二氧化硅对成纤维细胞和肺上皮细胞的DNA损伤作用

DNA damage in silica-exposed CHL and CCL-64 cell lines

目的 研究小剂量二氧化硅 (SiO2 )粉尘对中国仓鼠肺成纤维细胞 (CHL)和貂肺上皮细胞 (CCL 6 4)的DNA损伤作用。方法 采用彗星试验 ,按SiO2 粉尘不同的作用浓度 (终浓度 0、7 5、15、30、6 0、12 0mg/L)和时间分组 ( 1h、2h)来观察DNA损伤。以彗星尾长 (彗头末端到彗尾末端的长度 )作为DNA损伤程度的评价指标。结果 与对照组相比 ,SiO2明显增加了CHL及CCL 6 4细胞的DNA迁移距离 (P <0 0 1) ,在 7 5～ 12 0mg/L的剂量范围内 ,彗星尾长随作用剂量的增加而增加 ;一般 2h组比 1h组引起更严重的DNA损伤。结论 小剂量SiO2 粉尘确有遗传毒性 ,体外试验可致CHL细胞和CCL 6 4细胞DNA链断裂。由彗星试验的系列浓度SiO2

Objective To study the DNA damage in CHL and CCL-64 cell lines induced by low dose silica. Methods CHL and CCL-64 cells were exposed to silica suspension (the final concentrations of silica in medium were at range of 0, 7.5, 15, 30, 60 and 120 mg/L) and then incubated for 1 or 2 hours respectively. Comet assay was used and the tail lengths of comet (from end of heads to end of tails) were used to evaluate the degree of DNA damage. Results The tail lengths were significantly longer in exposed cells, including CHL and CCL-64 cells, compared with the matched controls (P<0.01), and increased in a dose-dependent manner from 7.5～120 mg/L silica. Generally, the tail length of comets in two-hour group were longer than that in one-hour group. Conclusion Silicon dioxide particles might have genotoxicity. It might induce DNA strand breakage in vitro in CHL and CCL-64 cell lines. The effects of two cell lines induced by silica and detected by comet assay seemed to be similar.