EFFECTS OF A SINGLE DOSE OF 7,12-DIMETHYLBENZ(A)-ANTHRACENE ON EPIDERMIS AND HAIR FOLLICLES OF MICE WITH NOTES ON CONCURRENT CHANGES IN OVARIES AND ADRENALS

Mice of three pure lines were painted with one application of approximately 075 mg. of 7,12-dimethylbenz(a)anthracene (DMBA) in acetone, and histologically examined at intervals up to 28 days thereafter. The surviving mice were painted with croton oil in acetone to establish that the dose of DMBA was effectively initiating. Macroscopic epilation started at 6 days, and had occurred in all mice by 11 days. Four days after DMBA, the superficial epidermis, distal parts of hair follicles and sebaceous glands were necrotic or destroyed. Regeneration of the epidermis took place by in growth from the surrounding untreated skin from 4 days onwards. From this regenerated epidermis new hair follicles were differentiated de novo. When the proximal part of the hair follicles survived, it formed cysts which underwent degeneration and absorption with foreign body reaction. Tumours arose from the superficial epidermis; the hair follicles played no part, and none of the tumours showed trichoepitheliomatous structure. Mast cells were associated with hair follicles, and were abundant in the stroma of papillomas, but not of carcinomas. The ovaries showed loss of oocytes in two of the strains from 6 days onwards; no recovery took place. In the C3H strain oocytic destruction was not so complete; biological testing showed them still viable 28 days and more after DMBA. The adrenal showed loss of medulla, zona reticularis and zona glomerulosa at from 7-9 days. Recovery took place from 19 days onwards; at no stage was there overt necrosis. © 1969, The British Empire Cancer Campaign for Research. All rights reserved.