超顺磁性氧化铁标记神经干细胞移植入局灶性脑缺血大鼠纹状体的MRI示踪及其对学习记忆的影响

目的 探讨以超顺磁性氧化铁（SPIO）标记的胎鼠神经干细胞（NSCs）移植入局灶性脑缺血大鼠纹状体的MRI示踪及其对学习与记忆的影响。方法 体外培养的胎鼠NSCs用Fe2O3-多聚左旋赖氨酸（Fe2O3-PLL）标记，普鲁士蓝和台盼蓝染色分别检测标记率和细胞活力。将大鼠随机分为A组（正常对照组）、B组（正常标记NSCs移植组）、C组（脑缺血组）、D组（标记NSCs移植组）、E组（未标记NSCs移植组）及F组（灭活标记NSCs移植组）。取C组、D组、E组和F组大鼠制备局灶性脑缺血模型；将标记及未标记的NSCs悬液及灭活的标记NSCs悬液分别定向注射于B组、D组、E组和F组大鼠左侧纹状体内；移植后3d、7d、2周、3周、4周，对A组、C组、D组和E组分别进行Y型电迷宫检测；对B组、D组和F组进行活体MRI示踪扫描；MRI扫描后的大鼠行脑组织切片普鲁士蓝染色，观察移植的NSCs分布。结果NSCs的FeO3-PLL标记率近100％，标记的NSCs细胞活力为95％。与C组比较，D组和E组移植后各时间点大鼠的学习与记忆能力明显改善（均P〈0.05）；MRI显示移植4周后D组移植区低信号影范围较大；脑组织切片可见移植的NSCs沿胼胝体向对侧迁移。结论 Fe2O3-PLL标记不影响NSCs活力；移植NSCs能改善脑缺血大鼠的学习与记忆功能；移植的NSCs可向病灶区迁移。

Magnetic resonance imaging tracking of SPIO-labeled embryonic neural stem cells transplantation into corpus striatum of the focal cerebral ischemia rats and the effects of learning and memory abilities

Objective To explore the magnetic resonance imging tracking of superparamagnetic iron oxid(SPIO) labeled embryonic neural stem cells (NSCs) transplantation into corpus striatum of the focal cerebral ischemia(FCI) rats and the effects of learning and memory abilities.Methods NSCs of embryonic rat were cultured in vitro and labeled with Fe2O3-mediated by poly-L lysine (PLL), with Prussian blue staining to evaluate the labeling rate and Trypan blue staining to observe cell viability of NSCs. The rats were randomly divided into groups A (normal control),B (normal labeled NSCs implanted),C (cerebral ischemia),D( labeled NSCs implanted),E (unlabeled NSCs implanted)and F (inactivated labeled NSCs implanted).The FCI models were made in groups C, D, E, F.The labeled NSCs or unlabeled NSCs or inactivated labeled NSCs were stereotaxically injected into the left corpus striatum of groups B,D,E,F respectively. The abilities of learning and memory were measured by the Y-type electronical maze in groups A, C, D, E after 3 d,7 d,2,3,4 weeks of transplantation respectively. MRI scanning was performed to monitor the NSCs in groups B, D, F at corresponding time. After MRI, the rats were killed and undergone Prussian blue staining of the brain histological section to observe the distribution of implanted NSCs.Results The labeling efficiency rate and cell viability of Fe2O3-PLL labeled NSCs were almost 100% and 95% respectively. Compared with group C, the abilities of learning and memory were significantly improved at each time point after transplantation in groups D, E (all P<0.05).The expanded low signal intensity could be observed at implanted areas by MRI in group D. Prussian blue staining demonstrated the labeled NSCs migrating into opposite side along corpus callosum.Conclusions The viabilities of labeled and unlabeled Fe2O3-PLL NSCs are almost same. The abilities of learning and memory can be improved after transplanted NSCs to FCI rat,and the transplanted NSCs can move to ischemia area.