Laboratory of Molecular Imaging, Department of Radiology, Zhongda Hospital, Southeast University, Nanjing, China.
Invest Radiol. 2010 Oct;45(10):625-33. doi: 10.1097/RLI.0b013e3181ed55f4.
It was unclear whether systemically administered mesenchymal stem cells (MSCs) labeled with magnetic nanoparticles can transdifferentiate into hepatocytes. In the present study, we built a new in vivo murine model for monitoring the transdifferentiation of magnetically labeled green fluorescent protein (GFP) positive MSCs into albumin-positive hepatocytes, under the carbon tetrachloride (CCl4) induced persistent liver damage. We also tracked magnetically labeled MSCs by using magnetic resonance imaging (MRI) in vivo.
Among the liver damage groups, magnetically labeled GFP-positive MSCs (group A), GFP-positive MSCs (group B), and saline alone (group C) were intravenously injected. In control groups without CCl4 administration magnetically labeled GFP-positive MSCs (group D) were infused, whereas nothing was given in group E. MRI examinations were performed 24 hours and 4 weeks after cell injection in group A, B, and C. Liver-to-muscle contrast-to-noise ratios on T2*-weighted MR images were measured. At 4 weeks, 3 serum biologic liver function markers were analyzed, and mice in all groups were killed for histologic examination.
The results showed that migration of transplanted magnetic labeled cells to the liver was successfully documented with in vivo MRI. Serum liver function markers were changed for all liver damage groups than nondamage control groups (P < 0.05), but still insignificant compared with group C (P > 0.05). Hematoxylin and eosin and Masson staining confirmed the presence of liver damage and hepatic fibrosis in group A, B, and C. Positive Prussian blue stained cells were highly correlated with GFP-positive cells in group A with an average matching rate of 95%. In group D, no iron-GFP-positive cells can be found in the liver. Albumin was expressed in (34% ± 6%) and (35% ± 7%) of GFP-positive cells in group A and B, respectively, and there was no significant difference between the 2 groups.
Our data demonstrate that magnetic labeling technique synchronized well in GFP expressing MSCs and did not interfere with the transdifferentiation process and amending function of MSCs in vivo. Both magnetically labeled and unlabeled MSCs appeared to have the potential to differentiate into hepatocytes.
目前尚不清楚经全身给药的磁纳米颗粒标记间充质干细胞（MSCs）是否能转分化为肝细胞。在本研究中，我们构建了一种新的体内小鼠模型，用于监测在四氯化碳（CCl4）诱导的持续性肝损伤下，磁性标记的绿色荧光蛋白（GFP）阳性 MSCs 向白蛋白阳性肝细胞的转分化，并通过体内磁共振成像（MRI）进行跟踪。
在肝损伤组中，静脉注射磁性标记的 GFP 阳性 MSCs（A 组）、GFP 阳性 MSCs（B 组）和单纯生理盐水（C 组）。在未给予 CCl4 处理的对照组中，静脉注射磁性标记的 GFP 阳性 MSCs（D 组），而 E 组则不给予任何处理。在 A、B 和 C 组，在细胞注射后 24 小时和 4 周进行 MRI 检查。测量 T2*-加权 MR 图像上肝与肌肉的对比噪声比。4 周后，分析所有组的 3 种血清生物学肝功能标志物，并处死所有组的小鼠进行组织学检查。
结果显示，体内 MRI 成功记录了移植的磁性标记细胞向肝脏的迁移。与非损伤对照组相比，所有肝损伤组的血清肝功能标志物均发生改变（P<0.05），但与 C 组相比仍无显著差异（P>0.05）。苏木精和伊红及 Masson 染色证实 A、B 和 C 组存在肝损伤和肝纤维化。普鲁士蓝染色阳性细胞与 A 组 GFP 阳性细胞高度相关，平均匹配率为 95%。在 D 组中，肝脏中未发现铁-GFP 阳性细胞。A 组和 B 组中分别有（34%±6%）和（35%±7%）的 GFP 阳性细胞表达白蛋白，两组之间无显著差异。
我们的数据表明，磁性标记技术与表达 GFP 的 MSCs 同步良好，且不会干扰 MSCs 的体内转分化过程和修复功能。磁性标记和非标记 MSCs 似乎都有分化为肝细胞的潜力。
