Polychlorinated biphenyl (PCB) toxicity in adult cynomolgus monkeys (M. fascicularis): a pilot study

Aroclor 1254 and Aroclor 1248, at doses of 11.7 and 4.7 mg/kg body weight (equivalent to 5 and 2 mg/kg/day), were given 3 days per week to groups of cynomolgus monkeys, and caused weight loss, fingernail loss, facial edema, epiphora, and death. Blood and adipose tissue PCB concentrations rose with the length of treatment. Tissue concentrations in blood, adipose tissue, liver and kidneys were highest in monkeys treated with Aroclor 1254, reflecting dose differences. There was considerable variation, both within and between groups, in hematologic responses to PCB treatment. Aroclor 1254-treated monkeys had depressed and weakly responsive erythropoiesis. Aroclor 1248-treated monkeys had active but ineffective or depressed erythropoiesis with severe macrocytic or moderate normocytic anemia. Biochemical determination of blood serum constituents revealed treatment and time-related trends towards hypoalbuminemia and increased alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, lactic dehydrogenase, cholesterol, triglycerides, total bilirubin and direct bilirubin values. Pathologic lesions common in both Aroclor groups were dilatation of meibomian glands duct; mucinous hyperplasia of the gastric mucosa; atrophy and loss of germinal centers in the splenic and other lymphoid follicles; enlargement, fatty degeneration, and necrosis of hepatocytes; bile duct and gall bladder epithelial cell hypertrophy and hyperplasia; and thyroid aberrations in follicular cell size and number of intracytoplasmic lysosomes. Lesions seen exclusively in an Aroclor 1254-treated monkey were widespread mucinous metaplasia and hyperplasia of the fundic mucosa. The results suggest that in general, cynomolgus monkeys may be more refractory or less susceptible to PCB toxicity than rhesus monkeys and, that Aroclor 1248 may be more toxic than Aroclor 1254.