Resveratrol neuroprotective effects during focal cerebral ischemia injury via nitric oxide mechanism in rats

Neuroprotective effects of Aframomum pruinosum seed extract against stroke in rat: Role of antioxidant and anti-inflammatory mechanisms

BACKGROUND

Stroke is a major cause of disability and neurological impairment worldwide. Effective prevention and management strategies are needed to reduce its burden. This study aimed to investigate the therapeutic effect of the seed ethanolic extract of Aframomum pruinosum (EEAP) on stroke and its related motor and cognitive deficits in rats.

MATERIALS AND METHODS

Stroke was induced by either middle cerebral artery occlusion (MCAO) or bilateral common carotid artery occlusion (BCCAO). In the MCAO model, rats received EEAP (75, 150, or 300 mg/kg) or N-acetyl-L-cysteine (100 mg/kg) orally for one week before 2 hours of occlusion, followed by reperfusion. Twenty-four hours after ischemia, brain was collected for infarct size using 2, 3, 5 -TriphenylTetrazolium Chloride (TTC) staining, oxidative stress markers and inflammatory cytokines (TNF-α, IL-1β) measurements. In the BCCAO model, rats underwent occlusion for 30 minutes and received EEAP or quercetin (25 mg/kg) for 7 days post-induction. Behavioral parameters were evaluated at the end of the treatment. Oxidative stress and inflammatory markers were measured in the cerebrum and cerebellum.

RESULTS

MCAO caused significant brain infarction, and increased lipid peroxidation, TNF-α and IL-1β contents. EEAP, rich in nerolidol, prevented these changes in a dose-dependent manner. BCCAO impaired the neurological function, mobility, and muscle strength of rats. It also increased lipid peroxidation and inflammatory cytokines in the cerebellum. EEAP significantly ameliorated these impairments.

CONCLUSION

EEAP exerts preventive and curative neuroprotective effects against ischemic stroke and its associated motor impairments at least partially through its antioxidant and anti-inflammatory properties, and its nerolidol content.

Effect and mechanisms of resveratrol in animal models of ischemic stroke: A systematic review and Bayesian meta-analysis

Resveratrol (RSV) holds promise as cerebroprotective treatment in cerebral ischemia. This systematic review aims to assess the effects and mechanisms of RSV in animal models of ischemic stroke. We searched Medline, Embase and Web of Science to identify 75 and 57 eligible rodent studies for qualitative and quantitative syntheses, respectively. Range of evidence met 10 of 13 STAIR criteria. Median (Q1, Q3) quality score was 7 (5, 8) on the CAMARADES 15-item checklist. Bayesian meta-analysis showed SMD estimates (95% CI) favoring RSV: infarct size (-1.72 [-2.03; -1.41]), edema size (-1.61 [-2.24; -0.98]), BBB impairment (-1.85 [-2.54; -1.19]), neurofunctional impairment (-1.60 [-1.92; -1.29]), and motor performance (1.39 [0.64; 2.08]); and less probably neuronal survival (0.63 [-1.40; 2.48]) and apoptosis (-0.96 [-2.87; 1.02]). Species (rat vs mouse) was associated to a larger benefit. Sensitivity analyses confirmed robustness of the estimates. Reduction of oxidative stress, inflammation, and apoptosis underlie these effects. Our results quantitatively state the beneficial effects of RSV on structural and functional outcomes in rodent stroke models, update the evidence on the mechanisms of action, and provide an exhaustive list of targeted signaling pathways. Current evidence highlights the need for conducting further high-quality preclinical research to better inform clinical research.

Potential Role of Natural Antioxidants in Countering Reperfusion Injury in Acute Myocardial Infarction and Ischemic Stroke

Stroke and acute myocardial infarction are leading causes of mortality worldwide. The latter accounts for approximately 9 million deaths annually. In turn, ischemic stroke is a significant contributor to adult physical disability globally. While reperfusion is crucial for tissue recovery, it can paradoxically exacerbate damage through oxidative stress (OS), inflammation, and cell death. Therefore, it is imperative to explore diverse approaches aimed at minimizing ischemia/reperfusion injury to enhance clinical outcomes. OS primarily arises from an excessive generation of reactive oxygen species (ROS) and/or decreased endogenous antioxidant potential. Natural antioxidant compounds can counteract the injury mechanisms linked to ROS. While promising preclinical results, based on monotherapies, account for protective effects against tissue injury by ROS, translating these models into human applications has yielded controversial evidence. However, since the wide spectrum of antioxidants having diverse chemical characteristics offers varied biological actions on cell signaling pathways, multitherapy has emerged as a valuable therapeutic resource. Moreover, the combination of antioxidants in multitherapy holds significant potential for synergistic effects. This study was designed with the aim of providing an updated overview of natural antioxidants suitable for preventing myocardial and cerebral ischemia/reperfusion injuries.

Ameliorating age-dependent effects of resveratrol on VPA-induced social impairments and anxiety-like behaviors in a rat model of Neurodevelopmental Disorder

Although anxiety disorders, as well as difficulties in social interaction, are documented in children with autism spectrum disorder (ASD) as a neurodevelopmental disorder, the effectiveness of potential therapeutic procedures considering age and sex differences is under serious discussion. The present study aimed to investigate the effect of resveratrol (RSV) on anxiety-like behaviors and social interaction in juvenile and adult rats of both sex in a valproic acid (VPA)-induced autistic-like model. Prenatal exposure to VPA was associated with increased anxiety, also causing a significant reduction in social interaction in juvenile male subjects. Further administration of RSV attenuated VPA-induced anxiety symptoms in both sexes of adult animals and significantly increased the sociability index in male and female juvenile rats. Taken together, it can be concluded that treatment with RSV can attenuate some of the harsh effects of VPA. This treatment was especially effective on anxiety-like traits in adult subjects of both sexes regarding their performance in open field and EPM. We encourage future research to consider the sex and age-specific mechanisms behind the RSV treatment in the prenatal VPA model of autism.

A meta-analysis of resveratrol protects against cerebral ischemia/reperfusion injury: Evidence from rats studies and insight into molecular mechanisms

Objective: To evaluate the neuroprotective effect of resveratrol (RES) in rat models of cerebral ischemia/reperfusion (I/R) injury.

Data sources: PubMed, Embase, MEDLINE, Cochrane Library, and Chinese databases were searched from their inception dates to July 2022. No language restriction was used in the literature search.

Date Selection: Studies were selected that RES were used to treat cerebral I/R injury in vivo. Two reviewers conducted literature screening, data extraction and methodological quality assessment independently.

Outcome measures: Cerebral infarct volume was included as primary outcome. The secondary outcomes included cerebral water content and neurological deficit scores. Malondialdehyde (MDA) and superoxide dismutase (SOD) were used to evaluate oxidative stress during medication.

Results: A total of 41 studies were included, and only a few of them the methodological quality was relatively low. Compared with the control group, RES significantly reduced the cerebral infarct volume (29 studies, standard mean difference (SMD) = −2.88 [−3.23 to −2.53], p < 0.00001) and brain water content (nine studies, MD = −9.49 [−13.58 to −5.40], p < 0.00001) after cerebral I/R injury, then neurological function was improved (15 studies, SMD = −1.96 [−2.26 to −1.65], p < 0.00001). The MDA level (six studies, SMD = −8.97 [−13.60 to −4.34], p = 0.0001) was decreased notably after treatment of RES, while the SOD level (five studies, SMD = 3.13 [−0.16 to 6.43], p = 0.06) was increased unsatisfactory. Consistently, subgroup analysis of cerebral infarct volume suggested that the optimal therapeutic dose is 30 mg/kg (eight studies, SMD = −5.83 [−7.63 to −4.04], p < 0.00001). Meanwhile, 60 min of occlusion (three studies, SMD = −10.89 [−16.35 to −5.42], p < 0.0001) could get maximum benefit from compared with 90 min and 120 min of occlusion. On the other hand, the publication bias cannot be ignored. The pharmacological mechanisms of RES on cerebral I/R injury models as reported have be summarized, which can be used for reference by researchers to further plan their future experiments.

