Supportive effects of human AGM region and fetal liver stromal cells on differentiation of murine embryonic stem cells into hematopoietic stem cells and in vivo hematopoietic reconstitution

AIM: To investigate the differentiation of murine embryonic stem cells (ESCs) into hematopoietic stem cells (HSCs) by the supportive effects of human aorta-gonad-mesonephros (AGM) region and fetal liver (FL) stromal cells.METHODS: E14 ESCs were induced into embryoid body (EB) first. Then the cells from EB were further co-cultured with human AGM region and FL stromal cells in non-contact system. On day 6, the cells derived from EB were collected for Sca-1⁺c-Kit⁺ cell analysis by flow cytometry, colony forming unit (CFU) assay and teratoma formation checking. BALB/c female mice conditioned with lethal dose of γ-ray irradiation were transplanted with EB cells from different culture systems. The survival rates, engraftment of donor cells, reconstitution of hematopoietic were monitored.RESULTS: Sca-1⁺c-Kit⁺ cells in EB cells co-cultured with human AGM region and FL stromal cells had the value of (21.96±2.54)%, and the total CFU was as (520±52)/10⁵ cells, which were statistically greater than those in EB cells only cultured with human AGM region stromal cells (P＜0.05). No teratoma was found in NOD-SCID mice after subcutaneous injection of EB cells co-cultured with human AGM region and FL stromal cells. In BALB/c female mice transplanted of EB cells co-cultured with human AGM region and FL stromal cells, the survival rate was 77.8%, and the peripheral blood cell count was obviously improved on day 14. PCR results showed the recipients all had sry gene copies from donor in bone marrow. The recipient mice transplanted with EB cells only cultured with human AGM region stromal cells all died within 15 days.CONCLUSION: Stromal cells from human AGM region and FL enhance the directed differentiation of ESCs into HSCs which can reconstruct hematopoiesis in vivo.     

Supportive effects of human aorta-gonad-mesonephero stromal cells on the directed differentiation of embryonic stem cells into hematopoietic stem cells

AIM: To direct embryonic stem cells (ESCs) into hematopoietic stem cells (HSCs) in vitro by simulating the hematogenic microenvironment in human early embryonic aorta-gonad-mesonephero (AGM) region.METHODS: Murine E14 embronic stem cell line was used for two-step differentiation.In the first step of primary differentiation,E14 ESCs were seeded into semisolid methylcellulose-based medium containing bone morphogenesis protein 4 (BMP4) and vascular endothelial growth factor (VEGF) for embryoid body (EB) formation.On days 3,6,9,12 and 15,single EB cells were analyzed for Flk-1+ cells amount through flow cytometry.In the second step,single cell from EB containing most Flk-1+ cells was further co-cultured with human AGM stromal cells in non-contact system.On co-culture days of 3,6,9 and 12 days,cells were collected for cell count,flow cytometry for Sca-1+c-kit+ cells analysis,and colony forming cell assay.RESULTS: During the EB formation,BMP4+VEGF promoted Flk-1+ cell genesis on day 9 at peak pencentage value of 27.53%±2.84％,which was statistically higher than that in control group as 8.77±1.10 (P<0.05).Collagenase-disassociated single cell from day 9 EB was co-cultured with human AGM stromal cells of hAGMS3 or hAGMS4 for further hematopoietic differentiation.On day 6 Sca-1+c-kit+ cells got to peak value as 7.31%±1.21％ ［(2.57±0.48) folds］ and 7.62%±1.52％ ［(2.35±0.36) folds］ in hAGMS3 and hAGMS4 feeder systems,respectively,both of which were greater than those values of no-stroma groups at the same culture duration (P<0.05).Colonogenic cell assay showed that these Sca-1+c-kit+ cells had ability of forming multiple lineage hematopoietic colonies.CONCLUSION: BMP4 in combination with VEGF promotes Flk-1+ cell genesis during EB formation in vitro.Stromal cells from early human embryonic AGM region further enhance the directed differentiation of these primitive cells into HSCs.This two-step induction differentiation model can be used for molecular mechanism study of ESCs hematopoietic differentiation.     

