磁性靶向材料介导骨髓间充质干细胞经静脉移植修复梗死心肌

Study on Recovery of Bone Myocardial Infarction by Intravenously Delivering Mesenchymal Stem Cell Using Magnetic Targeting Material Fe3O4-UA-g-P(UA-co-AA)

目的探讨用磁性靶向材料介导骨髓间充质干细胞(MSCs)经静脉移植时到达心肌梗死部位的程度以及对心肌梗死修复的影响。方法取体外扩增的第4代MSCs,先测定MSCs的表面标记,用含10μmol的5-氮杂胞苷诱导后,将MSCs细胞核DAPI(4,6-联脒-2-苯基吲哚)染色后备用移植。将28只SD大鼠分为3组,A组:10只,磁性靶向材料和MSCs接触结合后经大鼠尾静脉移植,将磁石接触心肌梗死部位皮肤表面30min后继续饲养;B组:9只,未与磁性靶向材料结合的MSCs经大鼠尾静脉移植;C组:9只,将MSCs直接移植心肌梗死部位。于移植2d后检查MSCs在梗死部位聚集的情况,30d后检查心肌梗死部位的功能及形态的改变。结果在透射电子显微镜下观察可见3～5个磁性靶向材料分子和MSCs的细胞膜结合。A组MSCs归巢率为38%,B组6%,C组53%,A组和C组聚集MSC数目明显多于B组(P<0.01)。A组和C组移植后左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)较移植前明显改善(LVEF46%±6%vs.38%±8%,51%±5%vs.35%±4%;LVFS28%±6%vs.20%±7%,32%±4%vs.20%±5%,P<0.05);光学显微镜下观察梗死心肌内均可找到标记DAPI的移植细胞。B组移植后左心室收缩功能各项指标无明显改善,光学显微镜下在梗死心肌内未找到标记了DAPI的移植细胞(MSCs归巢率为38%)。C组与A组结果比较差异无统计学意义,但实验过程中死亡率较高。结论磁性靶向材料介导MSCs经静脉移植方法能聚集更多的MSCs于梗死心肌部位,减小梗死区面积,有效改善心肌梗死后的心功能。

Objective To investigate the extent intravenously transplantation of mesenchymal stem cells （MSCs） mediated by magnetic targeting material arrive in the myocardial infarction region and its effects on the recovery of myocardial infarction. Methods Identify the phenotype of the fourth genet of ex vivo expanded MSCs, stain with DAPI after inducing with 10vmol/L 5- aza, then preserve the MSCs for transplantation. 28 SD rats were divided into three groups： group A （n = 10）, delivered MSCs combined with magnetic targeting material for 30 minutes to rats through tail vein, and kept on raising after placing magnets on the corresponding skin region to myocardial infarction area for 30min; group B （n= 9）, administration MSCs not conjuncted with magnetic targeting material through tail vein; group C （n = 9）, direct intramyocardial transplantation of MSCs. Two days after transplantation, evaluate the aggregation state of MSCs in the area of myocardial infarction; 30d later, estimate the functional and morphological changes in myocardial infarction region. Results We observed that each MSCs had 3- 5 molecules of magnetic targeting material attached to its membrane under transmission electron microscope. The homing rates of MSCs respectively were group A 38%, group B 6%, group C 53%. The number of aggregating MSCs of group A and group C was apparently more than that of group B（P〈0. 01）. After transplantation, the contraction indices of left ventricle in group A and group C had significant improvement as compared with that of pretransplantation （LVEF 46%±6% vs. 38%±8%, 51%±5% vs. 35%±4%; LVFS 28%＋6% vs. 20%±7%, 32%±4% vs. 20%±5%, P〈0.05） and administrated cells stained with DAPI could be detected in infarction region under optical microscope. After transplantation, the contraction indices of left ventricle in group B hadn＇t conspicuous improvement, and the transplanted cells labeled with DAPI could not be identified in infarction region under optical microscope （homing rate of MSCs 38%）. There was no statistically difference of results between group A and group C, but in experiment process, there was a high mortality in group C. Conclusion The method that intravenously delivery of MSCs mediated by magnetic targeting material could accumulate much more MSCs in infarction region, reduce infarction size, and effectively improve the cardiac function after infarction.