Abstract: Objective: To observe the role of purified mesenchymal stem cells (MSCs) derived from fetal blood on the neurological function in rats with middle cerebral artery occlusion (MCAO). Methods: Thirty adult male Wistar rats were randomly divided into three groups: the operation group, the transplantation of MSCs group and the injection of saline group. Functional outcome measurements were performed based on the modified neurological severity score(mNSS) at day 1, 7, 14, 21 and 28 after MACO. The survival, migration, expression of Nestin, glial fibriliary acidic protein (GFAP) and neuronspecific enolase(NSE) of 5bromo2deoxyuridine（BrdU）-labeled MSCs were detected by immunohistochemical double staining. Results: MSCs from the fetal blood had a powerful proliferation ability. MSCs significantly improved the neurological function (P<0.05). The engrafted cells survived and migrated to the ischemic tissues. (2.88±0.76) %， (5.24±1.06)% and (1.34±1.29)% of the MSCs respectively expressed Nestin, GFAP and NSE. Conclusion: After proliferation and purification, the MSCs in the fetal blood greatly improved the neuro logical function in rats with cerebral ischemia, meanwhile they may survive, migrate and differentiate into astrocytes or neurons.

Key words: Fetal blood, Stem cells, Hypoxiaischemia, brain, Transplantation, Rats, wistar