Supportive and expansive effects of aorta-gonad-mesonephros (AGM)-derived stromal cells on hematopoietic stem in vitro

AIM: To explore the supportive and expansive effects of aorta-gonad-mesonephros(AGM) region derived stromal cells on hematopoietic stem cells (HSC) in vitro.METHODS: The murine stromal cells were separated and cultured from AGM region of a 11 day postcoitum (dpc) mouse embryo and 6 week mouse. After identification by Wrights staining and flow cytometry, the stromal cells were co-cultured with the embryonic stem cell(ESC)-derived, cytokine-induced HSCs, and the maintenance and expansion of HSCs were evaluated by detecting CD34+，CD34+Sca-1+cells with flow cytometry.Blast colony-forming cell (BL-CFC) and high proliferative potential colony-forming cells(HPP-CFC) were determined by semi-solid medium clonal culture.RESULTS: AGM-derived and bone marrow(BM)-derived stromal cells were similar in morphology and phenotype, and had common character of stromal cells. Supported by AGM stromal cells or by BM stromal cells, more primitive progenitor cells HPP-CFC were expanded, but BL-CFC expansion was only detected in AGM-derived stromal cells. In the supporting of BM stromal cells CD34+ hematopoietic stem/progenitor cells were expanded 3-4 times, but no significant expansion in CD34+Sca-1+ cells was observed. While in the supporting of AGM stromal cells, both CD34+ hematopoietic stem/progenitor cells and CD34+Sca-1+ cells were expanded significantly from 4 to 5 times, respectively (P<0.05).CONCLUSION: AGM-derived stromal cells significantly support the expansion of HSC, and also maintain the self-renewal activity and multi-lineage differentiation of HSC in vitro.     

Tissue irradiation injury and past-transplantation distributing diversity of Sca-1 positive cells from murine fetal liver

AIM: To study the relationship between tissue irradiation injury and past-transplantation distributing diversity of Sca-1 positive cells from murine fetal liver and their offspring cells in multi-organs after syngeneic sex mismatch hematopoietic remodeling.METHODS: The Sca-1 positive cells from the livers of C57BL/ 6j male mouse fetus aged 14.5 day were identified and separated by quick PCR and magnetic cell sorting (MACS) techniques. In order to reconstruct hematopoiesis of the adult female mice, which were lethally irradiated with 8G of ［Co⁶⁰］, the 2×10⁴ of Sca-1+ cells were transplanted through caudal vein into each of them. After 6 months, these recipient mice were sacrificed, and their kidneys, livers, lungs, stomachs, and small intestines were taken out, fixed and slices were made. Fluorescence in situ hybridization was performed and observed by fluorescent microscope. Images were captured and analyzed through appropriative cool CCD and software. RESULTS: After 2×10⁴ of Sca-1+ cells were transfused, the hematopoietic function in the lethally irradiative female mice was completely restored. The cells containing Y chromosome were observed 6 months latter in multi-organs, including kidney, liver, lung, stomach, and small intestine. The frequency of the cells containing Y chromosome respectively was kidney (1.65±0.18)%, liver (0.90±0.10)%, lung (1.90±0.60)%, stomach (6.10±0.50)%, and small intestine (7.61±2.30)%, presented the trend of small intestine>stomach>lung>kidneys>liver. Combined informational analysis showed that the presenting frequency of the cells containing Y chromosome was consistent with the irradiative sensitivity of the organ. CONCLUSION: These findings suggest that the capability of differentiation of Sca-1 positive cells from murine fetal liver was potentially connected to the extent of damage in these organs when transferred in vivo.     

