烹调烟雾冷凝物对DNA完整性影响的研究

采用体外作用的方式探讨烹调烟雾致遗传损伤的机制。通过细胞毒性试验得出 :油烟冷凝物与大鼠肺Ⅱ型细胞生长抑制率之间存在剂量 -效应关系 (r=0 943,P <0 0 1) ,剂量在 2 0 μg ml及以上对细胞有明显毒性作用。在不产生细胞毒性作用的剂量范围内 ,单细胞凝胶电泳试验表明 :大鼠肺Ⅱ型细胞经油烟冷凝物染毒 2小时可引起细胞DNA链断裂 ,在 0～ 5 μg ml剂量范围内 ,损伤程度与剂量存在直线相关关系 (r=0 918,P <0 0 5 ) ;在 10 μg ml剂量下 ,DNA损伤已达最大程度。发生DNA损伤的细胞经修复培养 2小时后受损伤的DNA能被修复。油烟冷凝物对 30 μg小牛胸腺DNA交联试验显示 :在 5 0～ 80 0 μg剂量范围 ,DNA交联率与受试物间存在剂量 -效应关系 (r=0 96 3,P <0 0 1)。提示烹调烟雾冷凝物在较低作用剂量下就可导致大鼠肺Ⅱ型细胞DNA损伤 ,在一定剂量下可以导致DNA交联率的增加

Study on the effects of cooking oil fume condensate on the DNA integrality

The aim of this study was to study the DNA damage mechanisms of cooking oil fumes (COF) in vitro. The colorimetric MTT reduction assay was adopted to measure the effects of the cytotoxicity of COF condensate on type II pneumocytes from the lungs in the rats. The condensate of COF was of the dose-responsive effect on cell-inhibit rate to some extent (r = 0.943, P < 0.01). There is distinctive cytotoxicity on type II pneumocytes when concentration is higher than 20 micrograms/ml. The genotoxicities of COF condensate to type II pnemocytes were studied by modified alkaline single-cell gel using a electrophoresis(SCGE) assay(comet assay), the maximum concentration of condensate is below the concentration of cytotoxicity. The results showed that the condensate of COF was of the dose-responsive effect on the type II pneumocytes DNA damage to some extent(r = 0.918, P < 0.05) at the dosage of 0-5 micrograms/ml. The DNA damage reach to the maximum at the dosage of 10 micrograms/ml. The damaged DNA could be restored after been cultured for 2 hours. Calf thymus DNA cross-link after the administration of COF condensate were measured with ethidium bromide assay. It was found that condensate of COF was of the dose-responsive effect on the calf thymus DNA cross-links to some extent(r = 0.963, P < 0.01). The above results suggested that cooking oil fume condensate could induce DNA damage at much lower dosage and result in the increase of DNA cross-links in a certain concentration.