低剂量X线照射对成骨细胞纤维肌动蛋白的影响

Effects of low dose of X-ray radiation on the actin cytoskeleton of osteoblasts

目的 观察不同剂量X线照射成骨细胞后,细胞形态、胞内微结构及纤维肌动蛋白的变化.方法 采用医用直线加速器以0、0.5、5.0Gy作用成骨细胞（MC3T3-E1）后,用倒置相差显微镜观察细胞形态变化,透射电镜观察细胞内微结构变化以及异硫酸氢荧光素-鬼笔环肽（FITC-phalloidin）对各实验组细胞的纤维肌动蛋白（F-actin）进行染色,荧光显微镜下观察各实验组F-actin细胞骨架的变化.结果 X线照射后2h,0.5、5.0Gy组细胞F-actin绿色荧光强度明显低于未照射组（25.329±12.209、27.021±13.049比29.107±13.296）,差异有统计学意义（P＜0.05）.但24h后0.5、5.0Gy组细胞肌动蛋白骨架发生重构,F-actin染色逐渐增强、纤维增粗,照射后第3天时最为显著（38.687±18.072、36.039±12.128比35.645±17.213）,至第5天时F-actin染色逐渐恢复正常,与0Gy组接近（28.527±14.107、27.258±13.322比27.309±15.039）.结论 X线辐射短时间内能使成骨细胞骨架破坏、F-actin解聚,但随后细胞肌动蛋白骨架发生重构,F-actin表达增强,至第5天时逐渐恢复正常.

Objective To observe the effects of different doses of X-ray irradiation on the morphology,mierostructure changes and actin cytoskeleton of osteoblasts.The findings of this research will provide evidence for further study of low dose X-ray irradiation biological effects.Methods MC3T3-E1 cells were exposed to irradiation of 0.5,5.0 Gy.We investigated cellular morphological changes by phase contrast microscope and transmission electron microscopy.The organization of actin microfilaments was determined by immunofluorescence.Results After 2 h exposure to irradiation,the F-actin fluorescence intensity of ceils in 0.5,5.0 Gy group were significantly lower than non-irradiated group （25.329 ± 12.209,27.021 ± 13.049 vs.29.107 ± 13.296,P 〈 0.05）.But 24 hours later,the fluorescence intensity of F-actin in 0.5,5.0 Gy group increased gradually and the fiber stress also increased.The most significant changes appeared in the third day after X-ray irrddiation （38.687 ± 18.072,36.039 ± 12.128 vs.35.645 ± 17.213）.However,these changes gradually returned to normal in the fifth day,close to 0 Gy group （28.527 ±14.107,27.258 ±13.322 vs.27.309±15.039）.Conclusion Thecytoskeleton of MC3TE-E cells were destroyed after 2 hours,exposure to X-ray irradiation.Howerver,0.5,5.0 Gy X-ray irradiation induced reorganization of actin filaments of MC3T3 cells 1 d later.