Conclusion: RES might have a good neuroprotective effect on cerebral I/R injury in rats, then 30 mg/kg RES may be the optimal dose for treatment, and early administration of RES should be more neuroprotective. Also it need to be further verified through exploration of dose effect relationship, or delay administration or not.

Resveratrol pretreatment protects neurons from oxygen-glucose deprivation/reoxygenation and ischemic injury through inhibiting ferroptosis

Ferroptosis, a newly discovered iron-dependent cell death, is involved in brain ischemia-reperfusion injury. Iron scavengers or ferroptosis inhibitors could reduce infarct volume and improve neurological function in mice. Resveratrol has neuroprotective and neurorestorative effects. However, it is unclear whether resveratrol can play a neuroprotective role via inhibiting ferroptosis. Our study showed that resveratrol pretreatment had a similar effect with ferrostatin‑1, which inhibited neuronal ferroptosis-related changes, such as iron overload, damages of oxidation-reduction system, and destruction of mitochondrial structure, after oxygen-glucose deprivation/reoxygenation (OGD/R) and application of ferroptosis inducers. In addition, middle cerebral artery occlusion/reperfusion (MCAO/R) injury in vivo also induced ferroptosis, and resveratrol pretreatment could inhibit ferroptosis and reduce degenerative neurons, cerebral ischemic damage and infarction volume. Our results are the first to indicate that resveratrol pretreatment might inhibit ferroptosis induced by OGD/R and ferroptosis inducers in neurons, and MCAO/R in rats.

Resveratrol has an Overall Neuroprotective Role in Ischemic Stroke: A Meta-Analysis in Rodents

Background: Resveratrol, a natural polyphenolic phytoalexin, is broadly presented in dietary sources. Previous research has suggested its potential neuroprotective effects on ischemic stroke animal models. However, these results have been disputable. Here, we conducted a meta-analysis to comprehensively evaluate the effect of resveratrol treatment in ischemic stroke rodent models.

Objective: To comprehensively evaluate the effect of resveratrol treatment in ischemic stroke rodent models.

Methods: A literature search of the databases Pubmed, Embase, and Web of science identified 564 studies that were subjected to pre-defined inclusion criteria. 54 studies were included and analyzed using a random-effects model to calculate the standardized mean difference (SMD) with corresponding confidence interval (CI).

Results: As compared with controls, resveratrol significantly decreased infarct volume (SMD −4.34; 95% CI −4.98 to −3.69; p < 0.001) and the neurobehavioral score (SMD −2.26; 95% CI −2.86 to −1.67; p < 0.001) in rodents with ischemic stroke. Quality assessment was performed using a 10-item checklist. Studies quality scores ranged from 3 to 8, with a mean value of 5.94. In the stratified analysis, a significant decrease of infarct volume and the neurobehavioral score was achieved in resveratrol sub-groups with a dosage of 20–50 mg/kg. In the meta-regression analysis, the impact of the delivery route on an outcome is the possible source of high heterogeneity.

Conclusion: Generally, resveratrol treatment presented neuroprotective effects in ischemic stroke models. Furthermore, this study can direct future preclinical and clinical trials, with important implications for human health.

Inhibition of Long non-coding RNA zinc finger antisense 1 improves functional recovery and angiogenesis after focal cerebral ischemia via microRNA-144-5p/fibroblast growth factor 7 axis

Long non-coding RNA zinc finger antisense 1 (ZFAS1) has been probed in cerebral ischemia, while the regulatory mechanism of ZFAS1 in focal cerebral ischemia (FCI) via binding to microRNA (miR)-144-5p remains rarely explored. This study aims to decipher the function of ZFAS1 on FCI via sponging miR-144-5p to modulate fibroblast growth factor 7 (FGF7). The focal cerebral ischemia rat model was established by occlusion of the middle cerebral artery (MCAO) Lentivirus vectors altering ZFAS1, miR-144-5p or FGF7 expression were injected into rats before MCAO. Then, ZFAS1, miR-144-5p, and FGF7 levels were detected, the inflammatory factor level, oxidative stress level, angiogenesis, neurological function injury and neuronal apoptosis were assessed. The binding relations among ZFAS1, miR-144-5p and FGF7 were validated. ZFAS1 and FGF7 expression was elevated, while miR-144-5p expression was reduced in FCI rats. Decreased ZFAS1 or FGF7 or enriched miR-144-5p repressed the inflammatory response, oxidative stress, neuronal apoptosis, while it improved angiogenesis, and neurological function recovery; while up-regulated ZFAS1 exerted opposite effects. The augmented miR-144-5p or silenced FGF7 reversed the effects of enriched ZFAS1. ZFAS1 sponged miR-144-5p that targeted FGF7. Inhibition of lncRNA ZFAS1 improves functional recovery and angiogenesis after FCI via miR-144-5p/FGF7 axis. This study provides novel therapeutic targets for FCI treatment.

Neuroprotective Effect for Cerebral Ischemia by Natural Products: A Review

Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. Stroke is a disease with high prevalence and incidence, the pathogenesis is a complex cascade reaction. In recent years, it’s reported that a vast number of natural products have demonstrated beneficial effects on stroke worldwide. Natural products have been discovered to modulate activities with multiple targets and signaling pathways to exert neuroprotection via direct or indirect effects on enzymes, such as kinases, regulatory receptors, and proteins. This review provides a comprehensive summary of the established pharmacological effects and multiple target mechanisms of natural products for cerebral ischemic injury in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications. In addition, the biological activity of natural products is closely related to their structure, and the structure-activity relationship of most natural products in neuroprotection is lacking, which should be further explored in future. Overall, we stress on natural products for their role in neuroprotection, and this wide band of pharmacological or biological activities has made them suitable candidates for the treatment of stroke.

Danggui-Shaoyao-San (DSS) Ameliorates Cerebral Ischemia-Reperfusion Injury via Activating SIRT1 Signaling and Inhibiting NADPH Oxidases

Danggui-Shayao-San (DSS) is a famous Traditional Chinese Medicine formula that used for treating pain disorders and maintaining neurological health. Recent studies indicate that DSS has neuroprotective effects against ischemic brain damage but its underlining mechanisms remain unclear. Herein, we investigated the neuroprotective mechanisms of DSS for treating ischemic stroke. Adult male Sprague-Dawley (S.D.) rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus 22 h of reperfusion. Both ethanol extract and aqueous extract of DSS (12 g/kg) were orally administrated into the rats at 30 min prior to MCAO ischemic onset. We found that 1) ethanol extract of DSS, instead of aqueous extract, reduced infarct sizes and improved neurological deficit scores in the post-ischemic stroke rats; 2) Ethanol extract of DSS down-regulated the expression of the cleaved-caspase 3 and Bax, up-regulated bcl-2 and attenuated apoptotic cell death in the ischemic brains; 3) Ethanol extract of DSS decreased the production of superoxide and peroxynitrite; 4) Ethanol extract of DSS significantly down-regulated the expression of p67^phox but has no effect on p47^phox and iNOS statistically. 5) Ethanol extract of DSS significantly up-regulated the expression of SIRT1 in the cortex and striatum of the post-ischemic brains; 6) Co-treatment of EX527, a SIRT1 inhibitor, abolished the DSS’s neuroprotective effects. Taken together, DSS could attenuate oxidative/nitrosative stress and inhibit neuronal apoptosis against cerebral ischemic-reperfusion injury via SIRT1-dependent manner.

