Cytotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin on primary cultures of adult rat hepatocytes

Primary cultures of adult rat hepatocytes were used to study the cytotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Rats were treated with a single oral dose of 5, 10 or 25 Μg/kg of TCDD. At 2, 6, 10, 20, 30 days post-treatment, hepatocytes were isolated by a collagenase perfusion technique and maintained 48 hr as monolayers in serum-free medium in collagen-coated culture dishes. Uptake of ouabain was depressed in hepatocyte cultures isolated from all three doses of TCDD-treated rats. The effect was detected two days after TCDD-treatment and continued up to 30 days. The magnitude of the depression was directly related to the dose of TCDD. Hepatocyte cultures from TCDD-treated rats also showed depression in hormonally induced uptake of α-aminoisobutyric acid (AIB) and tyrosine aminotransferase (TAT) activity at 10 and 25 Μg/kg but not at 5 Μg/kg. These cytotoxic effects of TCDD could be demonstrated only when TCDD was given to rats prior to isolation of hepatocytes; no toxic effects were observed when TCDD was added directly to the hepatocyte cultures. Pretreatment of rats with 1,3,6,8-tetrachlorodibenzo-p-dioxin had no effect on ouabain uptake, AIB transport, or TAT activities.