| Part one. Research of the biologic characteristics of rat bone marrow mesenchymal stem ceUs (MSCs) in vitroBone marrow contains two prototypical stem cell populations. It's well known that one of them is hematopoietic stem cells, which provide a continuous source of progenitors for red cells, platelets, monocytes, and granulocytes. Another is the cells that meet the criteria for stem cells of non-hematopoietic precursors. These stem-like cells currently referred to either as bone marrow stromal cells (BMSCs) or as mesenchymal stem cells (MSCs). In the mid-1970s the pioneering work of Friedenstain discovered the fact that bone marrow contains the non-HSCs. Although the potential of multi-differentiation properties of MSCs have been recognized for two decades, there are still many questions that need to be studied further. In this paper thebiological characteristics of MSCs, such as the isolations, culture conditions, growth features and cells surface markers have been observed and studiedThe MSCs from Wistar rat were isolated by its characteristics of growing adherence to the plastic surface with tissue culture. The growth line was measured by MTT method. The growth features of MSCs were observed when cells were plated at two densities of 3 cells/cm2, 16 cells/cm2 with adding in EOF, bFGF and EGF+bFGF culture conditions. After 18 growth days the number of cells, CFU-Fs had been measured. The immunophenotype of MSCs were detected byFCM.Rat bone marrow, taken from femurs and tibias, were plated in a-MEM medium. Through the change of medium, HSCs were removed. The morphology of MSCs tended homogenous after 10~14days. Cells have fibroblastic-like morphology. MSCs were plated in a 75cm2 clulture flask with densities of 3 cells/cm2 and 16 cells/cm2, after 18 days the total yield per cell plated in a-MEM medium was approximately 56.89± 8.55 and 22.5 ± 2.64, respectively. The yield of CFU-F per 100 cells plated was 1.69±0.37 and 0.60±0.11, respectively. The growth factors, suchas EOF, bFGF stimulated the proliferation of MSCs. FCM showed that 83.1% of MSCs isolated by our method expressed CD90 and 80% of cells expressed CD71.From our experiment it can be concluded that MSCs can be isolated by its characteristic of adherence to the wall. It can be cultured in a long-term without obviously changing its morphology. There is still an obstacle to distinguish the cells from its morphology. Immunological cell phenotype assay is helpful to recognize MSCs. When MSCs were plated at different density, the yield of cells and CUF-F are different. Culturing in low density can produce more cells. The stimulating growth factors can also increase the cells production.Part two. Study on the neural differentiation of rat bone marrow mesenchymal stem cells (MSCs) in vitroHSCs in bone marrow continuously repopulate the blood cells of the circulation. While MSCs, the mesodermal elements normally give rise only to mesenchymal derivatives. Developmental procedure of cells is actually a progressive restriction procedure to cells fate. Early embryonic cells are totipotent. Postnatal stem cells are thought to differentiate only into cells of their resident tissues. MSCs, classicalmesodermal derivatives, represent a rare population in postnatal animals. Although not totipotent, they are capable of self-renewal and differentiate into more than one specialized cell type. It can differentiate into neurons and glia, traditional ectodermal cell in vivo and in vitro. These studies have rocked the developmental biologic theories that have been accepted for hundreds of years. It means that cells can reprogram or trans-differentiate from one germ layer to another. The capability of MSCs differentiate into neural cells under the induction of some factors in vitro has been studied in this paper.The brief experimental process is as follow: MSCs(P3~P4) were maintained in sub-confluent cultures in NIM with inducing the neuronal phenotype for 6 days, during this time the morphological...
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