress in Rat MCAO Models

Ischemic stroke is characterized by permanent or transient obstruction of blood flow, which initiates a cascading pathological process, starting from acute ATP loss and ionic imbalance to subsequent membrane depolarization, glutamate excitotoxicity, and calcium overload. These initial events are followed by neuroinflammation and oxidative stress, eventually causing neuronal neurosis and apoptosis. Complicated interplays exist between these steps happening across various stages, which not only represent the complicated nature of ischemic pathology but also warrant a detailed delineation of the underlying molecular mechanisms to develop better therapeutic options. In the present study, we examined the neuroprotective effects of polydatin against ischemic brain injury using a rat model of permanent middle cerebral artery occlusion (MCAO). Our results demonstrated that polydatin treatment reduced the infarction volume and mitigated the neurobehavioral deficits, sequentially rescued neuronal apoptosis. Ischemic stroke induced an elevation of neuroinflammation and reactive oxygen species, which could be attenuated by polydatin via the reduced activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. In addition, polydatin upregulated the endogenous antioxidant nuclear factor erythroid 2-related factor 2, heme oxygenase-1, the thioredoxin pathway, and eventually reversed ischemic-stroke-induced elevation of ROS and inflammation in ischemic cortical tissue. The diverse and broad actions of polydatin suggested that it could be a multiple targeting neuroprotective agent in ameliorating the detrimental effects of MCAO, such as neuroinflammation, oxidative stress, and neuronal apoptosis. As repetitive clinical trials of neuroprotectants targeting a single step of stroke pathological process have failed previously, our results suggested that a neuroprotective strategy of acting at different stages may be more advantageous to intervene in the vicious cycles in MCAO.

Retracted: microRNA-129-5p involved in the neuroprotective effect of dexmedetomidine on hypoxic-ischemic brain injury by targeting COL3A1 through the Wnt/β-catenin signaling pathway in neonatal rats

Our study aims to elucidate the mechanisms how microRNA-129-5p (miR-129-5p) involved in the neuroprotective effect of dexmedetomidine (DEX) on hypoxic-ischemic brain injury (HIBI) by targeting the type III procollagen gene (COL3A1) through the Wnt/β-catenin signaling pathway in neonatal rats. A total of 120 rats were obtained, among which 15 rats were selected as sham group and rest rats as model, DEX, DEX + negative control (DEX + NC), DEX + miR-129-5p mimics, DEX + miR-129-5p inhibitors, DEX + XAV-939, and DEX + miR-129-5p inhibitors + XAV-939 groups. A dual-luciferase reporter assay was performed for the target relationship between miR-129-5p and COL3A1. Weight rate and water content of cerebral hemisphere were detected. Quantitative real-time polymerase chain reaction and Western blot analysis were conducted to detect miR-129-5p expression and expressions of COL3A1, E-cadherin, T-cell factor (TCF)- 4, and β-catenin. The DEX, DEX + miR-129-5p mimics, DEX + XAV-939 groups had increased weight rate of the cerebral hemisphere, but decreased water content of left cerebral hemisphere, levels of COL3A1, β-catenin, TCF-4, and E-cadherin in the hippocampus compared with the model and DEX + miR-129-5p inhibitors groups. COL3A1 was verified as the target gene of the miR-129-5p. Compared with the DEX + NC and DEX + miR-129-5p inhibitors + XAV-939 groups, the DEX + XAV-939 and DEX + miR-129-5p mimics groups had elevated weight rate of the cerebral hemisphere, but reduced water content of left cerebral hemisphere, levels of COL3A1, β-catenin, TCF-4, and E-cadherin in the hippocampus. Our findings demonstrate that miR-129-5p improves the neuroprotective role of DEX in HIBI by targeting COL3A1 through the Wnt/β-catenin signaling pathway in neonatal rats.

Protective effects of polydatin in free and nanocapsulated form on changes caused by lipopolysaccharide in hippocampal organotypic cultures

BACKGROUND

Polydatin (PD) is a compound, originally isolated from the root and rhizome of the Chinese herb Polygonum cuspidatum. To date, various biological properties of this compound, such as analgesic, anti-pyretic or diuretic effects, have been shown. Recently, anti-oxidant and anti-inflammatory properties have been widely postulated, yet PD instability and low bioavailability limit its beneficial actions. Therefore, it has been suggested that an encapsulation process may be a promising strategy for overcoming these limitations and increasing the therapeutic efficacy of PD.

METHODS

We examined the effects of PD in two forms, including free and in PD-loaded polymeric nanocapsules, on lipopolysaccharide (LPS)-induced changes in hippocampal organotypic cultures.

