ABSTRACT
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.
ABSTRACT
BACKGROUND:Adipose-derived stem cells are easily col ected and abundantly cultured, which can proliferate rapidly when being cultured in vitro. With multi-directional differentiation potential, adipose-derived stem cells are expected as seed cells for tissue engineering. OBJECTIVE:To isolate, culture and identify of adipose-derived stem cells from Sprague-Dawley rats in vitro. METHODS:The subcutaneous adipose tissue was obtained from the iliac region of rats under the aseptic condition, and then was digested with 0.075%type Ⅰ col agenase and cultured in vitro. The morphology and proliferation characteristics of the cells were observed under an inverted phase contrast microscope. The third passage was put into gauge for growth curve by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and the cells were also identified by CD44, a stem cellmarker, with immunofluorescence staining. Adipose-derived stem cells were induced and differentiated into adipocytes in Dulbecco’s modified Eagle’s medium/Ham’s nutrient mixture F-12 containing 10%fetal bovine serum, dexamethasone and insulin, and then the cells were identified with oil red“O”staining. Adipose-derived stem cells were induced and differentiated into neural cells, and then the cells were identified with immunohistochemical staining. RESULTS AND CONCLUSION:The growth curve of adipose-derived stem cells was opposite-like“S”shape, and it strongly expressed CD44 that can designate a stem cell. The passage cells were exposed to a defined medium for adipocyte differentiation, and then could be stained with oil red. After being induced and differentiated into nerve cells, the cells expressed neuron-specific enolase. The adipose-derived stem cells of Sprague-Dawley rats are characterized by easy isolation, culture and proliferation in vitro, expressing related phenotypes of mesenchymal stem cells, as wel as induction and differentiation under certain conditions.