REPRODUCTIVE TOXICITY OF AROCLOR-1254 - EFFECTS OF OOCYTE, SPERMATOZOA, IN-VITRO FERTILIZATION, AND EMBRYO DEVELOPMENT IN THE MOUSE

Polychlorinated biphenyls (PCBs) have been reported to adversely affec t reproduction in laboratory and wild animals. The present study was u ndertaken to determine the toxic potential of Aroclor-1254 (A-1254) on in vitro fertilizing ability of oocytes and epididymal sperm and on p reimplantation embryo development in the mouse. A-1254 was added to th e IVF medium at concentrations of 0.01, 0.1, 1.0, and 10.0 mu g/mL. Cu mulus masses containing the oocytes were obtained from superovulated B 6D2F1 mice and were placed in the culture medium containing A-1254 to which epididymal sperm, capacitated in a medium without A-1254, were a dded. The IVF rate was assessed 20 to 24 h after insemination. A-1254 significantly reduced the mean percent ova fertilized even at 0.1 mu g /mL. Incubation of the cumulus masses in various concentrations of A-1 254 for 6 h, followed by insemination with sperm capacitated in the pr esence of A-1254, also significantly reduced the IVF rate. Capacitatio n of sperm in A-1254-containing medium, followed by co-culture with un treated oocytes, failed to affect the IVF rate. No significant effect on sperm motility was observed following exposure to 1 and 10 mu g/mL of A-1254. Estradiol-17 beta also reduced the IVF rate, however, the e ffect of A-1254 was more severe compared to the estradiol treatment. F urthermore, addition of A-1254 to the embryo culture medium was associ ated with a significant decrease in embryo growth at 48 h and 96 h. Th ese results demonstrate adverse effects of A-1254 on oocytes, IVF, and embryonic development in the mouse.