Generation of hematopoietic stem/progenitor cells with property of strengthened cell mediated immunity from an embryonic stem cell line

AIM:To induce lymphoid stem cells and/or T-cell precursors to differentiate into functional mature T lymphocyte, and to increase the surface marker of T lymphocytes such as CD₃⁺, while embryonic stem(ES) cells differentiated into hematopoietic stem/progenitor cells(HSPCs) in vitro. When they were injected into lethally irradiated mice, these differentiated cells had the advantage in immune reconstitution. METHODS:Embryonic stem cells formed embryoid bodies(EBs) in the medium containing methycellulose, hematopoietic growth factors(HGFs) was added to the culture system on the 6th day, thymopeptide was added at the same time. Flow cytometry were performed to detect the surface marker CD₃₄⁺ and CD₃⁺ of the differentiated cells. Finally the differentiated cells were injected into lethally irradiated mice, 60 days later, the incidence rate of graft versus host disease(GVHD) was taken as the mark of cell mediated immunity, PCR was performed to detect the sex determining region of the Y-chromosome(Sry) in bone marrow cells and spleen cells of the survival host female mice. RESULTS:The percentage of CD₃⁺ T lymphocytes was 10.52% and the incidence rate of GVHD was 0% on the 13th day, but they respectively rose up to 22.93% and 100% if thymopeptide was added in the procedure of inducing ES cells to differentiate into HSPC in vitro. CONCLUSION:The quantity of CD₃⁺ T lymphocytes increased in medium containing thymopeptide when ES cells differentiated into CD₃₄⁺ HSPC.     

Hemangioblastic characteristics of human adipose tissue-derived adult stem cells in vivo

AIM: To investigate whether Flk1+CD31-CD34- cells isolated from human adult adipose tissue have characteristics of hemangioblasts in vivo. METHODS: After sublethally irradiated (300cGy) with a caesium source, the female non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice were injected with human adipose tissue-derived Flk1+CD31-CD34- cells (105 cells per mouse) via tail vain with 0.4 mL Roswell Park Memorial Institute medium (RPMI-1640). The control mice received the same volume of RPMI-1640 medium. All mice were killed 2 months after transplantation for further study. The differentiation potential of Flk1+CD31-CD34- cells was assessed in bone marrow and gastrointestinal tract by the methods of flow cytometry, RT-PCR, FISH, and triple-color immunofluorescence. RESULTS: Flk1+CD31-CD34- human adipose tissue-derived adult stem cells differentiated into endothelial cells and hematopoietic cells at the single-cell level in vivo. CONCLUSION: Human adult adipose tissue-derived Flk1+CD31-CD34- cells bear characteristics of hemangioblast in vivo and may have potential application for the treatment of hematopoietic and vascular diseases.     

Aged bone marrow stem cells can be rejuvenated by cell fusion with young bone marrow stem cells

AIM: To investigate the function of aged bone marrow mesenchymal stem cells (BMSCs) fused with young BMSCs in mice. METHODS: The cell fusion model, which was made by C57BL/6 mouse BMSCs labeled with PKH26 membrane red fluorescence (young cells, age of 2-3 months, Y) and (old cells, age of 18-24 months, O), and young and old BMSCs of green fluorescent protein (GFP) transgenic C57BL/6 mouse, was established by the induction of polyethylene glycol 1500 (PEG 1500). The cell fusion rate and cell surface markers were detected by flow cytometry. The morphology and nuclear characteristics of the fused cells were observed under fluorescence microscopy. In this study, the age dependent changes in BMSCs proliferation and differentiation potential in Y group, O group, and another three fusion groups (Y-Y group, Y-O group, O-O group) were examined. The proliferation potentials in 5 groups were compared by counting cell numbers at days 2, 4, 6, and 8. The osteogenic and adipogenic differentiation potentials of the cells in 5 groups were determined by using standard differentiation procedures. RESULTS: The fusion rate of 30.45%±4.13% was obtained by PEG 1500 induction. No significant difference of the fusion rates in Y-Y, Y-O and O-O groups was observed. Fused BMSCs coincided with the common BMSCs were reactive to the BMSCs lineage-specific CD44, Sca-1 surface markers and negative for the hematopoietic stem cells (HSCs) lineage-specific surface markers such as CD34, CD117, CD31, and CD45. The percentage of increasing cell numbers in Y-O group was significantly higher than that in O-O group at days 2, 4, 6, and 8. The positive rate of the area stained with Alizarin red, which represents osteogenic differentiation potential of BMSCs, was significantly higher in Y-O group than that in O-O group ［(25.46%±1.52%) vs (13.85%±1.69%), P<0.01］. In Y-O group, the higher rate of the positive area stained with oil red O, which represents adipogenic differentiation potential of BMSCs, was observed as compared to that in O-O group ［(12.99%±2.61%) vs (6.03%±1.71%), P<0.05］. CONCLUSION: Aged bone marrow stem cells can be rejuvenated by cell fusion with young bone marrow stem cells, particularly the proliferation and differentiation potentials.     

