Induction of mitotic cell division disturbances and mitotic arrest by pyrethroids in V79 cell cultures

Five pyrethroids (fenvalerate, deltamethrin, cypermethrin, permethrin, cyfl uthrin) differing in their chemical purity were investigated on their cytot oxic effects, especially on their ability to induce mitotic cell division d isturbances using Chinese hamster lung cells of line V79. The colony formin g ability (CFA) resulted in distinct differences of the cytotoxic effect of the tested pyrethroids, whereby permethrin was found to be most toxic. Wit h the exception of fenvalerate all tested pyrethroids gave rise to inhibiti on of cell cycle progression as shown by G2/M-arrest of synchronized V79 ce lls by flow cytometry as well as by the increase of the mitotic index as ev aluated by light microscopy. The mitotic arresting activity could be attrib uted to the occurrence of abnormal mitotic figures such as initial and full C-metaphases. The results however indicate, that pyrethroids per se do not contribute to the cytotoxic effects but that other factors such as chemica l impurities, source as well as manufacturing process and isomer compositio n may be responsible for the observed cytotoxic effects. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.