64. Study on the DNA damage induced by coal tar pitch fume extracts in rat alveolar macrophage and i

癌變畸變突變001年10月第13卷第4期Carcinogenesis, Teratogenesis and Mutagenesis Vol 13 No 4 Oct., 200164. Study on the dna damage induced by coal tar pitch fume extracts in rat alveolar macrophage andit' s mechanismwU Yiming, Ll Zhichun, CHEN Chen, wU Yongjun, XU YubaoDepartment of Labor health and Toxicology School of Public Heath, Zhengzhou University, Zhengzhou 45005Abstract: The carcinogenic mechanism of coal tar pitch( ctP )as a recognized carcinogen has been studying. Itis widely believed that the carcinogenicity of CTP is based on the genotoxicity of CTP. In the process of carcino-genesis caused by extrinsic chemical substance the DNA damagecurred in theUPnow the most sensitive detecting endpoint for dna damage is to detect DNA single strand breaks. The singlecell gel electrophoresis has been rapidly becoming a widely used analytical procedure during the last few yearswhich can detect DNA strand breaks. The method is a fast relatively inexpensive easy to perform, non-Ilioactive, and very sensitive method. This method suits to different tests in vitro or in vivo. Virtually any eu-karyotic cell which could be made into single cell suspensions can be processed for analysis of dna damageusing the single cell gel electrophoresis. The aim of the study is to investigate the role of DNa damage inducedby CTP fume in rat AM, to examine the changes of RoS, MDa and SoD and to explore the mechanism of dNAdamage by CTP fume. The present study is in favor of studying the mechanism of mutagenesis and carcinogenesisduced by CTP. Method: The healthy male Wistar rats were anesthetized intraperitoneally with 40 mg pentobarbital sodium per kilogram of body weight. The animals were exanguinated by excising femoral and collectedthe rat alveolar macrophage by Josephs method. The concentration of AM had been regulated to 1.5 x 10 cellmI. AMs which had been cultured in 24-well culture plate were divided into 4 groups. These cells were expoured to 5.0 pg/ml extracts of coal tar pitch fume and contacted with 500 pM, 1 000 uM, and 2 000 uM ofGSH respectively. These cells were divided into 4 groups. After incubation 24 hours the indexes that had beenused above were measured. Results: ( The DNA strand breaks induced by coal tar pitch fume extracts: Afterundergoing electrophoresis the comet cells are seldom in control group but the comet cells increased sig-nificantly in experimental groups. When the concentration of CTP fume extracts increased from0 to 10.0 ug/mlthe incidences of comet cell increased from 6. 0% to 92.0%. There were significant differences in all groups(P<0.001 ). There was a dose-response relationship between the concentrations of CTP fume extracts and theincidences of comet cell. There were correlation relationship between the grade of dna damage and the con-centration of CTP fume extracts(P<0. 001).(2) The level of ROS induced by CTP fume extracts in AM: Afterincubation 24 h, the concentration of ROS increased. The difference between control group and experimentalgroups were significant( P<0.001). 33 The changes of MDA and SOD in AM induced by CTP fume extractsAs the concentration of coal tar pitch fume extracts increased the concentration of MDa increased too. The differences between experimental groups and control group were significant. But the difference of SOD activity in algroups weren t significant. The role of GSH interfere: GSH could protect the DNA of AM from DNA-damagenduced by CTP fume extracts. With the increasing of the concentration of GSH the incidences of comet celldecreased from 77. 0% to 16.0%. The differences of incidences of comet cell in all groups were different significantly. There was a dose-response relationship between the concentrations of GSh and the incidecomet cell. There was correlation relationship between the中國煤化工 f GSH(P<0.001). GSH could inhibit the increasing of ROS andCN GD activity in all groupsweren' t significant(P>0.05 ) Conclusion: Coal tar pitch fume extracts can induce DNA single strandbreaks in rat alveolar macrophage the single cell gel electrophoresis appears to be suitable to detect DNA strandbreaks in rat alveolar macrophage. @2 Coal tar pitch fume extracts can induce the rat alveolar macrophage to pro-癌變畸變突變200年10月第13卷第4期Carcinogenesis, Teratogenesis and Mutagenesis Vol 13 No 4 Oct., 2001duce reactive oxygen species( ROS ) and can induce lipid peroxidation: the DNA strand breaks induced by coaltar pitch fume extracts in AM are associated with the producing of ROS. @ GSH can inhibit coal tar pitch fumextracts-induced dna damage in rat alveola r macrophageKey words: single cell gel electrophoresis DNA damage i alveolar macrophage coal tar pitch文獻標識碼:A文章編號:004-616X(2001)4-0248-01中國煤化工CNMHG249