Health Implications of 2,3,7,8-Tetrachlorodibenzo-p-dioxin Exposure in Primates

Tetrachlorodibenzo-p-dioxin (TCDD) was administered in the diet at a level of 500 parts per trillion to eight adult female rhesus monkeys for nine months. Effects included acne, loss of hair and eyelashes and periorbital edema during the initial three months of exposure. There was also a decrease in 17β-estradiol and progesterone levels as well as the development of irregularities in their menstrual cycles. Inability to conceive and early abortions occurred in the animals following six months exposure to TCDD. Death in 5 of the 8 experimental animals was preceded by a severe pancytopenia. Microscopic changes included suppression of hematopoiesis in the bone marrow, hypocellularity of the lymphoid tissue, widespread hemorrhage, cardiac hypertrophy, edema and dilatation, hyperplasia and metaplasia of ductal tissue throughout the body, hypertrophic gastritis with ulceration, and dilatation of the biliary system. Death in most instances was attributed to the extensive hemorrhage that was associated with the thrombocytopenia.