EFFECTS OF POLYCHLORINATED-BIPHENYLS (PCBS) ON IN-VITRO FERTILIZATIONIN THE MOUSE

Polychlorinated biphenyls (PCBs) are industrial chemicals that are lon g-lasting global environmental contaminants. PCBs have been reported t o adversely affect reproduction in laboratory and wild animals by redu cing the incidence of breeding and the survival rate of young. The pre sent study was undertaken to determine the toxic potential of PCBs on in vitro fertilization (IVF) in the mouse. Aroclor 1221, 1254, and 126 8, and 3, 3', 4, 4'-tetrachlorobiphenyl (TCB), a PCB congener, were ad ded to IVF medium at various concentrations (0.01, 0.1, 1, and 10 mu g /mL), Cumulus masses containing oocytes were obtained from superovulat ed B6D2F1 mice and cultured in medium containing PCB to which capacita ted sperm were added. Oocytes were assessed for fertilization 20 to 24 h after insemination. A-1221, A-1268, and TCB reduced the fertilizati on rate at the 1 mu g/mL and 10 mu g/mL doses, while inhibition of fer tilization by A-1254 reached significance at 0.1 mu g/ml. Furthermore, all of these chemicals caused an increased incidence of degenerative ova and abnormal 2-cell embryos at the higher dose levels (1 mu g/mL a nd 10 mu g/mL). The results suggest that higher dosages of PCB and TCB adversely affect fertilization and cause an increased incidence of de generation of oocytes and abnormality in the early mouse embryos.