DETECTION OF MICRONUCLEI IN GILL CELLS AND HEMOCYTES OF MUSSELS EXPOSED TO BENZO[A]PYRENE

Mediterranean mussels were exposed to benzo[a]pyrene for 2 days at dos es which had previously caused the formation of specific adducts in gi ll DNA. Micronuclei and other nuclear abnormalities were detected in g ill cells and haemocytes in order to ascertain the induction of cytoge netic damage in two different target cells in parallel. A number of pr ocedural details were examined initially to improve the quality of sli des obtained from mussel cells. Adequate cytological preparations were obtained when gill cells and haemocytes were suspended, respectively, in Alsever and sea water with EDTA, cytospun and fixed with absolute methanol. In the exposed mussels, micronuclei significantly increased in both the large gill cells (the main cell type) and the agranular ha emocytes. Granular haemocytes, cells present in variable proportions b etween individual mussels, did not show cytogenetic damage except at t he highest B[a]P doses. In the same slides, steady levels of binucleat ed cells were detected, whereas the incidence of other nuclear abnorma lities was significantly higher in the exposed compared with control m ussels. Precise knowledge of the replication kinetics of gill cells an d haemocytes is still lacking.