Mesenchymal Stem Cells Differentiate Into Neuron-like Cells In Vitro And Promote Functional Recovery In Rat Middle Cerebral Artery Occlusion Model

The mesenchymal stem cells (MSCs) derived from bone marrow are a cell population with the multipotential ability and self-renewal capacity. Under some specific conditions or circumstances, they can differentiate into many kinds of nonhematopoietic tissues such as osteoblasts, cartilage cells, adipocytes, cadiocytes and neurocytes. Because MSCs can be obtained easily and expanded quickly in vitro, they can be used as the seed cells in cell transplantation for treating the nervous system diseases, thus leasing some new hope for the treatment of the cerebrovascular diseases.Many problems are yet to be solved in MSC's application in the treatment of the nervous system diseases. Remain unclear are themechanism and conditions of the induction and differentiation of MSCs into neuron-like cells, the mechanism of their survival and their involvement in repairing injured tissues, and the most appropriate time for the cell transplantation and the markers of MSC. So is for the best approach of transplantation and the identification of MSCs after cell transplantation.In this study, we isolated mononuclear cells with Percoll density gradient zonal centrifugation from the marrow of 4-week-old rats weighing 120-160 g, and MSCs were then screened by adhesion method and cultured in DMEM supplemented with 15% FBS. MSCs of the 5th generation were induced with lmmol/L beta mercaptoethanol (BME) and serum free media, and the induced cells were then identified with flow cytometry and immunohistochemistry methods. The middle cerebral artery occlusion (MCAO) models with thirty 16-week-old rats weighing 280-320g were set up The models were randomized into three groups and injected intravenously with phosphate-buffered saline (PBS) or 3× 10~6 MSCs labeled with BrdU at 1 or 7 days after MCAO. Behavioral tests were performed before MCAO and every 3 days after MCAO according to Combs DJ's method. Immunofluorescence laser scanning confocal was used to detect the neuron specific enolase (NSE) expression of MSCs transplanted into the rats 28 days after MCAO.Our results showed that MSCs could be cultured and multiplied in vitro. After induction, most of MSCs could differentiate into neuron-like cells, which could survive more than 2 weeks. The rats with early MSCs transplantation after MCAO recovered much more quickly than those with later transplantation and the control. Little difference was found...