Genetic Toxicity Evaluation of 1,1,1,2,3,3,3- Heptatfluoropropane. Volume 3.Results of Salmonella Typhimurium Histidine Reversion Assay (Ames Assay)

摘要

Under subcontract to ManTech Environmental Technology, Incorporated, GenesysResearch, Incorporated used L5 1 78Y mouse lymphoma cells from clone 3 .7.2C to assess the capability of III 2 3 3 3-heptafluoropropane (HFC-227ea) to induce gene and chromosomal mutations at the thymidine kinase (tk) locus in the absence and presence of exogenous S9 metabolic activation. The provided MSDS for HFC-227ea indicated that no information was available on the solubility of HFC-227ea in water To test this volatile material, cell cultures were placed in 15 ml round-bottom glass blood tubes sealed with serum stoppers, and, using a syringe, predetermined volumes of air were removed from each tube and nominal concentrations of HFC-227ea material were introduced. Three tubes were used for each concentration, a tube containing 5 ml of cells in media without metabolic activation, a tube containing 5 ml of cells in media plus the metabolic activation mixture, and a 'sham' tube containing only 5 ml of medium. After a four-hour exposure period at 370C, the sham tubes were allowed to cool to room temperature, and the concentrations of the test material were measured using infrared (IR) analysis. HFC-227ea was tested in a concentration range-finding assay and a mutagenesis assay, with each assay conducted in the absence and presence of metabolic activation. No concentration-related increases in toxicity were obtained in either assay of HFC-227ea. These results suggest that HFC-227ea may have been insoluble in cell culture medium. In the mutagenesis assay, the negative control cloning efficiencies and spontaneous mutation frequencies met the criteria for acceptability, and positive control mutant frequencies were within the historical ranges for the laboratory.