Neuroprotective Effect Of Ethyl Pyruvate Research Articles

Ethyl pyruvate attenuates cerebral hypoxia/reoxygenation injury in neuroblastoma cells: Role of GAS6/Axl signaling

BackgroundIschemic stroke, caused neurological dysfunction due to inadequate blood supply to brain, has a high morbidity and mortality. Ethyl pyruvate (EP), a simple aliphatic ester derived from pyruvic acid, has the advantages of safety and stability. Studies have confirmed that EP has anti-oxidative, anti-inflammation, anti-tumor, and other pharmacological effects, and it demonstrates significant therapeutic effects on multiple diseases. GAS6 and its high affinity Axl receptor play an important role in cell adhesion, anti-apoptosis, proliferation and migration by activating downstream signal transduction pathways. Previous studies have demonstrated the neuroprotective effects of the GAS6/Axl axis. MethodsA series of experimental methods were employed to confirm the effect of EP against cerebral hypoxia/reoxygenation (HR) injury. ResultsIn this study, the protective effect and mechanism of EP on HR injury in N2a cells was explored. The results found that treatment with EP could increase HR-injured neuronal viability, improve cell morphology, and reduce LDH release and ROS accumulation, thereby exhibiting a neuroprotective effect. Furthermore, EP treatment restored the down-regulated expression of GAS6, Axl, NQO1, PGC-1α, NRF1, and UCP2 caused by HR injury. Specifically, it was observed that the neuroprotective effect of EP was partially inhibited by GAS6 siRNA. ConclusionIn conclusion, these results suggest that EP treatment attenuates HR-induced oxidative stress injury in neuroblastoma cells via activating GAS6/Axl signaling.

Neuroprotective Effects of Ethyl Pyruvate against Aluminum Chloride-Induced Alzheimer's Disease in Rats via Inhibiting Toll-Like Receptor 4.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the formation of insoluble deposits of β-amyloid (Aβ) plaques within the parenchyma of the brain. The present study aimed to investigate the neuroprotective role of ethyl pyruvate against in vitro and in vivo model of aluminum chloride (AlCl3)-induced AD. Effect of ethyl pyruvate (5, 10, 20, 40mM) against AlCl3 (1250μM)-induced neurotoxicity in primary neuron-glial mixed cell culture was evaluated using cell viability assays (MTT assay as well as calcein-AM/propidium iodide fluorescent dyes). In vivo model, AlCl3 (50mg/kg) were given through intraperitoneal route (i.p.) once daily for 4weeks in rats and after 2weeks, ethyl pyruvate (50, 100, 200mg/kg/day) was co-administered with AlCl3 once daily via the oral route. The present study, in addition to perform histopathology of the brain, also estimated oxidant and antioxidant parameters as well as memory impairment using pole test, plus maze, and Morris water maze test. The binding mode of ethyl pyruvate in the hMD-2 was also studied. Results of in vitro studies showed that the AlCl3 administration resulted in neuronal cell death. AlCl3 administration in rats resulted in memory loss, oxidative stress (increasedlipid peroxide and nitric oxide), impairment of antioxidant mechanisms (superoxide dismutase, catalase, and reduced glutathione), and deposition of amyloid plaques in cerebral cortex region of the brain. AlCl3 also resulted in the overexpression of the TLR4 receptors in the brain tissues. Administration of ethyl pyruvate ameliorated the AlCl3-induced neurotoxicity in neuron-glial mixed cell culture as well as histopathological, neurochemical, and behavioral consequences of chronic administration of AlCl3 in the rat. Ethyl pyruvate showed a docking score of 4.048. Thus, ethyl pyruvate is effective against in vitro and in vivo models of AlCl3-induced AD.

596: Ethyl pyruvate: A novel approach to protect the fetus against antenatal inflammatory damage

