The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings have not been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of the NTP or the U.S. Government.
Ethylenediamine is used to control alkalinity, in fungicides, manufacturing of chelating agents (EDTA), as a solvent stabilizer, and a stabilizer in many dermatological creams and the smooth muscle relaxant aminophylline, as a chemical intermediate, an emulsifying agent, in antifreeze as a corrosion inhibitor, in rubber accelerators, and in neutralizing oils.. It was selected for evaluation as a sensitizing agent for contact hypersensitivity in mice.
The sample was obtained from Aldrich Chemical Co. (Milwaukee, WI) by way of the Research Triangle Institute (Research Triangle Park, NC) as a clear colorless liquid (99.9%, Lot/Batch # 6719-186-03, GAS # 107-15-3). It was prepared in 70% ethanol which also served as the vehicle. Primary irritancy studies indicated that 10% ethylenediamine was the minimum irritating concentration. In the hypersensitivity study mice were divided into 11 treatment groups of 8 mice/group as shown in Table 1. The mice were sensitized dermally to either 0, 0.3, 1.0, or 3.0% solutions of EDA daily for five consecutive days and challenged 7 days later with a 10% solution. A 0.5% solution of 1-fluoro-2,4-dinitrobenzene (DNFB, Sigma Chem. Corp.; Lot No. 611-13914; 98.6% pure as determined by HPLC), was used as challenge dose for a positive control. Site preparation included intradermal injection of Freund's complete adjuvant in some mice. Irritancy responses were determined by monitoring the extravasation of 1251 bovine serum albumin into the treated area. Hypersensitivity responses were determined by measurement of ear swelling.
A dose-dependent allergic contact hypersensitivity response to ethylenediamine was detected on the second day following challenge, using % ear swelling for analysis, in groups which were not pretreatment with Freund's complete adjuvant (FCA). A statistically significant (p<0.01) response was detected when 3.0% ethylenediamine was used for induction. When left ear thickness was used for analysis, no dose dependency could be detected. However, statistically significant responses were obtained with induction concentrations of 0.3% (p<0.05) and 1.0% (p<0.01) ethylenediamine with FCA pretreatment, and 0.3% (p<0.01) and 3.0% (p<0.05) without FCA pretreatment. On the first day following challenge there was not a dose dependent response. A group of mice pretreated with FCA, and induced with 1.0% ethylenediamine demonstrated a statistically significant (p<0.05) response, when left ear thickness was used for analysis. The positive control group produced a statistically significant contact hypersensitivity response at a sensitizing concentration of 0.25% and challenge concentration of 0.5% DNFB.
A significant dose-dependent contact hypersensitivity response could be demonstrated in B6C3F1 female mice with ethylenediamine.