ABSTRACT
BACKGROUND: A large number of studies mainly concern the proliferation effect of mesenchymal stem cells on hematopoietic stem cells in vitro and that bone marrow mesenchymal stem cell transplantation can reduce the death of hematopoietic cells caused by irradiation, increase the survival of bone marrow cells and repair hematopoiesis, while few of them investigate the repair of human umbilical cord blood mesenchymal stem cells transplantation on bone marrow hematopoiesis injury. OBJECTIVE: To explore the repair of hematopoietic microenvironment of bone marrow by human umbilical cord blood mesenchymal stem cells. METHODS: Male BALB/c mice were randomly divided into three groups. The mice in experimental group and control group were irradiated with total dose of 6-Gy X-ray to establish a mouse model of bone marrow hematopoietic injury. The normal group contained untreated normal mice. In the experimental group, CM-DiL labeled human umbilical cord blood mesenchymal stem cells were injected into the tail vein of each mouse at 5×106 (0.2 mL). The control group and the normal group received normal saline 0.2 mL through the tail vein. The peripheral blood hematology and bone marrow hematopoietic microenvironment repair were observed at 1, 5, 7, 14 and 21 days after cell transplantation. RESULTS AND CONCLUSION: Peripheral blood condition: At 1, 5 and 7 days after transplantation, the leucocyte, platelet, erythrocyte count and hemoglobin concentration in the experimental group and control group decreased progressively compared with the normal group. The most obvious decrease occurred on day 7. The trilineage recovered on day 14 after transplantation, basically returned to normal on day 21 after transplantation. Compared with the experimental group, the decrease of the trilineage in the control group was more obvious. The recovery was obvious faster in the experimental group than in the control group on day 14 after transplantation. Bone marrow smears: Bone marrow smears showed that the hematopoietic function was inhibited in the experimental group and the control group at 1, 5, 7, and 14 days after transplantation, especially on day 7. Bone marrow proliferation recovered on day 14 after transplantation. It was better in the experimental group than in the control group. On day 21 after transplantation, the hematopoietic function of bone marrow of mice in the experimental group and the control group recovered, and there was no difference between the experimental group and the control group compared with the normal group. Bone marrow pathological section: Bone marrow pathological sections showed that at 1, 5, 7, and 14 days after transplantation, the hematopoietic function of bone marrow in the experimental group and the control group was inhibited. On day 14 after transplantation, the bone marrow hematopoietic function of the experimental group and the control group began to recover, but the bone marrow proliferation of the experimental group was better than that of the control group. On day 21 after transplantation, there was no difference in the bone marrow proliferation between the experimental and the control groups and the normal group. The results suggested that human umbilical cord blood mesenchymal stem cells can promote the recovery of hematopoietic function of bone marrow.
ABSTRACT
Objective@#To explore the effects of shear stress on morphology, adhesion and proliferation of human umbilical cord blood mesenchymal stem cells(hUC-MSCs).@*Methods@#The hUC-MSCs were cultured in vitro until confluence and then placed in a flow system.The cells were subjected to different shear stress (1, 2, 3, 4 dye/cm2) for 2 hours and 6 hours, and no shear stress treatment cells served as a static control.The morphological changes of hUC-MSCs in different groups were analyzed by phase contrast microscopy and immunofluorescence.The mRNA expression levels of intercellular adhesion molecule-1 (ICAM-1) and Ki67 were detected by real-time PCR.@*Results@#Compared with the static control group, the hUC-MSCs cells were arranged in the direction of fluid after treated with shear stress.The immunofluorescence results showed that the cytoskeletal protein F-actin filaments was prolonged after shear stress.The cytoskeleton was further elongated in the 2 dye/cm2 for 6 hours group when compared with 2 dye/cm2 for 2 hours group, and the cytoskeleton was loosened when time extended to 6 hours.Real-time PCR results showed that the relative expressions of ICAM-1 mRNA and Ki67 mRNA in the static control group and different gradient shear stress groups were significantly different, with significant differences among them (F=17.141, P=0.000; F=11.336, P=0.001). The relative expression of ICAM-1 mRNA in the 1, 2, 3, 4 dye/cm2 shear stress group was 2.74±0.32, 9.77±1.19, 6.70±0.92 and 5.69±0.72, respectively, which was significantly higher than 1.00±0.28 in the static control group, with significant differences between them (all at P<0.05). The relative expression of Ki67 mRNA in the 3 dye/cm2 and 4 dye/cm2 shear stress group was 0.39±0.09 and 0.04±0.02, respectively, which was significantly lower than 1.00±0.24 in the static control group, with statistically significant differences between them (both at P<0.05).@*Conclusions@#After treated with fluid shear stress, hUC-MSCs are arranged in the direction of fluid.Shear stress can promote the adhesion of hUC-MSCs.As the increase of shear stress intensity, cell proliferation is inhibited.
