草甘膦对小鼠的致突变作用研究

背景与目的:研究草甘膦对小鼠的致突变作用.材料与方法:采用骨髓微核试验:以不同剂量(2 320、1 160、580 mg/kg)的草甘膦分2次经口灌胃染毒小鼠,每次间隔24 h,于末次染毒后6 h处死小鼠,检测骨髓嗜多染红细胞微核率;雄性小鼠精子畸形试验:设1 160、580、290 mg/kg的3个草甘膦剂量组,经口灌胃连续染毒5 d,于首次染毒后第1、4周分2批处死动物,常规观察精子畸形率、精子数和睾丸、附睾重量及其脏器系数的变化.两种实验同时设阴性对照组(蒸馏水)和阳性对照组(CP 40 mg/kg)结果:2 320mg/kg剂量组的微核率明显高于阴性对照组(P＜0.01),染毒剂量与骨髓微核率呈现剂量依赖关系(r=0.588,P＜0.01).草甘膦染毒后1周,与阴性对照组比较,580 mg/kg、1 160 mg/kg剂量组的精子畸形率增加而精子数减少(P＜0.05,P＜0.01),1 160 mg/kg剂量组的附睾重量及附睾系数明显下降(P＜0.05);草甘膦染毒后4周,与阴性对照组比较,1 160 mg/rg剂量组的精子畸形率增高,精子数减少(P＜0.05),睾丸和附睾重量减轻. 结论:在本实验条件下,草甘膦对小鼠具有生殖毒性并具有一定的致突变作用.

Study on Mutagenesis Induced by Glyphosate in Mice

BACKGROUND AND AIM: To explore the glyphosate-induced mutagenesis in mice. MATERIALS AND METHODS: In micronucleus test(MNT), glyphosate was given twice via intragastric administration to different groups of mice at different concentrations(2 320 mg/kg, 1 160 mg/kg, 580 mg/kg) at a 24-hour interval. Mice were killed 6 hours after last treatment to determine the micronucleus rates of polychromatic erythrocytes(PCE) in the bone marrow. For sperm shape abnormality test, all mice were treated with glyphosate for 5 consecutive days at concentrations of 1 160 mg/kg, 290 mg/kg and 580 mg/kg. In the 1st and 4th week after the first treatment, half of mice were killed each time to regularly examine the sperm aberration rates, to count the total number of sperm, to weigh the testis and the epididymis,and to observe the change of organ coefficient. RESULTS: The micronucleus rate of 2 320 mg/kg group was significantly higher than that of negative control(P<0.01).A dose-dependent response was observed between the treatment dose and the micronucleus rate(r=0.588,P<0.01). One week after the first treatment, compared with negative control, the 580 mg/kg, 1 160 mg/kg groups both showed increasing rate of sperm aberration and decreased total number of sperm(P<0.05,P<0.01),while the 1 160 mg/kg group showed significantly decrease in epididymis weight and its coefficient(P<0.05). Four weeks after the first treatment, by comparing to negative control, 1 160 mg/kg group showed increasing rate of sperm aberration and decreased total number of sperm(P<0.05),as well as a decline in the weights of testis and epididymis. CONCLUSION: In this study, glyphosate showed reproductive toxicity in mice and certain mutagenesis.