An Exercise Mimetic Approach to Reduce Poststroke Deconditioning and Enhance Stroke Recovery

Evidence supports early rehabilitation after stroke to limit disability. However, stroke survivors are typically sedentary and experience significant cardiovascular and muscular deconditioning. Despite growing consensus that preclinical and clinical stroke recovery research should be aligned, there have been few attempts to incorporate cardiovascular and skeletal muscle deconditioning into animal models of stroke. Here, we demonstrate in rats that a hindlimb sensorimotor cortex stroke results in both cardiovascular and skeletal muscle deconditioning and impairments in gait akin to those observed in humans. To reduce poststroke behavioral, cardiovascular, and skeletal muscle perturbations, we then used a combinatorial intervention consisting of aerobic and resistance exercise in conjunction with administration of resveratrol (RESV), a drug with exercise mimetic properties. A combination of aerobic and resistance exercise mitigated decreases in cardiovascular fitness and attenuated skeletal muscle abnormalities. RESV, beginning 24 hours poststroke, reduced acute hindlimb impairments, improved recovery in hindlimb function, increased vascular density in the perilesional cortex, and attenuated skeletal muscle fiber changes. Early RESV treatment and aerobic and resistance exercise independently provided poststroke benefits, at a time when individuals are rapidly becoming deconditioned as a result of inactivity. Although no additive effects were observed in these experiments, this approach represents a promising strategy to reduce poststroke behavioral impairments and minimize deconditioning. As such, this treatment regime has potential for enabling patients to engage in more intensive rehabilitation at an earlier time following stroke when mechanisms of neuroplasticity are most prevalent.

Resveratrol alleviates oxygen/glucose deprivation/reoxygenation‑induced neuronal damage through induction of mitophagy

Resveratrol confers neuroprotective effects in cerebral ischemia; however, the involvement of mitophagy in the neuroprotective function of resveratrol remains unclear. The aim of the present study was to investigate whether resveratrol exerts neuroprotective effects on primary cortical neurons subjected to oxygen/glucose deprivation/reoxygenation (OGD/R) via modulating mitophagy. The data demonstrated that resveratrol at 1–10 µM during reoxygenation improved cell viability and suppressed apoptosis following OGD/R in a concentration-dependent manner. Moreover, resveratrol alleviated OGD/R-induced loss of mitochondrial membrane potential and excessive oxidative stress. Confocal imaging of LC3 and TOM20 antibody-labeled mitochondria, as well as western blot analysis, demonstrated that mitophagy was further enhanced following resveratrol treatment. In addition, resveratrol was revealed to stimulate the phosphatase and tensin homolog-induced kinase 1/Parkin pathway. Mitophagy inhibition then inhibited the protective effects of resveratrol. These results indicated that resveratrol exerts its protective effects against OGD/R damage, at least in part, by promoting mitophagy.

Intravenous injection of apelin-13 improves sensory-motor balance deficits caused by cerebral ischemic reperfusion injury in male wistar rats via restoration of nitric oxide

It has been reported that apelin-13 possesses neuroprotective effects against cerebral ischemia/reperfusion injury (IRI). Disabilities in sense, movement and balance are the major stroke complications which, result in a high rate of mortality. Here, effects of intravenous (IV) injection of apelin-13 on the severity of neural death, infarct volume, neurological defects and its association with nitric oxide (NO) were investigated. A rat model of cerebral IRI was created by middle cerebral artery occlusion (MCAO) for 60 min and restoration of blood flow for 23 h. Animals were randomly assigned into six groups: sham, ischemia (MCAO), vehicle (MCAO + PBS) and three treatment groups (MCAO + apelin-13 in 10, 20, 40 μg/kg doses, IV). All injections were carried out via tail vein injection 5 min before reperfusion. Neural loss and infarct volume were evaluated by Nissl and 2,3,5-triphenyltetrazolium chloride (TTC) staining, respectively. Neurological defects were scored by standard modified criteria. Serum NO was measured by colorimetric method. Apelin-13 in doses of 20 and 40 μg/kg significantly reduced neural death, infarct volume and disturbance of sensory-motor balance compared to control and vehicle groups (p < 0.05). Serum NO levels reduced in MCAO groups compared to sham. Apelin-13 restored serum NO levels at 20 μg/kg dose (p < 0.05). Our data showed beneficial effect of IV injection of apelin-13 on sensory-motor balance defects by reducing neural death and restoration of serum NO levels. The present study shows the validity of apelin-13 in treatment of ischemic stroke in different administration methods.

Design, synthesis, and biological evaluation of ligustrazine/resveratrol hybrids as potential anti-ischemic stroke agents

To search for potent anti-ischemic stroke agents, a series of tetramethylpyrazine (TMP)/resveratrol (RES) hybrids 6a-t were designed and synthesized. These hybrids inhibited adenosine diphosphate (ADP)- or arachidonic acid (AA)-induced platelet aggregation, among them, 6d, 6g-i, 6o and 6q were more active than TMP. The most active compound 6h exhibited more potent anti-platelet aggregation activity than TMP, RES, as well as positive control ticlopidine (Ticlid) and aspirin (ASP). Furthermore, 6h exerted strong antioxidative activity in a dose-dependent manner in rat pheochromocytoma PC12 cells which were treated with hydrogen peroxide (H₂O₂) or hydroxyl radical (·OH). Importantly, 6h significantly protected primary neuronal cells suffered from oxygen-glucose deprivation/reoxygenation (OGD/R) injury, comparable to an anti-ischemic drug edaravone (Eda). Together, our findings suggest that 6h may be a promising candidate warranting further investigation for the intervention of ischemic stroke.

Sex dependent alterations of resveratrol on social behaviors and nociceptive reactivity in VPA-induced autistic-like model in rats

INTRODUCTION

The present study was designed to clarify the effects of resveratrol (RSV) on social behavioral alterations and nociceptive reactivity in valproic acid (VPA)-induced autistic-like model in female and male rats.

METHODS

Pregnant Wistar rats were randomly divided in five groups. Animals received saline, DMSO, VPA, RSV and RSV + VPA. VPA was administered (600 mg/kg, i. p.) on embryonic day 12.5 (E12.5) and pretreatment by resveratrol (3.6 mg/kg, s. c.) was applied on E6.5 until E18.5. All offspring were weaned on postnatal day 21 and the experiments were done in male and female rats on day 60. Social interaction, hot plate and tail flick tests were set out to assess social deficits and pain threshold, respectively. Sociability index (SI), Social novelty index (SNI) and latency time were calculated as the standard indices of social behaviors and pain threshold, respectively.

RESULTS

The results indicated that systemic intraperitoneal administration of VPA (600 mg/kg) significantly decreased SI and SNI in social interaction test (SIT) especially in male rats, indicating the social impairments caused by VPA. RSV (3.6 mg/kg, s. c.) reversed VPA-induced social deficits in male rats, but not in female group. VPA administration resulted in significant increase in latency time in the hot plate and tail flick tests in male rats, whereas it had no such dramatic effect in females. RSV administration in combination with VPA had no significant effect on latency time compared to the valproic acid group in male rats. It is important to note that RSV by itself had no significant effect on SI, SNI and latency time in female and male rats.

CONCLUSION

It can be concluded that valproic acid produces autistic-like behaviors and increases pain threshold in male rats which may be ameliorated at least in part by resveratrol administration. Further studies are needed to elucidate the molecular mechanisms involved in valproic acid and resveratrol-induced effects.

Effects of resveratrol postconditioning on cerebral ischemia in mice: role of the sirtuin-1 pathway

Evidence has demonstrated that resveratrol preconditioning exhibits neuroprotection against cerebral ischemia-reperfusion (IR) injury. The current investigation aimed to explore whether pharmacological postconditioning, by administering resveratrol, after a sustained ischemia and prior to prolonged reperfusion abrogates cerebral IR injury. Cerebral IR-induced injury mice model was employed in this study to evaluate the neuroprotective effects of pharmacological postconditioning with resveratrol (30 mg/kg; i.p.) administered 5 min before reperfusion. We administered sirtinol, a SIRT1/2 selective inhibitor (10 mg/kg; i.p.) 10 min before ischemia (17 min) and reperfusion (24 h), to elucidate whether the neuroprotection with resveratrol postconditioning depends on SIRT1 activation. Various biochemical and behavioural parameters and histopathological changes were assessed to examine the effect of pharmacological postconditioning. Infarct size is estimated using TTC staining. It was established that resveratrol postconditioning abrogated the deleterious effects of IR injury expressed with regard to biochemical parameters of oxidative stress (TBARS, SOD, GSH), acetylcholinesterase activity, behavioural parameters (memory, motor coordination), infarct size, and histopathological changes. Sirtinol significantly reversed the effect of resveratrol postconditioning. We conclude that induced neuroprotective benefits of resveratrol postconditioning may be the consequence of SIRT1 activation and resveratrol can be considered, for further studies, as potential agent inducing pharmacological postconditioning in clinical situations.

