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目的:探讨经静脉间充质干细胞(MSCs)移植对大鼠脑梗死体积的影响以及其向神经元细胞的转化和定向迁移情况。方法:对同种异体SD大鼠的MSCs进行体外分离、培养。应用大脑中动脉线栓栓塞法(MCAO)制作大鼠脑梗死模型。应用TTC染色法测定大鼠脑梗死体积。将SD大鼠分为MSCs静脉移植组和对照组。应用免疫组化法在梗死后测定NSE、NF-M和GFAP的表达。电子显微镜观察各组大鼠脑组织突触超微结构。结果:与对照组相比,经静脉MSCs移植可以减小缺血再灌注大鼠的脑梗死体积。经静脉移植MSCs2周后神经元样细胞的NSE、NF-M染色为阳性。而未分化的MSCs为阴性。GFAP染色为阴性。MSCs组和对照组电镜可见部分突触肿胀,微管和微丝断裂、排列紊乱,有些突起内见有絮状物,突触前膜和突触后膜肿胀,突触间隙模糊不清。和对照组相比,MSCs组突触界面曲率、突触后致密物质的厚度较大、突触间隙宽度较窄、突触活性带长度较长。结论:实验结果证明脉移植MSCs可以减小大鼠脑梗死体积,经静脉移植MSCs可定向迁移至脑梗死去并可向神经元转化,但并不转化为神经胶质细胞。此外静脉移植间充质干细胞可减轻神经元突触超微结构的损伤性改变,进一步证明了经静脉移植间充质干细胞对脑梗死的治疗作用。
Objective: To investigate the effect of transplanted mesenchymal stem cells (MSCs) on cerebral infarction volume and its transformation to neuronal cells and its directional migration. Methods: MSCs of SD rats were isolated and cultured in vitro. A rat model of cerebral infarction was established by middle cerebral artery occlusion (MCAO). The volume of cerebral infarction in rats was determined by TTC staining. SD rats were divided into MSCs vein graft group and control group. Immunohistochemistry was used to determine the expression of NSE, NF-M and GFAP after infarction. The ultrastructure of synapse in brain of each group was observed by electron microscope. Results: Compared with the control group, transvenous MSCs transplantation can reduce the volume of cerebral infarction in ischemia-reperfusion rats. NSE and NF-M staining of neuron-like cells after 2 weeks of MSCs transplanted were positive. While undifferentiated MSCs were negative. GFAP staining is negative. Electron microscopy showed some synapses were swollen in the MSCs group and the control group. The microtubules and the microfilaments were broken and disordered. Some of the protuberances were swollen in some protuberances. The synaptic and postsynaptic membranes swell and the synaptic cleft was blurred. Compared with the control group, the curvature of the synaptic interface, the thickness of the postsynaptic dense material, the narrow synaptic cleft width and the length of the synaptic active band in the MSCs group were longer. Conclusion: The experimental results show that MSCs transplanted can reduce the volume of cerebral infarction in rat. MSCs can be transplanted to cerebral infarction and transplanted into neurons, but not into glial cells. In addition, intravenous transplantation of mesenchymal stem cells can reduce the damage of synaptic ultrastructure of neurons, further demonstrating the therapeutic effect of intravenous transplantation of mesenchymal stem cells on cerebral infarction.