Effects of lead nitrate on postimplantation rat embryo development in vitro: Palminger I,∗ Kihlström I.† ∗Department of Toxicology, Biomedicum, Box 594, Uppsala University, Uppsala Sweden; †Department of Toxicology, Pharmacia LEO Therapeutics AB, Uppsala, Sweden

Abstract

Citrinin (a mycotoxin produced as a frequent contaminant of food and feed by numerous species of Aspergillus and Penicillium fungi) is embryo/fetoxic and embryocidal in mice and rats. The present study was designed to examine whether the in vivo observed developmental toxicity of citrinin could be recapitulated using the Hydra attenuata (HA) bioassay and then be confirmed in rat whole embryo culture (WEC). Results from the HA assay indicated that the minimal effective concentrations of citrinin required to elicit a toxic response in the adult hydra (MACA) and in the regenerating hydra (MACD) were 30 mg/l and 20 mg/l, respectively. The Hydra developmental hazard index (A/D ratio) was equal to 1.5, classifying citrinin as a coaffective developmental toxin. In WEC, rat embryos were cultured in homologous (rat) serum containing citrinin at various concentrations ranging from 0.0 and 300 μg/ml for a period of 45 h. The results indicated a concentration-dependent reduction in yolk sac diameter, crown-rump lenght, somite number, protein and DNA contents. No embryonic dysmorphogenesis was observed in any treatment group. Histological examination revealed severe diffuse mesodermal and ectodermal necrosis in embryos treated with 250 μg/ml citrinin. At lower concentrations of citrinin, embryos were neither grossly nor histologically different from controls. Both the HA and WEC bioassays demonstrated that citrinin is not a primary developmental toxin. The use of HA and WEC bioassays in tandem may facilitate the rapid detection and ranking of the developmental hazards of food and feedborne myocotoxins.