干细胞移植治疗大鼠后肢缺血中HIV-Tat-CLIO标记磁共振体内示踪的研究

目的 探讨人类免疫缺陷病毒tat蛋白转导域交连超顺磁氧化铁纳米颗粒(HIV-Tat-CLIO)标记、磁共振成像(MRI)无创体内示踪移植大鼠骨髓间充质干细胞(BMSC)的可行性和有效性.方法 SD人鼠28只,分为4组,每组7只,建立右后肢缺亦模型.A组移植HIV-Tat-CLIO标记的BMSC;B组移植HIV-Tat-CLIO与BrdU复合标记的BMSC;C组移植未标记的BMSC;D组注射无菌磷酸盐缓冲液(PBS).术后MRI示踪移植细胞,评估缺血改善程度,以及组织学检查.结果 B、C组分别死亡2只和1只.A、B组MRI结果相似:术后第3天,注射部位圆形低信号影,1周低信号灶离心性扩散成颗粒状,第2周低密度影进一步扩散,信号强度减弱,第4周信号强度进一步减弱,低密度颗粒扩散范围局限于原部位7 mm处.C、D组MRI阴性.缺血后肢平均皮肤温度、血管造影评分以及毛细血管密度A、B、C组间差异无统计学意义(P>0.05),均显著高于D组(P<0.05).D组的损伤评分明显高于其他3组,其他3组间差异无统计学意义.组织学检查与MRI结果一致.结论 HIV-Tat-CLIO标记、MRI可以有效地体内示踪植入大鼠缺血后肢的BMSC.对BM-SC改善缺血的效果无明显影响.

Magnetic resonance tracking of transplanted bone marrow mesenchysmal stem cells labeled by HIV-Tat-CLIO in rats with the hind limb ischemia

Objective To evaluate the feasibility of in vivo tracking transplanted bone marrow mesenchymal stern sells (BMSC) labeled by HIV transduction domain cross-linked iron oxide (HIV-Tat-CLIO) by magnetic resonance imaging (MRI) in rats with the hind limb ischemia. Methods Twenty-eight SD rats were divided into groups A, B, C, and D (7 each ). One week following the construction of the hind ischemia model ,transplantation at the ischemie thigh via intramuscular injection was conducted as fol-lows: BMSC labeled by HIV-Tat-CLIO alone in group A; BMSC labeled by HIV-Tat-CLIO plus 5-bromode-oxyuridine (BrdU) in group B;non-labeled BMSC in group C; PBS without BMSC in group D. MR1 was performed on the 3rd postoperative day and at 1 st, 2nd, and 4th week respectively, and digital subtraction angiogram (DSA) ,the impaired score of limb function, the skin temperature and histological examinations were performed as well. Results BMSC were positive for CD90, and negative for CD34 and CD45. Three rats in groups B and C died of incision infection or the anesthesia-related cause. MRI detected circular hy- pointense signals at the injection site on the 3rd day after the transplantation ,which gradually dispersed in-to small particles during the following 3 weeks. Four weeks after the transplantation, the skin temperature, the average angiographie score, and the capillary density were significantly higher in groups A, B and C than in group D. As for the impaired score of limb function, group D showed significantly higher values than other 3 groups. Conclusion MRI detection with preoperative HIV-Tat-CLIO labeling appeared to be ef-fective for in vivo tracking transplanted BMSC in rats with the hind limb ischemia.