基质干细胞及明胶微载体植入大鼠心脏的研究

Transplantation of mesenchymal stem cells and gelatin porous microcarriers into normal rat heart tissue

目的 探讨将来源于人类胚胎肝脏的基质干细胞（human fetal liver-delivered mesenchymal stem cells，HFMSCs）及明胶多孔微载体植入正常心肌组织促使心肌及微循环再生的可行性。方法 将SD大鼠分为细胞植入组（n=9）、微载体植入组（n=9）和对照组（n=4），分别在左心室室壁内注射80—100μl含HFMSCs的perfadex溶液、含微载体的perfadex溶液或单纯perfadex溶液。用超声心动图评定移植前后大鼠心脏功能，并分别于术后7、14d取出心肌组织作原位杂交、HE染色、免疫组化染色及混合淋巴细胞培养（MLC）。结果 细胞植入7d后，心脏功能有显著的增加，原位杂交显示，有较多细胞在心肌组织中存活，但免疫组化染色未发现植入细胞向心肌细胞方向的分化；至移植后第14天，移植细胞从心肌组织中消失，在注射局部发现大量巨噬细胞浸润，而体外MLC证实，此时HFMSCs有诱导sD大鼠内淋巴细胞增殖的效应。微载体植入7、14d后，心脏功能无明显增加，微载体仍集中在注射部位，并保持原有形状，其上有较多细胞生长贴附，免疫组化染色显示，这些细胞既不是心肌细胞，也不是毛细血管。结论 HFMSCs植入正常大鼠心脏组织中能短期存活并促进心脏功能增加，但因慢性免疫排斥反应，移植细胞在发生心肌分化之前在体内逐渐消失；明胶多孔微载体植入正常心肌组织后，不能促进心脏功能增加，也不能促使心肌及其微循环生长于其中。

Objective To investigate the feasibility of transplantation of human fetal liver-delivered mesenchymal stem cells （HFMSCs） and porous microcarries into normal heart tissue and whether it can improve heart function and regeneration of heart tissue. Methods SD rats were divided into HFMSCs injection group （ n = 9）, microcarrier injection group （n =9） and control group （n =4）, in which 80 -100μl Perfadex with HFMSCs or gelatin porous microcarriers or pure Perfadex was injected into the wall of left ventricle. Heart function was evaluated by UCG before and 7 d after transplantation. On day 7, 14, the survival of HFMSCs was tested by fluorescent in situ hybridization （FISH）, regeneration or cardiac differentiation by immunohistological staining against desmin, tropomyosin and lectin, cellular immune response by the infiltration of macrophages, and lymphocyte reaction to HFMSCs by mixed lymphocyte culture （MLC） in vitro. Results Seven days after injection, the HFMSCs survived and improved the heart function, though no sign of differentiation into cardiomyocytes was seen. On day 14, a large amount of macrophages infiltrated into injection sites, and MLC showed prominent enhancement of proliferation of lymphocytes, when no transplanted cells were detected in the myocardium. On day 7, 14, the microcarriers retained their round shape at the injection sites and were attatched by a large quantity of cells which were proven not cardiomyocytes or capilaries by immunohistological staining. Conclusion Transplantation of HFMSCs into normal heart improves heart function by short-period survival without differentiation, but the transplanted cells disappeared because of immune reaction. Transplantation of porous microcarriers into normal heart could not improve heart function either by regeneration of heart tissue or capilaries.