Evaluation of an exposure system using cells grown on collagen gels for detecting highly volatile mutagens in the CHO/HGPRT mutation assay

Abstract

Chinese hamster ovary (CHO) cells were grown on hydrated collagen gels, the overlaying medium removed leaving the cells at an air/collagen interface, and the cells exposed to a dynamic flow of ethylene oxide. Increases in CHO cell mutant frequency and decreases in cell viability were observed. To establish if the exposure system could be simplified, cells were exposed in sealed bottles (static system) to ethylene oxide. No substantial changes in cytotoxicity, mutant frequency, or effective concentration were noted when comparing static versus dynamic exposure systems. The general usefulness of the exposure system using cells grown on collagen gels was evaluated in a static system using propylene oxide and 1,2-dichloroethane, both of which were found to be mutagenic and cytotoxic. Comparatively, the exposure of cells by the collagen gel method was as effective in detecting genotoxic damage as were conventional methods (cells covered with medium) using cells grown on glass substrates. The exposure of CHO cells on collagen gels to highly volatile mutagens was simple and inexpensive, and may be generally useful in the detection of gaseous or volatile mutagens.