Neuroprotective Effects Of Erythropoietin Research Articles

The neuroprotective effect of erythropoietin on spinal motor neurons after nerve root avulsion injury in rats.

The rapid death of many spinal motor neurons after nerve root avulsion injury results in limited functional recovery following replantation surgery of avulsed nerves into the spinal cord. Therefore, we investigated the neuroprotective effect of erythropoietin (EPO) on motor neurons after nerve root avulsion injury using a rat model. After C6 nerve root avulsion injury, EPO (2680 U/kg) was injected subcutaneously once a day for 3 consecutive days with various starting time points. At 28 and 56 days after injury, histological and immunohistological investigations were performed. EPO-treated rats showed a significant increase in the number of surviving motor neurons at day 28 when the initial dose was started within 96 h after injury. In EPO-treated rats, superoxide formation in the motor neurons and proliferation of microglia were markedly suppressed in the acute phase. GAP-43-positive surviving motor neurons were significantly increased in EPO-treated rats at day 28. However, at 56 days after surgery, EPO-treated rats showed a much greater decrease of surviving motor neurons compared with those at day 28. The neuroprotective effect of EPO is not long lasting, but may prolong the time before replantation surgery.

The Neuroprotective Effect of Erythropoietin on Rotenone-Induced Neurotoxicity in SH-SY5Y Cells Through the Induction of Autophagy.

Currently, the autophagy pathway is thought to be important for the pathogenesis of Parkinson's disease (PD), and the modulation of autophagy may be a novel strategy for the treatment of this disease. Erythropoietin (EPO) has been reported to have neuroprotective effects through anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms, and it has also been shown to modulate autophagy signaling in an oxygen toxicity model. Therefore, we investigated the effects of EPO on autophagy markers and evaluated its neuroprotective effect on rotenone-induced neurotoxicity. We adapted the rotenone-induced neurotoxicity model to SH-SY5Y cells as an in vitro model of PD. We measured cell viability using MTT and annexin V/propidium iodide assays and measured intracellular levels of reactive oxygen species. Immunofluorescence analysis was performed to measure the expression of LC3 and α-synuclein. Intracellular signaling proteins associated with autophagy were examined by immunoblot analysis. EPO mono-treatment increased the levels of mammalian target of rapamycin (mTOR)-independent/upstream autophagy markers, including Beclin-1, AMPK, and ULK-1. Rotenone treatment of SH-SY5Y cells reduced their viability, increased reactive oxygen species levels, and induced apoptosis and α-synuclein expression, and simultaneous exposure to EPO significantly reduced these effects. Rotenone enhanced mTOR expression and suppressed Beclin-1 expression, indicating suppression of the autophagy system. However, combined treatment with EPO restored Beclin-1 expression and decreased mTOR expression. EPO protects against rotenone-induced neurotoxicity in SH-SY5Y cells by enhancing autophagy-related signaling pathways. The experimental evidence for the EPO-induced neuroprotection against rotenone-induced dopaminergic neurotoxicity may significantly impact the development of future PD treatment strategies.

Neuroprotective Effects of Erythropoietin in Patients with Severe Closed Brain Injury.

Our research was focused on the neuroprotective function of erythropoietin (Epo) in patients with severe closed traumatic brain injury (TBI). Our model examined the influence of the outcome and neurological recovery in 42 adults with TBI who were admitted to ICU within 6 hours of their injury and were recruited into a randomized controlled study of two groups; only the patients of the intervention group received 10,000 i.u. of Epo for 7 consecutive days. A prognostic model based on CRASH II injury model and outcome was measured by survival and Glasgow Outcome Scale-Extended version (GOS-E) score at 6 months post-injury. Six patients (18.7%) died during the first two weeks; 4 of the control group and 2 of the intervention group. A mortality rate of 22.2% and 8.3% for the control and intervention group respectively was observed. A lower rate of good outcome (GOS-E score > 4) at 6 months was mentioned among patients of the control group. The study provides evidence of lower mortality and better neurological outcome for the patients who received Epo increasing the possibility that Epo therapy could be used in clinical practice, limiting neuronal damage induced by TBI.

