多聚左旋赖氨酸协同超顺磁性氧化铁标记大鼠C6脑胶质瘤细胞

Labeling of C6 rat glioma cells with poly-L-lysine and super paramagnetic iron oxide particles

目的 观察多聚左旋赖氨酸（PLL）协同超顺磁性氧化铁（SPIO）对大鼠C6胶质瘤细胞的标记率及对标记细胞生物活性的影响.方法 将未标记的C6胶质瘤细胞设为对照组,25 mg/L SPIO（A组）、25mg,LSPIO＋0.75mg,LPLL（B组）、50mg,LSPIO＋1.5mg,LPLL（C组）标记的C6胶质瘤细胞设为实验组.各组细胞处理后分别培养6、24及48 h进行MTS细胞活性检测;普鲁士蓝染色评定标记率;3.0 T MRI GRE/30° T2＊WI序列对各组细胞体外成像,比较R2＊值及信号强度差异.结果 各实验组细胞处理后48 h均未见细胞活性显著降低（均P〉0.05）.普鲁士蓝染色显示B组、C组细胞标记率均达到98%以上,而A组约为70%,SPIO与PLL混合标记细胞随SPIO浓度增高染色程度逐渐加深.3.0T MRI体外细胞成像对标记细胞有较敏感的信号变化,对照组及A、B、C组R2＊值分别为11.76±5.74、12.13±4.39、61.22±27.85、90.07±35.59,对照组与A组间R2＊值差异无统计学意义（P〉0.05）;B、C组分别与其它各组间比较差异均有统计学意义,且此两组之间差异亦有统计学意义（均P〈0.01）.结论 PLL可增强SPIO对C6脑胶质瘤细胞的标记作用并对标记细胞活性未产生明显影响.3.0T MRI GRE/30°T2＊WI序列对离体标记细胞有较敏感的信号变化,R2＊值随着细胞内SPIO浓度的增加而增大.25 mg/L SPIO＋0.75 mg,L PLL可获得满意的体外标记效果.

Objective To investigate the labeling rate with poly-L-lysine （PLL） and super paramagnetic iron oxide particles （SPIO） for C6 rat glioma cells and the impact of PLL and SPIO on labeled cell bioactivity. Methods C6 rat glioma cells were incubated without SPIO or PLL （control group）, with 25 mg/L SPIO （group A）, 25 mg/L SPIO＋0.75 mg/L PLL （group B）, and 50 mg/L SPIO＋1.5 mg/L PLL （group C） , respectively. The labeled cell bioactivity was analyzed by MTS assay （mono-nuclear cell direct cvtotoxicity assay） at different incubation time （6, 24 and 48 h） after treatment, and the labeling rate was detected by Prussian Blue staining. The labeled cells mass were imaged in vitro using a 3.0 T MRI scanner with GRE/30° T2＊WI sequence. The R2＊ values and signal intensity were compared among these groups. Results Up to 48 h post-labeling, there was no significant decrease of cell bioactivity in all labeled cell groups （all P〉0.05）. Prussian Blue staining showed that the labeling rate was 〉98% in group B and C compared with about 70% in group A. The staining appeared increasingly darker in SPIO/PLL mixed labeled cells along with higher concentration of SPIO. 3.0 T MRI was signal-sensitive for the labeled cells. The R2＊ values were 11.76±5.74, 12.13±4.39, 61.22±27.85 and 90.07±35.59 for control group and group A, B and C, respectively. Difference of R2＊ value was not found between control group and group A （P〉0.05）, but was found between group B and C, meanwhile R＊ values of group B and C were significantly different with control group and group A （all P〈0.01）. Conclusions PLL may enhance the efficiency of SPIO labeling for C6 glioma cells and has no significant impact on the cell bioactivity. 3.0 T MRI with GRE/30° T2＊WI sequence is signal-sensitive for labeled cells in vitro. The R2＊ value may increase along with intracellular SPIO level. 25 mg/L SPIO＋0.75 mg/L PLL may yield satisfactory labeling for rat C6 glioma cells in vitro.