OBJECTIVE: To explore the relationship between injury age and expressions of erythropoietin (EPO) and its receptor EPOR in the brain tissue of rats after cerebral injury. METHODS: Seventy-two rats were randomly divided into control group (36 rats) and cerebral injury group (36 rats). The rats were sacrificed at 1, 2, 4, 8, 12, 24 h after cerebral injury (6 rats at each time point) and the brain tissues were extracted. The expressions of mRNA and protein of EPO and EPOR at different time points were detected by real-time fluorescent quantitative PCR and Western bloting. RESULTS: The expressions of EPO and EPOR increased within 24 h after injury. The expressions of mRNA and protein of EPO were related to the injury age, and the correlations were 0.875, 0.911, respectively (P < 0.05). The expressions of mRNA and protein of EPOR were related to the injury age, and the correlation coefficients were 0.936, 0.905, respectively (P < 0.05). CONCLUSION The expressions of EPO and EPOR increase gradually in the early stage of the rat's cerebral injury, which are associated with the injury age and could be a useful value for estimating injury age.
Animals ; Brain/metabolism* ; Brain Injuries/pathology* ; Erythropoietin/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Rats ; Receptors, Erythropoietin/metabolism* ; Time Factors

The function of erythropoietin (EPO) is recognized as a stimulator for proliferation of red blood cell (RBC), however,recent studies have showed that EPO and EPO-R are widely distributed in nervous system, which indicates that it may also have important functions in nervous system. Studies proved its neuroprotective effects, especially in ischemic-hypoxic nerve tissues. These effects are mainly activated through several signal transduction pathway downstream and multiple mechanisms are involved. As a neuroprotective factor, EPO has been investigated in the clinical studies, which may lead to the clinical application in the future.
Erythropoietin ; metabolism ; physiology ; Humans ; Neurophysiology ; Neuroprotective Agents ; Signal Transduction

Erythropoietin (EPO) is an acidic glycoprotein that was first detected as a hematopoietic factor and its synthesis is triggered in response to cellular hypoxia-sensing. EPO binds to type I cytokine receptors, which associate with the non-receptor tyrosine kinase Jak2, and thereby activate Stat 5a/5b, Ras/MAPK, and PI3-K/Akt signaling pathways. The recent discovery shows that there is a specific EPO/EPO-receptor system in the central nervous system (CNS), independently of the haematopoietic system. Hypoxia and anemia can up-regulate EPO/EPOR expressions in the CNS. Further studies demonstrate that EPO has substantial neuro-protective effects and acts as a neurotrophic factor on central cholinergic neurons, influencing their differentiation and regeneration. EPO also exerts neuro-protective activities in different models of brain damage in vivo and in vitro, such as hypoxia, cerebral ischaemia and sub-arachnoid haemorrhage. EPO may also be involved in synaptic plasticity via the inhibition or stimulation of various neurotransmitters. Therefore, human recombinant EPO that activate its receptors in the central nervous system might be utilized in the future clinical practice involving neuroprotection and brain repair.
Animals ; Brain ; metabolism ; Cell Differentiation ; drug effects ; Erythropoietin ; metabolism ; pharmacology ; Humans ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; metabolism ; pharmacology ; Receptors, Erythropoietin ; metabolism

This study was aimed to explore the expression of erythropoietin receptor (EPOR) on acute leukemia cells and its clinical significance. Bone marrow of 40 patients with acute leukemia (AL) and 24 patients with normal bone marrow as control group were collected. Samples came from outpatients and inpatients in our hospital. EPOR mRNA was detected by reverse transcription-PCR. The results showed that there was EPOR expression on AL cells, the expression rate was 57.5%, and the average expression level (Gray value) was 0.3549 ± 0.2800, but both were lower than that in control group (p < 0.05). There was no significant statistic difference of expression rate between acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) (p > 0.05), and expression level of AML EPOR was higher than that of ALL (p < 0.05). It is concluded that there is EPOR expression on AL cells, while the expression rate and expression level are lower than those in control group (p < 0.05). There is no significant statistic difference of the expression rate between AML and ALL (p > 0.05), and the expression level of AML EPOR is higher than that of ALL (p < 0.05).
Case-Control Studies ; Humans ; Leukemia, Myeloid, Acute ; genetics ; metabolism ; RNA, Messenger ; genetics ; Receptors, Erythropoietin ; genetics ; metabolism

OBJECTIVETo study the expression of erythropoietin (EPO) and its receptor (EPOR) in the brain of newborn rats suffering fetal distress.

METHODSA model of fetal distress was prepared by ligating bilateral uterine arteries of the rats with full-term pregnancy for 10 minutes before cesarean sections. The expression levels of EPO and EPOR in the brain of newborn rats were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot at 0, 2, 6, 12, 24, 48, 72 hrs and 7 days after birth. Serum EPO levels were measured using ELISA simultaneously. The newborn rats born by cesarean sections which were not subjected to uterine artery ligation were used as the control group.

RESULTSThe expression of EPO protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6 and 12 hrs after birth (P<0.05). The expression of EPOR protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6, 12, 24 and 48 hrs, and 3 days after birth (P<0.05). Serum EPO levels in the fetal distress group were significantly higher than in the control group 2 hrs after birth.

CONCLUSIONSThe EPO and EPOR levels in the brain increase quickly after birth in newborn rats suffering from fetal distress. The EPOR is high expressed for a longer time than EPO. This can provide a basis for the treatment of neonatal brain damage induced by fetal distress by exogenous EPO.

Animals ; Animals, Newborn ; Brain ; metabolism ; pathology ; Erythropoietin ; blood ; genetics ; Female ; Fetal Distress ; metabolism ; Pregnancy ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Erythropoietin ; blood ; genetics

AIMTo observe change of binding activity of HIF-1 with erythropoietin (EPO) hypoxia response element (HRE) in the hippocampus of mice preconditioned to hypoxia and explore relationship between the changes and the preconditioning.

METHODSThe hippocampus was removed from mice exposed to hypoxia for 0 run (control group), 1 run (H1 group) and 4 runs(H4 group). Electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP)and real time PCR were used to detect the change of activity of HIF-1 on HRE of EPO.

RESULTSBoth in vitro and in vivo binding tests showed that the HIF-1 DNA-binding activities were increased in group H1 and markedly increased in group H4.

CONCLUSIONThe increase of HIF-1 and HRE of EPO binding activities is thought be involved in hypoxic preconditioning.

Animals ; Erythropoietin ; metabolism ; Hippocampus ; metabolism ; Hypoxia ; metabolism ; Hypoxia-Inducible Factor 1 ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Response Elements

OBJECTIVE: To explore the expression of hypoxia inducible factor-1alpha (HIF-1alpha) and erythropoietin in the hippocampus of aging rats, and to investigate the role of HIF-1alpha and erythropoietin in the aging of nervous system. METHODS: The expression of Nissl body, HIF-1alpha, and erythropoietin in the CA1 region of the hippocampus in different months was observed by Nissl staining and immunohistochemical technique. RESULTS: Nerve cells became bigger and appeared sparse, and the Nissl bodies decreased with age. HIF-1alpha positive cells increased significantly with age in the CA1 region of the hippocampus (P<0.05). The expression of erythropoietin presented a parabola with aging in the CA1 region of the hippocampus. The increase from 3 to 18 months and the reduction from 18 to 30 months of erythropoietin positive cells had statistical significance (both P<0.05). CONCLUSION HIF-1alpha and erythropoietin are parallelly incremental before middle age, and are separated after middle age, suggesting decreased activity of HIF-1alpha and recession of protein synthesis function may be the main reasons for decreased expression of erythropoietin in the brain during aging. Strengthened endogenous HIF-1alpha activity and supply of exogenous erythropoietin may delay the aging of the nervous system.
Aging ; metabolism ; Animals ; Erythropoietin ; metabolism ; Hippocampus ; metabolism ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVEFunctionally, erythropoietin (EPO) can promote the proliferation and growth of erythroid progenitor cells, and it is widely used in the treatment of anemia in chronic diseases caused by tumor and inflammation. However, it is unclear whether EPO has any effect on tumor cell iron metabolism and tumor cell proliferation. The purpose of this study was to explore the effects of recombinant human EPO (rhEPO) on the expression of transferrin receptor (TfR, CD(71) antigen) of leukemic cell K562 and its relation to cell cycle.

METHODSIn vitro culture of K562 cell was performed with additions of various concentrations of rhEPO and Fe. Treatments were terminated at 24 h and 72 h, respectively. Then each group of cells was incubated with FITC-IgG antibody to CD(71) or PI, a kind of DNA dye. And TfR expression and DNA synthesis status were analyzed by flow-cytometry.

RESULTS(1) The expression of TfR by K562 cells increased significantly when incubated for 72 h with different concentrations of rhEPO. The measurement values of 5 U/ml, 10 U/ml and 20 U/ml groups were 12.2 +/- 1.40, 10.7 +/- 0.99 and 11.1 +/- 0.90, respectively. They were markedly increased when compared with that of control group (6.27 +/- 0.11, P < 0.05). (2) When incubated with rhEPO (5 u/ml) alone or combined with FeCl(3) (100 micro mol/L), the percentages of cells in S phase were 51.1% and 59.6%, respectively. They significantly increased when compared with that of control group (42.9%, P < 0.05).

