骨髓间充质干细胞移植加重大鼠主动脉血管成形术后再狭窄程度

Bone marrow mesenchymai stem cell transplantation aggravates postangioplasty aortic restenosis in rats

目的探讨骨髓间充质干细胞（MSCs）移植对大鼠血管成形术后再狭窄的影响。方法随机将大鼠分为正常对照、损伤和损伤加MSCs移植组，用经皮冠状动脉腔内成形术（PTCA）导管扩张大鼠胸腹主动脉创建动脉损伤模型。贴壁法培养大鼠MSCs，经4，6-联脒-2-苯基吲哚（DAPI）荧光标记后，以2×10^6数量经导管注入移植组大鼠主动脉内。术后第1、2、6周取材寻找DAPI标记的MSCs，行组织形态学及血小板衍生的生长因子受体（PDGFR）家族干细胞因子的受体（c—kit），增殖细胞核抗原（PCNA），平滑肌肌动蛋白（αSMA）免疫组化分析。结果移植术后1～2周，可见DAPI标记MSCs归巢到损伤内膜表面或中膜近内膜处，并表达d—SMA。移植组和损伤组新生内膜表面均表达少量c-kit，两组之间无明显差别。正常对照组血管中膜α-SMA均匀强表达，PCNA表达微弱，无新生内膜。移植组新生内膜中PCNA和α—SMA表达均强于损伤组。术后6周，移植组新生内膜／中膜面积百分比和管腔面积狭窄率均较损伤组明显增加，差异具有统计学意义。结论经主动脉移植的骨髓MSCs可归巢到严重受损的主动脉内膜上，并分化为平滑肌样细胞，参与新生内膜的形成，加重大鼠血管成形术后再狭窄程度。

Objective To observe the effect of bone marrow mesenchymal stem cell transplantation on postangioplasty aortic restenosis in rats. Methods 48 SD rats were randomly divided into normal control group, balloon injury group, balloon injury and MSCs transplantation group. MSCs were pre-labeled by DAPI （25μg/ml） and then infused into aorta through the balloon catheter （MSCs 2 × 10^6/animal）. Thoracic aorta were taken for histological examination （ frozen and paraffin sections） at 1,2,6 weeks post angioplasty, respectively. DAPI labeled MSCs were detected under immunofluorescence microscopy. Expressions of c-kit, proliferating cell nuclear antigen （ PCNA）, smooth muscle alpha-actin （α-SMA） in aorta were determined by immunocytochemistry using related antibodies. Results The DAPI-labeled MSCs could be detected on impaired intimae and α-SMA expression was seen in these cells 1 weeks after MSCs transplantation. Similar weak c-kit expression in neointima was found in both injury and transplantation group at 2 weeks （ P 〉 0. 05 ）. Expressions of PCNA and α-SMA in the neointima were significantly higher in transplantation group than in injury group at 2 weeks. Intima/tunica media area ratio and luminal stenosis ratio were significantly increased in transplantation group than injury group at 6 weeks （ all P 〈 0. 05 ）. Conclusion Bone marrow MSCs transplanted post aortic angioplasty could home to serious wounded aortic intima, differentiate into smooth muscle like cells, promote neointima cellular proliferation and aggravate postangioplasty aortic restenosis in rats.