Weekly i.m. injections of the polycyclic hydrocarbon carcinogens, 7,12-dimethylbenz(a,h)anthracene (DMBA; 25 mg/kg/injection) and benzo(a)pyrene (50 mg/kg/injection) were given for a period of up to 22 weeks to chickens (SC strain) beginning at age 4 weeks. Atherosclerotic lesions of the abdominal aorta occurred more frequently and were larger in the DMBA- and benzo(a)pyrene-treated birds than in controls. These lesions were proliferative in character as indicated by a higher [3H]thymidine autoradiographic labeling index compared to the underlying medial cells of the aorta. Measurements of serum cholesterol in DMBA-treated birds showed no differences from controls. Although both carcinogens accelerated the development of atherosclerotic plaques, DMBA was more potent than benzo(a)pyrene.
This investigation was supported by Center Programs of the National Institute of Environmental Health Sciences Grant ES 00260 and National Cancer Institute Grant CA 13343.