BMSC定向分化为神经干样细胞后移植改善脊髓损伤大鼠的神经功能

目的 研究骨髓间充质干细胞(BMSC)定向分化为神经干样细胞后进行移植,改善脊髓损伤大鼠神经功能的作用及其机制,探讨适宜的移植时间.方法 取培养至第3代的BMSC,将其定向分化为神经干样细胞,并采用免疫荧光染色法进行鉴定.移植前用5溴2脱氧尿嘧啶核苷(BrdU)标记细胞,移植时将其缓慢输注到损伤部位.实验分3组,移植Ⅰ组和移植Ⅱ组分别于脊髓损伤后1和2周进行移植,对照组操作同移植Ⅰ组,仅将移植用细胞悬液改为等量的生理盐水.移植后1~6周,对各组大鼠进行运动功能评分,采用荧光免疫化学染色检测移植细胞的存活、分化及神经纤维再生的情况.采用HE染色观察脊髓损伤区的病理学改变.结果 BMSC诱导培养3 d后,神经巢蛋白呈阳性表达,将诱导后的细胞球继续培养,可见细胞均有不同程度的神经丝蛋白(NF200)及胶质纤维酸性蛋白(GFAP)阳性表达.移植后两移植组大鼠的运动功能评分均显著高于对照组(P＜0.05),移植Ⅰ组尤为明显.2个移植组均有大量的5溴2脱氧尿嘧啶核苷(BrdU)和神经巢蛋白双阳性细胞及部分BrdU和NF200双阳性细胞填充于脊髓损伤区,同时可见明显的神经纤维再生,脊髓损伤处的空洞面积明显小于对照组(P＜0.05),而移植I组神经功能的改善较移植Ⅱ组更加明显.结论 BMSC可定向诱导、分化为神经干样细胞,将其移植后可有效改善脊髓损伤大鼠的神经功能,脊髓损伤1周后的移植效果优于损伤2周后移植.

Abstract：

Objective To study the effect and mechanism of the neurological function recovery in rats with spinal cord injury (SCI) rats after the transplantation of neural stem cells which are directly differentiated from bone marrow mesenchymal stem cells (BMSC), and to investigate the suitable engraftment time.Methods The BMSC at 3rd passage were differentiated into neural stem cells (NSC), and immunofluorescence staining was used to identify the NSC. The oriented-induced cells were labeled with Brdu 3 days before they were transplanted, and they were slowly injected into the injured site of the SCI rats. The SCI rats were randomly divided into group Ⅰ (transplantation at first week postinjury), group Ⅱ (transplantation at 2nd week postinjury) and control group (the operation was the same as group Ⅰ, but the cell suspension was replaced by the equal volume of normal saline). The BBB scores after transplantation were recorded. The distribution and differentiation of transplanted cells were observed by using immunofluorescence staining with antibodies against Brdu combined with Nestion and Brdu combined with NF200. NF200 immunofluorescence staining was used to show the regeneration of nerve fibers. The pathological changes of the injured site were observed by HE staining.Results The nestin expression was positive after the BMSC were differentiated for 3 days, and if the induced spherical cells were cultured continuously, the different levels of NF200 and GFAP were found. BBB scores in group Ⅰ and group Ⅱ were significantly higher than in control group (P<0.05), especially in group Ⅰ. The immunofluorescence showed that a large number of Brdu and Nestin double-positive cells and some Brdu and NF200 double-positive cells filled the injured site and linked the two sides of the injured area in group Ⅰ and group Ⅱ, and the lesion area of the spinal cord was reduced as compared with control group (P<0.05). More importantly, further reduction in lesion area and improvement in neurological function were observed in group Ⅰ.Conclusion The BMSC can be differentiated into NSC. The transplantation of the NSC could effectively promote the nerve function recovery after SCI, and the effect of transplantation at first week postinjury was better than at 2nd week postinjury.

Improvement of neurological function in rats with spinal cord injury after the transplantation of neural stem cells directly differentiated from bone marrow mesenchymal stem cells

Objective To study the effect and mechanism of the neurological function recovery in rats with spinal cord injury (SCI) rats after the transplantation of neural stem cells which are directly differentiated from bone marrow mesenchymal stem cells (BMSC), and to investigate the suitable engraftment time.Methods The BMSC at 3rd passage were differentiated into neural stem cells (NSC), and immunofluorescence staining was used to identify the NSC. The oriented-induced cells were labeled with Brdu 3 days before they were transplanted, and they were slowly injected into the injured site of the SCI rats. The SCI rats were randomly divided into group Ⅰ (transplantation at first week postinjury), group Ⅱ (transplantation at 2nd week postinjury) and control group (the operation was the same as group Ⅰ, but the cell suspension was replaced by the equal volume of normal saline). The BBB scores after transplantation were recorded. The distribution and differentiation of transplanted cells were observed by using immunofluorescence staining with antibodies against Brdu combined with Nestion and Brdu combined with NF200. NF200 immunofluorescence staining was used to show the regeneration of nerve fibers. The pathological changes of the injured site were observed by HE staining.Results The nestin expression was positive after the BMSC were differentiated for 3 days, and if the induced spherical cells were cultured continuously, the different levels of NF200 and GFAP were found. BBB scores in group Ⅰ and group Ⅱ were significantly higher than in control group (P<0.05), especially in group Ⅰ. The immunofluorescence showed that a large number of Brdu and Nestin double-positive cells and some Brdu and NF200 double-positive cells filled the injured site and linked the two sides of the injured area in group Ⅰ and group Ⅱ, and the lesion area of the spinal cord was reduced as compared with control group (P<0.05). More importantly, further reduction in lesion area and improvement in neurological function were observed in group Ⅰ.Conclusion The BMSC can be differentiated into NSC. The transplantation of the NSC could effectively promote the nerve function recovery after SCI, and the effect of transplantation at first week postinjury was better than at 2nd week postinjury.