Interaction of benzo[a]pyrene with CYP 1A and SODs in Chamelea gallina haemocytes.

Several enzymes are involved in B[a]P (carcinogenic PAH compound) biotransformation and the CYPlA subfamily represent the main forms of P450 identified in marine invertebrates. The P450 dependent oxidative metabolism of B[a]P leads to the production of ROS. About this, SOD represents an appropriate response to oxidative injury as a mechanism of protection against increasing ROS levels. This research was focused on the study of the induction of CYP lA and SODs in haemocytes (immune system of invertebrates) of Chamelea gallina (Adriatic bivalve) exposed to B[a]P. l l i Clams were exposed to 0.5 mg/L B[a]P dissolved in sea water by acetone. Samples were taken at 0- (control), 24 h, 7 and 12 days of exposure. The controls with acetone were performed during the exposure. The B[a]P were analyzed in total soft tissues of pooled animals by HPLC, CYP lA and SOD were detected in pooled haemocytes, by WB and by spectrophotometrical analyses. After 24 h, B[a]P was accumulated very quickly, the increase was further rapid at 7 days of exposure (p<0.05 than the control) with similar values after 12 days. Two bands were detected from CYP lA (58 and 61 kDa), without differences of expression while a significant decrease in MnSOD activity and expression were observed after 7 days of exposure (p<O.O l). Cu/ZnSOD and ECSOD expression showed the same behaviour of MriSOD (p<0.05). No interactions due to acetone were recorded on CYP and SOD. The decrease in MnSOD might be associated with a lowering antioxidant capability of haemocytes, while the absence of CYP lA induction was imputable to the pivot role of digestive gland in biotransformation process ofB[a]P respect to haemocytes. Overall, the results indicate that Chamelea may be a useful organism for ecotoxicological studies.