Directional differentiation of bone marrow mesenchymal stem cells into oligodendrocytes induced by the combination of various neurotrophic factors / 中国组织工程研究

ABSTRACT

BACKGROUND: Myelination following axonal regeneration is a key factor affecting the recovery of spinal cord injury. Oligodendrocyte survival directly affects the myelination following axonal regeneration. OBJECTIVE: To investigate the feasibility of differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into oligodendrocytes induced by neurotrophic factors. DESIGN, TIME AND SETTING: The cell molecular biology in vitro study was performed at the Laboratory of Department of Orthopaedics, Tongji Hospital from September 2006 to June 2007. MATERIALS A total of 5 Sprague Dawley rats aged 2-4 weeks, of both gender were selected. Bilateral femur and tibia bone marrow was obtained to harvest BMSCs. METHODS: At passage 4, BMSCs were incubated in serum-free medium, supplemented with N2, 20 ng/mL basic fibroblast growth factor, 20 ng/mL epidermal growth factor for 48 hours, and incubated in medium containing 500 ng/mL insulin-like growth factor I and N2 for 3 days. MAIN OUTCOME MEASURES: Morphological changes were observed using an phase contrast microscope. Semiquantitative RT-PCR was utilized to detect specific marker mRNA expression of oligodendrocytes. Using neuron marker anti-microtubule-associated protein, astrocyte marker anti-glial fibrillary acidic protein, oligodendrocyte marker anti-galactocerebroside, anti-myelin basic protein antibody, immunocytochemical staining was performed to detect the positive rate of the differentiation of BMSCs into oligodendrocytes. RESULTS: Morphological changes in BMSCs during the differentiation into oligodendrocytes After the induction, a majority of BMSCs presented the morphological characteristics of oligodendrocytes. Cytoplasm retraction towards nucleus, cell process extension towards outwards, and strong refraction were found. With the prolongation of time, several cell processes connected and formed a typical net-shape structure. Specific marker mRNA expression of oligodendrocytes Following induction, specific strap of myelin basic protein mRNA and galactocerebroside mRNA could be detected. Positive rate of oligodendrocytes During induction, the positive rates of galactocarebroside, myelin basic protein and microtubule-associated protein were 65%, 45% and 10%, respectively. CONCLUSION: The combination of epidermal growth factor, basic fibroblast growth factor and insulin-like growth factor can effectively promote the directional differentiation of BMSCs into oligodendrocytes.