Resveratrol downregulates the TLR4 signaling pathway to reduce brain damage in a rat model of focal cerebral ischemia

Previous studies have demonstrated that inflammation and disruption of the blood-brain barrier (BBB) are important pathological processes during focal cerebral ischemia. Therefore, the present study evaluated the neuroprotective effects of resveratrol against brain damage, inflammation and BBB disruption in rats with focal cerebral ischemia and assessed the potential underlying molecular mechanisms. Sprague-Dawley rats underwent cerebral ischemia/reperfusion (IR) and then received intraperitoneal resveratrol (10 and 100 mg/kg) 2 h following the onset of ischemia. Following 24 h of ischemia, neurological deficit scores, cerebral infarctions, morphological characteristics, cerebral water content, myeloperoxidase (MPO) activity and Evans blue extravasation were assessed. Additionally, the protein expression levels of Toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB p65 were detected using western blot analyses, the mRNA expression levels of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) were examined by reverse-transcription polymerase chain reaction, and tumor necrosis factor (TNF)-α and interleukin (IL)-1β blood levels were determined by ELISA. Resveratrol significantly reduced neurological deficit scores, cerebral infarct sizes, neuronal injury, MPO activity and EB content. Cerebral ischemia increased the expression levels of TLR4, NF-κB p65, COX-2, MMP-9, TNF-α and IL-1β, but all of these factors were reduced by resveratrol. In conclusion, the present data suggest that resveratrol reduces inflammation, BBB disruption and brain damage in rats following focal cerebral ischemia. Additionally, the neuroprotective effects of resveratrol against cerebral ischemia may be associated with downregulation of the TLR4 pathway.

Brain SIRT1 Mediates Metabolic Homeostasis and Neuroprotection

Sirtuins are evolutionarily conserved proteins that use nicotinamide adenine dinucleotide (NAD+) as a co-substrate in their enzymatic reactions. There are seven proteins (SIRT1-7) in the human sirtuin family, among which SIRT1 is the most conserved and characterized. SIRT1 in the brain, in particular, within the hypothalamus, plays crucial roles in regulating systemic energy homeostasis and circadian rhythm. Apart from this, SIRT1 has also been found to mediate beneficial effects in neurological diseases. In this review, we will first summarize how SIRT1 in the brain relates to obesity, type 2 diabetes, and circadian synchronization, and then we discuss the neuroprotective roles of brain SIRT1 in the context of cerebral ischemia and neurodegenerative disorders.

(-)-α-bisabolol prevents neuronal damage and memory deficits through reduction of proinflammatory markers induced by permanent focal cerebral ischemia in mice

The pathophysiology of ischemic stroke involves multiple events such as inflammation and oxidative stress which will lead to neuronal death and cognitive deficits. The (-)-α-bisabolol is a monocyclic sesquiterpene alcohol found in various plants and mainly in Matricaria chamomilla, which exerts antioxidant, anti-inflammatory, and anti-apoptotic activities. The aim of this work was to investigate the neuroprotective effects of (-)-α-bisabolol in mice underwent permanent occlusion of the middle cerebral artery (pMCAO). Animals were treated with (-)-α-bisabolol (50, 100 and 200 mg/kg/day, orally) or vehicle (3% tween 80) one day before and 1 h after pMCAO and the treatment continued once daily for the following five days. The treatment with (-)-α-bisabolol (100 and 200 mg/kg) significantly reduced the infarcted area and neurological deficits caused by pMCAO. (-)-α-bisabolol at the 200 mg/kg dose increased cell viability and decreased neuronal degeneration, as evaluated by cresyl violet and Fluoro-Jade C stainings, respectively. (-)-α-bisabolol also increased the locomotor activity which was reduced by cerebral ischemia and improved pMCAO-induced working, spatial, object recognition, and aversive memories deficits. (-)-α-bisabolol (200 mg/kg) significantly prevented the increase of myeloperoxidase (MPO) activity, TNF-α immunoreactivity in the temporal cortex, and the increase of iNOS both in the temporal cortex and in the striatum. (-)-α-bisabolol treatment also prevented astrogliosis in these areas. These data showed that (-)-α-bisabolol provides neuroprotective action probably due to its anti-inflammatory activity, although other mechanisms cannot be discarded.

Molecular mechanism of estrogen-mediated neuroprotection in the relief of brain ischemic injury

Background

This study aimed to explore the molecular mechanism of estrogen-mediated neuroprotection in the relief of cerebral ischemic injury. The gene expression profiles were downloaded from Gene Expression Omnibus database, and differentially expressed genes (DEGs) were identified using limma package in R software. Further, DEGs were subjected to Gene Ontology (GO) cluster analysis using online Gene Ontology Enrichment Analysis Software Toolkit and to GO functional enrichment analysis using DAVID software. Using the Gene Set Analysis Toolkit V2, enrichment analysis of Kyoto Encyclopedia of Genes and Genomes pathways was performed. In addition, protein-protein interaction (PPI) network was constructed using STRING database, and submodule analysis of PPI network. Lastly, the significant potential target sites of microRNAs (miRNAs) were predicted using Molecular Signatures Database, and the function analysis of targets of predicted miRNA was also performed using DAVID software.

Results

In total, 321 DEGs were screened in the estrogen-treated sample. The DEGs were mainly associated with intracellular signaling and metabolic pathways, such as calcium channel, calcineurin complex, insulin secretion, low-density lipoprotein reconstruction, and starch or sugar metabolism. In addition, GO enrichment analysis indicated an altered expression of the genes related to starch and sucrose metabolism, retinol metabolism, anti-apoptosis (eg., BDNF and ADAM17) and response to endogenous stimulus. The constructed PPI network comprised of 243 nodes and 590 interaction pairs, and four submodules were obtained from PPI network. Among the module d, four glutamate receptors as Gria4, Gria3, Grin3a and Grik4 were highlighted. Further, 5 novel potential regulatory miRNAs were also predicted. MIR-338 and MIR520D were closely associated with cell cycle, while the targets of MIR-376A and MIR-376B were only involved in cell soma.

Conclusions

The DEGs in estrogen-treated samples are closely associated with calcium channel, glutamate induced excitotoxicity and anti-apoptotic activity. In addition, some functionally significant DEGs such as BDNF, ADAM17, Gria4, Gria3, Grin3a, Grik4, Gys2 and Ugtla2, and new miRNAs like MIR-338 and MIR-376A were identified, which may serve as potential therapeutic targets for the effective treatment of cerebral ischemic injury.

Electronic supplementary material

The online version of this article (10.1186/s12863-018-0630-y) contains supplementary material, which is available to authorized users.

Resveratrol Treatment in Different Time-Attenuated Neuronal Apoptosis After Oxygen and Glucose Deprivation/Reoxygenation via Enhancing the Activation of Nrf-2 Signaling Pathway In Vitro

Recent studies have indicated that resveratrol has protective effects against cerebral ischemia/reperfusion injury. However, the best therapeutic time for resveratrol treatment after acute ischemic stroke remains unknown. We aim to investigate whether resveratrol, administrated at different times after neuronal oxygen and glucose deprivation/reoxygenation (OGD/R) reduced neuronal injury in vitro. There were six experimental groups: normal, model, resveratrol pretreatment, resveratrol post-treatment, resveratrol OGD-treatment, and resveratrol whole-processing group. We found that resveratrol in a concentration-dependent manner decreased the activity of lactate dehydrogenase (LDH) and increased the activity of superoxide dismutase (SOD). Moreover, resveratrol, administrated at different times, increased neuronal viability, reduced neuronal apoptosis, upregulated the protein expressions of Nuclear factor erythroid 2-related factor 2 (Nrf-2), NAD(P)H: quinone oxidoreductase 1 (NQO-1), heme oxygenase 1 (HO-1), and Bcl-2, downregulated the protein expression of Caspase-3, and promoted Nrf-2 to transfer into the nuclei from the cytoplasm. The most effective treatment group was the whole-processing treatment group. These results suggest that resveratrol treatment at different times increased neuronal viability and inhibited neuronal apoptosis in vitro, at least in part, via enhancing the activation of the Nrf-2 signaling pathway.

