Formation of DNA adducts following laboratory exposure of the mussel, Mytilus edulis, to xenobiotics

Abstract

32P-Postlabelling was used to determine the formation of bulky hydrophobic DNA adducts following exposure of mussels ( Mytilus edulis) to the aromatic amide, 2-acetylaminofluorene (2AAF). Mussels were exposed to 2AAF either in their seawater (5 ppm) or by injection into the posterior adductor muscle (50 mg/kg total wt.). A major band of radioactivity close to the chromatogram origin was located following analysis of digestive gland DNA from treated mussels which was not present in controls. Identical adduct profiles were obtained irrespective of the route of exposure. This indicates that M. edulis can metabolize 2AAF to genotoxic products in vivo. The formation of 8-hydroxydeoxyguanosine (8OHdG) was used as a marker of oxidative DNA damage. No significant increase in 8OHdG was observed following in vivo exposure of mussels to two redox cycling compounds, menadione (100 ppb) and nitrofurantoin (100 ppb). Since treatment with these compounds has previously been shown to cause increased oxyradical production, the results may reflect limited access of reactive oxygen species to cellular DNA.