Objective To explore the mechanisms that bone marrow derived-multipotent adult progenitor cells (MAPCs) transplant into the brain and differentiated into neuron cells reduce neurological functional deficits in rats.Methods We establish successfully rat models of parkinson' s disease,sequentially,we injected MAPCs into left striatum,for cellular identification,MAPCs were prelabeled with bromodeoxyuridine(BrdUrd).By three months post-injection,behavioral tests,immuno-fluorescence method,reverse transcription-polymerase chain reaction (RT-PCR) were used to evaluate and analyze that MAPCs differentiate into neuron-like cells and how MAPCs restore cerebral function.Results Compared with control animals,MAPCs-derived DA neurons caused gradual and sustained behavioral restoration of DA-mediated motor asymmetry.at the 4th/8th/12th week after cell transplantation,the rotation turns within 1 hour of control group were 687.8 ±2.7,754.1 ± 13.4,763.2 ± 14.8 respectively,while that of MAPCs group were 528.0 ± 12.7,440.5 ± 12.0,435.0 ± 7.1 respectively ( P ＜ 0.05 ).After implantation,MAPCs could survive and differentiate into neuron-like cells in substantia nigra and striatum,including dopamine-neurons.Real-time PCR revealed significantly higher DBH ( 1.64-fold increase),DAT ( 1.55-fold increase) and NGF ( 1.77-fold increase) mRNA levels in the MAPCs group,which suggested MAPCs derived neurons could performed the function of dopamine neurons.Conclusion These results demonstrate that transplanted MAPCs can develop spontaneously into DA neurons.Such DA neurons can restore cerebral function and behavior in rat models of Parkinson' s disease.