大鼠脂肪干细胞磁性标记及MRI成像研究

目的探索菲立磁和转染试剂体外磁性标记大鼠脂肪干细胞（ADSCs）的可行性。方法从成年大鼠脂肪组织中分离获取ADSCs进行培养传代，用Feridex-多聚左旋赖氨酸（FE—PLL）复合物标记ADSCs，普鲁士兰染色和台盼蓝排除实验等方法鉴定“FE—PLL”标记的ADSCs的效率和细胞活力。同时对“FE—PLL”标记的ADSCs行体内外MRI成像。结果普鲁士蓝染色显示“FE—PLL”标记的ADSCs胞质内出现细小的蓝色铁颗粒，标记率100％。标记ADSCs24h及1、2、3w的台盼蓝拒染率与未标记ADSCs相比较差异无统计学意义（P〉0．05）。体外MRI显示磁标记的ADSCs在T2WI上可使信号明显降低，采用T2WI和T2^＊WI对经立体定向仪移植的标记ADSCs进行活体示踪，二者均可显示MR信号降低，以T2^＊WI最敏感。结论应用Feridex（FE—PLL）复合物标记ADSCs安全、有效；MRI可在活体下无创性示踪ADSCs。

Magnetic labeling and MR imaging of rat adipose tissue-derived stromal cells

Objective To explore the feasibility of Feridex-poly-1-lysine （FE-PLL） complex-labeled adipose-derived stromal cells （ADSCs） in rats. Methods Under the sterile condition, ADSCs were isolated from adult rat adipose tissue and cultured. Feridex-poly-1-lysine complex was used to label ADSCs, prussian blue staining and typan-blue exclusion test were used to evaluate the labeling efficiency of FE-PLL complex labeled ADSCs and cell viability, respectively. Meanwhile MR imaging was performed for cell suspensions and in vivo tracing of labeled ADSCs after transplantation into rat brain. Results Numerous intracytoplastic iron particles were stained with prussian blue. Typan-blue exclusion test showed that the viability of the labeled cells after labeling had no significant difference to that of non-labeled cells at 24 h, 1 w , 2 w and 3 w （P〉0.05）. In vitro MRI showed the suspension of labeled ADSCs by FE-PLL complex made T2 signal intensity decrease significantly. The implanted labeled ADSCs were both visible on T2WI and T2^ ＊WI as a hypointense area at the injection site, and T2 ^＊ WI was the most sensitive sequence to detect the labeled cells. Conclusion Magnetic labeling of rat ADSCs with FE-PLL complex is safe and efficient and MRI can trace the labeled ADSCs in vivo after transplantation.