温室土壤有机物提取物分析及其致DNA损伤作用

Chemical analysis of extractable organic matter from vegetable greenhouse soil and DNA damage in mice

目的评价温室土壤有机物污染情况,并探讨其致DNA损伤作用。方法于2010年5月,采用气相色谱-质谱(GC-MS)法对某蔬菜大棚土壤和对照(非污染)区土壤样品中有机提取物(extractable organic matter,EOM)的主要成分进行检测分析。将40只健康10周龄清洁级雄性昆明小鼠随机分为5组,分别为阴性对照(DMSO-植物油体积比为6∶4)组、阳性对照(100 mg/kg环磷酰胺腹腔注射)组和温室土壤EOM低剂量(0.5 g/ml)、中剂量(1.5 g/ml)和高剂量(3.0g/ml)染毒组,每组8只。采用经口灌胃方式,每天一次,连续染毒4周。采用彗星试验检测小鼠外周血淋巴细胞DNA损伤。结果温室土壤样品检出的主要污染物为胺类、烷烃类、苯系物、多环芳烃和邻苯二甲酸酯类,其种类及含量均多于对照区土壤。与阴性对照组比较,1.5、3.0 g/ml EOM染毒组小鼠外周血淋巴细胞头尾光密度比以及各剂量EOM染毒组小鼠外周血淋巴细胞尾长和Olive尾矩均较高,差异有统计学意义(P<0.05);且随着EOM染毒剂量的升高,小鼠外周血淋巴细胞尾长、头尾光密度比和Olive尾矩均呈剂量依赖性升高(P<0.05)。结论温室土壤除受烷烃类和胺类等有机污染外,其多环芳烃、苯系物、烯烃类和邻苯二甲酸酯类等污染亦较严重。温室土壤EOM具有致DNA损伤作用。

Objective To evaluate the organic pollution levels in the vegetable greenhouse soil and to study DNA damage induced by the extractable organic matter （EOM） from the soil. Methods EOM were obtained by the method of soxhlet extraction from greenhouse soil and the control soil with no pollution in May, 2010, and were analyzed with GC-MS. The EOM from greenhouse soil were fed to mice via gavage with the final concentration of 0, 0.5, 1.5 and 3.0 g/ml respectively per day for four weeks. DMSO was used as a negative control and cyclophosphamide （CP） as the positive control. After treatment, DNA damage of peripheral blood lymphocyte induced by EOM was detected by the comet assay. Results The amines, alkanes, benzene series, polycyclic aromatic hydrocarbon and phthalates were detected in the EOM of greenhouse soil, and the levels of which were several times as higher as those of control soil. The tail length, tail DNA percent and Olive tail moment increased significantly in the groups exposed to the 1.5 g/ml or 3.0 g/ml EOM compared with the control group with a dose- dependent manner. Conclusion The vegetable greenhouse soil in the investigated area is polluted by amines, alkanes, benzene series, polycyclic aromatic hydrocarbon and phthalates, which may induce the DNA damage.