低剂量辐射对人骨髓间充质干细胞造血生长因子表达量的影响

Effect of low dose radiation on expression of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow

目的:探讨低剂量辐射(LDR)对人骨髓间充质干细胞(BM-MSC)的兴奋性效应及其分子机制。方法:应用体外传代培养的P4和P5BM-MSC,采用X射线照射,分为50、75和100mGy3个照射剂量组,剂量率为12.5mGy.min-1,每组细胞设对应假照组,采用ELISA方法检测LDR后BM-MSC细胞因子表达量的变化。结果:与同一时间假照组比较,50、75和100mGyX射线照射人BM-MSC后,在培养24和48h时干细胞因子(SCF)分泌量均有升高趋势,仅75mGy照射后48h时SCF分泌量明显升高,与同一时间假照组比较差异有显著性(P<0.05);50和75mGy照射组在24和48h,100mGy照射组在24h时IL-6分泌量明显升高,与同一时间假照组比较差异有显著性(P<0.05);50、75和100mGy照射BM-MSC后,与同一时间假照组比较,除50mGy照射后72h外,M-SCF分泌量在照射后在24、48和72h均明显升高(P<0.05),以75mGy照射后72h升高最明显。结论:LDR对BM-MSC有兴奋效应,表现为细胞生长加速,同时在一定时间内可以使造血生长因子表达量增多。

Objective To study the changes of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow （BM-MSC） pretreated with low dose radiation （LDR） . Methods The cultured P4 and P5 BM-MSCs were exposed to X rays at the doses of 50 , 75 and 100 mGy （dose rate 12.5 mGy·min^-1）. The changes of levels of stem cell factor （SCF）, IL-6, macrophage colony-stimulating factor （M-CSF） secreted by BM- MSCs pretreated with LDR were determined by ELISA method. Results As compared with control group at the same time, the levels of SCF in experimental group had a tendency of increasing after 24 h and 48 h radiation, but only in 75 mGy group the sCF level was obviously increased （P〈0.05）. The levels of IL-6 in 50 and 75 mGy groups at 24 h and 48 h , in 100 mGy group at 24 h were obviously increased compared with control group （P〈0. 05） . The levels of M-CSF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h were also increased （P〈0.05）, it increased markedly in 75 mGy dose group at 72 h. Conclusion LDR has hormesis effect on BM-MSCs . After LDR, the BM-MSCs grow faster and in a certain phase the expression levels of hematopoietic growth factors are increased.