脑缺血再灌注损伤大鼠尾静脉移植脐带间充质干细胞的安全性*

背景：尾静脉移植干细胞穿过血脑屏障到达宿主脑损伤区域内的具体机制尚不明确。 目的：观察尾静脉移植人脐带间充质干细胞治疗脑缺血再灌注损伤大鼠的效果及安全性,并探讨其作用机制。 方法：通过密度梯度离心法结合贴壁筛选法获取人脐带间充质干细胞并以BrdU标记。Sprague-Dawley大鼠以改良线栓法制作大脑中动脉缺血再灌注模型,移植A组在造模后第7天、移植B组在造模后第14天通过尾静脉移植人脐带间充质干细胞,模型组不做处理。 结果与结论：①移植后7,14,28,35,42,49,56 d,2个移植组mNSS评分低于模型组(P < 0.05)。移植后7,14,28,35,42,49 d,移植A组mNSS评分低于B组(P < 0.05)。模型组在造模后第35天、移植A组在第42天、移植B组在第49天时mNSS评分进入平台期。②2个移植组大鼠脑组织未见到CD11b、MPO单染阳性细胞,可见Brdu+Nestin、Brdu+MAP-2、Brdu +GFAP、Brdu+FⅧ,Brdu+VEGF双染阳性细胞。结果表明人脐带间充质干细胞经尾静脉途径移植可以在宿主脑内存活,通过生成神经元样和神经胶质样细胞、促进新生血管形成并分泌神经营养因子等因素促进大鼠神经功能恢复,且未发现明显免疫排斥反应及异常分化细胞,具有较高的安全性。关键词：尾静脉;细胞移植;人脐带间充质干细胞;脑缺血;大鼠 缩略语注释：hUC-MSCs：human umbilical cord  mesenchymal stem cells,人脐带组织间充质干细胞 doi:10.3969/j.issn.1673-8225.2012.14.023

Tail vein transplantation of human umbilical cord mesenchymal stem cells for treatment of cerebral ischemia-reperfusion injury in rats

BACKGROUND: The specific mechanism of tail vein transplantation of stem cells through the blood-brain barrier to reach the host brain damage region is not clear. OBJECTIVE: To evaluate the safety of tail vein transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) for the treatment of cerebral ischemia-reperfusion injury in Sprague-Dawley (SD) rats and to investigate its possible mechanism. METHODS: hUC-MSCs were isolated using density gradient centrifugation combined with adherent screening method, and then labeled with BrdU. SD rats were used to establish the middle cerebral artery ischemia-reperfusion model with modified suture method. Rats of transplantation group A at 7 days after injury and group B at 14 days were given hUC-MSCs through the tail vein. Rats in the model group were left intact.  RESULTS AND CONCLUSION: (1) The mNSS score of transplantation group A and group B was lower than that of model group after transplantation for 7, 14, 28, 35, 42, 49 and 56 days (P < 0.05), and the mNSS score of transplantation group A was lower than that of transplantation group B after transplantation for 7, 14, 28, 35, 42 and 49 days (P < 0.05). The mNSS score reached the plateau phase at 35 days in model group, 42 days in transplantation group A and 49 days in transplantation group B. (2) Brdu+Nestin, Brdu+microtubule-associated protein 2, Brdu+glial fibrillary acidic protein, Brdu+factor Ⅷ and Brdu+vascular endothelial growth factor immunohistochemical double staining positive cells could be seen at the center of damage site in rats of the group A and group B, there were no CD11b and MPO immunohistochemical single staining positive cells. hUC-MSCs transplantation through tail vein is able to survive in the host brain damage region and improve the recovery of the neural function of ischemic brain injury rats. The mechanism may be related to the transplanted cells differentiating into neuron-like and glial-like cells, which promote the angiogenesis and secret the neurotrophic factors. In this study, no obvious immune rejection and tumor cells were found, and the transplantation has high safety.