Differentiation of Sca-1+ cells from murine fetal liver into renal cells in mice with acute renal failure

AIM: To study the effect of acute renal failure (ARF) on the differentiated frequency of Sca-1+ cells from murine fetal liver in irradiated mice. METHODS: The Sca-1+ cells from murine fetal liver were isolated with magnetic cell sorting (MACS) technique, the sex of which was identified by PCR. The 2×104 Sca-1+ cells were transplanted into a lethally irradiated (［60Co］, 8 Gy) inbred female mouse. After 8 weeks, these recipient mice were divided to A, B, and C groups at random (A group: irradiated; B group: ARF; C group: ARF and Sca-1+). The mice in B and C groups were induced to ARF with 50% (V/V) glycerin (11.6 mL/kg). 72 hours later, the mice in C group were injected with the fresh prepared Sca-1+ cells again. 8 weeks later, mice were sacrificed, and their kidneys were taken out, fixed and slices were prepared. Fluorescence in situ hybridization (FISH) of renal slices was performed and the pictures of them were taken and analyzed. RESULTS: The cells containing Y chromosome were found in renal slices from the mice in A, B and C groups, which located in epithelial cells of renal tubules, interstitium, glomeruli, and glomerular margin and increased gradually. The double and encircle zone of Y chromosome cells were found in the slices from the mice in B and C groups separately, which was consist of new renal tubules. The differentiation frequency of Sca-1+ cells in kidney in A, B and C groups were (1.65±0.18)%， (8.58±1.34)% and (18.13±1.91)%， respectively, which showed significant difference between former group and later group (P<0.01). CONCLUSION: The differentiation of Sca-1+ cells from murine fetal liver into renal cells and tissue is promoted by physiological microenvironment of acute damage and regeneration.     

Fetal liver-derived Sca-1+ cells can differentiate into both neurons and astrocytes in vivo

AIM: To determine whether Sca-1⁺ cells from fetal liver can differentiate into neural cells. METHODS: The sex of 14.5-day-old murine fetuses was determined by PCR analysis of sry gene, and Sca-1⁺ cells from male fetal liver were isolated with a magnetic cell sorting kit, 2×10³ of which were then transplanted into lethally irradiated female mice. The donor cells and their characteristics in recipient brains were identified and detected by FISH and immunohistochemistry double-staining analysis at 60, 120, 180 days after transplantation. RESULTS: There existed many male cells in brains of female recipients, some of them express neuron-specific nuclear protein (NeuN), and some of them express the astrocyte-specific marker, i.e. glial fibrillary acidic protein (GFAP). CONCLUSION: Sca-1⁺ cells from fetal liver, which contain hematopoietic stem cells, can differentiate into neuronal cells and astrocytes in the brains of adult mice.     

