ABSTRACT
BACKGROUND: It has been reported that in China, human bone marrow mesenchymal stem ceils are mostly harvested from adults. Studies on bone marrow mesenchymal stem cells in children are few.OBJECTIVE: To isolate and expand bone marrow mesenchymal stem cells from children, and to analyze the biological characteristics of bone marrow mesenchymal stem cells and their potential of differentiating into osteoblasts, adipocytes and neural like cells.DESIGN: Observational comparative study.SETTING: Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: Experiments were performed at the Laboratory of Department of Orthopaedics of Wuhan Tongji Hospital from March to September 2006. Bone marrow mesenchymal stem cells were collected from one boy patient and two girl patients aged 5-8 years, who received pelvis osteotomy for dysplasia of the hip joint. The experimental procedures were approved by the Hospital Ethics Committee and family members of all children patients singed the informed consent.Dexamethasone, vitamin C, β-sodium glycerophosphate, 3-1sobutyl-1-methylxanthine, insulin, indometacin and butylated hydroxyanisole were bought from Sigma Company. Dimethyl sulphoxide was purchased from Amersco Company.METHODS: Bone marrow mesenchymal stem cells were cultured from mononuclear cells isolated over a Percoll gradient.Bone marrow mesenchymal stem cells were observed under an inverted phase contrast microscope. Bone marrow mesenchymal stem cells could differentiate into osteoblasts, adipocytes and neural like cells with osteoblast inductor (β-sodium glycerophosphate, dexamethasone, vitamin C), lipoblast inductor (dexamethasone, 3-isobutyl-1-methylxanthine,bovine insulin, indometacin) and serum-free medium inductor (dimethyl sulphoxide, butylated hydroxyanisole) respectively.Osteoblast marker (alkaline phosphatase, osteocalcin mRNA, calcium node), adipocyte marker (lipid droplet, PPAR γ-2mRNA) and neural ceil-like marker (nissl body, neuron specific enolase, neurofilament protein) were respectively determined by the immunohistochemical method, polymerase chain reaction and immunocytochemical method.MAIN OUTCOME MEASURES: ①Appearance and proliferation of bone marrow mesenchymal stem ceils from children,and ②determination results of osteoblast, adipocyte and neural cell markers.RESULTS: ①Children bone marrow mesenchymal stem cells could easily adhere to the wall, appeared fusiform, had high reproductive activity and arranged vortically after fusing. ②Appearance of bone marrow mesenchymal stem cells changed after receiving inductor. Osteoblast marker, adipocyte marker and neural cell-like marker were positive after chemical staining, polumerase chain reaction and immunocyte staining.CONCLUSION: Children bone marrow mesenchymai stem cells show stable proliferation, passage and multi-direction differentiation towards osteoblasts, adipocytes and neural like cells.