NOS3 Inhibition Confers Post-Ischemic Protection to Young and Aging White Matter Integrity by Conserving Mitochondrial Dynamics and Miro-2 Levels

White matter (WM) damage following a stroke underlies a majority of the neurological disability that is subsequently observed. Although ischemic injury mechanisms are age-dependent, conserving axonal mitochondria provides consistent post-ischemic protection to young and aging WM. Nitric oxide synthase (NOS) activation is a major cause of oxidative and mitochondrial injury in gray matter during ischemia; therefore, we used a pure WM tract, isolated male mouse optic nerve, to investigate whether NOS inhibition provides post-ischemic functional recovery by preserving mitochondria. We show that pan-NOS inhibition applied before oxygen-glucose deprivation (OGD) promotes functional recovery of young and aging axons and preserves WM cellular architecture. This protection correlates with reduced nitric oxide (NO) generation, restored glutathione production, preserved axonal mitochondria and oligodendrocytes, and preserved ATP levels. Pan-NOS inhibition provided post-ischemic protection to only young axons, whereas selective inhibition of NOS3 conferred post-ischemic protection to both young and aging axons. Concurrently, genetic deletion of NOS3 conferred long-lasting protection to young axons against ischemia. OGD upregulated NOS3 levels in astrocytes, and we show for the first time that inhibition of NOS3 generation in glial cells prevents axonal mitochondrial fission and restores mitochondrial motility to confer protection to axons by preserving Miro-2 levels. Interestingly, NOS1 inhibition exerted post-ischemic protection selectively to aging axons, which feature age-dependent mechanisms of oxidative injury in WM. Our study provides the first evidence that inhibition of glial NOS activity confers long-lasting benefits to WM function and structure and suggests caution in defining the role of NO in cerebral ischemia at vascular and cellular levels.SIGNIFICANCE STATEMENT White matter (WM) injury during stroke is manifested as the subsequent neurological disability in surviving patients. Aging primarily impacts CNS WM and mechanisms of ischemic WM injury change with age. Nitric oxide is involved in various mitochondrial functions and we propose that inhibition of glia-specific nitric oxide synthase (NOS) isoforms promotes axon function recovery by preserving mitochondrial structure, function, integrity, and motility. Using electrophysiology and three-dimensional electron microscopy, we show that NOS3 inhibition provides a common target to improve young and aging axon function, whereas NOS1 inhibition selectively protects aging axons when applied after injury. This study provides the first evidence that inhibition of glial cell NOS activity confers long-lasting benefits to WM structure and function.

Cerebral ischemia and neuroregeneration

Cerebral ischemia is one of the leading causes of morbidity and mortality worldwide. Although stroke (a form of cerebral ischemia)-related costs are expected to reach 240.67 billion dollars by 2030, options for treatment against cerebral ischemia/stroke are limited. All therapies except anti-thrombolytics (i.e., tissue plasminogen activator) and hypothermia have failed to reduce neuronal injury, neurological deficits, and mortality rates following cerebral ischemia, which suggests that development of novel therapies against stroke/cerebral ischemia are urgently needed. Here, we discuss the possible mechanism(s) underlying cerebral ischemia-induced brain injury, as well as current and future novel therapies (i.e., growth factors, nicotinamide adenine dinucleotide, melatonin, resveratrol, protein kinase C isozymes, pifithrin, hypothermia, fatty acids, sympathoplegic drugs, and stem cells) as it relates to cerebral ischemia.

Protection from spinal cord ischemia-reperfusion damage with alpha-lipoic acid preconditioning in an animal model

Background

This study aims to investigate whether preconditioning with alpha-lipoic acid has any protective effect in neuronal damage in an experimental spinal cord ischemia-reperfusion injury model.

Methods

Eighteen adult male New Zealand rabbits (2.4-3.5 kg) were equally divided into sham, control and treatment groups. The abdominal aorta was occluded for 30 min proximally 1 cm below the renal artery and distally 1 cm above the bifurcation using aneurysm clips in control and treatment groups. Treatment group received intraperitoneal 100 mg/kg lipoic acid 20 min before aortic cross-clamping. The animals were sacrificed 48 hours after the operation and spinal cord segments between L2 and L5 were removed for biochemical and histopathological analysis. Levels of glutathione, malondialdehyde, total nitrate/nitrite, advanced oxidation protein products, catalase, superoxide dismutase, and glutathione peroxidase were examined in spinal cord.

Results

Preconditioning with alpha-lipoic acid demonstrated significantly favorable effects in all measured parameters of oxidative stress. Histopathological evaluation of the tissues also demonstrated significantly decreased neuronal degeneration, axonal damage, and microglial and astrocytic infiltration in the treatment group compared to the control group.

Conclusion

The results of this study indicate that alpha-lipoic acid administration before aortic cross-clamping has significant neuroprotective effect on spinal cord injury in rabbits.

Resveratrol reversed chronic restraint stress-induced impaired cognitive function in rats

Chronic stress occurs in everyday life, and often results in memory impairments and depressive symptoms. Resveratrol is a natural polyphenol that possesses numerous biological properties, including potent antidepressant‑like effects. The present study aimed to examine the effects of resveratrol treatment on chronic restraint stress (CRS)‑induced cognitive impairment and to explore the underlying molecular mechanisms. Male Wistar rats were exposed to CRS for 21 days in order to induce depressive‑like behavior. The results demonstrated that CRS (6 h/day, 21 days) was able to induce cognitive deficits in rats, as evidenced by Morris water maze and novel object recognition tests. In addition, CRS exposure significantly decreased the mRNA and protein expression levels of hippocampal brain‑derived neurotrophic factor (BDNF) in the rats. Conversely, chronic treatment with resveratrol (80 mg/kg, i.p.; 21 days) significantly prevented the behavioral and biochemical alterations induced by CRS. The effects of resveratrol were nearly identical to those observed with fluoxetine treatment. In conclusion, the present study demonstrated that resveratrol may be a potential therapeutic agent for the treatment of chronic stress‑induced cognitive impairments, and its underlying molecular mechanism may be associated with the increased levels of hippocampal BDNF.

Endothelial nitric oxide synthase inhibition triggers inflammatory responses in the brain of male rats exposed to ischemia-reperfusion injury

Nitric oxide (NO) derived from endothelial NO synthase (eNOS) plays a role in preserving and maintaining the brain's microcirculation, inhibiting platelet aggregation, leukocyte adhesion, and migration. Inhibition of eNOS activity results in exacerbation of neuronal injury after ischemia by triggering diverse cellular mechanisms, including inflammatory responses. To examine the relative contribution of eNOS in stroke-induced neuroinflammation, we analyzed the effects of systemic treatment with l-N-(1-iminoethyl)ornithine (L-NIO), a relatively selective eNOS inhibitor, on the expression of MiR-155-5p, a key mediator of innate immunity regulation and endothelial dysfunction, in the cortex of male rats subjected to transient middle cerebral artery occlusion (tMCAo) followed by 24 hr of reperfusion. Inducible NO synthase (iNOS) and interleukin-10 (IL-10) mRNA expression were evaluated by real-time polymerase chain reaction in cortical homogenates and in resident and infiltrating immune cells isolated from ischemic cortex. These latter cells were also analyzed for their expression of CD40, a marker of M1 polarization of microglia/macrophages.tMCAo produced a significant elevation of miR155-5p and iNOS expression in the ischemic cortex as compared with sham surgery. eNOS inhibition by L-NIO treatment further elevated the cortical expression of these inflammatory mediators, while not affecting IL-10 mRNA levels. Interestingly, modulation of iNOS occurred in resident and infiltrating immune cells of the ischemic hemisphere. Accordingly, L-NIO induced a significant increase in the percentage of CD40⁺ events in CD68⁺ microglia/macrophages of the ischemic cortex as compared with vehicle-injected animals. These findings demonstrate that inflammatory responses may underlie the detrimental effects due to pharmacological inhibition of eNOS in cerebral ischemia.

