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BACKGROUND:Stromal cellderived factor 1 in chemotactic migration of endogenous neural stem cells plays a very important role, but the specific migration mechanism is unclear OBJECTIVE:To observe the effects of exogenous stromal cellderived factor 1 on chemotactic migration and proliferation of neural stem cells in the rat hippocampus METHODS:Exogenous stromal cellderived factor 1 (5μL, 500μ/L) was injected into the hippocampus of Sprague-Dawley rats to establish animal models. Brain tissues were taken after days 3, 7, 14 and 21 of perfusion to prepare paraffin sections. Thereafter, nestin expression in the injection region and hippocampus was detected using immunohistochemical method. Experimental control and blank control groups were set. RESULTS AND CONCLUSION:Paraffin section immunohistochemical results displayed the number of nestin-positive cells in the injection and the hippocampus was gradual y increased. At 3 and 7 days, nestin expression was a little and increased at 14 days, forming a migration tendency to the injection region. At 21 days, there were more nestin-positive cells in the injection area and hippocampus. However, there were no changes as above in the experimental control and blank control groups. The results showed that exogenous stromal cellderived factor 1 may induce the proliferation of neural stem cells in the hippocampus and may be involved in chemotactic migration of endogenous neural stem cells.
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BACKGROUND:The mechanisms of mesenchymal stem cells directional y homing to infarcted myocardium post myocardial infarction are stil unclear. OBJECTIVE:To investigate the role of stromal cellderived factor-1 (SDF-1)/C-X-C chemokine receptor 4 (CXCR4) axis on mesenchymal stem cellmigration promoted by mononuclear cells after myocardial infarction. METHODS:Cardiomyocytes and mesenchymal stem cells were respectively isolated from suckling and adult Sprague-Dawley rats. Twelve healthy Sprague-Dawley rats were selected (six rats for myocardial infarction models and six for sham models), then circulating mononuclear cells were isolated. 4,6-Diamino-2-phenyl indole-labeled mesenchymal stem cells, cardiomyocytes and mononuclear cells were cultured into the upper, middle and lower layers of the tri-chamber coculture system, respectively. In this experiment, there were four groups:myocardial infarction group, AMD3100 (CXCR4 inhibitor) group, sham group and blank control group. After 48 hours, the number of migrating mesenchymal stem cells with blue-lighting nucleus was calculated under fluoroscope. Immunocytochemistry and immunofluorescent staining was used to detect SDF-1 expression in cardiomyocytes and CXCR4 expression in mesenchymal stem cells, respectively. RESULTS AND CONCLUSION:Migrating mesenchymal stem cells with positive expression of CXCR4 were observed in each group other than the blank control group. The number of migrating mesenchymal stem cells was higher in the myocardial infarction group than in the other groups. Tumor necrosis factor-αneutralizing antibody and CXCR4 inhibitor AMD3100 could obviously reduce the number of migrating mesenchymal stem cells (P<0.05). Cardiomyocytes in each group expressed SDF-1 positively. The gray values of SDF-1 expression in the myocardial infarction and AMD3100 groups were significantly higher than those in the sham and blank control groups (P<0.05). SDF-1/CXCR4 axis plays a certain role in mesenchymal stem cells migration promoted by mononuclear cells after myocardial infarction.
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BACKGROUND:Recent studies have found that bone marrow mesenchymal stem cells play an important role in the development of multiple myeloma, especial y for angiogenesis, but whether the pro-angiogenesis ability of bone marrow mesenchymal stem cells in multiple myeloma in active and remissive state is different is yet unclear. OBJECTIVE:To investigate the difference in the pro-angiogenesis ability of bone marrow mesenchymal stem cells in multiple myeloma in active and remissive state. METHODS:Bone marrow samples were extracted from 13 patients with multiple myeloma before treatment and after four therapeutic cycles to isolate bone marrow mesenchymal stem cells. ELISA assay was used to detect levels of vascular endothelial growth factor, hepatocyte growth factor and basic fibroblast growth factor in the supernatant of bone marrow mesenchymal stem cells. The proliferative ability and movement of human umbilical vein endothelial cells cultured in the supernatant of bone marrow mesenchymal stem cells were detected by MTT assay and Transwel assay, respectively. The pro-angiogenesis ability of bone marrow mesenchymal stem cells was measured by Matrigel in vitro. RESULTS AND CONCLUSION:The levels of vascular endothelial growth factor, hepatocyte growth factor and basic fibroblast growth factor in the cellsupernatant were significantly higher in active myeloma than those in remissive myeloma (P<0.05). The supernatant of bone marrow mesenchymal stem cells of active myeloma more significantly promoted the proliferation, migration and blood vessel formation of human umbilical vein endothelial cells than that of remissive myeloma in a dose-dependent manner (P<0.05). These findings indicate that bone marrow mesenchymal stem cells from active myeloma have stronger pro-angiogenesis ability than those from remissive myeloma.
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BACKGROUND:The homing ability of mesenchymal stem cells is closely associated with the effects of celltransplantation. Clarifying the mechanism of chemotaxis and migration wil contribute to enhance the clinical application of mesenchymal stem cells. OBJECTIVE:To investigate the effect of Cdc42 in the homing of human umbilical cord mesenchymal stem cells. METHODS:First, mesenchymal stem cells were isolated from human umbilical cord, and co-cultured with tumor necrosis factorα, interleukin-1β, and transforming growth factorβ. Western blot assay was used to test the level of Cdc42. Besides, Cdc42 siRNA was synthesized by chemical method to transfect the cells, and cellmigration and adhesion were measured by Transwel and Matrigel separately. Meanwhile, the activity of signal molecule, extracellular regulated protein kinase 1/2, was evaluated by western blot. RESULTS AND CONCLUSION:The results indicated that the inflammation factors induced the highly expression of Cdc42 in human umbilical cord mesenchymal stem cells, almost double level to controls. siRNA notably inhibited the migration and adhesion of human umbilical cord mesenchymal stem cells through Cdc42 down-regulation, and the extracellular regulated protein kinase 1/2 and phosphorylation form were also decreased simultaneously. In a word, we speculate Cdc42 plays a role in the chemotaxis of human umbilical cord mesenchymal stem cells in vitro.