骨髓间充质干细胞不同移植途径治疗大鼠脊髓损伤的比较

背景：在适当的生长环境下，中枢神经系统内的一些受损的神经元轴突有少许再生，并能与靶细胞形成功能性的突触联系。 目的：比较局部注射和尾静脉注射途径移植骨髓间充质干细胞对大鼠脊髓损伤神经功能恢复的作用。 设计、时间及地点：细胞组织学对照观察，于2007-03/2008-04在承德医学院完成。 材料：健康成年雄性SD大鼠40只，由解放军军事医学科学院动物中心（北京）提供。 方法：取4只大鼠，采用密度梯度离心法和贴壁法体外分离培养骨髓间充质干细胞，传至第2代于临用前24 h行BrdU标记。余36只大鼠均建立T12脊髓损伤模型，1周后随机分为3组，局部注射组于损伤部位上下位点注射1×106个骨髓间充质干细胞至损伤大鼠体内；尾静脉注射组通过尾静脉移植等量骨髓间充质干细胞至损伤大鼠体内；模型对照组不行细胞移植。 主要观察指标：神经功能缺损BBB评分，苏木精-伊红染色病理学检测，细胞分化免疫组化染色结果。 结果：细胞移植后2，4，6周，模型对照组神经功能缺损BBB评分均显著低于局部注射组、尾静脉注射组（F=721.373，F=1 114.450，F=1 004.099，P均 < 0.01）；局部注射组神经功能缺损BBB评分均显著高于尾静脉注射组（t=55.261，t=71.385，t=78.135，P均 < 0.01）。苏木精-伊红染色结果显示，模型对照组损伤脊髓组织有较多空腔，横断处形成大量空泡；局部注射组无明显空腔，空泡小而少，间质水肿较轻。移植后4，6周，部分植入的骨髓间充质干细胞呈微管相关蛋白2及胶质纤维酸性蛋白双阳性表达。 结论：局部注射和尾静脉注射两种途径移植的骨髓间充质干细胞均可在脊髓损伤处存活、分化并改善神经功能，且局部注射的效果优于尾静脉注射。

Comparison of various mesenchymal stem cell transplantation pathways for treatment of spinal cord injury in rats

BACKGROUND: Under a suitable growth environment, regeneration appeared in some injured neuronal axons in the central nervous system, which can form functional synaptic correlation with target cells. OBJECTIVE: To compare effects of bone marrow mesenchymal stem cell transplantation on the recovery of neurological function in rats with spinal cord injury. DESIGN, TIME AND SETTING: The cytohistology controlled study was conducted at the Chengde Medical College from March 2007 to April 2008. MATERIALS: A total of 40 healthy adult male Sprague Dawley rats were obtained from the Animal Center, Academy of Military Medical Sciences of Chinese PLA. METHODS: Bone marrow mesenchymal stem cells (BMSCs) were isolated from four rats, and cultivated in vitro using the density gradient centrifugation and the adherence in vitro separation. At the second passage, BMSCs were labeled with BrdU at 24 hours before use. The remaining 36 rats were employed to establish the T12 spinal cord injury models. Following 1 week, rats were randomly assigned into 3 groups. 1×106 BMSCs were infused into the upper and lower injured region in the local injection group. 1×106 BMSCs were injected into rats in the caudal vein injection group. Rats in the model control group did not undergo cell transplantation. MAIN OUTCOME MEASURES: Basso Beattie Bresnahan (BBB) was used to detect neurologic impairment. Pathological changes were observed using hematoxylin-eosin staining. Cell differentiation was observed utilizing immunohistochemistry. RESULTS: At 2, 4 and 6 weeks following cell transplantation, BBB score was significantly lower in the model control group than in the local injection and the caudal vein injection group (F=721.373, F=1 114.450, F=1004.099, P < 0.01). BBB score was significantly higher in the local injection group than in the caudal vein injection group (t=55.261, t=71.385, t=78.135, P < 0.01). Hematoxylin-eosin staining demonstrated many cavities and plenty of vacuole in spinal cord tissues in the model control group. No cavities, small and few vacuoles and slightly interstitial edema were detected in the local injection group. At 4 and 6 weeks after transplantation, microtubule-associated protein-2 and glial fibrillary acidic protein were positively expressed in some implanted BMSCs. CONCLUSION: Transplanted BMSCs via local injection and caudal vein injection can survive and differentiate at injured area of the spinal cord and can improve neurological function. Therapeutic efficacy via local injection is better than via the caudal vein injection.