放射损伤对于移植的骨髓间充质干细胞在受体大鼠不同器官中植入的影响

目的： 探讨放射损伤对于骨髓间充质干细胞（MSCs）移植后在受体大鼠不同器官中植入的影响以及可能的机制。方法：采用DNA缺口末端标记法(TUNEL)检测正常对照组和单纯放射组大鼠心脏、肾脏、肝脏、肺脏的细胞凋亡率。应用密度梯度离心法结合贴壁法提取雄性大鼠骨髓MSCs，培养后把MSCs移植到［60COγ］照射和未经照射的雌性大鼠体内，通过PCR和Y染色体荧光原位杂交（Y- FISH）示踪雄性大鼠MSCs在雌性大鼠体内的分布情况。结果：照射后大鼠心脏、肾脏、肝脏、肺脏细胞凋亡率显著高于对照组。PCR结果显示照射后移植MSCs的大鼠心脏、肾脏、肝脏、肺脏和外周血中可以扩增出Sry基因的DNA序列，而且Y- FISH显示照射后移植MSCs的大鼠在心脏、肾脏、肝脏、肺脏中可发现Y染色体阳性的细胞。但是未经照射行MSCs移植的大鼠在上述器官中未发现Y染色体阳性的细胞。结论：全身放射促进组织细胞的凋亡，并导致移植的MSCs在受体大鼠心脏、肾脏、肝脏和肺脏的植入。

Effect of irradiation on the engraftment of rat bone marrow mesenchymal stem cells in different organs of recipient rats

AIM: To investigate the effect of irradiation on the engraftment of rat bone marrow mesenchymal stem cells in different organs of recipient rats and possible mechanisms. METHODS: The apoptosis in the irradiated rats heart, kidney, liver and lung was assessed by terminal deoxynucleotidyl transferase dUTP nickend labeling (TUNEL) at day 14 after irradiation. MSCs cultured from male rats were delivered systemically into irradiated ［60COγ］ and nonirradiated syngeneic female rats sacrificed at day 28 after MSCs transplantation. Tracking of MSCs was determined by PCR and Y chromosome fluorescent in situ hybridization (Y-FISH). RESULTS: The numbers of apoptotic cells in the heart, kidney, liver and lung were significantly greater in the irradiated rats compared with those in the nonirradiated controls. Sry gene was amplified in the irradiated recipient heart, kidney, liver and lung. Moreover, Y chromosome positive cells in these organs of the irradiated recipient rats were observed. However, no Sry gene sequence and cells with Y chromosome were found in the nonirradiated recipients. CONCLUSION: Whole body irradiation induces apoptosis and results in engraftment of MSCs in the recipients heart, kidney, liver and lung.