Efficient production of neuron-like cells from embryonic stem cells induced by astrocyte-conditioned medium in vitro

AIM:To investigate whether efficient production of neuron-like cells from embryonic stem cells (ESCs) can be indued by astrocyte-conditioned medium (ACM) in vitro. METHODS:Based on the 4-/4+ protocol established by Bain, two groups were studied:ATRA group, ATRA with ACM group. ESCs were induced into neuron-like cells by means of three-step differentiation in vitro. The totipotency of ESCs was identified by the observation of cells’ morphology and the formations of teratoma in immunocomprised mice. The cell differentiation was evaluated continuously by detection of the cellular specific markers of neural stem cell, neurons and astrocytes such as nestin, NF-200, NSE and GFAP using immuno-histochemistry assay. RESULTS:(1) The ESC-D3 cells kept the ability of differentiation into cellular derivations of all three primary germ layers after continuous passage culture. (2) The ratio of NF-200 and NSE positive cells in the cells induced by ATRA with ACM was higher than that in the cells induced by ATRA only. (3) Finally, the positive rate of the neuron-like cells was up to 73.5% in the group induced by ATRA with ACM. CONCLUSION:The ESCs are induced into neuron-like cells with high purity and efficiency by ATRA with ACM.     

Generation of thalassemia-specific integration-free induced pluripotent stem cells and determination of their differentiation ability

AIM: To generate thalassemia-specific integration-free induced pluripotent stem cells(iPSC) and to detect their ability of differentiation into hematopoietic precursors.METHODS: The plasmids pEB-C5 and pEB-Tg were transfected into the fibroblast cells from hemoglobin Bart's hydrops fetalis's skin by the method of nuclear transfection to reprogramm the cells into iPSC. The ability of the iPSC to differentiate into 3-germ layer cells was determined. The iPSC were cocultured with mouse OP9 cells to differentiate into hematopoietic precursors and the hematopoietic precursor specific antigens were detected. RESULTS: The integration-free iPSC from hemoglobin Bart's hydrops fetalis's skin fibroblasts were successfully derived, and had the ability to differentiate into 3 germ layers. When cocultured with OP9 cells for 9 d, the positive rate of hematopoietic progenitor cell marker CD34 was 18.7%, and the CD34 and CD45 double positive rate was 12.2%. CONCLUSION: Hemoglobin Bart's hydrops fetalis's skin fibroblasts can be successfully induced into "integration-free" iPSC. This cell line has the ability to differentiate into 3 germ layers, and can be differentiated into hematopoietic precursors when cocultured with OP9 cells.     

The transdifferentiation of Sca-1+ cells from murine fetal liver

AIM:To explore transdifferentiation potential of Sca-1⁺ cells from murine fetal liver. METHODS:2×10³ of Sca-1⁺ cells from male murine fetal liver were transfused into female mouse irradiated lethally with γ ray from ⁶⁰ Co source (10 Gy) via tail vein. Two months later, FISH and immunohistochemistry were used to detect the situation for transdifferentiating of the donor cells (male cells) in tissues of female recipient mouse. RESULTS:The renal tubular epitheliocyte-like and neurocyte-like cells with Y chromosome were found on the sections of renal and brain tissues from female recipient mice. These cells have phenotype characteristics of RCA⁺/CD₄₅^-F_4/80^- and NueN⁺/CD₄₅^-F_4/80^-, respectively. CONCLUSION:The evidence is provided for Sca-1⁺ cells from murine fetal liver to transdifferentiate into both renal and brain tissue cells.     

Transfusion of mesenchymal stem cells improve the hematopoiesis in mice with aplastic anemia by regulating immune cells

