In vitro exposure to pyrethroid-based products disrupts development of mouse preimplantation embryos

The objective of this study was to evaluate the potential toxicity of pyrethroids (deltamethrin, permethrin, fenvalerate, lambda-cyhalothrin), commercial pyrethroid-based products DECIS EW 50 (deltamethrin mixture), TOP SPOT ON STRONGER (permethrin mixture), as well as related secondary ingredients on mouse preimplantation embryo development. Two-cell stage embryos were in vitro cultured with addition of the listed chemicals until blastocyst formation. All active pyrethroids negatively affected embryonic development at 1000 mu M concentration. Decreased quality of obtained blastocysts in permethrin, fenvalerate and lambda-cyhalothrin-treated embryos was revealed as well. Deltamethrin showed harmful impact on embryo development at 100 mu M concentration. Lower concentrations of pyrethroids (1, 10 mu M) had no effect on embryo development. The presence of DECIS EW 50 containing deltamethrin at 100 mu M caused degeneration of all embryos. Similarly, TOP SPOT ON STRONGER containing 100 mu M of permethrin impaired embryonic development and quality of obtained blastocysts. Evaluated secondary ingredients (butylhydroxyanisol, butylhydroxytoluen, butylparaben and cyclohexanone) at corresponding concentrations showed damaging impact on preimplantation embryo development as well. Our results indicate that the embryotoxic potential of active pyrethroids is relatively low, whereas pyrethroid-based products have relatively high potential to impair mouse preimplantation development. Embryotoxicity of commercial products is probably attributable to the presence of secondary ingredients.