In pregnancies complicated by inflammation, activation of RAGE signaling pathways may be responsible for poor fetal and neonatal outcomes including stillbirth and neonatal brain injury. Ethyl pyruvate (EP) improved survival in murine models of endotoxemia via RAGE inhibition, and was already shown to be safe in humans. We investigated the effect of maternal administration of EP on neonatal growth and neurodevelopmental outcome using a genetically engineered over-expressing RAGETg murine model of in-utero inflammation. Saline or endotoxin (LPS, 5 or 10 μg/dam) were given intra-peritoneal (i.p.) on day 15 (d0=sperm plug), in mice randomly assigned to the following groups: 1) RAGETg and 2) Wild-type (WT) (n=9-30 pups/group) as controls. EP (40 mg/kg) was administered i.p. 2 hours later. Doses were chosen based on prior experiments demonstrating live birth. Pups underwent post-natal daily behavioral testing (i.e. cliff aversion, forelimb grasp, negative geotaxis) from birth to day 14 of life. Using immunohistochemistry (IHC), we assessed cortical neuronal density in animals sacrificed on day 20 of life. 1) In-utero exposure to EP did not increase post-natal mortality rate; 2) Compared to control, weight gain was inhibited in WT receiving LPS5 (p=0.02), which was ameliorated by EP (p=0.0001); 3) WT and RAGETg mice exposed to LPS demonstrated delay in achieving behavioral milestones, an effect reversed by EP (p<0.001, Figure); 4) WT and RAGETg mice showed improved neurobehavioral battery with EP independent of fetal gender; 5) EP protected against LPS-induced cortical neuronal loss (p=0.001) by IHC. We report a novel neuroprotective effect of EP from perinatal inflammatory insult.

Ethyl pyruvate alleviates early brain injury following subarachnoid hemorrhage in rats.

Previous studies have demonstrated the neuroprotective effects of ethyl pyruvate in central nervous system (CNS) diseases. However, whether ethyl pyruvate attenuates early brain injury after subarachnoid hemorrhage (SAH) remains unknown. This study was conducted to investigate the potential effects of ethyl pyruvate on early brain injury induced by SAH and explore the underlying mechanisms. Eighty-eight male Sprague-Dawley rats were used. An SAH model was induced by endovascular perforation. Ethyl pyruvate (100mg/kg) or a vehicle was administered intraperitoneally at 1h after SAH induction. SAH grade, neurological scores, brain water content, Evans blue extravasation, Western blots, and immunofluorescence were used to study the mechanisms of ethyl pyruvate. Ethyl pyruvate treatment inhibited microglia activation and reduced the expression of proinflammatory cytokines (IL-1β and TNF-α). Ethyl pyruvate treatment also prevented disruption of tight junction proteins (occluding and claudin-5) and reduced expression of MMP-9. In addition, ethyl pyruvate treatment markedly reduced TUNEL-positive cells and expression of cleaved caspase-3. Our results indicated that ethyl pyruvate treatment attenuated early brain injury and improved neurological function after SAH by inhibiting microglia activation and apoptosis and stabilizing the BBB.

Neuroprotective effect of ethyl pyruvate against Zn2+ toxicity via NAD replenishment and direct Zn2+ chelation

Ethyl pyruvate (EP) is a simple aliphatic ester of pyruvic acid and has been shown to have robust protective effect in various pathological conditions. A variety of mechanisms have been reported to underlie the protective effects of EP, which include anti-inflammatory, anti-oxidative, and anti-apoptotic functions. Recently, we reported that EP suppressed high mobility group box 1 (HMGB1) release from primary microglial cells via direct Ca2+ chelation. In the present study, we investigated whether and how EP chelates Zn2+ in neurons when it is present at toxic levels. In cortical neurons treated with 40 μM of Zn2+ for 24 h, both EP and pyruvate significantly suppressed neuronal cell death, although the potency of pyruvate was greater than that of EP, and that NAD replenishment contributed to the neuroprotective effects of both pyruvate and EP. However, when cortical neurons were exposed to acute treatment of Zn2+ (400 μM, 15 min), EP, but not pyruvate, significantly suppressed neuronal death, despite the fact that NAD replenishment by EP was weaker than that by pyruvate. Spectrophotometric studies revealed that EP directly chelates Zn2+, and this was confirmed in physiological contexts, such as, NMDA-treated primary cortical cultures and OGD-subjected hippocampal slice cultures, in which EP suppressed intracellular Zn2+ elevation and neuronal cell death. In addition, EP markedly reduced the expressions of PARP-1 and of the NADPH oxidase subunit in Zn2+-treated primary cortical neurons, well known Zn2+-induced downstream processes. Together, these results show EP suppresses Zn2+ induced neurotoxicity via dual functions, chelating Zn2+ and promoting NAD replenishment.

