Abstract:

To study the expression and variety of nerve growth factor （NGF） and it＇s receptor in differentiation from mesenchymal stem cells （MSCs） into neuron-like cells and explore a mechanism of the differentiation of MSCs into neurons. METHODS：The experiment was carried out in the Center Laboratory and Modality Laboratory of North China Coal Medical University between October 2005 and August 2006. MSCs were harvested from healthy adult SD rats for passage. The fifth generation MSCs were collected and pre-induced in pre-induction liquor containing L-DMEM, 1 mmol/L β-mercaptoethanol and 20% FBS. 24 hours later, MSCs were cultured with induction liquor containing L-DMEM and 5 mmol/L β-mercaptoethanol for 5 hours after removing pre-induction liquor. Cell morphology was observed under inverted phase contrast microscope. The differentiated cells were identified with immunochemical methods. Nissl＇s body was stained with toluidine blue, and then observed and photographed under light microscope. MSCs were measured by immunohistochemical method before and after induction, and mRNA of the cells was isolated before and after induction. The expression of NGF and TrkA mRNA were measured by reverse transcription polymerase chain reaction （RT-PCR）. RESULTS：①Culture of MSCs： MSCs grew well and adhered to the flask wall. Most showed long fusiformm Cells after passage had similar form as primary cells and grew rapidly.②Differentiation of MSCs： MSCs were deflated, stereo and irregular, and partial cells had thin digitations, of which about 2% cells became ball-like shape and had short prominence, like neurons. 5 hours later, MSCs differentiation reached the peak, and the cells did not change obviously, and showed typical neuron shape. Immunocytochemical detection showed that neuronspecific enolase and glial fibdllary acidic protein were positive.③Nissl＇s body was not found in non-induced MSCs. 5 hours after induction, most cells were positively stained, and dark blue granulo-Nissl＇s body in kytoplasm.④NGF and TrkA mRNA by RT-PCR： The NGF and TrkA mRNA could be detected in MSCs before and after induction, the expression of NGF mRNA had no change, on the contrary, the TrkA mRNA decreased after induction （P 〈 0.05）. CONCLUSION：①MSCs are differentiated into neuron-like cells successfully, and the MSCs express the NGF and TrkA mRNA before and after differentiating into neuron-like cells.②The NGF mRNA express steadily, but the TrkAmRNA decrease after differentiation, and the path of NGF/TrkA may take part in the differentiation of the MSCs into neuron-like cells.[著者文摘]