Neuroprotective effect of erythropoietin against pressure ulcer in a mouse model of small fiber neuropathy.

An increased risk of skin pressure ulcers (PUs) is common in patients with sensory neuropathies, including those caused by diabetes mellitus. Recombinant human erythropoietin (rhEPO) has been shown to protect the skin against PUs developed in animal models of long-term diabetes. The aim of this work was to determine whether rhEPO could prevent PU formation in a mouse model of drug-inducedSFN. Functional SFN was induced by systemic injection of resiniferatoxin (RTX, 50 µg/kg, i.p.). RhEPO (3000 UI/kg, i.p.) was given the day before RTX injection and then every other day. Seven days after RTX administration, PUs were induced by applying two magnetic plates on the dorsal skin. RTX-treated mice expressed thermal and mechanical hypoalgesia and showed calcitonin gene-related peptide (CGRP) and substance P (SP) depletion without nerve degeneration or vascular dysfunction. RTX mice developed significantly larger stage 2 PUs than Vehicle mice. RhEPO prevented thermal and mechanical hypoalgesia and neuropeptide depletion in small nerve fibers. RhEPO increased hematocrit and altered endothelium-dependent vasodilatation without any effect on PU formation in Vehicle mice. The characteristics of PUs in RTX mice treated with rhEPO and Vehicle mice were found similar. In conclusion, RTX appeared to increased PU development through depletion of CGRP and SP in small nerve fibers, whereas systemic rhEPO treatment had beneficial effect on peptidergic nerve fibers and restored skin protective capacities against ischemic pressure. Our findings support the evaluation of rhEPO and/or its non-hematopoietic analogs in preventing to prevent PUs in patients with SFN.

The neuroprotective effect of erythropoietin on experimental Parkinson model in rats

Dopaminergic neuronal loss in Parkinson's disease (PD) results from oxidative stress, neuroinflammation and excitotoxicity. Because erythropoietin (EPO) has been shown to have antioxidant, anti-inflammatory and neuroprotective effects in many previous studies, present study was designed to evaluate the effect of EPO on rotenone-induced dopaminergic neuronal loss. The rats in which PD was induced by stereotaxical infusion of rotenone showed increased MDA and TNF-alpha levels and decreased HVA levels. On the other hand, EPO treatment resulted in markedly decreased MDA and TNF-alpha levels and increased HVA levels. EPO treatment in rotenone-infusion group resulted in improvement of striatal neurodegeneration and a significant increase in decreased total number of neurons and immunohistochemical TH positive neurons. Results of the present study demonstrate the neuroprotective, anti-inflammatory and antioxidant effects of EPO in a rotenone-induced neurodegenerative animal model.

Neuroprotective effects of erythropoietin in focal brain ischemia in rats.

Neuroprotective effect of erythropoietin administered before ischemia has been previously demonstrated. The efficiency of erythropoietin administration after ischemia was not studied, though in case of success these protocols would be applied in clinical neurology. In our experiments on the model of transitory focal ischemia, erythropoietin was injected intraperitoneally during the early and delayed postischemic period (3 and 12 h). The size of the necrotic zone, neurological deficit, and the severity of brain edema were evaluated in 48 h. Injection of erythropoietin in 3 and 12 h after ischemia significantly reduced the size of necrosis (p = 0.0007 and p=0.0016, respectively), neurological deficit (p=0.0013 and p=0.0062, respectively), and brain edema (p=0.02 and p=0.0186, respectively). Injection of erythropoietin after transitory focal cerebral ischemia produced a pronounced neuroprotective effect.

