[Treatment of stroke in rats with bone marrow mesenchymal stem cells]

To investigate the effects of treatment of stroke in rats with bone marrow mesenchymal stem cells (BMSCs) and mechanism thereof.

Bone marrow of a healthy volunteer was collected and the BMSCs were separated with density gradient centrifugation. The hBMSC were cultivated and harvested until the third passage. A number of adult male Sprague-Dawley rats received corresponding behavioral training before surgery and underwent transient middle cerebral arterial occlusion (MCAO) for 2 hours. Sixty of them showing the scores of 6 approximately 12 according to the modified neurological severity score system were randomly divided into 2 groups: treatment group (n = 48, injected into the cortex around the ischemic areas with hBMSCs 3x10(5)/15 microl) and control group (n = 12, injected with D-Hanks solution 15 microl 24 hours after the establishment of MCAO models. Morris water maze test, Rotarod test and adhesive-removal test were performed since the 4th day to the 32 day after transplantation once every 3 days. 1, 2, 3, and 4 weeks after the transplantation 12 rats from each group were killed randomly to take out their brains. Immunofluorescence was used to identify the migration, survival and differentiation of the hBMSC.

A large number of hBMSC could be seen within 2 weeks after transplantation. The number of hBMSC decreased since the 21st day after transplantation and few cells could be found at the end of 1 month after. No definite evidence supported the differentiation of neural cells derived from the hBMSCs during the whole process. Morris water maze test showed that the mean escape time 1 week after transplantation of the treatment group was (69 +/- 10) s, significantly shorter than that of the control group [(120 +/- 0) s, P < 0.05] The significant difference persisted until the 4(th) week (P > 0.05). Rotarod test with the speed of 10 r/min showed that the mean latency period 10 days after transplantation of the treatment group was (167 +/- 18) s, significantly longer than that of the control group [(37 +/- 19) s, P < 0.05]. The significant difference persisted until the experimental terminal. The adhesive-removal test showed that the mean latency period 13 days after transplantation of the treatment group was (33 +/- 8) s, significant shorter than that of the control group [(84 +/- 13) s, P < 0.05]. The significant difference persisted until the experimental terminal.

Injection of hBMSCs into brain cortex improves neurological functional recovery after stroke. The transplanted cells can migrate and survive for a certain period, but no hBMSC express proteins phenotype of neural cells.