Resveratrol protects against ICV collagenase-induced neurobehavioral and biochemical deficits

Background

Indeed, intracerebral hemorrhage (ICH) account for only 15% of all strokes but it is one of the most devastating subtype of stroke associated with behavioral, cognitive and neurological deficits. The primary cause of neurological deficits in ICH is the hematoma growth, generation of free radicals, inflammatory cytokines and exhausting endogenous anti-oxidant machinery. It has been found that neuroinflammation following ICH leads to exaggeration of hallmarks of ICH. With this background, the study was aimed to evaluate the protective effect of resveratrol (RSV) in intracerebroventricular (ICV) collagenase (COL) induced neurological deficits in rats.

Methods

The present study was designed to explore the protective effects of resveratrol (5, 10, 20 mg/kg) against ICV-COL induced ICH. Animals were subjected to a battery of behavioral tests to access behavioral changes, including neurological scoring tests (cylinder test, spontaneous motility, righting reflex, horizontal bar test, forelimb flexion), actophotometer, rotarod, Randall Sellito and von Frey. Post stroke depression was estimated using forced swim test (FST). Memory deficit was monitored using Morris water maze (MWM).

Results

Chronic treatment with RSV (20 mg/kg) for 21 days restored various behavioral changes, including neurological scoring tests (cylinder test, spontaneous motility, righting reflex, horizontal bar test, forelimb flexion), actophotometer, rotarod, Randall Sellito and Von Frey. RSV also restores increase in immobility time forced swim test used to evaluate post stroke depression and impaired memory deficit in Morris water maze. RSV administration also attenuated increased nitro-oxidative stress and TNF-α level. RSV being a potent antioxidant also restores changes in endogenous anti-oxidant levels.

Conclusion

In conclusion, our research demonstrates that RSV has a protective effect against ICH by virtue of its anti-inflammatory property and antioxidant and nitrosative stress restoring property.

Anticonvulsant activity of resveratrol-loaded liposomes in vivo

Resveratrol (3,5,4'-stilbenetriol), a natural polyphenol produced by various plants, has attracted attention over the past decade because of its multiple beneficial properties, including anti-inflammatory, anti-oxidant and chemopreventive, yet, there is limited information about its antiepileptic effects. Moreover, its poor solubility in water and low bioavailability are the challenging issues. In the present study, we aimed to investigate effects of free resveratrol and resveratrol delivered in amphipathic liposomal delivery system, which has a high blood-brain barrier crossing potential, on penicillin-induced epileptic seizure model. For this purpose, adult male Sprague-Dawley rats were divided into four groups as saline (Control), liposome (LIP), free resveratrol (RES) and resveratrol+liposome (RES+LIP). Penicillin-induced epileptic activity was recorded for 120 min by electrocorticography. Glutathione S-transferase (GST), Glutathione (GSH), Superoxide dismutase (SOD) and Malondialdehyde (MDA) assays were performed in brain tissues collected. Our results showed that RES+LIP was the most effective anticonvulsant treatment on penicillin-induced epileptic seizures when compared to control, as RES+LIP immediately decreased the number of spikes per minute. GST and SOD activity, as well as the GSH levels, were significantly increased in the RES+LIP group as compared with the control group. Also, the MDA levels were significantly higher in the RES+LIP compared to RES and control groups. In conclusion, RES+LIP treatment was more effective on the decrease in spike frequency and spike amplitudes than other treatments. Our results suggest that the RES+LIP is more effective than RES on penicillin-induced epileptiform activity.

Targeting Nitric Oxide with Natural Derived Compounds as a Therapeutic Strategy in Vascular Diseases

Within the family of endogenous gasotransmitters, nitric oxide (NO) is the smallest gaseous intercellular messenger involved in the modulation of several processes, such as blood flow and platelet aggregation control, essential to maintain vascular homeostasis. NO is produced by nitric oxide synthases (NOS) and its effects are mediated by cGMP-dependent or cGMP-independent mechanisms. Growing evidence suggests a crosstalk between the NO signaling and the occurrence of oxidative stress in the onset and progression of vascular diseases, such as hypertension, heart failure, ischemia, and stroke. For these reasons, NO is considered as an emerging molecular target for developing therapeutic strategies for cardio- and cerebrovascular pathologies. Several natural derived compounds, such as polyphenols, are now proposed as modulators of NO-mediated pathways. The aim of this review is to highlight the experimental evidence on the involvement of nitric oxide in vascular homeostasis focusing on the therapeutic potential of targeting NO with some natural compounds in patients with vascular diseases.

The role of S-methylisothiourea hemisulfate as inducible nitric oxide synthase inhibitor against kidney iron deposition in iron overload rats

Background:

Iron dextran is in common use to maintain iron stores. However, it is potentially toxic and may lead to iron deposition (ID) and impair functions of organs. Iron overload can regulate the expression of inducible nitric oxide synthase (iNOS) in some cells that has an important role in tissue destruction. S-methylisothiourea hemisulfate (SMT) is a direct inhibitor of iNOS, and this study was designed to investigate the effect of SMT against kidney ID in iron overload rats.

Materials and Methods:

24 Wistar rats (male and female) were randomly assigned to two groups. Iron overloading was performed by iron dextran 100 mg/kg/day every other day for 2 weeks. In addition, during the study, groups 1 and 2 received vehicle and SMT (10 mg/kg, ip), respectively. Finally, blood samples were obtained, and the kidneys were prepared for histopathological procedures.

Results:

SMT significantly reduced the serum levels of creatinine and blood urea nitrogen. However, SMT did not alter the serum levels of iron and nitrite, and the kidney tissue level of nitrite. Co-administration of SMT with iron dextran did not attenuate the ID in the kidney.

Conclusion:

SMT, as a specific iNOS inhibitor, could not protect the kidney from ID while it attenuated the serum levels of kidney function biomarkers.

Mitochondrial function in hypoxic ischemic injury and influence of aging

Mitochondria are a major target in hypoxic/ischemic injury. Mitochondrial impairment increases with age leading to dysregulation of molecular pathways linked to mitochondria. The perturbation of mitochondrial homeostasis and cellular energetics worsens outcome following hypoxic-ischemic insults in elderly individuals. In response to acute injury conditions, cellular machinery relies on rapid adaptations by modulating posttranslational modifications. Therefore, post-translational regulation of molecular mediators such as hypoxia-inducible factor 1α (HIF-1α), peroxisome proliferator-activated receptor γ coactivator α (PGC-1α), c-MYC, SIRT1 and AMPK play a critical role in the control of the glycolytic-mitochondrial energy axis in response to hypoxic-ischemic conditions. The deficiency of oxygen and nutrients leads to decreased energetic reliance on mitochondria, promoting glycolysis. The combination of pseudohypoxia, declining autophagy, and dysregulation of stress responses with aging adds to impaired host response to hypoxic-ischemic injury. Furthermore, intermitochondrial signal propagation and tissue wide oscillations in mitochondrial metabolism in response to oxidative stress are emerging as vital to cellular energetics. Recently reported intercellular transport of mitochondria through tunneling nanotubes also play a role in the response to and treatments for ischemic injury. In this review we attempt to provide an overview of some of the molecular mechanisms and potential therapies involved in the alteration of cellular energetics with aging and injury with a neurobiological perspective.

Neuroprotection and antioxidants

Ischemia as a serious neurodegenerative disorder causes together with reperfusion injury many changes in nervous tissue. Most of the neuronal damage is caused by complex of biochemical reactions and substantial processes, such as protein agregation, reactions of free radicals, insufficient blood supply, glutamate excitotoxicity, and oxidative stress. The result of these processes can be apoptotic or necrotic cell death and it can lead to an irreversible damage. Therefore, neuroprotection and prevention of the neurodegeneration are highly important topics to study. There are several approaches to prevent the ischemic damage. Use of many modern therapeutical methods and the incorporation of several substances into the diet of patients is possible to stimulate the endogenous protective mechanisms and improve the life quality.

