[Abstract ] Objective To explore the effective method of induction of Schwann cell-like differentiation in bone mesenchymal stem cell (BMSC)of adult rat in vitro.Methods Primary culture of Schwann cell and isolated culture of BMSC were separately conducted.According to different induction methods,the cells were divided into chemical induction group and co-culture induction group.The growth of Schwann cell and BMSC was observed under light microscope.These two kinds of cells were identified by immunofluorescence staining [detecting Schwann cell marker proteins:glial fibrillary acidic protein (GFAP) antibody and S-100 antibody] and flow cytometry.The shape and growth of cells in two groups were dynamically observed by light microscope.The induced differentiation was evaluated with immunofluorescence staining at 3 rd day after co-culture induction in the co-culture induction group and at 4 h and 1 st day after chemical induction in the chemical induction group.Results In the chemical induction group,the BMSC appeared typical Schwann cell-like morphology.The positive expression of GFAP antibody appeared at 4 h after preliminary induction.Meanwhile,the positive expression rate of GFAP and S-100 antibody was (80.9 ± 3.5)% and (59.0 ±1.1 )% at 1 st day after induction.The induced BMSC began to die at 2nd day after chemical induction and most of the induced BMSC had died at 3 rd day after chemical induction.At 3 rd day after co-culture induction,few induced BMSC showed obvious morphological changes like those in chemical induction group.The positive expression rate of GFAP and S-100 antibody was (89.8 ±2.4)% and (80.9 ±1.7)%. The positive expression rate of GFAP and S-100 antibody in the co-culture induction group was higher than those in the chemical induction group and the difference had statistical significance (all in P <0.01).Conclusions The co-culture induction not only has obvious effect on Schwann cell-like differentiation in BMSC,but also promotes the survival and proliferation of BMSC.Thus,co-culture induction is more safe and effective than chemical induction.