RESULTS

Our results indicated that free and encapsulated PD diminished cell death processes and attenuated the secretion of pro-inflammatory cytokines induced by LPS administration. Additionally, PD in both forms strongly inhibited the production of nitric oxide and down-regulated the level of iNOS enzyme in LPS-stimulated hippocampal cultures.

CONCLUSION

Taken together, our study showed that PD exerts anti-inflammatory and anti-oxidant properties in LPS-treated hippocampal organotypic cultures. Furthermore, we show that the encapsulation procedure preserved the features of the free form of this compound, and therefore, the polymeric nanocapsules containing PD may be used as a novel and promising delivery system in therapeutic strategies.

Polydatin-induced cell apoptosis and cell cycle arrest are potentiated by Janus kinase 2 inhibition in leukemia cells

Polydatin (PD), a natural precursor of resveratrol, has a variety of biological activities, including anti‑tumor effects. However, the underlying molecular mechanisms of the anti-cancer activity of PD has not been fully elucidated. The present study demonstrated that PD significantly inhibited the proliferation of the MOLT-4 leukemia cell line in a dose‑ and time-dependent manner by using Cell Counting Kit‑8 assay. PD also dose-dependently increased the apoptotic rate and caused cell cycle arrest in S phase in MOLT‑4 cells, as revealed by flow cytometry. In addition, PD dose-dependently decreased the mitochondrial membrane potential and led to the generation of reactive oxygen species in MOLT-4 cells. Western blot analysis revealed that the expression of anti‑apoptotic protein B-cell lymphoma 2 (Bcl-2) was decreased, whereas that of pro‑apoptotic protein Bcl‑2‑associated X was increased by PD. Furthermore, the expression of two cell cycle regulatory proteins, cyclin D1 and cyclin B1, was suppressed by PD. Of note, the pro‑apoptotic and cell cycle‑inhibitory effects of PD were potentiated by Janus kinase 2 (JAK2) inhibition. In conclusion, the results of the present study strongly suggested that PD is a promising therapeutic compound for the treatment of leukemia, particularly in combination with JAK inhibitors.

Polydatin Protects Bone Marrow Stem Cells against Oxidative Injury: Involvement of Nrf 2/ARE Pathways

Polydatin, a glucoside of resveratrol, has been reported to possess potent antioxidative effects. In the present study, we aimed to investigate the effects of polydatin in bone marrow-derived mesenchymal stem cells (BMSCs) death caused by hydrogen peroxide (H₂O₂), imitating the microenvironment surrounding transplanted cells in the injured spinal cord in vitro. In our study, MTT results showed that polydatin effectively prevented the decrease of cell viability caused by H₂O₂. Hochest 33258, Annexin V-PI, and Western blot assay showed H₂O₂-induced apoptosis in BMSCs, which was attenuated by polydatin. Further studies indicated that polydatin significantly protects BMSCs against apoptosis due to its antioxidative effects and the regulation of Nrf 2/ARE pathway. Taken together, our results indicate that polydatin could be used in combination with BMSCs for the treatment of spinal cord injury by improving the cell survival and oxidative stress microenvironments.

Nephroprotective Effects of Polydatin against Ischemia/Reperfusion Injury: A Role for the PI3K/Akt Signal Pathway

Oxidative stress and inflammation are involved in the pathogenesis in renal ischemia/reperfusion (I/R) injury. It has been demonstrated that polydatin processed the antioxidative, anti-inflammatory, and nephroprotective properties. However, whether it has beneficial effects and the possible mechanisms on renal I/R injury remain unclear. In our present study I/R models were simulated both in vitro and in vivo. Compared with vehicle control, the administration of polydatin significantly improved the renal function, accelerated the mitogenic response and reduced cell apoptosis in renal I/R injury models, strongly suppressed the I/R-induced upregulation of the expression of tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2, inducible nitric oxide synthase, prostaglandin E-2, and nitric oxide levels, and dramatically decreased contents of malondialdehyde, but it increased the activity of superoxide dismutase, glutathione transferase, glutathione peroxidase and catalase, and the level of glutathione. Further investigation showed that polydatin upregulated the phosphorylation of Akt in kidneys of I/R injury dose-dependently. However, all beneficial effects of polydatin mentioned above were counteracted when we inhibited PI3K/Akt pathway with its specific inhibitor, wortmannin. Taken together, the present findings provide the first evidence demonstrating that PD exhibited prominent nephroprotective effects against renal I/R injury by antioxidative stress and inflammation through PI3-K/Akt-dependent molecular mechanisms.