Phytochemicals in Ischemic Stroke

Stroke is the second foremost cause of mortality worldwide and a major cause of long-term disability. Due to changes in lifestyle and an aging population, the incidence of stroke continues to increase and stroke mortality predicted to exceed 12 % by the year 2030. However, the development of pharmacological treatments for stroke has failed to progress much in over 20 years since the introduction of the thrombolytic drug, recombinant tissue plasminogen activator. These alarming circumstances caused many research groups to search for alternative treatments in the form of neuroprotectants. Here, we consider the potential use of phytochemicals in the treatment of stroke. Their historical use in traditional medicine and their excellent safety profile make phytochemicals attractive for the development of therapeutics in human diseases. Emerging findings suggest that some phytochemicals have the ability to target multiple pathophysiological processes involved in stroke including oxidative stress, inflammation and apoptotic cell death. Furthermore, epidemiological studies suggest that the consumption of plant sources rich in phytochemicals may reduce stroke risk, and so reinforce the possibility of developing preventative or neuroprotectant therapies for stroke. In this review, we describe results of preclinical studies that demonstrate beneficial effects of phytochemicals in experimental models relevant to stroke pathogenesis, and we consider their possible mechanisms of action.

Resveratrol Pretreatment Decreases Ischemic Injury and Improves Neurological Function Via Sonic Hedgehog Signaling After Stroke in Rats

Resveratrol has neuroprotective effects for ischemic cerebral stroke. However, its neuroprotective mechanism for stroke is less well understood. Beneficial actions of the activated Sonic hedgehog (Shh) signaling pathway in stroke, such as improving neurological function, promoting neurogenesis, anti-oxidative, anti-apoptotic, and pro-angiogenic effects, have been noted, but relatively little is known about the role of Shh signaling in resveratrol-reduced cerebral ischemic injury after stroke. The present study tests whether the Shh pathway mediates resveratrol to decrease cerebral ischemic injury and improve neurological function after stroke. We observed that resveratrol pretreatment significantly improved neurological function, decreased infarct volume, enhanced vitality, and reduced apoptosis of neurons in vivo and vitro after stroke. Meanwhile, expression levels of Shh, Ptc-1, Smo, and Gli-1 mRNAs were significantly upregulated and Gli-1 was relocated to the nucleus. Intriguingly, in vivo and in vitro inhibition of the Shh signaling pathway with cyclopamine, a Smo inhibitor, completely reversed the above effects of resveratrol. These results suggest that decreased cerebral ischemic injury and improved neurological function by resveratrol may be mediated by the Shh signaling pathway.

Resveratrol Enhances Neuroplastic Changes, Including Hippocampal Neurogenesis, and Memory in Balb/C Mice at Six Months of Age

Resveratrol (RVTL) is a flavonoid found in red wine and has been publicized heavily as an anti-aging compound. Indeed, basic research confirms that although there is much hype in the promotion of RVTL, flavonoids such as RVTL have a wide range of biological effects. We here investigated the effects of RVTL treatment on hippocampal plasticity and memory performance in female Balb/C mice, a strain with low baseline levels of adult neurogenesis. Two weeks of treatment with RVTL (40 mg/kg) induced the production of new neurons in vivo by increasing cell survival and possibly precursor cell proliferation. In addition, RVTL decreased the number of apoptotic cells. The number of doublecortin (DCX)-expressing intermediate cells was increased. RVTL stimulated neuronal differentiation in vitro without effects on proliferation. In the dentate gyrus, RVTL promoted the formation and maturation of spines on granule cell dendrites. RVTL also improved performance in the step down passive avoidance test. The RVTL-treated mice showed increase in the levels of two key signaling proteins, phospho-Akt and phospho-PKC, suggesting the involvement of these signaling pathways. Our results support the vision that flavonoids such as resveratrol deserve further examination as plasticity-inducing compounds in the context of successful cognitive aging.

Natural polyphenols based new therapeutic avenues for advanced biomedical applications

Polyphenols are naturally occurring, synthetic or semisynthetic organic compounds that offer a vast array of advanced biomedical applications. The mostly researched polyphenolic compounds are resveratrol and flavanols, notably (-)-epicatechin. The ongoing research on clinically important resveratrol and flavanols has revealed their potentials as extremely efficient drug agents that can be leveraged for new therapeutic designs for combating stroke related injuries, cancer and renal failures. Here, we have highlighted recent developments in this area with an emphasis on the biomedical applications of polyphenols. Also, a perspective on the future research directions has been discussed. We believe that this review would facilitate further research and development of polyphenols as a therapeutic avenue in medical science.

Enabling dual cellular destinations of polymeric nanoparticles for treatment following partial injury to the central nervous system

Following neurotrauma, oxidative stress is spread via the astrocytic syncytium and is associated with increased aquaporin 4 (AQP4), inflammatory cell infiltration, loss of neurons and glia and functional deficits. Herein we evaluate multimodal polymeric nanoparticles functionalized with an antibody to an extracellular epitope of AQP4, for targeted delivery of an anti-oxidant as a therapeutic strategy following partial optic nerve transection. Using fluorescence microscopy, spectrophotometry, correlative nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy, in vitro and in vivo, we demonstrate that functionalized nanoparticles are coated with serum proteins such as albumin and enter both macrophages and astrocytes when administered to the site of a partial optic nerve transection in rat. Antibody functionalized nanoparticles synthesized to deliver the antioxidant resveratrol are effective in reducing oxidative damage to DNA, AQP4 immunoreactivity and preserving visual function. Non-functionalized nanoparticles evade macrophages more effectively and are found more diffusely, including in astrocytes, however they do not preserve the optic nerve from oxidative damage or functional loss following injury. Our study highlights the need to comprehensively investigate nanoparticle location, interactions and effects, both in vitro and in vivo, in order to fully understand functional outcomes.

Sirt1 in cerebral ischemia

Cerebral ischemia is among the leading causes of death worldwide. It is characterized by a lack of blood flow to the brain that results in cell death and damage, ultimately causing motor, sensory, and cognitive impairments. Today, clinical treatment of cerebral ischemia, mostly stroke and cardiac arrest, is limited and new neuroprotective therapies are desperately needed. The Sirtuin family of oxidized nicotinamide adenine dinucleotide (NAD⁺)-dependent deacylases has been shown to govern several processes within the central nervous system as well as to possess neuroprotective properties in a variety of pathological conditions such as Alzheimer's Disease, Parkinson's Disease, and Huntington's Disease, among others. Recently, Sirt1 in particular has been identified as a mediator of cerebral ischemia, with potential as a possible therapeutic target. To gather studies relevant to this topic, we used PubMed and previous reviews to locate, select, and resynthesize the lines of evidence presented here. In this review, we will first describe some functions of Sirt1 in the brain, mainly neurodevelopment, learning and memory, and metabolic regulation. Second, we will discuss the experimental evidence that has implicated Sirt1 as a key protein in the regulation of cerebral ischemia as well as a potential target for the induction of ischemic tolerance.

Sustained neurological recovery induced by resveratrol is associated with angioneurogenesis rather than neuroprotection after focal cerebral ischemia

According to the French paradox, red wine consumption reduces the incidence of vascular diseases even in the presence of highly saturated fatty acid intake. This phenomenon is widely attributed to the phytoalexin resveratrol, a red wine ingredient. Experimental studies suggesting that resveratrol has neuroprotective properties mostly used prophylactic delivery strategies associated with short observation periods. These studies did not allow conclusions to be made about resveratrol's therapeutic efficacy post-stroke. Herein, we systematically analyzed effects of prophylactic, acute and post-acute delivery of resveratrol (50mg/kg) on neurological recovery, tissue survival, and angioneurogenesis after focal cerebral ischemia induced by intraluminal middle cerebral artery occlusion in mice. Over an observation period of four weeks, only prolonged post-acute resveratrol delivery induced sustained neurological recovery as assessed by rota rod, tight rope and corner turn tests. Although prophylactic and acute resveratrol delivery reduced infarct volume and enhanced blood-brain-barrier integrity at 2 days post-ischemia by elevating resveratrol's downstream signal sirtuin-1, increasing cell survival signals (phosphorylated Akt, heme oxygenase-1, Bcl-2) and decreasing cell death signals (Bax, activated caspase-3), a sustained reduction of infarct size on day 28 was not observed in any of the three experimental conditions. Instead, enhanced angiogenesis and neurogenesis were noted in animals receiving post-acute resveratrol delivery, which were associated with elevated concentrations of GDNF and VEGF in the brain. Thus, sustained neurological recovery induced by resveratrol depends on successful brain remodeling rather than structural neuroprotection. The recovery promoting effect of delayed resveratrol delivery opens promising perspectives for stroke therapy.

