血小板第4因子对急性放射损伤小鼠骨髓基质细胞的保护作用

Protective effects of platelet factor 4 on bone marrow stromal cells of acute radiation injury in mice

目的:探讨血小板第4因子(plateletfactor4,PF4)对小鼠5.0Gyγ射线全身照射后骨髓基质细胞(bonemarrowstromalcell,BMSC)的保护作用,进一步探讨PF4对造血的辐射防护机制.方法:40只雄性小鼠随机分为4组:①单纯放射组(R),②放射+PF4组(R+P),③正常+PF4组(N+P),④正常对照组(N).小鼠照射前分别于26和20hipPF4,每次剂量50μg/kg.于照射后3d取BMSC体外培养,倒置显微镜下观察贴壁细胞生长状况,并于培养10d后用流式细胞仪测定贴壁细胞的细胞周期和DNA含量,免疫组化(SP法)检测细胞p27kip1表达.结果:放射损伤小鼠BMSC24h贴壁率4组依次为37%,58%,74%,79.3%;流式细胞仪检测结果表明R组G0+G1期细胞显著高于其余3组,而G2+M期细胞显著低于其余三组,DNA含量显著低于其余3组;R组p27kip1表达明显强于其余3组.结论:PF4对放射损伤的BMSC有保护作用,可能与抑制p27kip1表达有关.

AIM： To investigate the protective effects of platelet factor 4 （PF4） on bone marrow stromal cells （ BMSCs） of radiated mice and to study the protective mechanism of hematopoietic radiation injury in mice. METHODS： Forty male mice were randomized to four groups （ R, R ＋ P, N＋P and N） and two of groups （R, R ＋P） were exposed whole-bodily to 5.0 Gy ^60Co y-rays. The mice were treated with injections of PF4 （50μg/kg）, ip twice at an interval of 6 h and 20 h. After the second injection, they were irradiated. The cell cycle and apoptosis of bone marrow stromal cells （BMSCs） cultured in vitro after radiation were analyzed by FACS after ten days＇ culture. The expression of p27^kipl. in the cells was detected using immunohistochemistry. RESULTS, The 24th hour adhesion rate of BMSC in radiated mice respectively reached 37%, 58%, 74% and 79.3%. The cell percentage of G0＋ G1 phase increased and those of G2 ＋ M decreased in R group, compared with those in R ＋ P, N ＋ P and N groups. But the DNA content of the radiated group of BMSC decreased remarkably compared with those in the other three groups. The expression of p27^kipl. was down-regulated compared with that of BMSC without PF4 protection. CONCLUSION： The protective effects of PF4 on BMSCs with radiated injury probably result from the inhibition of the expression of p27^kipl.