PCB 128-induced ultrastructural lesions in the rat liver

PCB 128 (2,2',3,3',4,4'-hexachlorobiphenyl) prepared in 4% corn oil and mixed in diets was given to weanling Sprague-Dawley rats. The animals were placed in eight groups, each comprising 10 males or 10 females; each group received a diet that contained 0.05, 0.5 or 5 ppm PCB. Ten animals of each gender that served as the controls were given diets mixed with only corn oil. Thirteen weeks after the commencement of dosing, animals were euthanized and liver specimens were harvested and prepared for transmission electron microscopy. The architecture of the liver parenchymal cell was indistinguishable in the animals of the lowest concentration group from those in the controls. However, smooth endoplasmic reticulum profiles increased, and abnormal mitochondria were noted in the liver of rats, regardless of gender, from 0.5 and 5 ppm groups. Based on our previous work, PCB 128 is estimated to be equally toxic as PCB 153, another di-ortho substituted PCB congener.