Resveratrol neuroprotection in stroke and traumatic CNS injury

Resveratrol, a stilbene formed in many plants in response to various stressors, elicits multiple beneficial effects in vertebrates. Particularly, resveratrol was shown to have therapeutic properties in cancer, atherosclerosis and neurodegeneration. Resveratrol-induced benefits are modulated by multiple synergistic pathways that control oxidative stress, inflammation and cell death. Despite the lack of a definitive mechanism, both in vivo and in vitro studies suggest that resveratrol can induce a neuroprotective state when administered acutely or prior to experimental injury to the CNS. In this review, we discuss the neuroprotective potential of resveratrol in stroke, traumatic brain injury and spinal cord injury, with a focus on the molecular pathways responsible for this protection.

Acidic FGF promotes neurite outgrowth of cortical neurons and improves neuroprotective effect in a cerebral ischemic rat model

Acidic fibroblast growth factor (aFGF) is a neurotrophic factor which is a powerful neuroprotective and neuroregenerative factor of the nervous system. Prior study had shown that levels of FGFs significantly increase following ischemic injury, reflecting a physiological protection mechanism. However, few reports demonstrated the efficacy of applying aFGF in cerebral ischemia. A recent report showed that the intranasal aFGF treatment improved neurological functional recovery; however, it did not significantly reduce the lesion size in ischemic rats. The present study examines the neuroprotective effect of aFGF on cortical neuron-glial cultures under oxygen glucose deprivation (OGD)-induced cell damage and investigates whether epidural application of slow-released aFGF could improve benefit on ischemic stroke injury in conscious rats. We used a topical application of aFGF mixed in fibrin glue, a slow-release carrier, over the peri-ischemic cortex and examined such treatment on cerebral infarction and behavioral impairments of rats subjected to focal cerebral ischemia (FCI). Results demonstrate that aFGF effectively protected cortical neuron-glial cultures from OGD-induced neuronal damage. Neurite extension from cortical neurons was significantly enhanced by aFGF, mediated through activation of AKT and ERK. In addition, topical application of fibrin glue-mixed aFGF dose-dependently reduced ischemia-induced brain infarction and improved functional restoration in ischemic stroke rats. Slow-released aFGF not only protected hippocampal and cortical cell loss but reduced microglial infiltration in FCI rats. Our results suggest that aFGF mixed in fibrin glue could prolong the protective/regenerative efficacy of aFGF to the damaged brain tissue and thus improve the functional restorative effect of aFGF.

L-NAME combats excitotoxicity and recuperates neurological deficits in MCAO/R rats

PURPOSE OF RESEARCH

Since, transient focal cerebral ischaemia exhibits detrimental effect not only during the course of ischaemia but also after the onset of reperfusion, the current study is focussed on identifying the appropriate therapeutic time point at which NG-nitro-l-arginine methyl ester (l-NAME) exerts better neuroprotection.

PRINCIPAL RESULTS

Pre-ischaemic administration of l-NAME ameliorated neurological deficits much better than the during ischaemic and post-ischaemic groups. Pre-ischaemic l-NAME has also mitigated glutamate excitotoxicity, increased glutamine synthetase activity, ATP and NAD levels, decreased nitrate/nitrite content, down regulated TNF-α and upregulated IL-10 expressions and reduced the cerebral infarction significantly than the during ischaemic and post-ischaemic groups.

MAJOR CONCLUSION

Current study revealed that l-NAME improved neurological deficit at the pre-ischaemic state in transient focal cerebral ischaemia and has also significantly ameliorated glutamate excitotoxicity. Though l-NAME showed neuroprotective effects when administered at during and post-ischaemia (during reperfusion), it exerts considerable neuroprotection when administered pre-ischaemically.

Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed.

Resveratrol: A Focus on Several Neurodegenerative Diseases

Molecules of the plant world are proving their effectiveness in countering, slowing down, and regressing many diseases. The resveratrol for its intrinsic properties related to its stilbene structure has been proven to be a universal panacea, especially for a wide range of neurodegenerative diseases. This paper evaluates (in vivo and in vitro) the various molecular targets of this peculiar polyphenol and its ability to effectively counter several neurodegenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases and amyotrophic lateral sclerosis. What emerges is that, in the deep heterogeneity of the pathologies evaluated, resveratrol through a convergence on the protein targets is able to give therapeutic responses in neuronal cells deeply diversified not only in morphological structure but especially in their function performed in the anatomical district to which they belong.

Poor outcome of experimental ischemic stroke in type 2 diabetic rats: impaired circulating endothelial progenitor cells mobilization

BACKGROUND

It is well accepted that type 2 diabetic mellitus (T2DM) results in the poor outcome of ischemic stroke. However, the mechanisms by which T2DM causes aggravated cerebral ischemic/reperfusion (I/R) injury are not clear. Recently, endothelial progenitor cells (EPCs) are considered to be related with the outcome of ischemic stroke. More importantly, T2DM can affect the function of circulating EPCs. This study tried to investigate whether T2DM worsens the cerebral I/R injury via affecting circulating EPCs.

METHODS

We used high-fat diet-fed and low-dose streptozotocin-treated male rats receiving middle cerebral artery occlusion surgery as animal model of focal cerebral I/R injury with T2DM (diabetic operated). And the rats were divided into 4 groups: normal sham, diabetic sham, normal operated, and diabetic operated. We measured the circulating EPCs counts and the levels of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) in peripheral plasma of 4 groups.

RESULTS

We found that diabetic rats subjected to I/R exhibited significantly severe deterioration in neurologic deficits compared with nondiabetic counterparts, which manifested higher infarct volume and cell apoptosis as well as lower neurologic defective score. There was no significant difference on the plasma glucose of groups before cerebral I/R injury compared with that of the groups posterior to cerebral I/R injury despite cerebral I/R injury had the tendency to increase the plasma glucose no matter in the presence or the absence of T2DM. In addition, there were the marked downregulation of circulating EPCs counts and the levels of VEGF and eNOS in diabetic rats before the cerebral I/R injury. Despite I/R injury without T2DM, there was a significant increase in the circulating EPCs counts, the circulating EPCs counts in I/R injury with T2DM group were significantly decreased compared with those in the other 3 groups. We also observed that the level of eNOS was significantly improved by I/R injury without considering the presence of T2DM.

CONCLUSIONS

Thus, our present study suggested that it might be the impaired EPCs mobilization into the blood that contributed to the worse outcome of cerebral I/R injury with T2DM.

Resveratrol up-regulates AMPA receptor expression via AMP-activated protein kinase-mediated protein translation

Resveratrol is a phytoalexin that confers overall health benefits including positive regulation in brain function such as learning and cognition. However, whether and how resveratrol affects synaptic activity remains largely unknown. α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are glutamatergic receptors that mediate the majority of fast excitatory transmission and synaptic plasticity, and thus play a critical role in higher brain functions, including learning and memory. We find that in rat primary neurons, resveratrol can rapidly increase AMPAR protein level, AMPAR synaptic accumulation and the strength of excitatory synaptic transmission. The resveratrol effect on AMPAR protein expression is independent of sirtuin 1 (SIRT1), the conventional downstream target of resveratrol, but rather is mediated by AMP-activated protein kinase (AMPK) and subsequent downstream phosphoinositide 3-kinase (PI3K)/Akt signaling. Application of the AMPK specific activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) mimics the effects of resveratrol on both signaling and AMPAR expression. The resveratrol-induced increase in AMPAR expression results from elevated protein synthesis via regulation of the eukaryotic initiation factor (eIF) 4E/4G complex. Disruption of the translation initiation complex completely blocks resveratrol-dependent AMPAR up-regulation. These findings indicate that resveratrol may regulate brain function through facilitation of AMPAR biogenesis and synaptic transmission.