AIM: To study the possible immunologic mechanism of mesenchymal stem cells (MSCs) by which the hematopoiesis of mice with aplastic anemia (AA) is improved. METHODS: The mice model of immuno-mediated aplastic anemia was established. Thirty BALB/c mice were divided into 3 groups: radiation group, AA model group and MSCs group. The mice in radiation group only had processing of 5 Gy ［60Co］γ radiation. The mice in AA model group were intravenously injected with the cell suspension of thymocyte and lymph-node cell mixture (prepared from DBA/2 mice, 1×106 cells) after 5 Gy ［60Co］γ radiation. The animals in MSCs group received the same treatment as the mice in AA model group did, and afterwards was injected with 1×106 MSCs intravenously at 3 days. All the mice in the 3 groups were observed and analyzed the following parameters: peripheral blood cells, pathological features of bone marrow, the relation between the changes of peripheral CD4+, CD8+, CD4+/CD8+, NK cells and the hematopoiesis. RESULTS: After 5 Gy ［60Co］γ radiation, the peripheral blood cells in all groups decreased at 7 days, while at 21 days those in MSCs group and radiation group restored to normal but those in AA model group was still at lower level. At 7 days, the cells of CD4+, CD8+ and CD4+/CD8+ in each group were similar without statistical difference, but the number of NK cells in MSCs group was quite lower than that in the other 2 groups (P<0.05). At 14 days, the CD4+ cells in all groups were obviously decreased, while the CD8+ cells in MSCs group and AA model group were significantly higher than those in radiation group. At 21 days, the CD8+ and NK cells in MSCs group were quite the same as those in radiation group while those in AA model group were obviously higher compared to the other 2 groups. The number of adipose cells observed in the pathological slice of femoral bone in MSCs group and radiation group was no difference while that in AA model group was much higher. CONCLUSION: MSCs transfusion improves the hematopoiesis in mice with aplastic anemia by regulating the functions of immune cells.     

Biological characteristics and induced differentiation of bone marrow-derived mesenchymal stem cells from sensitized mice in vitro

AIM: To evaluate the biological characteristics and differentiating potentials of bone marrow-derived mesenchymal stem cells (MSCs) from sensitized mice by allogeneic splenocyte transfusion in vitro. METHODS: Adherent culture method was applied for culturing the bone marrow-derived MSCs from sensitized mice. The cell morphology was examined and the surface marker profiles were analyzed by flow cytometry. The differentiating potentials of the MSCs into osteogenic, adipogenic and myogenic lineages were explored. The bone marrow-derived MSCs from the normal mice were collected and served as controls. RESULTS: Both the bone marrow-derived MSCs from sensitized and normal mice were exhibited a homogeneous distinctive morphology and were positive for the surface markers CD29, CD105, CD44 and Sca-1, negative in CD 34 and CD11b. The abilities of both MSCs to differentiate into osteogenic, adipogenic and myogenic pathways in the same condition were also observed. CONCLUSION: There is no difference in the biological characteristics and induced differentiating potentials between the sensitized mouse bone marrow-derived MSCs by allogeneic splenocytes transfusion and the MSCs from normal mice.     

Metanephric cell microenvironment induces embryonic stem cells to differentiate toward renal cells

AIM: To explore the effects of metanephric cell microenvironment on inducing embryonic stem cells (ESCs) to differentiate toward renal cells.METHODS: Embryoid bodies (EBs) of D3 mouse embryonic stem cells were prepared by hanging drop culture, and the EBs were co-cultured indirectly with metanephric cells derived from E12.5 d mouse embryo. The EBs cell with spontaneous differentiation was used as the control. The proteins of Pax2 and WT-1 were analyzed by immunofluorescence assay. The mRNA expression of Pax2, WT-1, Lim1, Sall1, Emx2, GDNF, Wnt4, BMP7, Nephl, Nephrin, KSP and CD24 genes was detected by RT- PCR.RESULTS: The genes related to kidney development were expressed in the EBs cells after co-culture on day 3, and the mRNA expression of Pax2, WT-1, Emx2, GDNF, Nephl, Nephrin, KSP and CD24 was stronger than those in control group. Pax2 positive cells were found on day 3 in the co-cultured EBs cells, and the positive cells increased on day 5 and day 7. WT-1 protein positive cells were found in the co-cultured EBs cells on day 5. No Pax2 or WT-1 positive cell was observed in control group.CONCLUSION: Metanephric cell microenvironment promotes ESCs differentiation toward renal cells.     