Abstract W MP84: Erythropoietin Inhibits Oxidation of Tetrahydrobiopterin and Restores Bioavailability of Endothelial Nitric Oxide in Cerebral Microvessels of Hph-1 Mice

Background: While reported neuroprotective effects of erythropoietin (EPO) make it an appealing candidate for its evaluation in protection of neurovascular unit during cerebrovascular or neurodegenerative disorders, effects of EPO on cerebral microvessels, the vascular component of neurovascular unit, have not been studied to date. The present study was designed to determine the effects of EPO in cerebral microvessels derived from wild-type mice and also from hph-1 mice, a genetic mouse model of BH4 deficiency. Methods: Hph-1 mice and wild-type littermates (C57BL/6 background) were administered recombinant human EPO (1000 U/kg/day) intraperitoneally for 3 days. Following treatment, mice were killed by injection of an overdose of pentobarbital, brains were removed and cerebral microvessels were isolated. Results: Treatment of wild-type mice with EPO did not affect BH4 bioavailability, superoxide anion production or basal cGMP levels. We have reported that cerebral microvessels of hph-1 mice demonstrated reduced bioavailability of BH4, increased production of superoxide anions and impaired endothelial NO/cGMP signaling. Treatment of hph-1 mice with EPO attenuated the levels of 7,8-dihydrobiopterin (7,8-BH2; P<0.05, n=5), oxidized product of BH4, and significantly increased the ratio of BH4 to 7,8-BH2 (P<0.05, n=5), indicative of increased bioavailability of BH4 for eNOS activation. Increased superoxide anion production in cerebral microvessels of hph-1 mice were attenuated by EPO treatment (P<0.05, n=5). While eNOS expression remained unchanged, levels of cGMP were significantly increased on EPO treatment in hph-1 mice (P< 0.05, n=6). Furthermore, EPO treatment selectively increased expression of manganese superoxide dismutase. Conclusion: The ability of EPO to attenuate oxidative stress and restore bioavailability of endothelial NO in cerebral microvessels may help to explain mechanisms responsible for cerebrovascular protective effects of EPO.

Therapeutic effects of nonerythropoietic erythropoietin analog ARA290 in experimental autoimmune encephalomyelitis rat

ARA290 is a nonerythropoietic analog of erythropoietin (EPO) containing 11 amino acids which provides the anti-inflammatory and neuroprotective effects of EPO without stimulating hematopoiesis. Here we studied the therapeutic effects of ARA290 in experimental autoimmune encephalomyelitis (EAE) Lewis rats. Therapeutic (from Day 7 to Day 18 or from Day 9 to Day 19) administration of ARA290 (35, 70μg/kg, intra-peritoneal) to EAE rats once daily significantly reduced the severity and shortened the duration of clinical score, reduced the accumulation of inflammatory cells in EAE spinal cords and suppressed mRNA levels of interleukin-1β (IL-1β), IL-17, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), inducible nitric oxide synthase (iNOS), matrix metalloproteinase 9 (MMP9) and transcription factor T-bet in spinal cords of EAE rats. Furthermore, ARA290 treatment reduced the helper T cell number in lymph nodes and circulation in EAE. In vitro study showed that ARA290 dose-dependently inhibited antigen specific- and antigen non-specific-lymphocyte proliferation as well. In addition, ARA290 altered the cytokine milieu to favor the polarization of Th2 and regulatory T (Treg) cells but suppressed the polarization of Th1 and Th17 cells in EAE lymph nodes. In summary, our study here showed that ARA290 could alter T cell function to suppress inflammation to ameliorate EAE, suggesting that ARA290 may be a new therapeutic candidate for multiple sclerosis.

EPO-Dependent Activation of PI3K/Akt/FoxO3a Signalling Mediates Neuroprotection in In Vitro and In Vivo Models of Parkinson’s Disease

Erythropoietin (EPO) may become a potential therapeutic candidate for the treatment of the neurodegenerative disorder -- Parkinson's disease (PD), since EPO has been found to prevent neuron apoptosis through the activation of cell survival signalling. However, the underlying mechanisms of how EPO exerts its neuroprotective effect are not fully elucidated. Here we investigated the mechanism by which EPO suppressed 6-hydroxydopamine (6-OHDA)-induced neuron death in in vitro and in vivo models of PD. EPO knockdown conferred 6-OHDA-induced cytotoxicity. This effect was reversed by EPO administration. Treatment of PC12 cells with EPO greatly diminished the toxicity induced by 6-OHDA in a dose- and time-dependent manner. EPO effectively reduced apoptosis of striatal neurons and induced a significant improvement on the neurological function score in the rat models of PD. Furthermore, EPO increased the expression of phosphorylated Akt and phosphorylated FoxO3a, and abrogated the 6-OHDA-induced dysregulation of Bcl-2, Bax and Caspase-3 in PC12 cells and in striatal neurons. Meanwhile, the EPO-dependent neuroprotection was notably reversed by pretreatment with LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K). Our data suggest that PI3K/Akt/FoxO3a signalling pathway may be a possible mechanism involved in the neuroprotective effect of EPO in PD.

Neuroprotective Effects of Erythropoietin in Patients with Carbon Monoxide Poisoning

The purpose of this study was to evaluate the efficacy of erythropoietin (EPO) for treating patients with carbon monoxide (CO) poisoning. We conducted a randomized, prospective study of 103 patients with CO poisoning in two groups: an EPO group (n = 54; patients received EPO) and a placebo group (n = 49; patients received normal saline). The study endpoints were the functional outcome at day 30 (the Barthel index and neurologic sequelae), National Institutes of Health Stroke Scale (NIHSS) score, and the levels of S-100β. At 18 days, the NIHSS score improved significantly and S-100β levels significantly decreased in patients in the EPO group. At 30 days, patients in the EPO group had a superior Barthel index and fewer patients had delayed neurologic sequelae (DNS). This study demonstrated that early administration of EPO to patients with CO poisoning improved neurological outcomes and reduced the incidence of DNS.

Neuroprotective effect of erythropoietin on nandrolone decanoate-induced brain injury in rats

Anabolic–androgenic steroids (AAS) are used in the medical treatment of many disorders. Erythropoietin (EPO) is a hematopoietic cytokine that has anti-apoptotic, anti-oxidative, and anti-inflammatory effects. The aim of the present study is to investigate the neuroprotective effects of EPO in the hippocampus, parietal cortex and prefrontal cortex, in brain damage due to nandrolone decanoate. 35 Wistar male rats were randomly divided into: (1) control group, (2) sham group, (3) nandrolone decanoate group (ND, intramuscular, 10mg/(kgweek), 8 weeks), (4) ND+low dose EPO treated group (ND+L-EPO) and (5) ND+high dose EPO treated group (ND+H-EPO). EPO was administrated by intraperitoneal injection at a dose of 100U/(kgday) for L-EPO treatment and at a dose of 500U/(kgday) for H-EPO treatment during 8 weeks. The number of neurons of CA1, CA2, CA3 and dentate gyrus of hippocampus, parietal cortex and prefrontal cortex were significantly less in the ND group compared with the control group. Treatment with H-EPO significantly preserved the number of neurons in hippocampus when compared with ND administrated. Besides, H-EPO treatment decreased the number of TUNEL-positive and active caspase-3 positive cells and MDA levels and increased GPx levels when compared to ND group. In conclusion, abuse of AAS causes reduction in the number of neurons in hippocampus, parietal cortex and prefrontal cortex regions and increases oxidative damage and therefore H-EPO may be useful as a neuroprotective agent in brain injury.

Erythropoietin attenuates 6-hydroxydopamine-induced apoptosis via glycogen synthase kinase 3β-mediated mitochondrial translocation of Bax in PC12 cells

The aim of this study was to determine the mechanism by which erythropoietin (EPO) suppressed 6-hydroxydopamine (6-OHDA)-induced apoptosis. Our results showed that 6-OHDA remarkably decreased phosphorylation of glycogen synthase kinase 3β (GSK3β) as well as enhanced the level of Bax in the mitochondria. Besides, 6-OHDA decreased the mitochondrial expression of Bcl-2 without altering the cytoplasmic expression of Bcl-2. In line with these results, 6-OHDA treatment enhanced the apoptosis and caspase 3 activity in PC12 cells. These findings indicated that mitochondrial dysfunction was involved in the neurotoxicity of 6-OHDA and GSK3β might act upstream of Bax/Bcl-2 and the caspase 3 pathways in 6-OHDA-treated PC12 cells. Furthermore, EPO reduced 6-OHDA-induced growth inhibition. Western blot exhibited that GSK3β inhibitor 4-benzyl-2-methyl-1, 2,4-thiadiazolidine-3, 5-dione (TDZD8) and EPO not only increased the phosphorylation of GSK3β but also inhibited the mitochondrial translocation of Bax. In agreement with these results, EPO and TDZD8 obviously increased the mitochondrial expression of Bcl-2. Finally, TDZD-8 and EPO significantly suppressed the enhanced apoptosis and activity of caspase 3 induced by 6-OHDA. Taken together, GSK3β-mediated mitochondrial cell death pathway is involved in the neuroprotective effect of EPO against 6-OHDA-induced apoptosis.

Current Opinions on Epidemiology, Treatment and Outcome After Traumatic Brain Injury

Objective: The objective of this article is to provide an overview on current incidences of traumatic brain injury (TBI) with special focus on current surgical and non-surgical treatment options as well as outcome. Method: A Medline database search was performed using various combinations of the search terms “traumatic brain injury”, “TBI”, “treatment”, “outcome” “pediatric”, “intracranial hypertension”, “epidemiology” and “incidence”. Results: We found an incidence of TBI of 332/100,000 inhabitants in Germany per year and 219-345/100,000 TBI occurring in children. TBI is still the leading cause of mortality and morbidity worldwide. The overall mortality after TBI is described with 1%. Typical symptoms of TBI represent headache, nausea and vomiting, dizziness, blurred vision, paresis, aphasia, seizures and impaired coordination on the physical side. Cognitive impairments include attention, memory and concentration disorders or decreased processing speed whereas behavioural symptoms present as depression, anxiety, agitation or aggression. Persistence of these symptoms results in a vicious cycle of impaired skill acquisition and an adaptive deficit with increased academic failure, unemployment and loss of salary, social and behavioural dysfunction and isolation. The injury severity of TBI is commonly classified according to the established Glasgow Coma Scale (GCS) and the TCDB classification in CT-Scans. Established non-surgical treatment of intracranial pressure after TBI emphasizes on hyperventilation, hypothermia as well as application of mannitol, hypertonic saline solution or barbiturates. Recently, neuroprotective effects of erythropoietin (EPO) have been demonstrated. Surgical therapy consists of lumbar drainage of cerebrospinal fluid, decompressive craniotomy, and the evacuation of mass lesions. Conclusion: While scientific data concerning the classification of TBI, treatment and outcome prediction has significantly progressed over the last two decades identifying risk factors and treatment options, further research is needed consolidating first-, second- and third-tier treatment. Identifying treatment pathways based upon potential predictive factors and rehabilitative outcome is thought to improve family support of patients concerned and to optimize health care requirements.

Neuroprotection of erythropoietin and methylprednisolone against spinal cord ischemia-reperfusion injury

Recent research based on various animal models has shown the neuroprotective effects of erythropoietin (EPO). However, few studies have examined such effects of EPO in the clinic. In this study we enrolled patients with spinal cord ischemia-reperfusion (I-R) injury to investigate the clinical application of EPO and methylprednisolone (MP) for the neuroprotection against spinal cord I-R injury. Retrospective analysis of 63 cases of spinal cord I-R injury was performed. The Frankel neurological performance scale was used to evaluate the neurological function after spinal cord injury (SCI), including 12 cases of scale B, 30 cases of scale C, and 21 cases of scale D. These cases were divided into 2 groups: group A (27 cases) got treatment with both EPO and MP; group B (36 cases) got treatment with MP only. The neurological function of patients after treatment was evaluated by American Spinal Cord Injury Association (ASIA) index score, and activity of daily living (ADL) of the patients was also recorded. All patients got follow-up and the follow-up period ranged from 24 to 39 months (mean 26 months). There was no significance difference in neurological function between groups A and B before the treatment (P>0.05). However, the neurological function and ADL scores were significantly improved 1 week, 1 year or 2 years after the treatment compared to those before the treatment (P<0.05), and the improvement was more significant in group A than in group B (P<0.05). It is suggested that the clinical application of EPO and MP provides the neuroprotection against spinal cord I-R injury.

L-DOPA neurotoxicity is prevented by neuroprotective effects of erythropoietin

The neurotoxicity of L-3,4-dihydroxyphenylalanine (L-DOPA), one of the most important drugs for the treatment of Parkinson's disease, still remains controversial, although much more data on L-DOPA neurotoxicity have been presented. Considering the well known neuroprotective effects of erythropoietin (EPO), the inhibitory effects of EPO on L-DOPA neurotoxicity need to be evaluated. Neuronally differentiated PC12 (nPC12) cells were treated with different concentrations of L-DOPA and/or EPO for 24h. Cell viability was evaluated using trypan blue, 4′,6-diamidino-2-phenylindole (DAPI) and TUNEL staining, and cell counting. Free radicals and intracellular signaling protein levels were measured with 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) and Western blotting, respectively. L-DOPA reduced nPC12 cell viability at higher concentrations, but combined treatment with EPO and L-DOPA significantly restored cell viability. Free radicals and hydroxyl radical levels increased by L-DOPA were decreased after combined treatment of L-DOPA and EPO. Levels of survival-related intracellular signaling proteins decreased in nPC12 cells treated with 200μM L-DOPA but increased significantly in cells treated with 200μM L-DOPA and 5μM EPO. However, cleaved caspase-3, a death-related protein, increased in nPC12 cells treated with 200μM L-DOPA but decreased significantly in cells treated with 200μM L-DOPA and 5μM EPO. Pretreatment with LY294002, a phosphatidylinositol 3-kinase inhibitor, prior to combined treatment with EPO and L-DOPA almost completely blocked the protective effects of EPO. These results indicate that EPO can prevent L-DOPA neurotoxicity by activating the PI3K pathway as well as reducing oxidative stress.

Neuroprotection by local intra-arterial infusion of erythropoietin after focal cerebral ischemia in rats

<title/>Objectives: The neuroprotective effect of erythropoietin has been demonstrated by ischemia and reperfusion models in adult and neonatal rodents. However, administration of high-dose erythropoietin has potential complications. The goal of this study was to determine whether local infusion of low dose erythropoietin offers neuroprotective effects after ischemia and reperfusion injury.Methods: Adult male Sprague-Dawley rats subject to middle cerebral artery occlusion were randomly divided into three groups: (1) sham group: the rats received the same procedure as the other two groups except that no suture was inserted; (2) vehicle group: intra-artery local infusion of saline was administered via middle cerebral artery after reperfusion; and (3) treatment group: 50 U/kg intra-artery local infusion of erythropoietin was administered via middle cerebral artery after reperfusion. Neurological deficit scores and infarct volume (determined by hematoxylin-eosin staining) were evaluated 48 hours after reperfusion. Apoptosis was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The expression of vascular endothelial growth factor and phosphorylated extracellular signal-regulated kinase were investigated by immunohistochemistry method.Results: The results show that intra-artery local infusion of erythropoietin, via the middle cerebral artery, significantly reduced neurological deficit scores, foot fault number, and the infarct volume at 48 hours after reperfusion. Significant reductions were also found in the number of positive cells stained by TUNEL assay within the ischemic core and penumbra. Furthermore, local infusion of erythropoietin increased the expression of phosphorylated extracellular signal-regulated kinase and vascular endothelial growth factor.Discussion: Local infusion of low-dose erythropoietin via the middle cerebral artery is shown to be neuroprotective against cerebral ischemia and reperfusion injury. The mechanism of neuroprotection may be associated with the increased expression of phosphorylated extracellular signal-regulated kinase and vascular endothelial growth factor.