CONCLUSIONSIron is very important for the proliferation of both normal cells and leukemic cells. It is essential to the activity of ribonucleotide reductase (RR). The authors hypothesized that rhEPO would increase the expression of TfR and intracellular iron content of leukemic cells, which would enhance the DNA synthesis and cell proliferation. Therefore, the clinical application of rhEPO to promote erythropoiesis of cancer patients should be cautious.

Cell Cycle ; drug effects ; Erythropoietin ; pharmacology ; Flow Cytometry ; Humans ; K562 Cells ; Receptors, Transferrin ; metabolism ; Recombinant Proteins

OBJECTIVEErythropoietin and erythropoietin receptor (EPO-R) are expressed in many kinds of tumors. The EPO/EPO-R signaling is involved in tumor cell proliferation, invasion and angiogenesis. The aim of this study was to detect the expression of EPO-R in non-small cell lung cancer (NSCLC), and explore its correlation with angiogenesis.

METHODSThe expression patterns of EPO and EPO-R in 31 cases of NSCLC tissues were detected by immunohistochemistry, and that in benign lung lesions of 21 patients as control. To analyze the correlation of EPO/EPO-R expression patterns and clinicopathological factors. CD34 was used to label the vascular endothelial cells and calculate the microvessel density (MVD).

RESULTSThe positive rates of EPO and EPO-R expression in NSCLC were 67.7% and 96.8%, respectively, significantly higher than those in the control ones. The positive rates of EPO and EPO-R expression in adjacent tissues were 19.4% and 35.5%, and in benign lesions were 9.5% and 19.0%, respectively (P < 0.001). The expression patterns of EPO/EPO-R were not related with pTNM stage, histological type, histological grade and lymph node metastasis (P > 0.05). Increased MVD was correlated with poor differentiation, lymph node metastasis, and advanced stage.

CONCLUSIONSHigh expression of EPO/EPO-R in NSCLC patients suggest that they may be involved in tumorigenesis. EPO/EPO-R expression and MVD are closely related, and they might be an endogenous stimulant of angiogenesis during the progression of non-small cell lung cancer. It may provide evidence for clinical diagnosis.

Antigens, CD34 ; metabolism ; Carcinoma, Non-Small-Cell Lung ; blood supply ; metabolism ; pathology ; Erythropoietin ; metabolism ; Humans ; Lung Neoplasms ; blood supply ; metabolism ; pathology ; Lymphatic Metastasis ; Microvessels ; pathology ; Neoplasm Staging ; Neovascularization, Pathologic ; Receptors, Erythropoietin ; metabolism

OBJECTIVETo evaluate the effect of pretreatment with erythropoietin (EPO) on disordered pro- and anti- inflammatory balance in rats with severe acute pancreatitis (SAP) and explore the underlying mechanisms.

METHODSNinety healthy male SD rats were randomized equally into sham-operated group, SAP group and EPO pretreatment group. SAP model was induced in the latter two groups by retrograde injection of 1 ml/kg 3.5% sodium traurocholate into the biliopancreatic duct. In EPO group, 3000 U/kg EPO (1000 U/ml) was administered intravenously 1 h before SAP, and normal saline was administered in the other two groups. Serum amylase activity, interleukin-10 (IL-10)and IL-18 levels were measured at different time points after the operation. The translocation and activation of nuclear factor-κB (NF-κB) in the pancreatic tissue was detected using immunofluorescence staining, and pancreatic pathologies were evaluated.

RESULTSCompared with SAP group, EPO group showed a markedly decreased activation rate of NF-κB after SAP except for 12 h (P<0.05), significantly decreased serum amylase activity at 3, 6, and 12 h (P<0.05) and decreased serum IL-18 levels at 3, 6, 24 h (P<0.05), whereas serum IL-10 underwent no significant changes. The rats in EPO group showed an obviously milder pancreatic pathology than those in SAP group at 6, 12, and 24 h (P<0.05).

CONCLUSIONEPO can effectively inhibit NF-κB activation by regulating the inflammatory mediators and restoring the pro-and anti-inflammatory balance to alleviate SAP in rats.

Acute Disease ; Animals ; Cytokines ; metabolism ; Erythropoietin ; therapeutic use ; Interleukin-10 ; metabolism ; Interleukin-18 ; metabolism ; Male ; NF-kappa B ; metabolism ; Pancreatitis ; drug therapy ; Rats ; Rats, Sprague-Dawley