Acute toxicity of polychlorinated dibenzofurans in CF-1 mice

Eight-week-old CF-1 mice, male and female, were given synthesized polychlorinated dibenzofurans (PCDF) orally, sc, or ip as a single exposure. The oral LD50 was approximately 200 mg/kg in males and 400 mg/kg in females. In mice that died, hepatomegaly and atrophy of the thymus were consistent findings; subcutaneous edema and dermal alterations also occurred frequently. In surviving mice, the liver showed small necrotic foci accompanied by cellular infiltrates in sections stained with hematoxylin and eosin. Ultrastructural alterations of hepatocytes 30 days after exposure consisted of a marked increase in lipid droplets and moderate hypertrophy of smooth-surfaced endoplasmic reticulum. From these results, it was concluded that the nature of toxic responses to PCDF was similar to that associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin.