Mutagenicity and cytotoxicity of 2-methoxyethanol and its metabolites in Chinese hamster cells (the CHO/HPRT and AS52/GPT assays)

Abstract

2-Methoxyethanol (ethylene glycol monomethyl ether) (EGME), is one of the most commonly used solvents for industrial and consumer products. Although the solvent has been shown to be a reproductive toxin the genotoxic activities of EGME especially its metabolites, have not been adequately investigated. The mutagenicity and cytotoxicity of EGME and its major metabolites, methoxyacetaldehyde (MALD) and methoxyacetic acid (MAA) in Chinese hamster ovary (CHO) cells were therefore examined by us. We have determined the mutagenicity of these compounds at the hypoxanthine-guanine phosphoribosyltransferase ( hprt) locus in CHO-K1-BH4 cells (CHO/HPRT assay) and the xanthine-guanine phosphoribosyl transferase ( gpt) locus in CHO AS52 cells (AS52/GPT assay). The results show that these chemicals are not mutagenic to the hprt locus in CHO-K1-BH4 cells either with or without rat liver S9 mix as the metabolic activating system. With AS52 cells, only MALD is mutagenic in the absence of S9. It induced a dose-dependent mutagenic response. A dose-dependent cytotoxicity was induced by all compounds in both cell lines. MALD is the most and EGME is the least cytotoxic compounds. Our study shows that a metabolite of EGME, MALD, is highly cytotoxic and likely induces deletion-type mutations in AS52 cells. The genotoxic effect of EGME is, therefore, dependent upon its metabolism and its detection is dependent upon the assays used.