放线菌素D对仓鼠成纤维细胞V79靶细胞和旁观者细胞活力和染色体畸变的影响

目的:观察放线菌素D(actinomycin D,ACTD)对中国仓鼠成纤维细胞V79靶细胞和旁观者细胞的细胞活力和染色体畸变的影响,以确定ACTD能否诱导旁观者效应的发生。方法:用不同剂量ACTD(0、0.25、0.5、1.0、2.0、4.0和8.0 mg/L)处理V79靶细胞1 h,并选择其中4 mg/L ACTD作用1 h开始计时,分别在第4、8、12和24 h时取靶细胞去细胞培养液(conditionedmedium,CM),培养正常细胞24 h后,进行旁观者效应的观察。用MTT法测定靶细胞和旁观者细胞活力;并对靶细胞和旁观者细胞进行染色体畸变分析。结果:随着ACTD剂量的增加,靶细胞的活力下降,存在明显的剂量一效应关系(P0.05)。4 mg/L ACTD作用1h时细胞活力接近50%且稳定。旁观者细胞活力在用4～12 h CM培养时逐渐增加(P0.05),用24 h CM时又下降(P0.05),4 h CM诱导旁观者细胞损伤的作用最强。靶细胞的染色体畸变率随ACTD剂量的增加而增高,具有剂量-效应关系(P0.05)。旁观者细胞染色体畸变以4 h CM诱导的作用最强,随着加入CM时段的延后,损伤逐渐减轻(P0.05),在24 h CM又趋严重(P0.05);旁观者细胞与靶细胞染色体畸变类型相似,以断裂为主,伴有少量环形染色体、碎片和双着丝粒染色体。结论:ACTD可以诱导旁观者效应的发生,染色体畸变在靶细胞和旁观者细胞均以断裂为主。

Effect of actinomycin D on cell viability and chromosome aberration in hamster fibroblast V79 target and bystander cells

OBJECTIVE:To observe the effect of actinomycin D(ACTD) and conditioned medium on cell viability and chromosome aberration in hamster fibroblast V79 cells to determine whether actinomycin D could induce bystander effect.METHODS:V79 cells were treated with ACTD for 1 h at different doses(0,0.25,0.5,1.0,2.0, 4.0 and 8.0 mg/L).The 4 mg/L ACTD-conditioned medium(CM) was collected at 4,8,12 and 24 h after treatment for 1 h to culture bystander cells to observe the bystander effect.Cell viability was evaluated by MTT assay;chromosome damage was detected using the conventional analysis of chromosomal aberrations.RESULTS:Cell viability of ACTD- treated V79 cells was reduced in a dose-dependent manner(P<0.05),was close to 50 percent and stable when ACTD was at 4 mg/L for 1 h.Cell viability of CM-treated bystander cells increased significantly in a time-dependent manner(P<0.05) till a rebound in 24 h CM(P<0.05).The bystander effect in the 4 h CM was the strongest.Chromosome aberration rate in ACTD-treated cells increased significantly in a ACTD dose-dependent manner(P<0.05).Chromosome aberration rate in CM-treated bystander cells decreased significantly in a time-dependent manner(P<0.05) till a rebound in 24 h CM,with the 4 h CM being the highest.Type of chromosome aberration in bystander cells was mainly breakages along with ring chromosome,fragmented and dicentric chromosome similar to exposed cells.CONCLUSION:ACTD could induce bystander effect in V79 cells.Chromosome aberration type consisted of mainly breakages in both ACTD-treated cells and CM-treated bystander cells.