Objective In view of the fact that asbestos is not only a key occupational hazard, but also an important environmental pollutant, it is necessary to develop a proper method to decrease the carcinogenecity of asbestos...Objective In view of the fact that asbestos is not only a key occupational hazard, but also an important environmental pollutant, it is necessary to develop a proper method to decrease the carcinogenecity of asbestos fibers. This study was designed to determine if the surface modification of chrysotile asbestos fiber (CAF) with rare earth compounds (REC) can ameliorate CAF-induced DNA damages in human embryo lung (HEL) cells. Methods After incubation with REC solution at different concentrations at room temperature for 1 h, natural and REC-pretreated CAF was added to cell culture at various doses. At the selected time as the experiment designed, DNA damages of the HEL cells were detected by Unscheduled DNA Synthesis (UDS) and Single Cell Gel Electrophoresis (SCGE) assays. Results The UDS induced by natural CAF was elevated with the increase of CAF doses. There was a good dose-response relationship between the UDS and the amount of CAF in the medium and the coefficient of correlation (R) was 0.958 at P<0.05. In REC-pretreated CAF groups, the UDS declined with the increase of REC doses. Both catalase (CAT) and dimethylsulfoxide (DMSO) also reduced the CAF-induced enhancement of UDS. In SCGE assay, CAF induced DNA chain breakage and the magnitude of DNA chain breakage increased in a dose-dependent manner and the coefficient of correlation (R) was 0.992 at p<0.01, while REC-pretreated CAF significantly decreased the induction of DNA chain breakage in a dose-dependent manner(r=0.989, p<0.05). Conclusion It can be concluded that CAF-induced DNA damages in HEL cells may be partly mediated by oxygen derivatives, and the surface modification of CAF with REC might hide critical sites on the fiber surface, thereby reducing the fiber-mediated production of oxygen derivation and lowering the CAF-induced UDS and DNA chain breakage in HEL cells.展开更多
It has been verified that asbestos induce neoplastic transformation of several rodent cell lines in vitro. Very little information is available, however, on asbestos induced human cell line transformation and onc...It has been verified that asbestos induce neoplastic transformation of several rodent cell lines in vitro. Very little information is available, however, on asbestos induced human cell line transformation and oncogene activation in the development of asbestos induced cell transformation. This study was designed to investigate the induction of cell transformation and transcriptional changes of the c myc oncogene by chrysotile asbestos fibers (CAF) in human embryo lung (HEL) cells. Surface modified CAF soaked in aluminium citrate (AC), rare earth compounds (REC) or sodium selenite (SS) solutions were used to observe the effects of surface modification on chrysotile induced cell transformation and transcriptional changes in the c myc oncogene. The results showed that the natural CAF caused dose dependent increases in transformed foci, along with increased transcription of the c myc oncogene in HEL cells, while the pretreated CAF induced fewer transformed foci and less c myc oncogene transcription than the natural CAF. The percent inhibition of equivalent AC, REC and SS were 38.9%, 50.0%, 33.3% (for transformation focus), 81.6%, 69.5%, 89.9% (for c myc oncogene transcription), respectively. These results indicated that CAF may induce cell transformation and transcriptional changes and that the carcinogenicity of CAF might be reduced by pretreatment of CAF with the above mentioned compounds.展开更多
文摘Objective In view of the fact that asbestos is not only a key occupational hazard, but also an important environmental pollutant, it is necessary to develop a proper method to decrease the carcinogenecity of asbestos fibers. This study was designed to determine if the surface modification of chrysotile asbestos fiber (CAF) with rare earth compounds (REC) can ameliorate CAF-induced DNA damages in human embryo lung (HEL) cells. Methods After incubation with REC solution at different concentrations at room temperature for 1 h, natural and REC-pretreated CAF was added to cell culture at various doses. At the selected time as the experiment designed, DNA damages of the HEL cells were detected by Unscheduled DNA Synthesis (UDS) and Single Cell Gel Electrophoresis (SCGE) assays. Results The UDS induced by natural CAF was elevated with the increase of CAF doses. There was a good dose-response relationship between the UDS and the amount of CAF in the medium and the coefficient of correlation (R) was 0.958 at P<0.05. In REC-pretreated CAF groups, the UDS declined with the increase of REC doses. Both catalase (CAT) and dimethylsulfoxide (DMSO) also reduced the CAF-induced enhancement of UDS. In SCGE assay, CAF induced DNA chain breakage and the magnitude of DNA chain breakage increased in a dose-dependent manner and the coefficient of correlation (R) was 0.992 at p<0.01, while REC-pretreated CAF significantly decreased the induction of DNA chain breakage in a dose-dependent manner(r=0.989, p<0.05). Conclusion It can be concluded that CAF-induced DNA damages in HEL cells may be partly mediated by oxygen derivatives, and the surface modification of CAF with REC might hide critical sites on the fiber surface, thereby reducing the fiber-mediated production of oxygen derivation and lowering the CAF-induced UDS and DNA chain breakage in HEL cells.
文摘It has been verified that asbestos induce neoplastic transformation of several rodent cell lines in vitro. Very little information is available, however, on asbestos induced human cell line transformation and oncogene activation in the development of asbestos induced cell transformation. This study was designed to investigate the induction of cell transformation and transcriptional changes of the c myc oncogene by chrysotile asbestos fibers (CAF) in human embryo lung (HEL) cells. Surface modified CAF soaked in aluminium citrate (AC), rare earth compounds (REC) or sodium selenite (SS) solutions were used to observe the effects of surface modification on chrysotile induced cell transformation and transcriptional changes in the c myc oncogene. The results showed that the natural CAF caused dose dependent increases in transformed foci, along with increased transcription of the c myc oncogene in HEL cells, while the pretreated CAF induced fewer transformed foci and less c myc oncogene transcription than the natural CAF. The percent inhibition of equivalent AC, REC and SS were 38.9%, 50.0%, 33.3% (for transformation focus), 81.6%, 69.5%, 89.9% (for c myc oncogene transcription), respectively. These results indicated that CAF may induce cell transformation and transcriptional changes and that the carcinogenicity of CAF might be reduced by pretreatment of CAF with the above mentioned compounds.
