Formaldehyde-induced cytotoxic, genotoxic and mutagenic response in human lymphocytes and Salmonella typhimurium

The incidences of chromatid-type aberrations and sister-chromatid exchanges were significantly increased in human lymphocytes treated with formaldehyde (FA) in vitro. In the presence of the mammalian metabolic activation system, i.e. S9 mix, the yields were reduced, although not to control levels. With S9 mix the structural chromosome damage induced by exposure to 1.0 mM FA was qualitatively and quantitatively identical to that induced by 0.05 mM cyclophosphamide (used as positive control for metabolic activation). Cell proliferation was clearly reduced with or without the presence of S9 mix. In a plate assay with Salmonella typhimurium strain TA100 in the absence and presence of S9 mix, a weak mutagenic response was observed. Using the pre-incubation method, FA induced without S9 mix a 1.6-fold and with S9 mix a 2.7-fold increase of revertant numbers over controls.