Differentiation of bone marrow mesenchymal stem cells transplanted into the brain in rats with cerebral infarction and its effect on the recovery of nerve functions / 中国组织工程研究

ABSTRACT

BACKGROUND: The study about the multiple differentiation potentials of the mesenchymal stem cells is still on the stage of the animal experimentation. Can mesenchymal stem cells have the ability to differentiate into certain tissues and develop the corresponding functions after they are transplanted into certain tissues?OBJECTIVE: To observe the differentiation of the bone marrow mesenchymal stem cells into the nerve and its effect on the nerve functional recovery after they are transplanted into the peripheral zone of the ischemic infarction focus of the cerebral cortex.DESIGN: A randomized controlled study.SETTING: The Department of Anatomy of the School of Basic Medical College of Sun Yat-sen University; the Department of Neurology of the First Hospital of Sun Yat-sen University; Department of Pathology of the Medical College of Jinan University.MATERIALS The experiment was conducted at the Medical College of Sun Yat-sen University from November 2002 to November 2003. Forty-eight male SD rats were chosen and randomly divided into two groups, with 32 rats in cerebral infarction model group and 16 in the non-model control group. In the cerebral infarction group, the rats were randomly divided again into two groups 16 rats in the transplantation group and 16 in the phosphate buffered fluid group. The anterior fontanel taken as the reference point, 5 μL(5 × 104 L-1) of the bone marrow mesenchymal stem cells or the phosphate buffered fluid was respectively transplanted at the site 3 mm away on the caudal side and 1.5 mm aside at the depth of 2. 0 - 3. 0 mm.METHODS: The bone marrow mesenchymal stem cells were obtained through the separation and purification of the bone marrow of the ribs taken away in the thoracic surgery from the patients without the hematological diseases, and then the cells underwent in vitro culture, the amplification and the identification. At the 2nd and 6t1 weekend after the transplantation,the rats of every group were anesthetized, and the samples were taken from the transplantation site and made into the 25 μm of continuous frozen section. Then, the immunohistochemical method was used for the detection of the expressions of neuron specific enolase, neurofibril protein, glial fibrillary acidic protein, and nidogen to evaluate the ability of the bone marrow mesenchymal stem cells to differentiate into neurons and glial cells. Eight rats of the transplantation group and 8 rats of the phosphate buffered fluid group were randomly taken out, and 2 and 6 weeks before and after the transplantation the bar walking test evaluation method was used to identify the general status and reaction ability of the rats. Sixteen rats of the control group were assessed at the same time.enolase, neurofibril protein, glial fibrillary acidic protein and nidogen in the bar walking test.2nd weekend after the transplantation, there were positive expressions of glial fibrillary acidic protein and nidogen at the transplantation site of the bone marrow mesenchymal stem cells. At the 6th weekend there were positive expressions of neuron specific enolase and neurofibril protein at the transplantation site of the bone marrow mesenchymal stem cells. While in the phosphate buffered fluid group, there were negative expressions of neuron specific enolase, neurofibril protein, glial fibrillary acidic protein and nidosymptoms in the control group and the evaluation scores were all 9. 2 weeks after the transplantation, and the evaluation scores of the motor function in the transplantation group were higher than the ones in the phosphate buffered fluid group, [(6.7±0.9), (5.3-±1.0), (P ＜0.05)]. Six weeks after the transplantation, the evaluation scores of the motor function in the transplantation group were also higher than those in the phosphate buffered fluid group[(8.9±1. 1),(7.2±0.8),(P ＜0.05)].CONCLUSION: After their transplantation into the central nervous system,the bone marrow mesenchymal stem cells showed the ability to differentiate into neurons and glial cells, in which the characteristics of some neurons and glial cells were found. Bar walking test found that the evaluation scores of the motor function in the transplantation group were higher than those in the phosphate buffered fluid group, which suggests that the bone marrow mesenchymal stem cells have a significant effect on restoration of the functions of the nerves.