有机膨润土遗传毒性的体外试验研究

目的 体外试验研究有机膨润土的遗传毒性.方法 人B淋巴母细胞(HMy2.CIR)染毒0、1.88、3.75、7.50、15.00μg/ml有机膨润土24、48、72 h,并设硫酸钙(30μg/ml)和游离SiO2(30、240μg/ml)为阴性和阳性颗粒对照.用彗星试验和胞浆分裂阻滞微核试验(cytokinesis-block micronucleus,CBMN)检测有机膨润土颗粒部分和可溶性部分的遗传毒性.结果 彗星试验结果表明,有机膨润土组彗星尾部DNA百分含量(%tail DNA)随染毒剂量和时间的增加而增高,剂量为15.00 μg/ml、染毒时间24、48、72 h时的%tail DNA分别为3.20±0.19、4.63±0.88和9.49±1.31,均明显高于30μg/ml硫酸钙组(分别为1.40±0.11、1.37±0.22和0.90±0.16)和30μg/ml二氧化硅组(分别为1.83±0.21、1.41±0.27和2.48±0.25),差异均有统计学意义(P＜0.01).CBMN试验结果发现,有机膨润土组(除1.88μg/ml染毒24h外)微核率(MNF)均明显高于30μg/ml硫酸钙组(分别为1.33‰±0.58‰、1.33‰±1.15‰和1.33‰±0.58‰)和30μg/ml二氧化硅组的MNF(分别为2.00‰±0.00‰、1.68‰±0.58‰和2.33‰±0.58‰),差异有统计学意义(P＜0.01).2种试验结果还表明有机膨润土可溶性部分并不诱发遗传毒性.结论 体外试验有机膨润土可诱发人B淋巴细胞系DNA损伤和微核率增高,毒性主要来源于不可溶部分.

Genotoxicity of organic bentonite particles in vitro

Objective To study the genotoxicity induced by organic bentonite particles in vitro.Methods Human B lymphoblast cells(HMy2.CIR)were exposed to organic bentonite particles at the doses of 0,1.88, 3.75,7.50 and 15.00 μg/ml for 24,48 and 72 h,calcium sulfate(30 μg/ml)and SiO2(30 and 240 μg/ml)served as negative and positive controls, respectively.The genotoxicity of organic bentonite particles and soluble fraction was detected using comet assay and Cytokinesis-block micronucleus(CBMN)assay.Results The results of comet assay indicated that % tail DNA increased with the exposure doses and time in organic bentonite group, % tail DNA at the dose of 15.00 μg/ml for 24 h, 48 h and 72 h in organic bentonite group were 3.20±0.19,4.63±0.88 and 9.49±1.31 respectively which were significantly higher than those in calcium sulfate group(1.40±0.11,1.37±0.22 and 0.90±0.16)and those in 30 μg/ml SiO2 group(1.83±0.21,1.41±0.27 and 2.48±0.25)(P＜0.01).The results of CBMN assay showed that micronucleus frequencies(MNF)in organic bentonite group(except for 1.88 μg/ml for 24 h)were significantly higher than those in 30 μg/ml calcium sulfate group(MNF for 24, 48 and 72 h were 1.33‰±0.58‰, 1.33‰±1.15‰ and 1.33‰±0.58‰)and those in 30 μg/ml SiO2 group(2.00‰±0.00‰, 1.68‰±0.58‰ and 2.33‰±0.58‰)(P＜0.01).The results of two assays demonstrated that the soluble fraction of organic bentonite did not induce the genotoxicity.Conclusion The organic bentonite dusts can induce the genotoxicity in vitro, which may be from the particle fraction.