Chronic Toxicity of 3,4,3′,4′-Tetrachlorobiphenyl in the Marmoset Monkey (Callithrix Jacchus)

In this study, cotton top marmoset monkeys were orally dosed with varying amounts of 3,4,3′,4′-tetrachlorobiphenyl (TCB) over 18-23 weeks. Severe toxicity was observed in the highest dose group (3 mg/kg), including rapid weight loss, alopecia, abnormal nail growth, and scaly skin. Hematological and biochemical analyses showed mild leukocytosis, anemia, elevated triglyceride, and cholesterol levels. Histopathological changes were dose-dependent, affecting multiple tissues, including skin, salivary glands, stomach, duodenum, ovaries, and thyroid. Toxicity was less severe at 1 mg/kg and minor at 0.1 mg/kg. The marmoset monkey was less sensitive to TCB toxicity compared to rhesus monkeys, but the observed changes were similar to those in humans and other primates exposed to PCBs, suggesting the marmoset as a valuable model for studying human-related PCB toxicity.