Natural history of TCDD‐induced liver lesions in rats as observed by transmission electron microscopy during a 32‐week period after a single intraperitoneal injection

Forty‐two male rats were injected with a single intraperitoneal dose of TCDD in acetone and corn oil and sacrificed after 2, 4, 8, 16, 24, and 32 weeks, to study the long‐term effects of a single injection. The liver lesions become progressively worse up to the 16th week and appear thereafter to slowly regress.