Hepatocyte ultrastructure following exposure to aroclors and pure polychlorinated biphenyls

Three agriculturally important minor species, the goat, rabbit, and duck, were exposed to various subclinical levels of pure polychlorinated biphenyls (PCBs) and/or PCB mixtures (Aroclors) for short periods of time. Upon sacrifice, liver samples were prepared for ultrastructural observation. Regardless of species, hepatocytes displayed qualitatively similar morphological responses to PCB exposure. At lower exposure levels, cellular changes included increased density of mitochondrial matrix and proliferation of endoplasmic reticulum. At higher exposure levels, degradative changes such as cytoplasmic loss and peripheralization of cytoplasm and organelles became more obvious. When compared quantitatively, it was obvious that goats were much more sensitive to PCB exposure than either rabbits or ducks. Goats showed extensive hepatocyte degradation (cytoplasmic and nucleoplasmic leaching) at exposures of 2 mg/kg body weight of Aroclor 1254. Such species-related differences in response to chlorinated biphenyls cautions against the use of single species animal models in xenobiotic exposure studies.