亚硝酸钠诱导L929细胞增殖毒物兴奋效应

目的采用体外细胞毒性检测方法研究亚硝酸钠(NaNO₂)对L929细胞增殖的影响,探讨在此过程中遗传物质的损伤情况。方法体外培养L929细胞,用溴化四氮唑蓝法检测不同浓度NaNO₂对细胞增殖的影响;并采用单细胞凝胶电泳技术及KCl-十二烷基磺酸钠沉淀法(K-SDS)检测NaNO₂对L929细胞DNA损伤及DNA-蛋白质交联的作用。结果 NaNO₂处理L929细胞48h后,细胞增殖出现毒物兴奋效应(hormesis),其剂量范围约为0～0.0384mg/L;染毒剂量为0.02、1 500 mg/L时,细胞尾长分别为(2.72±1.99)、(3.26±3.09)μm,尾DNA%分别为(7.87±6.63)%及(7.75±4.90)%,Olive尾矩分别为(0.80±0.64)及(0.79±0.64),与阴性对照组〔(1.83±1.08)μm、(6.07±3.59)%、(0.43±0.28)〕比较,差异均有统计学意义(P<0.05);2、20、1 500 mg/L剂量组的DNA-蛋白质交联系数大于阴性对照组(P<0.05),且呈现剂量-效应关系。结论 NaNO₂可诱导L929细胞出现毒物兴奋效应,并且在其剂量范围内可诱导细胞遗传物质的断裂性损伤。

Hormesis of cell proliferation induced by sodium nitrite in L929 fibroblasts

Objective To explore the effects of sodium nitrite(NaNO2) on cell proliferation and DNA damage in L929 fibroblasts.Methods Methyl thiazol tetrazolium(MTT) method was used to evaluate the cellular toxicity of NaNO2 on cell viability of L929 cells,and the single cell gel electrophoresis(SCGE) as well as KCl-sodium dodecyl sulfate(SDS) assay were implied to detect DNA damage and DNA-protein crosslink(DPC).Results Hormesis was observed when L929 cells were exposed to certain concentrations of NaNO2 for 48 hr with a hormetic zone from 0 to 0.0384 mg/L.Under the exposure of 0.02 mg/L and 1 500 mg/L NaNO2,the tail length of DNA(2.72±1.99,3.26±3.09 μm),tail DNA%(7.87±6.63,7.75±4.90%),and Olive tail moment(0.80±0.64,0.79±0.64) of L929 cells were significantly different from those of the control group(P<0.05).DPC was observed for the cells under exposures of 2 mg/L,20 mg/L,and 1 500 mg/L NaNO2 compared with those of the control group in a dose dependent manner.Conclusion NaNO2 can induce hormesis and DNA fracture damage in L929 cells.