Dermal oncogenicity studies on ethylenediamine in male C3H mice

• Published in: Fundamental and applied toxicology 1984-01, Vol.4 (4), p.641-645
• Main Authors: DePas, Linval R., Fowler, Edward H., Yang, Raymond S.H.
• Format: Article
• Language: English
• Subjects: Animals; Body Weight - drug effects; Ethylenediamines - toxicity; Male; Mice; Mice, Inbred C3H; Skin Neoplasms - chemically induced; Time Factors
• ISSN: 0272-0590; 1095-6832
• DOI: 10.1016/0272-0590(84)90055-1

The dermal oncogenic potential of ethylenediamine (EDA) was assessed by applying 25 μl of a 1% solution in deionized water to the skin of 50 male C3H/HeJ mice. This was the highest concentration not producing irritation or weight changes in a preliminary 2-week study. Two EDA samples (Nos. 1 and 2) from different production sources were tested. Applications were made thrice weekly until the death of the animals. A negative control group received deionized water only. This group and the EDA-treated groups were individually housed. A fourth group of 40 mice, housed 5 per cage, received 0.1% 3-methylcholanthrene (MC) in acetone as a positive control substance. A fifth group of 40 mice, housed 5 per cage, also received deionized water to determine the effect of group housing on survival. No skin tumors were observed in the EDA-treated groups. In the positive control group, however, 39 animals (98%) had skin tumors including 37 (92%) with confirmed squamous cell carcinomas. Eleven mice (22%) which received EDA No. 1 had dermal fibrosis indicative of probable skin irritation in this group; there was no such lesion in the controls. The mean survival times were 639, 626, and 598 days for the EDA No. 1, water control, and EDA No. 2 groups, respectively. The survival time of the EDA No. 2 group was significantly reduced compared to the individually housed water controls by one of two statistical tests. Irrespective of this difference, the study is considered to be a valid assessment of the oncogenic potential of EDA No. 2 because the magnitude of the difference in mean survival time was small. The group-housed water controls showed markedly reduced survival time (mean = 488 days) compared to the singly housed controls. Neither EDA sample was oncogenic under the conditions of this study.