| Stem cells are self-renewing, unspecialized cells that can give rise to multiple types of all specialized cells of the body. Stem cells can be obtained from the embryo, They are expected to be the new source for tissue engineering seed cells. The previous study was to test the hypothesis that ecto-mesenchymal stem cells of the first branchial arch show properties of pluripotent stem cells. Moreover, the other mesenchymal stem cells such as marrow mesenchymal stem cell could trans-differentiation from one tissue to another tissue which has paved the way for potential use of stem cells in treatment of diseases.It has been known as "ecto-mesenchyme" when cranial neural crest migrates into facial process. Migration of ecto-mesenchymal cells from the cranial neural crest to gives rise to progency of different phenotypes including neurogenic, myogenic, chrondrogenic, osteogenic, and odontogenic cells, which form many of the oral and dental tissues with the exception of the enamel organ. These neural crest-derived ecto-mesen chymal stem cells may be pluripotent stem cells which have the self-renew ability.The aim of the present study was to prove the hypothesis that ecto-mesenchymal cells show properties of pluripotent stem cells, simultaneously, through tissue-engineering approaches to repair impairment will also be discussed.Part 1: Biologic Characterization and Induction Study ofUndifferentiated Ecto-mesenchymal Stem CellsEcto-mesenchymal stem cells were enzymatically isolated from the rat embryo; ecto-mesenchymal stem cells express HNK-1 in accord with migrating neural crest cells; the expression of S-100 and vimention was also consistent with the neural crest origin of these cells; cells didn't expressed GFAP, NF, CK. Importantly, these cells were able to renew themselves while grown in the presence of LIF and yet remained the potential to differentiate into different phenotypic progeny, thereby displaying the characteristics of stem cells. bFGF could stimulate EMSCs proliferate activity.The fates of pluripotent ecto-mesenchymal stem cells may be dictated by different grow factors. Chondrocyte could be induced by cartilage promoting culture medium which contain TGF- β, IGF, Vitamin C and Dexasone. EMSCs could be induced by DMSO to differentiate to skeleton cells; cells appear the expression of myoblast relation proteins such as myosin, myoD and myogenin. These result indicated that EMSCs is a special kind of cell that has a unique capacity to renew itself and to give rise to specialized cell types.Part 2: Studies on trauma repair in tissues regeneration2.1 Studies on the function of EMSCs on total body irradiation inratsEMSCs was transplanted on total body irradiation in rats, Sprague- Dawley male rats were randomly divided into ectomesenchymal stem cells group,esposure group, fibroblast group and control group, the front three groups were irradiated with 6.0cGy 60Co Y rays.The number of their bone marrow nucleated cells was counted. The forming ability of CFU-GM and the bone marrow histopathology were also observed. Some of organs were observed by HE staining and fluorescence microscope. EMSCs could increase the number of bone marrow nucleated cells and peripheral lood white cell count, and improve the forming ability of CFU-GM. These results indicated that the EMSCs have characteristics of stem cells. EMSCs...
|
PDF Full Text Request