ABSTRACT
Objective To induce the differentiation of human umbilical cord blood MSCs into osteoblasts in vitro,and to study the method of inducing MSCs to differentiate into osteoblasts under specific microenvironment.Methods MSCs was obtained from human umbilical vein,and isolated by density gradient method.The morphological changes of MSCs were observed by using dexamethasone,beta sodium phosphate and vitamin C.The proliferation and differentiation of MSC in cord blood were studied by means of optical microscope,transmission electron microscope and alkaline phosphatase staining.The expression of bone morphogenetic protein 2 mRNA in human umbilical cord blood MSCs after osteogenic was inducted by RT-PCR.Results After the umbilical cord blood MSCs were differentiated into osteoblastic cells in microenvironment,fusiform cells became polygonal,irregular shape,local cells presented overlapping growth.After 10 days,the cells gradually presented square,crystal particles of high refraction,and began to show the characteristics of osteoblasts.The expression of bone morphogenetic protein 2 mRNA was positive in alkaline phosphatase staining and alizarin red staining.Conclusion Human umbilical cord blood MSCs can be induced into osteoblasts in vitro,which is an ideal seed cell for bone tissue engineering.
ABSTRACT
Objective:To explore the effect of intratracheal transplantation human umbilical cord blood mesenchymal stem cells on pulmonary interstitial fibrosis by bleomycin in mice,compare the treatment in pulmonary fibrosis of intratracheal transplantation with tail vain injection human umbilical cord blood mesenchymal stem cells.Methods:The second generation of HUCBMSCs were cultured to the fourth generation.Sixty specific pathogen free male Kunming mice were randomly divided into 4 groups:negative control group ( Cont group) ,bleomycin group( BLM group) ,HUCBMSCs transplantation groupⅠ( MⅠgroup) and HUCBMSCs transplantation groupⅡ(MⅡ group),each group 15 mice.Pulmonary fibrosis models were induced by bleomycin via intratracheal perfusion in the latter three groups.Twenty four hours after model establishment,5-bromo-2-deoxyuridine( Brdu) marked HUCBMSCs were poured in trachea in MⅠgroup ,the same were injected into tail vein in MⅡ group.At the 7th,14th,28th day,5 mice in each group were executed re-spectively.The morphological changes of the lung tissues were observed by HE staining and Masson staining.The localization and distribution of human umbilical cord blood mesenchymal stem cells were determined by the method of immunohistochemistry.The hydroxyproline contents were measured by alkali hydrolysis assay.The protein levels of transforming growth factor β-1 ( TGF-β1 ) and smooth muscle alpha-actin(α-SMA) were detected by Western blot.Results:In the two mesenchymal stem cell transplantation groups, there were Brdu marked cells at the 7th,14th,28th days in lung tissue.The alveolitis and fibrosis in lung of the two mesenchymal stem cell transplantation groups were milder than which of the the bleomycin group(PMⅠ,MⅡgroup>Cont group(P0.05).Conclusion:The colonization of human umbilical cord blood mesenchymal stem cells can be seen in the damaged tissue via intratracheal transplantation which can alleviate pulmonary fibrosis in mice caused by bleomycin.