DOSE-DEPENDENT SIZE INCREASES OF AORTIC LESIONS FOLLOWING CHRONIC EXPOSURE TO 7,12-DIMETHYLBENZ(A)ANTHRACENE

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (2) , 588-592
Abstract
The prevalence, size and patterns of distribution of arterial lesions (plaques) were investigated in cockerels exposed chronically to [the carcinogen] 7, 12-dimethylbenz(a)anthracene (DMBA). Animals, from 5-20 wk of age, received weekly i.m. injections of 5, 10 or 20 mg DMBA per kg, dissolved in dimethyl sulfoxide. Control animals received weekly injections of dimethyl sulfoxide. All animals were sacrificed at 21 wk. The entire aorta from each animal was cut transversely into 5 mm segments. The cross-sectional area of plaques was determined by light microscopic analysis of sections taken from the face of each segment. Plaque frequency was similar in DMBA-treated and control groups. Mean plaque cross-sectional area was 7- to 11-fold higher for the treatment groups than for the controls. The distribution of plaque areas in treated animals and controls was consistent with a log normal distribution. Median cross-sectional area and plaque volume index each increased in a linear fashion with DMBA dose. Small plaques were present in all groups. Large plaques were present only in DMBA-treated animals. Labeling indices of plaques, although low, were 2.3- to 26-fold higher than for underlying medial smooth muscle cells. The primary response to chronic DMBA exposure is a dose-dependent size increase of spontaneous aortic lesions and not the induction of new lesions.

This publication has 1 reference indexed in Scilit: