Protective Effect Of Erythropoietin Research Articles

Erythropoietin ameliorates cognitive deficits by improving hippocampal and synaptic damage in streptozotocin-induced diabetic mice

Recent studies have shown that erythropoietin (EPO) is an effective neuroprotective and neurotrophic agent for neurological disorders, such as traumatic brain injury and Alzheimer's disease. However, the effectiveness of EPO administration against diabetic cognitive impairments has rarely been examined. In this study, we investigated the effects of EPO on streptozotocin (STZ)-induced male C57BL/6 J mice. Then, we sought to clarify the mechanisms of EPO-mediated neuroprotection in high-glucose (HG)-stimulated HT22 cells. In vivo, we found that STZ-induced diabetic mice showed impaired spatial learning and memory, which was alleviated by EPO treatment. EPO also significantly lowered elevated fasting blood glucose levels, improved pancreatic and hippocampal damage, and restored oxidative stress in the STZ-induced diabetic mice. In vitro, EPO markedly increased cell viability, restrained the expression of pro-apoptotic Bax, enhanced the expression of pro-caspase 3, anti-apoptotic Bcl-2, brain-derived neurotrophic factor (BDNF) and postsynaptic density 95 (PSD-95), and attenuated the upregulation of N-methyl-d-aspartic acid (NMDA) receptor subunits NR1, NR2A and NR2B in HG-induced HT22 cells. The protective effects of EPO was obviously abolished by treatment with an NMDA receptor agonist. Our findings revealed that EPO impedes hippocampal and synaptic damage and neuronal apoptosis by regulating BDNF and PSD-95 expression through NMDA receptors, thereby ameliorating cognitive impairments in mice with T1DM.

The protective effect of erythropoietin on ischemia- reperfusion injury caused by ovarian torsion-detorsion in the experimental rat model

ABSTRACT Ovarian torsion is one of the most dangerous gynecological emergencies requiring surgery. A total of 50%–90% ovarian torsion cases are caused by physiological cysts, endometriosis, and other benign or malignant ovarian neoplasms. The aim of the study was to investigate the effects of erythropoietin (EPO) treatment on ischemia/reperfusion (IR) injury caused by ovarian torsion/detorsion (T/D) injury. Thirty female Wistar albino rats were divided into five groups as follows: Group I: Control; Group II: Torsion (T); Group III: Torsion/Detorsion(T/D); Group IV: Torsion/Detorsion (T/D) + EPO; Group V: EPO. Sections of the ovaries were evaluated for histopathological changes with hematoxylin and eosin stain, a immunohistochemical assay for caspase 3 expression, and the TUNEL assay for apoptosis. Ovarian sections from torsion/detorsion and torsion groups showed more hemorrhage, vascular congestion, edema, degenerative granulosa, and stromal cells. Fewer histopathological changes were found in EPO and T/D + EPO groups. Caspase 3 and TUNEL positive cells were significantly increased in the torsion/detorsion group as compared with the other groups (p < 0.05). Treatment with erythropoietin decreased the number of caspase 3 and TUNEL positive cells. The results of the study showed that erythropoietin administration is effective for recovery from degenerative changes in the ovary induced by the torsion-detorsion injury.

Erythropoietin protects the inner blood-retinal barrier by inhibiting microglia phagocytosis via Src/Akt/cofilin signalling in experimental diabetic retinopathy.

Microglial activation in diabetic retinopathy and the protective effect of erythropoietin (EPO) have been extensively studied. However, the regulation of microglia in the retina and its relationship to inner blood-retinal barrier (iBRB) maintenance have not been fully characterised. In this study, we investigated the role of microglia in iBRB breakdown in diabetic retinopathy and the protective effects of EPO in this context. Male Sprague Dawley rats were injected intraperitoneally with streptozotocin (STZ) to establish the experimental model of diabetes. At 2h after STZ injection, the right and left eyes were injected intravitreally with EPO (16mU/eye, 2μl) and an equivalent volume of normal saline (NaCl 154mmol/l), respectively. The rats were killed at 2 or 8weeks after diabetes onset. Microglia activation was detected by ionised calcium binding adaptor molecule (IBA)-1 immunolabelling. Leakage of the iBRB was evaluated by albumin staining and FITC-dextran permeability assay. BV2 cells and primary rat microglia under hypoxic conditions were used to model microglial activation in diabetic retinopathy. Phagocytosis was examined by confocal microscopy in flat-mounted retina preparations and in microglia and endothelial cell cocultures. Protein levels of IBA-1, CD11b, complement component 1r (C1r), and Src/Akt/cofilin signalling pathway components were assessed by western blotting. In diabetic rat retinas, phagocytosis of endothelial cells by activated microglia was observed at 8weeks, resulting in an increased number of acellular capillaries (increased by 426.5%) and albumin leakage. Under hypoxic conditions, activated microglia transmigrated to the opposite membrane of the transwell, where they disrupted the endothelial cell monolayer by engulfing endothelial cells. The activation and phagocytic activity of microglia was blocked by intravitreal injection of EPO. In vitro, IBA-1, CD11b and C1r protein levels were increased by 50.9%, 170.0% and 135.5%, respectively, by hypoxia, whereas the phosphorylated proteins of Src/Akt/cofilin signalling pathway components were decreased by 74.2%, 47.8% and 39.7%, respectively, compared with the control; EPO treatment abrogated these changes. In experimental diabetic retinopathy, activated microglia penetrate the basement membrane of the iBRB and engulf endothelial cells, leading to iBRB breakdown. EPO exerts a protective effect that preserves iBRB integrity via activation of Src/Akt/cofilin signalling in microglia, as demonstrated in vitro. These data support a causal role for activated microglia in iBRB breakdown and highlight the therapeutic potential of EPO for the treatment of diabetic retinopathy. Graphical abstract.

Helix B surface peptide reduces sepsis-induced kidney injury via PI3K/Akt pathway.

Helix B-Surface peptide (HBSP) is the latest discovered erythropoietin (EPO) analogue that can retain the activity of EPO. EPO, which is widely used for treating renal anemia, has recently been proved to have protective effects on ischemia-reperfusion injury of brain, heart and kidney. The protective effects of EPO and HBSP on cardiac function were found in rats with myocardial ischemia. However, the effect of HBSP on sepsis-induced renal injury is still unclear. Establishment of rat kidney injury model and treated with HBSP and lipoposaccharide. Renal injury in rats was observed by hematoxylin-eosin staining and injury index score. Levels of serum creatinine (SCr), blood urea nitrogen (BUN) and Cystatin C (Cys C) were detected using fully automatic biochemical analyzer, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β were detected by enzyme-linked immunosorbent assay. Western blot analysis was performed to determine the role of HBSP in phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Acute kidney injury (AKI) appeared after modeling, however, HBSP alleviated the pathological conditions of the kidney injury. In addition, HBSP lowered kidney injury index score in the rats, and decreased the levels of SCr, BUN, Cys C, TNF-α, IL-6 and IL-1β, moreover, HBSP also showed the effect of activating PI3K/Akt pathway. HBSP alleviated lipoposaccharide-induced AKI and improved kidney function of the rats with sepsis. More importantly, the effects of HBSP on lipoposaccharid-induced AKI were realized via activating PI3K/Akt pathway. The findings in the current study provide new insights into the therapeutic mechanism for treating the disease.

Protective impacts of erythropoietin on myelinization of oligodendrocytes and schwann cells in CNS and PNS following cuprizone-induced multiple sclerosis- histology, molecular, and functional studies

BackgroundMultiple sclerosis (MS) is known as one of the chronic inflammatory diseases characterized by lesions in the central nervous system (CNS) and peripheral nervous system(PNS) resulting in serious cognitive or physical disabilities as well as neurological disorders. Thus, protective effects of erythropoietin(EPO) on myelinization of oligodendrocytes and schwann cells respectively in CNS and PNS following MS induced by cuprizone (CPZ) administration in young female mice. MethodologyTo meet the objectives of this study; a chow with 0.2 % CPZ was used to feed young female C57BL/6 J mice for six weeks. After three weeks, EPO (5000 IU/kg body weight) was administered via daily intra-peritoneal injection for simultaneous treatment of the mice. Measurement of latency and amplitude of the compound muscle action potential (CMAP) of gastrocnemius muscle was also performed every week during a six-week demyelination interval, and then examinations were fulfilled on the histological sections of the brain and sciatic nerve.Therefore, we focused on the removal of the sciatic and sciatic nerve specimens and analysis of the use of the stereological procedures, western blot, immuno-histochemistry, and gene expression. ResultsAccording to the results of this study, MBP levels increased in oligodendrocytes (OLs) in the treated mice. Moreover, EPO could concurrently enhance motor coordination and muscle activity. Analysis showed the significant enhancement of the gene expression of MBP, MAG, and S100, as well as stereological variables in the treatment group in comparison with the cuprizone (CPZ) group. ConclusionFindings could help further understand the alleviation of the detrimental impacts of CPZ using the OLs that would be capable of increasing the level of S100, MAG, and MBP.

Erythropoietin protects outer blood-retinal barrier in experimental diabetic retinopathy by up-regulating ZO-1 and occludin.

To explore the mechanisms of erythropoietin (EPO) in maintaining outer blood-retinal barrier (BRB) in diabetic rats. Sprague-Dawley rats were rendered diabetic with intraperitoneal injection of streptozotocin, and then followed by intravitreal injection of EPO. Two and four weeks later, the permeability of outer BRB was examined with FITC-dextran leakage assay, following a method to demarcate the inner and outer retina based on retinal blood supply. The glyoxal-treated ARPE-19 cells, incubated with EPO, soluble EPO receptor (sEPOR), Gö6976, or digoxin, were studied for cell viability and barrier function. The expressions of ZO-1, occludin, VEGFR2, HIF-1α, MAPKs, and AKT were examined with Western blot and immunofluorescence. The major Leakage of FITC-dextran was detected in the outer nuclear layer in both 2- and 4-week diabetic rats. The leakage was largely ameliorated in EPO-treated diabetic rats. The protein expressions of ZO-1 and occludin in the RPE-Bruch's membrane choriocapillaris complex were significantly decreased, whereas HIF-1α and JNK pathways were activated, in 4-week diabetic rats. These changes were prevented by EPO treatment. The in vitro study with ARPE-19 cells confirmed these changes, and the protective effect of EPO was abolished by sEPOR. Gö6976 and digoxin rescued the tight junction and barrier function in glyoxal-treated ARPE-19 cells. In early diabetic rats, the outer BRB might be more severely damaged and its breakdown is the major factor for retinal oedema. EPO maintains the outer BRB integrity through down-regulation of HIF-1α and JNK signallings, and thus up-regulating ZO-1 and occludin expressions in RPE cells.

Effects of erythropoietin preconditioning on acute renal injury induced by cardiopulmonary bypass in rats

Objective To investigate the renal protective effect of erythropoietin (EPO) preconditioning on acute renal injury induced by cardiopulmonary bypass (CPB) in rats. Methods 40 male Sprague-Dawley rats were randomly divided into four groups: Sham, Control, Low and High EPO.24 h after the CPB, Blood samples were collected for assays of serum creatinine (Cr), meanwhile renal samples were obtained for the determination of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), nuclear factor-κB p65 (NF-κB p65), intercellular adhesion molecule-1 (ICAM-1), and for histologic examination. Results Compared with Control group (141.99±6.96) μmol/L, the levels of Cr decreased in Low EPO (91.52±5.43) μmol/L and High EPO group (67.52±5.63) μmol/L (P<0.01), levels of TNF-α [(9.41±0.72), (7.85±0.67) ng/mg], IL-1β [(12.35±1.43), (10.18±2.01) ng/mg], IL-6 [(8.25±0.65), (6.08±0.72) ng/mg], NF-κB p65 (0.165±0.003, 0.151±0.005), ICAM-1 (6.847±0.310, 5.013±0.462) in renal tissue of the Low and High EPO treated animals were significantly lower than those of the Control group (13.29±1.21) ng/mg, (18.39±1.79) ng/mg, (10.95±1.03) ng/mg, (0.189±0.009), (9.109±0.371) (all P<0.01). Histopathologic finding of the CPB group conflrmed that there was renal impairment by cast formation and tubular necrosis in the tubular epithelium. These changes were markedly reversed in EPO groups, High does EPO had a better renal protective effect (P<0.01). Conclusion EPO was effective on preventing CPB-induced renal injury probably through its downregulation of NF-κB p65. Furthermore, EPO attenuated these above changes dose dependently. Key words: Erythropoietin; Nuclear factor-κB p65; Acute renal injury; Cardiopulmonary bypass

Effects of erythropoietin administrated by intranasal on nerve function and CD31 in cerebral ischemia reperfusion rats

Objective To explore the protective effect of erythropoietin(EPO) administrated by intranasal on cerebral ischemia reperfusion in rats with acute cerebral infarction reperfusion. Methods Total of 100 SD rats were divided into model control group, sham operation group, intraperitoneal administration group (IPEPO group), nasal saline group (INNS group) group, and nasal drug delivery group (INEPO group) with 20 in each group.The middle cerebral artery occlusion model of rat was established by thread embolism method and the NSS method was used to evaluate the neural behavior of rats.The expression of EPO in peripheral blood, cerebrospinal fluid and brain regions of rats were detected by Elisa.The vascular endothelial growth factor(VEGF) in brain was detected by immunofluorescence and then the density of newborn blood vessels in the brain was measured. Results Fifteen days after the operation, the NSS score of INEPO group(3.80±1.61) was significantly lower than that of IPEPO group (11.53±2.11), and the difference was statistically significant(P<0.01). And the levels of EPO in blood, cerebrospinal fluid and different brain regions of rats in INEPO group were higher than that of INNS group(all P<0.01). Compared with IPEPO group, the level of EPO cerebrospinal fluid and different brain regions of rats in INEPO group increased obviously, the difference was statistically significant (all P<0.01), and the EPO concentration of the olfactory bulb was the most obvious(INEPO group: (1 456.90±128.22)pg/ml, IPEPO group: (426.11±36.68)pg/ml, P<0.01). Seventy-two hours after operation, the expression of CD31 in ischemic penumbra of rats of model control group (18.21±3.45), INNS group(18.54±2.58), IPEPO group(27.01±2.13)and INEPO group(35.52±2.79)was increased compared with sham operation group (5.14±1.28), and the difference was statistically significant (all P<0.05). The expression of CD31 in IPEPO group and INEPO group was significantly higher than that in INNS group (P<0.05). In INEPO group, the expression of CD31 increased significantly compared with that of IPEPO group (P<0.05). Conclusion Nasal administration of EPO can effectively improve the neurological function of rats with ischemia-reperfusion, and increase the expression of CD31 in the brain tissue of rats.The effect of nasal administration is better than that of intraperitoneal administration. Key words: Nasal administration; Erythropoietin; Ischemia reperfusion; Cerebral infarction; Angiogenesis; Rat

Changes in kidney tissue and effects of erythropoietin after acute heart failure

Impairment of cardiac function causes renal damage. Renal failure after heart failure is attributed to hemodynamic derangement including reduced renal perfusion and increased venous pressure. One mechanism involves apoptosis and is defined as cardiorenal syndrome type 1. Erythropoietin (EPO) is a cytokine that induces erythropoiesis under hypoxic conditions. Hypoxia inducible factor 1 alpha (HIF-1α) plays a regulatory role in cellular response to hypoxia. Protective effects of EPO on heart, kidney and nervous system are unrelated to red blood cell production. We investigated early changes in and effects of EPO on renal tissues of rats with myocardial infarction by morphology and immunohistochemistry. Coronary artery ligation was used to induce myocardial infarction in Wistar rats. Group 1 comprised sham operated rats; groups 2, 3 and 4 included rats after coronary artery ligation that were sacrificed 6 h after ligation and that were treated with saline, 5,000 U/kg EPO or 10,000 U/kg EPO, respectively; group 5 included rats sacrificed 1 h after ligation. Group 2 showed increased renal tubule damage. Significantly less tubule damage was observed in EPO treated groups. EPO and EPO receptor (EPO-R) immunostaining intensities increased slightly for group 5 and became more intense for group 2. EPO and EPO-R immunostaining was observed in the interstitial area, glomerular cells and tubule epithelial cells of EPO treated groups. HIF-1α immunostaining was observed in collecting tubules in the medulla only in group 2. Caspase-3 immunostaining is an indicator of apoptosis. Caspase-3 staining intensity decreased in renal medulla of EPO treated groups. EPO treatment may exert a protective effect on the renal tissues of patients with cardiorenal syndrome.

Erythropoietin as an add-on treatment for cognitive side effects of electroconvulsive therapy: a study protocol for a randomized controlled trial

BackgroundElectroconvulsive therapy (ECT) is the most effective treatment for severe depression, but its use is impeded by its cognitive side effects. Novel treatments that can counteract these side effects may therefore improve current treatment strategies for depression. The present randomized trial investigates (1) whether short-term add-on treatment with erythropoietin (EPO) can reduce the cognitive side -effects of ECT and (2) whether such effects are long-lasting. Further, structural and functional magnetic resonance imaging (MRI) will be used to explore the neural underpinnings of such beneficial effects of EPO. Finally, the trial examines whether potential protective effects of EPO on cognition are accompanied by changes in markers of oxidative stress, inflammation, and neuroplasticity.Methods/designThe trial has a double-blind, randomized, placebo-controlled, parallel group design. Patients with unipolar or bipolar disorder with current moderate to severe depression referred to ECT (N = 52) are randomized to receive four high-dose infusions of EPO (40,000 IU/ml) or placebo (saline). The first EPO/saline infusion is administered within 24 h before the first ECT. The following three infusions are administered at weekly intervals immediately after ECT sessions 1, 4, and 7. Cognition assessments are conducted at baseline, after the final EPO/saline infusion (3 days after eight ECT sessions), and at a 3 months follow-up after ECT treatment completion. The neuronal substrates for potential cognitive benefits of EPO are investigated with structural and functional MRI after the final EPO/saline infusion. The primary outcome is change from baseline to after EPO treatment (3 days after eight ECT sessions) in a cognitive composite score spanning attention, psychomotor speed, and executive functions. With a sample size of N = 52 (n = 26 per group), we have ≥ 80% power to detect a clinically relevant between-group difference in the primary outcome measure at an alpha level of 5% (two-sided test). Behavioral, mood, and blood-biomarker data will be analyzed using repeated measures analysis of covariance. Functional MRI data will be preprocessed and analyzed using the FMRIB Software Library.DiscussionIf EPO is found to reduce the cognitive side effects of ECT, this could have important implications for future treatment strategies for depression and for the scientific understanding of the neurobiological etiology of cognitive dysfunction in patients treated with ECT.Trial registrationClinicalTrials.gov, NCT03339596. Registered on 10 November 2017.

Pre-Treatment with Erythropoietin Attenuates Bilateral Renal Ischemia-Induced Cognitive Impairments.

One of the most common causes of mortality in acute kidney injury is brain dysfunction. Here we investigated the possible protective effect of erythropoietin (EPO) on cognitive impairments induced by bilateral renal ischemia (BRI). Eighty male Wistar rats were allocated into 8 groups: 1, 2) Sham +V (Vehicle), 3, 4) Sham+EPO, 5, 6) BRI+V, 7, 8) BRI+EPO. The groups followed by the reperfusion periods of 24hours (24 h) and 1week (1w). EPO or saline was administrated 30 min before surgery (1000 IU/kg, i.p). The cognitive function was assessed by passive avoidance learning and Morris water maze tests. Hippocampal brain-derived neurotrophic factor (BDNF) protein expression was assessed by western blotting. BUN (blood urea nitrogen) and creatinine (Cr) concentrations were significantly increased in BRI+V group 24 h after reperfusion. BRI+V rats had just an increased level of BUN but not Cr 1w after reperfusion. EPO reversed passive avoidance learning impairments observed in BRI+V group 24 h after reperfusion. There were no significant differences in spatial and passive avoidance learning between experimental groups 1w after reperfusion and histological evaluation confirmed the behavioral data. BRI significantly decreased the BDNF protein expression in the hippocampus and EPO increased that 24 h after operation. These observations showed protective effect of EPO against cognitive dysfunctions following BRI 24 h after reperfusion through increase in BDNF protein expression.

Renoprotective effect of erythropoietin via modulation of the STAT6/MAPK/NF-κB pathway in ischemia/reperfusion injury after renal transplantation.

Ischemia/reperfusion injury (IRI) commonly occurs in renal transplantation. Erythropoietin (EPO) exerts a protective effect in IRI. To investigate the underlying molecular mechanism, rat models of renal IRI were established and treated with EPO and/or lentivirus-mediated EPO-siRNA, the signal transducer and activator of transcription 6 (STAT6) inhibitor AS1517499, the JNK inhibitor SP600125, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580, and the nuclear factor (NF)-κB inhibitor lactacystin. Histological examination revealed that EPO protected the kidney from IRI, through decreasing the extent of tissue congestion and inflammatory cell infiltration; however, EPO siRNA did not exert the same protective effect. In addition, the EPO level was inversely associated with renal IRI. EPO downregulated the expression of interferon-γ, interleukin (IL)-4, creatinine and caspase-3, and upregulated the expression of IL-10, thymic stromal lymphopoietin, STAT6, p-JNK and p-p38, while the opposite effects were observed with the administration of EPO-siRNA and the specific respective inhibitors. Further results revealed that MAPK (p-JNK and p-p38) acted upstream of NF-κB, and that NF-κB signaling regulated the expression of caspase-1 and -3, which may be responsible for the cytotoxicity associated with IRI. Taken together, the results of the present study demonstrated that EPO exerted a protective effect in renal IRI via the STAT6/MAPK/NF-κB pathway. This protective effect of EPO may improve reperfusion tolerance in ischemic kidneys and benefit transplant recipients.

Protective effect of erythropoietin on renal function after releasing of bilateral ureter obstruction in rats and mechanism

Objective To investigate the mechanism of protective effect of erythropoietin (EPO) on renal function after releasing of bilateral ureter obstruction (BUO) in SD rats. Methods Thirty-two SD rats were divided into 4 groups randomly (BUO group, BUO-R group, BUO-R+ EPO group and Sham group; n=8). The BUO model was built by bilateral ureteral ligation. EPO was given to BUO-R+ EPO rats 1 h after releasing of BUO, and then repeated 12, 24, 36, 48 h thereafter and the same volume of normal saline was simultaneously given to BUO-R rats. The urine samples were collected 24 h before death and then blood samples were collected from inferior vena cava. The kidneys at both sides were harvested 72 h after releasing of BUO to examine the effect of EPO on the expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 by immunohistochemistry and real-time quantitative polymerase chain reaction (Real-time PCR). Results The osmotic pressure in BUO-R+ EPO group was higher than that in BUO-R group, while lower than that in Sham group [(1 164±93) vs. (715±76) vs. (1 835±98) mosm/kg, P=0.000]. The hematal concentrations of urea and CREA in BUO group [(58.40±4.63) mmol/L and (277.30±11.26) μmol/L] were higher than those in other three groups, while they were higher in BUO-R+ EPO group [(12.20±2.34) mmol/L and (34.70±4.58) μmol/L] than those in Sham group [(6.40±0.75) mmol/L and (20.50±3.71) μmol/L], but lower than those in BUO-R group [(25.70±3.26) mmol/L and (52.60±7.83) μmol/L], P=0.000. Immunohistochemistry showed the expression levels of TNF-α and IL-6 were strongest in BUO group and weakest in Sham group, while those were stronger in BUO-R group than in BUO-R+ EPO group. Real-time PCR showed that the expression of TNF-α and IL-6 mRNA in BUO group was the most, while that in Sham group was the least, and that in BUO-R+ EPO group was less than in BUO-R group. Conclusion EPO could promote the recovery of renal function by inhibiting inflammatory reaction in BUO-R rats. Key words: Erythropoietin; Ureter obstruction; Kidney; Inflammatory reaction

Evaluation of the effect of erythropoietin + corticosteroid versus corticosteroid alone in methanol-induced optic nerve neuropathy

Purpose: Following methanol intoxication, optic nerve neuropathy may occur, which is currently treated by different therapeutic regimens. Erythropoietin (EPO) has recently been introduced as a good therapeutic option in methanol-induced optic neuropathy. The aim of the current study was to evaluate the efficacy of EPO in improvement of the visual disturbances in methanol-intoxicated patients.Materials and methods: In a case-control study, all patients who had referred to our toxicology centre with confirmed diagnosis of methanol toxicity were considered to be included. Of them, those who had referred with visual disturbances, survived, and their visual disturbances had not improved after haemodialysis were entered. Cases received EPO and corticosteroids while controls only received corticosteroids. They were then compared regarding their visual outcome.Results: All five patients in the control group mentioned that after discharge, their visual acuity had improved while in the cases, three mentioned visual improvement, two mentioned their visual acuity had deteriorated after discharge, two mentioned no change in their visual acuity and three mentioned that their visual acuity had first improved but then deteriorated with a mean two-month interval period. In fundoscopic evaluations, two controls had normal fundospcopy while eight cases had abnormal fundoscopy (p = 0.055).Conclusions: Protective effect of EPO on methanol-induced optic nerve may be strong at the beginning of the intervention but is probably transient.

The protective effect of erythropoietin on the experimental light-induced retinal degeneration of rat

Objective To investigate the protective effect of erythropoietin(EPO) on the structure and function of light-induced damage in rat retina. Methods The animal model of light-induced retinal degeneration was made. Thirty-six SD rats were randomly divided into experimental group, peritoneal injection with EPO and control group, peritoneal injection with the same amount of normal saline. The EPO and EPOR expression were observed in two groups. The structure and thickness of the retina and ERG before and after light explosure were observed. Results The gray value of EPO and EPOR expression in any layer of the retina reached peak value at 24 hours after light explosure.EPO and EPOR expression at 6, 24 and 72 hours were higher than that of before light explosure. The difference were statistically significant(P=0.002, 0.000, 0.000; P=0.001, 0.000, 0.000). Seven days after light explosure, the outer retina thickness of two groups markedly reduced(P=0.000), but the reduction of outer retina thickness in experimental group was less than that in control group(P=0.000). The amplitude of a-wave and b-wave in two groups decreased remarkably at 1 day, 1 week and 2 weeks after light explosure, but the amplitude of a-wave and b-wave in experimental group was higher than those in control group(P=0.013-0.039). Conclusion Endogenous EPO and EPOR express increasingly after light damage. Systemic exogenous EPO plays a protective role in light-induced damage in retina. Key words: Erythropoietin; Animal model; Retina; Light-induced damage

Erythropoietin attenuates axonal injury after middle cerebral artery occlusion in mice

Objective: Erythropoietin (EPO) confers potent neuroprotection against ischemic injury through a variety of mechanisms. However, the protective effect of EPO on axons after cerebral ischemia in adult mice is rarely covered. The purpose of this study was to investigate the potential neuroprotective effects of EPO on axons in mice after cerebral ischemia.Methods: A total of 30 adult male C57 BL/6 mice were treated with EPO (5000 IU/kg) or vehicle after transient middle cerebral artery occlusion (MCAO). The mortality rate of each experimental group was calculated. Neurological function was assessed by Rota-rod test. Frozen sections from each mouse brain at 14 days after reperfusion were used to evaluate the fluorescent intensity of myelin basic protein (MBP) and neurofilament 200 (NF-200). Immunofluorescence staining and Western blotting were used to assess the protein level of β-amyloid precursor protein (β-APP) and glial fibrillary acidic protein (GFAP), a marker of mature astrocytes. The protein levels of the myelin-derived growth inhibitory proteins, neurite growth inhibitor-A (Nogo-A), myelin-associated glycoprotein (MAG) and oligodendrocyte-myelin glycoprotein (OMG) were also examined by Western blot after MCAO.Results: The survival rate of the vehicle group 14 days after cerebral ischemia-reperfusion was 50%, which increased to 80% after EPO treatment at the start of reperfusion. EPO improved neurobehavioral outcomes at days 3 and 7 after MCAO was compared with the vehicle group (P < 0.05). Furthermore, EPO ameliorated demyelination, demonstrated by upregulation of the MBP/NF-200 ratio. Meanwhile, increased levels of β-APP, GFAP, Nogo-A, and MAG after MCAO were reduced by EPO treatment (P < 0.05).Conclusion: EPO treatment attenuates axonal injury and improves neurological function after cerebral ischemia in adult mice.

The protective effects of erythropoietin on photoreceptor damage by formaldehyde.

The photoreceptor layer of retina has important role for sight. The previous study showed that accidental formaldehyde injection caused ischemia and damage in the retina. On the other hand the erythropoietin prevents neuronal injury of ischemic damage. The aim of this study was to survey the effect of erythropoietin on retro bulbar formaldehyde injected photoreceptor layer of rat retina. 30 adult rats were used and divided into three groups: 1- control group, 2- formaldehyde group (1 ml retro bulbar injected by 10% formaldehyde solution), 3- erythropoietin group (5000 units/kg immediately intraperitoneally injected by erythropoietin after formaldehyde injection for 7 days). The photoreceptor layer of retina studied using a transmission electron microscope. Our observation showed that disorganization and vacuolization in outer segment and inner segment, pyknotic and karyolysis in outer nuclear layer were seen in formaldehyde group. But the minor sign of pathology such as lightly vacuolization in inner segment were obvious in erythropoietin group. We concluded that formaldehyde caused damage in photoreceptor layer and erythropoietin was improvement this injury.

Renal tissue pro-inflammatory gene expression is reduced by erythropoietin in rats subjected to hemorrhagic shock.

BackgroundHemorrhagic shock (HS) is a condition produced by considerable loss of intravascular volume, which may eventually lead to organ damage and death.ObjectivesIn the present study, the potential implication of the kidney tissue tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) were evaluated in the protective effects of erythropoietin (EPO) during HS.Materials and MethodsMale Wistar rats were randomized into three experimental groups; Sham, HS (hemorrhagic shock and resuscitation), and EPO (erythropoietin). HS was induced by 50% blood volume hemorrhage over 30 minutes. After 2 hours, resuscitation was performed within 30 minutes. In the EPO group, EPO (300 IU/kg, i.v.) was administered 10 minutes before HS induction. Urine was collected to determine urinary N-acetyl-β-D-glucosaminidase (NAG) activity level. The kidney cytokines (TNF-α, IL-6 and IL-10) mRNA expressions were measured by real-time polymerase chain reaction (PCR).ResultsHS rats showed significant increase in urinary NAG activity compared to the sham group. EPO significantly attenuated the rises in urinary NAG activity compared to the HS group. In the HS animals, renal TNF-α and IL-6 mRNA expressions increased whereas no difference was observed in IL-10 mRNA expression between the HS and sham groups. EPO was able to decrease renal TNF-α and IL-6 production and increase IL-10 mRNA expression.ConclusionsIn this study, we demonstrated that EPO attenuates kidney damage in rats subjected to HS. The beneficial effects of EPO may be at least partly mediated by modifications in the inflammatory cascade.

The protective effect of erythropoietin on renal function after releasing of bilateral ureter obstruction in young rat

Objective To investigate the protective effect of erythropoietin (EPO) on renal function after releasing of bilateral ureters obstruction (BUO-R) in young SD rats. Methods From October 2015 to June 2016, forty young SD rats were bought and equally divided into 4 groups randomly (BUO group, BUO-R group, BUO-R+ EPO group and Sham group; n=10) according to random number table. The BUO model was built by bilateral ureteral ligation. EPO (500 U/kg) was given to BUO-R+ EPO rats immediately after releasing of BUO, and then repeated 2d, 4d and 6d thereafter and the same volume of normal saline was simultaneously given to BUO-R rats. The Sham group was prepared in parallel by laparotomy and free dissection of bilateral ureters but not ligated. The urine samples were collected by metabolic cage 24h before death and then blood samples (1 ml) were collected from inferior vena cava. Results The urine osmolarity of Sham group was the highest [(1 794±103)mOsm/kg], BUO-R+ EPO group was (1 257±82)mOsm/kg, and BUO-R group was the lowest [(756±69)mOsm/kg]; Whereas the urine output of Sham group was the lowest [(26±5)μl/(min·kg)], BUO-R+ EPO group was (48±7)μl/(min·kg), and BUO-R group was the highest [(71±9)μl/(min·kg)]; P<0.05. The concentrations of urinary K+ , Na+ and creatinine in BUO-R+ EPO group were [(133.8±5.8)mmol/L, (134.7±4.9)mmol/L and (3 549±482)μmol/L]lower than those in Sham group [(154.7±6.5)mmol/L, (149.3±7.8)mmol/L and (4 537±624)μmol/L], but higher than those in BUO-R group [(112.4±7.2)mmol/L, (106.5±6.3)mmol/L and (2 612±536)μmol/L], P<0.05. The concentrations of hematal K+ , urea and creatinine in three experimental groups were all higher than those in Sham group; of which the hematal K+ , urea and creatinine in BUO group were the highest[(12.1±0.7)mmol/L, (47.6±6.0)mmol/L and (252.8±18.7)μmol/L], the BUO-R group took the second place [(8.5±0.5)mmol/L, (7.8±0.4)mmol/L and (55.2±4.8)μmol/L], and the BUO-R+ EPO group came third [(7.4±0.5)mmol/L, (6.4±0.3)mmol/L and (36.4±3.6)μmol/L], while the Sham group were the lowest [(6.8±0.3)mmol/L, (5.6±0.24)mmol/L and (23.6±2.7)μmol/L]; P<0.05. While the hematal Na+ concentration in BUO group was the lowest [(126.4±5.9)mmol/L], and BUO-R group was the highest [(147.3±4.9)mmol/L], the Sham group was the second lowest [(136.7±4.3)mmol/L], and the BUO-R+ EPO group was the second highest [(141.5±5.7)mmol/L], P<0.05. Conclusion EPO could promote the recovery of renal function and normalize the altered renal water and salt handling function in young BUO-R rats. Key words: Erythropoietin; Ureter obstruction; Renal function

Protective effect of erythropoietin on myocardial apoptosis in rats exposed to carbon monoxide

AimsCardiac complications are common in carbon monoxide (CO) poisoning and associated with high morbidity and mortality. We have previously shown that erythropoietin (EPO) could reduce CO-induced cardiac ischemia in rat. In the current study, the anti-apoptotic effect of EPO during CO cardiotoxicity was investigated in order to elucidate the mechanism of EPO anti-ischemic action. Main methodsWistar rats were exposed to CO (250, 1000 and 3000ppm). EPO (5000IU/kg) was administered to all groups by intraperitoneal injection at the end of CO exposure period. TUNEL and caspase-3 activity levels were assessed to investigate the effects of CO exposure and subsequent EPO administration on myocardial apoptosis. The changes of mitochondrial membrane potential (MMP) were also assessed with sensitive lipophilic dye JC-1 by flow cytometry. The roles of Bcl2 and Bax in EPO protective effect were investigated by Western blotting. Key findingsMyocardial apoptosis was observed following CO exposure. Moreover, mitochondrial membrane depolarization and significant reduction in Bcl2/Bax ratio were shown following CO poisoning especially at 3000ppm. On the other hand, EPO administration could effectively suppress apoptosis in myocardial cells. Also, EPO significantly prevented the CO-induced depolarization of MMP (p<0.001) and preserved Bcl2/Bax ratio (p<0.01). SignificanceEPO reduces myocardial injury due to CO intoxication. Thus EPO could be suggested as a possible candidate for the management of CO cardiotoxicity with clinical applications.