The influence of preliminary irritation by acetic acid or croton oil on skin tumour production in mice after a single application of dimethyl-benzathracene, benzopyrene, or dibenzanthracene.

A W Pound

doi:10.1038/bjc.1968.64

Abstract

Groups of mice were given a single application of acetic acid to one side of the skin of the back. Other groups were given an application of croton oil to the whole area of the skin of the back, a control group had no application of croton oil. At the same time as, 24 hours, 72 hours, or 9 days after the application of acetic acid or croton oil, the mice were given a single application of one of the carcinogenic hydrocarbons DMBA, BP or DBA, to the whole area of the skin of the back. The number of tumours produced was greater in areas that had the preliminary treatment with acetic acid or croton oil at the same time or 24 hours before the carcinogen. There was a doubtful effect at an interval of 3 days and no effect at 9 days. It is considered that proliferating epidermal cells are more susceptible to the action of the carcinogens perhaps during replication of DNA.

Highlights

MethodsRandom bred male mice of the strain " Hall " (Pound, 1962) from the Department of Pathology at the Royal Brisbane Hospital were used
In the control Experiment V, no tumours appeared during 40 weeks observation of the mice that had a single application of acetic acid (75 survivors) or croton oil (82 survivors)
The smallest doses (9 jug. per sq. cm.) of the carcinogenic hydrocarbons did not produce any clinically obvious changes in the skin and did not alter the changes visible to the naked eye in areas previously treated with croton oil or acetic acid

Summary

Methods

Random bred male mice of the strain " Hall " (Pound, 1962) from the Department of Pathology at the Royal Brisbane Hospital were used. The animals were about 7 weeks of age and weighed 24-26 g. They were housed in stainless steel compartments, each holding 10 mice, with a bed of coarse sawdust that was changed weekly, and were fed the diet previously used (Pound and Withers, 1963) supplied, with water, in excess of their needs. The animal house was air-conditioned at 22° C. Chemicals Acetic acid, Osta Chemical Company, analytical reagent.

Results

Discussion

Conclusion