Neuroprotective effect of ethyl pyruvate in vincristine and cisplatin induced neuropathic pain

Aim of Study: The aim of the present work was to screen synthetic compound Ethyl Pyruvate (EP) for its potential use in chemotherapeutic drugs induced neuropathic pain. Materials and Methods: In vincristine induced neuropathy model, Vincristine sulfate (50 μg/kg i.p.) for 10 consecutive days was administered to induce neuropathy in rats with EP for 14 days. In cisplatin induced neuropathy model, cisplatin was administered at a dose of (2 mg/kg i.p.) twice a week for 5 weeks with EP for 5 weeks daily in this model. The effect of ethyl pyruvate in tail heat immersion, paw pressure and acetone drop tests were performed to assess the degree of spinal thermal sensation, mechanical hyperalgesia and cold allodynia, respectively. Vacuolar changes, necrosis and cellular infiltration of sciatic nerve were assessed histopathologically. The levels of various antioxidants were determined to assess oxidative stress. Results: In vincristine and cisplatin induced neuropathy models, co-administration of EP 100 mg/kg significantly attenuated reduction of nociceptive threshold in tail heat immersion test and threshold in paw pressure along with the increased score in the acetone drop test. EP 100 mg/kg significantly attenuated reactive changes in histopathology and increase in oxidative stress. Conclusion: The observed neuroprotective effect can be attributed to the antioxidant property of EP. Therefore, with support from the literature and data in hand it seems quite evident that EP 100 mg/kg exerted its beneficial effects in vincristine and cisplatin induced peripheral neuropathic pain.

Up-down Regulation of HO-1 and iNOS Gene Expressions by Ethyl Pyruvate via Recruiting p300 to Nrf2 and Depriving It from p65

Ethyl pyruvate (EP), a simple ester of pyruvic acid, has been shown to exert robust neuroprotection in various neuropathological conditions, such as, cerebral ischemia and KA-induced seizure animal models. The neuroprotective effect of EP is attributable to the anti-inflammatory, anti-oxidative, and anti-apoptotic effects. In the present study, we investigated convergence of anti-inflammatory and anti-oxidative functions of EP and present a novel molecular mechanism underlying anti-inflammatory effects of EP, which is conveyed by p300, a transcriptional co-activator for both Nuclear factor E2-related factor 2 (Nrf2) and p65. In BV2 cells, a microglia cell line, EP induced translocation of Nrf2 from the cytosol to the nucleus and enhanced the expression of hemeoxygenase 1 (HO-1) in a dose-dependent manner and 1h incubation with 10mM EP increased HO-1 to 4.9-fold. Nrf2 was found to translocate from the cytosol to the nucleus beginning 30min after EP-treatment and binds to the antioxidant response element (ARE) located on HO-1 promoter. Interestingly, LPS-induced inducible NO synthase (iNOS) induction was substantially suppressed in EP-pre-treated BV2 cells and it was reverted by Nrf2 knockdown. We found that EP-induced Nrf2 accumulation in the nucleus recruits p300, a transcriptional co-activator of both Nrf2 and p65, inhibiting p65-p300 interaction. Competition between Nrf2 and p65 for p300 binding was confirmed by glutathione S-transferase (GST) pull down assay and reporter gene analysis. These results demonstrate that EP induced nuclear translocation of Nrf2 which binds to ARE along with p300 and hampers iNOS expression via depleting p300 from p65. This is a novel anti-inflammatory mechanism conveyed by EP, which enhances protective effect by converging anti-inflammatory and anti-oxidative effects and might be applicable to various Nrf2-activating agents, such as phytochemicals.

Ethyl pyruvate ameliorates intracerebral hemorrhage-induced brain injury through anti-cell death and anti-inflammatory mechanisms

Ethyl pyruvate (EP) is a pyruvate derivative and known to be cytoprotective in various pathological conditions through anti-cell death and anti-inflammatory mechanisms. The present study investigated the neuroprotective effect of ethyl pyruvate using a mouse model of collagenase-induced intracerebral hemorrhage (ICH). Our results showed that EP treatment to mice reduced brain edema and improved neurological function after ICH. Delayed treatment with EP until 6h after ICH to mice was still neuroprotective. We further demonstrated that EP protected neurons from hemoglobin-induced cell death in vitro and neuronal cell degeneration in ICH mice. Moreover, EP exerted anti-inflammatory effects by inhibiting microglia activation, nuclear factor-κB (NF-κB) DNA binding activity and subsequent downstream pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)) production. Taken together, these results suggest that EP exerts neuroprotective effect via anti-cell death and anti-inflammatory actions. EP is a potential novel treatment for ICH patients and deserves further investigation.

