Tissue dose, DNA adducts, oxidative DNA damage and CYP1A-immunopositive proteins in mussels exposed to waterborne benzo[a]pyrene

Induction and elimination of bulky benzo[a]pyrene-related DNA adducts and 8-oxodGuo in mussels Mytilus galloprovincialis exposed in vivo to B[a]P-contaminated feed

“…As antioxidant defenses are greater in the digestive gland than gills (Livingstone & Pipe 1992), the absence of B[a]P effect on the gill 8-oxodGuo level observed in our experiment may have been due to lower ROS production in this tissue related to lower phase I activities (Stegeman 1985). However, this result is in contrast with the reported effect of waterborne B[a]P exposure (0.5 to 1000 ppb B[a]P) on the level of mussel gill 8-oxodGuo (Canova et al 1998). In the latter study, significantly higher 8-oxodGuo levels were observed following 48 h exposure to 5, 50 and 100 ppb B[a]P and 72 h exposure to 5, 50, 100, 1000 ppb B[a]P, with values of the same order as those recorded in our study.…”

“…As no decrease was observed in halfdosed mussels at Day 21 with a B[a]P mussel content of 340 mg kg -1 dry wt mussel, such an induction may coincide with an exposure level corresponding to a concentration in mussel greater than 340 mg B[a]P kg -1 dry wt. This seems to be in accordance with the results obtained in mussel digestive gland DNA by Canova et al (1998), which showed a dose-response increase in digestive gland 8-oxodGuo levels after 72 h exposure to concentrations ranging from 0 to 100 ppb B[a]P and decreased levels for higher concentrations (500, 1000 ppb) all leading to estimated B[a]P mussel contents greater than 387 mg kg -1 dry wt mussel. In the present study, the decrease in 8-oxodGuo levels during depuration in mussels exposed to 50 mg B[a]P kg -1 dry wt mussel d -1 also suggested the existence of DNA repair mechanisms.…”

“…In the latter study, significantly higher 8-oxodGuo levels were observed following 48 h exposure to 5, 50 and 100 ppb B[a]P and 72 h exposure to 5, 50, 100, 1000 ppb B[a]P, with values of the same order as those recorded in our study. However, the dose-response effect was not significant in the study of Canova et al (1998) due to decreased levels or the absence of any effect at intermediate/higher B[a]P concentrations.…”

Bioaccumulation and biochemical responses in mussels exposed to the water-accommodated fraction of the <i>Prestige</i> fuel oil

“…This lack of response in our study is supported by the fact that much higher levels of encapsulated Ph, Fl and BaP, than those found in our mussels, were required to exert an effect on CAT and NADPH reductase in M. edulis (Krishnakumar et al, 1997) or for water-borne BaP to cause CYP1A induction and oxidative damage in M. galloprovincialis (Canova et al, 1998). In fact, dilutions lower than 1:500 of the WAF of the Prestige oil were necessary to induce the MFO dependent EROD activity in exposed RTG-2 cells (Navas et al, 2006).…”

“…Furthermore, most of those controlled experiments are focused on particular highly toxic/carcinogenic oil components, such as benzo[a]pyrene (BaP) (Canova et al, 1998;Okay et al, 2000;Akcha et al, 2000;Cheung et al, 2004). This may be adequate for certain types of oils enriched in high molecular weight PAHs; however, this is not the case of the Prestige spill in which the alkylated 2-3 aromatic ring PAHs predominate (Albaigés and Bayona, 2003).…”