High expression of CD34, Sca-1, Bcl-2 and desmin proteins in mouse muscle-derived stem cells

AIM: To explore the characteristics and phenotype of the muscle-derived stem cells(MDSCs) of mouse.METHODS: Skeletal muscle specimens were harvested from C57BL/6 mice of 2 weeks old. Preplate technique was applied to isolate MDSCs. The cellular growth status and morphology of the primary MDSCs were observed. The sphere-forming, proliferation and differentiation assays were performed and flow cytometry(FCM), immunocytochemistry and Western blotting were used to characterize MDSCs.RESULTS: The isolating process contained 6 consecutive days of differentiated attachment. MDSCs were round or short spindle-shaped cells. The growth curve of MDSCs showed logarithmic growth, and the doubling time of MDSCs was(9.69±2.08) h. Cloning efficiency of MDSCs was(13.35±2.54)%. When the cells at high confluence(>50%) or cultured with low concentration of serum(2% FBS), they tended to fuse to form myotubes. The observations of FCM and immunofluorescence showed that the phenotypic characteristics of MDSCs were antibody-positive for CD34, Sca-1, Bcl-2 and desmin(>90%). With increasing the level of cell purification, the upregulation of desmin expression and the downregulation of α-SMA expression from preplate 1 cells(PP1) to preplate 6 cells(PP6) were observed by Western blotting.CONCLUSION: The preplate technique can effectively isolate MDSCs. MDSCs express the antigens of CD34, Sca-1, Bcl-2 and desmin at high levels, and the 4 proteins can be used to identify MDSCs. With a high proliferating ability in vitro, MDSCs are ideal seed cells for tissue engineering.     

Effect of proliferating cell nuclear antigen specific antisense oligonucleotide on differentiation of cord blood CD34+ cells

AIM:To study the effect of proliferating cell nucler antigen antisense oligonucleotide on ex vivo expansion of cord blood CD34+ hematopoietic stem/progenitor cells. METHODS:CD34+ cells were purified from fresh cord blood by immunomagnetic beads. CD34+ cells were incubated in liquid culture system with different concentrations of PCNA-ASODN. Using flow cytometry, the number of different kinds of stem/progenitor cells and PCNA expression were measured after CD34+ cell incubation. RESULTS:PCNA was lowly expressed in low experiential group, with a positive rate of (27.2±3.6)% and (19.0±1.5)%, the positive rate of control group was (53.8±8.3)% (P<0.01), a high significant difference was observed. Just in low concentration of PCNA-ASODN, the percentage of CD34+cells were increased to (33.4±3.2)%, CD34+CD38-cells expanded (57.8±9.9) folds, and the percentage of CD34+cells were (25.2±2.6)% (P<0.01), the CD34+CD38-cells expanded (43.5±7.4) folds (P<0.05), it has significant difference compared with the control group. CONCLUSION:Low concentration of PCNA-ASODN decreases PCNA expression effectively, slows down differentiation of CD34+cells during ex vivo expansion procedure, and improves the expansion efficiency.     

Purification and differentiation potentiality of fetal liver mesenchymal stem cells from mouse

AIM: To purify and investigate the differentiation potentials of fetal liver mesenchymal stem cells (flMSCs) from murine in vitro.METHODS: flMSCs from mouse fetuses at embryonic and fetal day (ED)13.5 or ED14.5 were isolated by adhering to plastic and passaged by modified method.Cell cycle and phenotype were analyzed by flow cytometry.The cell differentiation was induced by special induction media.The cells differentiated to adipose,cartilaginous and osteoid tissues were identified with oil red O,Toluid blue,alkaline phosphatease (ALP) and von Kossa’s staining.The cells differentiated to neural-like cells were detected by RT-PCR and immuno-staining.RESULTS: Fibroblast-like cells predominated in culture.(83.76±2.88)% of flMSCs stayed in the G₀/G₁ phases.Homogenous cells were positive for mesenchymal lineage markers CD44,CD29,but not for markers of hematopoietic cells CD45,CD11b.flMSCs were able to differentiate into adipogenic,chondrogenic,osteogenic and neurogenic cells.CONCLUSION: flMSCs can be purified by modified plastic-attachment method and have multiple differentiation,which is available to stem cell therapy for various diseases.