Neuroprotective effects of erythropoietin in preterm infants

The dramatic increase in survival of extremely premature infants has been associated with a growing population of individuals with neurodevelopmental disabilities. To date, clinical trials of neuroprotective agents in preterm infants have been limited, but new data suggest that erythropoietin might have important neuroprotective effects in these vulnerable infants.

Erythropoietin may modify tyrosine kinase activity for its neuroprotective action in mice

The neuroprotective effect of erythropoietin (EpO) was evaluated against MgCl 2 induced cerebral ischemia. EpO (500 IU/kg i.p) prevented the MgCl 2 (0.5M) induced cerebral ischemia in the mice. EpO also reduced the bleeding time in mice by 7.64 %. Pretreatment with tyrosine kinase inhibitor, Genistein (6mg/kg i.p) attenuated the neuroprotective effect of EpO and reversed the effects of EpO on bleeding time in mice. These studies suggest that EpO is protective against MgCl 2 induced cerebral ischemia and a role for tyrosine kinase enzyme in this action is suggested based on the results of this study.

Erythropoietin may Modify Tyrosine Kinase Activity for its Neuroprotective Action in Mice

The neuroprotective effect of erythropoietin (EpO) was evaluated against MgCl 2 induced cerebral ischemia. EpO (500 IU/kg i.p) prevented the MgCl 2 (0.5M) induced cerebral ischemia in the mice. EpO also reduced the bleeding time in mice by 7.64 %. Pretreatment with tyrosine kinase inhibitor, Genistein (6mg/kg i.p) attenuated the neuroprotective effect of EpO and reversed the effects of EpO on bleeding time in mice. These studies suggest that EpO is protective against MgCl 2 induced cerebral ischemia and a role for tyrosine kinase enzyme in this action is suggested based on the results of this study.

Neuroprotective effects of erythropoietin on 6-hydroxydopamine-treated ventral mesencephalic dopamine-rich cultures

Parkinson's disease (PD) is a neurodegenerative disorder with motor symptoms caused by the loss of dopaminergic (DA) cells and consequently dopamine release in the nigrostriatal system. In vivo and in vitro 6-hydroxydopamine (6-OHDA) PD models are widely used to study the effect of striatal dopamine depletion as well as novel neuroprotective or restorative therapeutic strategies for PD. In the present study, we investigated in vitro the toxicity of 6-OHDA on DA neurons derived from E14 rat ventral mesencephalon (VM) and the neuroprotective efficiency of erythropoietin (Epo) on VM-derived cell cultures against 6-OHDA toxicity. Using E14 VM-derived DA-rich primary cultures, we could demonstrate that 6-OHDA toxicity works in a time-and concentration-dependent way, and leads to cell death not only in DA cells but also in non-DA cells in direct relation to concentration and incubation times. In addition, we found that 6-OHDA toxicity induces caspase-3 activation and an increment of intracellular reactive oxygen species (ROS) in VM-derived cultures. When 6-OHDA-treated VMs were cultured in the presence of the anti-apoptotic protein erythropoietin (Epo), the total neuronal population, including the DA neurons, was protected. However, untreated VM cultures exposed to Epo showed an increase in the total neuronal population, but not an additional increase in DA neuron cell number. These findings suggest that 6-OHDA toxicity is time and concentration-dependent and does not exclusively affect DA neurons. In high concentration and long incubation times, 6-OHDA influences the survival of other neuronal and non-neuronal cell populations derived from the VM cultures. 6-OHDA toxicity induces caspase-3 activation, indicating cell death via the apoptotic pathway which could be restricted or even prevented by pre-exposure to Epo, known to interact via the apoptotic pathway. Our results support and expand on previous findings showing that Epo is an interesting candidate molecule to mediate neuroprotective effects on DA neurons in PD. Furthermore, it could be used in promoting the survival of DA neurons after transplantation in clinical trials.