ABSTRACT
OBJECTIVES: Erythropoietin may have neuroprotective potential after ischemia of the central nervous system. Here, we conducted a study to characterize the protective effects of erythropoietin on retinal ganglion cells and gliotic reactions in an experimentally induced oligemia model. METHODS: Rats were subjected to global oligemia by bilateral common carotid artery occlusion and then received either vehicle or erythropoietin via intravitreal injection after 48 h; they were euthanized one week after the injection. The densities of retinal ganglion cells and contents of glial fibrillary acidic protein (astrocytes/Müller cells) and cluster of differentiation 68 clone ED1 (microglia/macrophages), assessed by fluorescence intensity, were evaluated in frozen retinal sections by immunofluorescence and epifluorescence microscopy. RESULTS: Retinal ganglion cells were nearly undetectable one week after oligemia compared with the sham controls; however, these cells were partially preserved in erythropoietin-treated retinas. The contents of glial fibrillary acidic protein and cluster of differentiation 68 clone ED1, markers for reactive gliosis, were significantly higher in retinas after bilateral common carotid artery occlusion than those in both sham and erythropoietin-treated retinas. CONCLUSIONS: The number of partially preserved retinal ganglion cells in the erythropoietin-treated group suggests that erythropoietin exerts a neuroprotective effect on oligemic/ischemic retinas. This effect could be related to the down-modulation of glial reactivity, usually observed in hypoxic conditions, clinically observed during glaucoma or retinal artery occlusion conditions. Therefore, glial reactivity may enhance neurodegeneration in hypoxic conditions, like normal-tension glaucoma and retinal ischemia, and erythropoietin is thus a candidate to be clinically applied after the detection of decreased retinal blood flow.
Subject(s)
Animals , Male , Retinal Ganglion Cells/drug effects , Erythropoietin/pharmacology , Neuroprotective Agents/pharmacology , Glial Fibrillary Acidic Protein/drug effects , Retinal Diseases/pathology , Cell Count , Hematopoietic Cell Growth Factors/pharmacology , Rats, Wistar , Carotid Artery, Common/surgery , Carotid Artery Injuries/surgery , Disease Models, Animal , Ectodysplasins/drug effectsABSTRACT
Objective To investigate the potential of stromal cells from human umbilical cord blood cultured in vitro to secrete hematopoietic growth factors. Methods The expressions of hematopoietic growth factors of stromal cells from human umbilical cord blood and bone marrow were detected by ELISA kits at different time points. Results Stromal cells from human umbilical cord blood could secrete thrombopoietin (TPO), granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF). The peak levels of TPO and SCF were found at 7 d after culture in vitro, but then the levels of these factors decreased gradually. Stromal cells from human umbilical cord blood secreted more SCF and GM-SCF, but less TPO than human bone marrow stromal cells. Conclusion Our results demonstrate that stromal cells from human umbilical cord blood could sustain hematopoiesis by secreting multiple types of hematopoietic growth factors such as TPO, GM-CSF, and SCF.
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Objective To study the role of hematopoietic growth factor(HGF)of placenta chorionic villus in fetal hematopoiesis during embryo ontogeny by observation of the appearance time and the content changes with the fetal growth, which was compared with HGF in cord blood. Methods Thirty embryo villus (2 g each) and 30 cord blood (2 mL each) were collected separately from early pregnant stage(6- 8 weeks), middle pregnant stage(16-22 weeks)and late pregnant stage (37-42 weeks). The levels of HGF were detected by enzyme - linked immunosorbent assay. Results HGF were produced on the early pregnant stage and the content of FL-T3,IL-3 increased gradually.There were significantly differences at different stages(P
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Objective: To investigate the role of recombinant human hematopoietic growth factors(HGFs) in committed differentiation of purified CD34+ cells derived from human borrow cells.Methods: A sterilized separation system for purification of CD34+ hematopoietic stem/progentior cells(HSC/HPC) was established by means of StemsepTM according to the strategy of negative selection on immunomagnetic separation.CD34+ cells were committedly differentiated with various combination of cytokines in liquid culture systems and the expanded cell number,CD33+ cell ratio,granucytopoietic progenitor cell and erythropoietic progenitor cell number were detected.Results: A combination of five HGFs including FL,Tpo,SCF,IL-3,and Epo was identified as the most potent combination inducing CD34+ cells to differentiate into erythropoietic cells.Two weeks later BFU-E and CFU-E were increased by 27.12?3.95 and 30.65?40.26 fold respectively;CD71+ cell rate was 61.20?5.31%;A combination of six HGFs including FL,Tpo,SCF,IL-3,GM-CSF and G-CSF was identified as the most potent combination inducing CD34+ cells to differentiate into granucytopoietic cells.CFU-GM was increased by 29.87?10.52 fold,and CD15+ cell rate was 56.18?6.57%.Conclusion: Appropriate HGFs combination may induce CD34+ cells to proliferate and differentiate into lots of blood cells.【
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Objective:To explore the effect of TSPG (total saponins of panax ginseng) on gene expression of IL-3 which is one of the important hematopoietic growth factor at early stage of hematopoiesis.Methods:Techniques of RT-PCR and in situ hybridization were used.Results:A band corresponding to IL-3 was observed after RNA extraction from TSPG stimulated Jurkat cells were subjected to RT-PCR,while such band was not observed after RNA extraction from unstimulated Jurkat cells were subjected to RT-PCR.Comparing with the control group,both quantity and intensity of IL-3mRNA expression in fetus thymocytes and splenocytes induced by TSPG were obviously promoted.Conclusion:TSPG can induce human lymphocytes to express IL-3 mRNA,thus promote human hematopoiesis at early stage.
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Objective: To investigate the role of recombinant human hematopoietic growth factors(HGFs) in expansion of purified CD34+ cells derived from human cord blood.Methods: A sterilized separation system for purification of CD34+ hematopoietic stem / progentior cells(HSC/HPC) was established by means of StemsepTM according to the strategy of negative selection on immunomagnetic separation.CD34+ cells were expanded with various combination of cytokines in a 21-day liquid culture systems.Results: A combination of seven HGFs including FL,Tpo,SCF,IL-3,GM-CSF,G-CSF and Epo was identified as the most potent combination of those tested,and it increased total nucleated cell by 1627.57?52.93 fold,total progenitor cells(CFCs) by 56.78?8.13 fold and CD34+ cell by 41.09?4.11 fold,respectively.Among the HGFs examined,FL and Tpo were the most potent ones for expanding cord blood CD34+ cells.Maximal expansions of CFCs and CD34+ cells were observed during the first two weeks of culture.Conclusion: Under conditions of appropriate HGFs combination and expansion duration,it is possible to expand cord blood CD34+ cells ex vivo for transplantation and therapeutic gene transfer.