TISSUE DOSE, DNA-ADDUCTS, OXIDATIVE DNA-DAMAGE AND CYP1A-IMMUNOPOSITIVE PROTEINS IN MUSSELS EXPOSED TO WATERBORNE BENZO[A]PYRENE

A collaborative study was performed on Mediterranean mussels (Mytilus galloprovincialis) exposed to a wide dose-range (0.5-1000 ppb) of benz o[a]pyrene (B[a]P). We selected this model polycyclic aromatic hydroca rbon in order to confirm the formation of a specific DNA adduct, previ ously detected in gill DNA, and to clarify the in vivo effects of this mutagenic chemical requiring host-metabolism in mussels, B[a]P concen tration reached consistently higher values in the digestive gland than in other analyzed tissues of mussels exposed to B[a]P for 2 or 3 days . With the exception of some values at 1000 ppb of B[cr]P, DNA adduct levels increased significantly with the dose in gills and digestive gl and and ranged from 0.054 to 0.789 adducts per 10(8) nucleotides (mean values per dose-point). Conversely, more complex dose-response relati onships were found by detecting in parallel the levels of an oxidative DNA lesion (8-OHdC) and of CYP1 A-immunopositive proteins (the latter measured in the digestive gland only), Overall, the formation of DNA adducts, the evidence of oxidative DNA damage, and changes in CYP1 A-i mmunopositive protein levels support the hypothesis that B[a]P can ind uce DNA damage in mussels through a number of different molecular mech anisms. (C) 1998 Elsevier Science B.V.