Ethyl pyruvate protects against lipopolysaccharide-induced white matter injury in the developing rat brain

The neuroprotective effects of ethyl pyruvate (EP) have been proved in several brain injury models, yet very little is known about its action on neonatal white matter injury. To investigate the effect of EP on white matte damage, a stereotactic intracerebral injection of lipopolysaccharide (LPS, 1mg/kg) was performed on postnatal day 5 Sprague–Dawley rat pups, and EP was administrated intraperitoneally at a dose of 40mg/kg immediately, 1h and 12h after LPS exposure. Significantly, treatment with EP reduced LPS-induced ventricle dilation, loss of O4+ and O1+ oligodendrocytes, apoptosis of oligodendrocytes, and hypomyelination. The protective effect of EP was associated with suppressed inflammatory responses, indicated by the inhibition of activation of microglia and astrocytes, as well as the decreased expression of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) in rat brains. Also, EP prevented the elevation of cleaved caspase-3 in periventricular white matter tissue after LPS insult. Taken together, these results suggest that EP confers potent protection against LPS-induced white matter injury via its anti-inflammatory and anti-apoptotic properties.

Ethyl pyruvate promotes spinal cord repair by ameliorating the glial microenvironment

Spinal cord injury (SCI) triggers a series of endogenous processes, including neuroinflammation and reactive astrogliosis, which may contribute to the failure of neural regeneration and functional recovery. In the present study, the effect of ethyl pyruvate on spinal cord repair was explored. Functional assessment and histological analyses of astrogliosis, neuroinflammation, neuronal survival and axonal regeneration were performed to investigate the effects of ethyl pyruvate (0.086, 0.215, 0.431 or 0.646 mmol·kg(-1) ·day(-1) ) on spinal cord repair in a rat model of SCI. The effect of ethyl pyruvate (5, 10 or 15 mM) on astrocytic activation was also evaluated in an in vitro'scratch-wound' model. Functional assessment showed evident improvement of behavioural functions in the ethyl pyruvate-treated rats. Reactive astrogliosis was significantly inhibited in vivo, after injection of ethyl pyruvate (0.431 mmol·kg(-1) day(-1) ), and in vitro'scratch-wound' model in the presence of 10 or 15 mM ethyl pyruvate. The difference between effective concentration in vitro and in vivo suggests that the inhibitory effect of ethyl pyruvate on astrogliosis in damaged spinal cord is indirect. In addition, ethyl pyruvate (0.431 mmol·kg(-1) day(-1) ) attenuated SCI-induced neuroinflammation; it decreased the Iba-1-, ED-1- and CD11b-positive cells at the lesion site. Importantly, histological analyses showed a significantly greater number of surviving neurons and regenerative axons in the ethyl pyruvate-treated rats. Ethyl pyruvate was shown to inhibit astrogliosis and neuroinflammation, promote neuron survival and neural regeneration, and improve the functional recovery of spinal cord, indicating a potential neuroprotective effect of ethyl pyruvate against SCI.

Ethyl pyruvate has a neuroprotective effect through activation of extracellular signal-regulated kinase in Parkinson’s disease model

Ethyl pyruvate (EP), a simple derivative of endogenous pyruvate, has an anti-inflammatory function. Recently, the protective neurological effects of EP have been reported in cell culture and animal models of neurological diseases. The present study investigates the protective effects of EP on dopaminergic cell death in Parkinson’s disease models. The selective death of dopaminergic neurons in substantia nigra was prevented by EP in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse models. EP also suppressed the 1-methyl-4-pyridinium-induced cell death of SH-SY5Y cells and restored the phosphorylation of extracellular signal-regulated kinase. Thus, EP has neuroprotective effects of EP in Parkinson’s disease and its related signaling pathways.

Ethyl Pyruvate Inhibits Peroxynitrite-induced DNA Damage and Hydroxyl Radical Generation: Implications for Neuroprotection

Ethyl pyruvate (EP) has recently been reported to afford protection against neurodegenerative disorders. However, the mechanism underlying EP-mediated neuroprotection remains to be elucidated. Because peroxynitrite has been extensively implicated in the pathogenesis of various forms of neurodegenerative disorders via its cytotoxic effects, this study was undertaken to investigate whether the neuroprotective effect of EP is associated with inhibition of peroxynitrite-induced DNA strand breaks, a critical event leading to peroxynitrite elicited cytotoxicity. Incubation of phiX-174 plasmid DNA with 3-morpholinosydnonimine (SIN-1), a peroxynitrite generator, led to the formation of both single- and double-stranded DNA breaks in a concentration- and time- dependent manner. The presence of EP (0.5-10 mM) was found to significantly inhibit SIN-1-induced DNA strand breaks in a concentration-dependent fashion. The consumption of oxygen induced by 250 microM SIN-1 was found to be decreased in the presence of EP (0.5-10 mM), indicating that EP might affect the auto-oxidation of SIN-1. It was observed that incubation of the plasmid DNA with authentic peroxynitrite caused significant DNA strand breaks, which could also be dramatically inhibited by EP (0.5-10 mM). EPR spectroscopy in combination with spin-trapping technique using 5,5-dimethylpyrroline-N- oxide (DMPO) as a spin trap demonstrated the formation of DMPO-hydroxyl radical adducts (DMPO-OH) from authentic peroxynitrite, and that EP at 0.5-10 mM inhibited the adduct signal in a concentration-dependent manner. Taken together, these results demonstrate for the first time that EP can inhibit peroxynitrite-mediated DNA damage and hydroxyl radical generation.

