| Mesenchymal stem cells (MSCs) is another kind of tissue stem cell following hematopoietic stem cell. At present, multipotent MSCs have been reported to be present in bone marrow, umbilical cord blood, synovium of joint, fetal blood, fetal liver and connective tissues of skeletal muscle and dermis. Here, we examined the isolation, expansion, committed induction of human bone marrow and umbilical cord blood MSCs in vitro, and also investigated the migration and differentiation of human bone marrow MSCs in vivo, which will provide theoretical foundation and technical method for clinic disease therapy by stem cells.1. Bone marrow MSCs are multipotent tissue stem cells that can be induced in vitro to differentiate into mesenchymal and non-mesenchymal cells. Here, we examined the isolation, purification, expansion and differentiation of human bone marrow MSCs into neurocytes in vitro. Human bone marrow samples were obtained from normal person. Bone marrow mononuclear cells were isolated with 1.073g/mL Percoll. MSCs were obtained by removing the non-adherent cells. MSCs were purified and expanded with Mesencult?medium. 5.0 X 105 primary MSCs were expanded for twelve passages, and 2.3 X 109 MSCs were obtained, and increased about 4.6 X104 folds. FACS results showed that bone marrow MSCs did not express antigens CD34 and CD 11 a, and expressed CD29 and CD71. Passage 2, 6 and 10 of bone marrow MSCs were induced to differentiate into neuroncytes. The results indicated that about 80% cells exhibited typical neuron-like phenotype. Immunohistochemistry staining showed that induced different-passage MSCs expressed neurofilament (NF) and neuron-specific enolase (NSE). Special Nissl bodies were obvious in the neuron-like cells by histochemistry staining. It suggested that humanbone marrow MSCs were capable of expanding rapidly and differentiating into neurocyte in vitro.2. MSCs were found in umbilical cord blood. This study examined the isolation, purification, expansion and differentiation of human umbilical cord blood MSCs to neurocytes in vitro. Umbilical cord blood samples were allowed to drain from the end of the cord into glass bottles with 20U/mL preservative-free heparin. The mononuclear cells were fractionated on a density gradient (Ficoll-Hypaque, 1.077g/mL). MSCs were obtained by removing the non-adherent cells. MSCs were purified and expanded with Mesencult?medium. 6.6 XI0s primary MSCs were expanded for ten passages, and 9.9 X108 MSCs were obtained, which increased about 1.5 X 103 folds. FACS results showed that umbilical cord blood MSCs did not express antigens CD34, CDlla and CDllb, and expressed CD29 and CD71, which was identical to that of human bone marrow-derived MSCs. Passage 2, 5 and 8 of umbilical cord blood MSCs were induced to differentiate into neuroncytes. The results indicated that about 70% of cells exhibited typical neuron-like phenotype. Immunohistochemistry staining revealed that induced different-passage MSCs expressed NF and NSE; Special Nissl body was obvious in the neuron-like cells by histochemistry staining. It suggested that human umbilical cord blood MSCs were capable of expanding rapidly and differentiating into neurocyte in vitro.3. To probe into the differentiation route of MSCs to neurocyte, the specific mark of nerve stem cell, Nestin, was detected by RT-PCR. The result showed that MSCs did not express Nestin, and induced cells expressed Nestin. It suggested that MSCs differentiated firstly into nerve stem cells, and then differentiated into neurocyte.4. To study the physiological function of induced cell, whole-cell recording of induced cell was finished by patch-clamp technique. The results demonstrated that K+ channel current was activated slowly and the extroverted commutation appeared, which were similar to the electrophysiological features of neurons.5. MSCs are excellent seed cells for treating nervous system diseases, damages, genetic defects and degeneration diseases. Here, human MSCs with enhanced green fluorescent protein (EGFP) were injected int...
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