[Study on the effects of cooking oil fume condensate on the DNA integrity]

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.