Combination Treatment with Ethyl Pyruvate and Aspirin Enhances Neuroprotection in the Postischemic Brain

Ethyl pyruvate (EP), a simple aliphatic ester of pyruvic acid, has been shown to act as an anti-inflammatory molecule in various pathological conditions, which include sepsis or hemorrhagic shock. Recently, we showed that ethyl pyruvate has a neuroprotective effect in the postischemic brain and also in KA-induced pathogenesis in the brain. In this study, we examined whether aspirin augments neuroprotective effect of ethyl pyruvate in transient focal ischemia model by complementing the neuroprotective effects of ethyl pyruvate. Although, most of neuroprotective effect of aspirin has been attributed to the anti-platelet action, aspirin also has direct neuroprotective effects, including NF-kappaB inhibition. Ethyl pyruvate dose-dependently suppressed infarct formation in the postischemic brain, wherein intravenous administration of 5 mg/kg ethyl pyruvate 30 min after the occlusion reduced infarct volume to 34.5 +/- 15.5% (n = 6, P < 0.01) of that of the untreated control. In combination with aspirin (5 mg/kg, i.v.), the neuroprotective effect was enhanced, resulting in 16.0 +/- 5.9% (n = 6, P < 0.01) infarct volume. The time window for synergistic neuroprotection by ethyl pyruvate and aspirin extended to 9 h post-MCAO. The synergistic reduction in infarct volume was accompanied by suppression of the clinical manifestations associated with cerebral ischemia including motor impairment and neurological deficits. Inflammatory processes including microglial activation and proinflammatory cytokine expression were notably suppressed by the combination treatment in the postischemic brain and in primary microglia cultures, wherein ethyl pyruvate and aspirin modulate NF-kappaB signaling differentially. Aspirin interferes with IkappaB phosphorylation and degradation in the cytoplasm, possibly by specifically inhibiting IkappaB kinase-beta, whereas, the effect of ethyl pyruvate seems to occur in the nucleus, where it may interfere with the binding of NF-kappaB to responsive promoter elements in the target genes. Similar enhancement in neuroprotective effect was also observed in primary cortical cultures after NMDA or Zn(2+) treatment or oxygen-glucose deprivation. Together, these results indicate that combination treatment of ethyl pyruvate and aspirin affords synergistic neuroprotection in the postischemic brain with a wide therapeutic window, in part via differential modulation of the NF-kappaB signaling pathway.

Neuroprotective Effects of Ethyl Pyruvate on Brain Energy Metabolism after Ischemia-Reperfusion Injury: A 31P-Nuclear Magnetic Resonance Study

The neuroprotective effects of ethyl pyruvate (EP), a stable derivative of pyruvate, on energy metabolism of rat brain exposed to ischemia-reperfusion stress were investigated by (31)P-nuclear magnetic resonance ((31)P-NMR) spectroscopy. Recovery level of phosphocreatine after ischemia was significantly greater when superfused with artificial cerebrospinal fluid (ACSF) with 2 mM EP than when superfused with ACSF without EP. EP was neuroprotective against ischemia only when administered before the ischemic exposure. Intracellular pH during ischemia was less acidic when superfused ahead of time with EP. EP did not show neuroprotective effects in neuron-rich slices pretreated with 100 microM fluorocitrate, a selective glial poison. It was suggested that both the administration of EP before ischemic exposure and the presence of astrocytes are required for EP to exert neuroprotective effects. We suggest the potential involvement of multiple mechanisms of action, such as less acidic intracellular pH, glial production of lactate, and radical scavenging ability.

Neuroprotective effects of ethyl pyruvate on brain energy metabolism after ischemia depend on glial cells: A 31P-NMR study

Neuroprotective effects of ethyl pyruvate on brain energy metabolism after ischemia depend on glial cells: A 31P-NMR study