Barrier cream application reduces the formation of DNA adducts in lung tissue of mice dermally exposed to used gasoline engine oil.

Abstract

Epidemiological evidence suggests that auto mechanics are at higher risk for lung and urinary bladder cancer. Used gasoline engine oils (UGEO), a common exposure for many mechanics, are carcinogenic and increase carcinogen-DNA adduct levels in the skin and lungs of mice treated topically. The ability of a barrier cream to reduce dermal absorption of carcinogens in UGEO was evaluated. Groups of five animals were treated topically for 5 days with 25 microliters/day UGEO. A barrier cream was applied to two groups prior to exposure. Skin of both groups was washed with a commercial hand cleaner, the first group, one hour after UGEO application, the other, eight hours after application. Two other groups did not receive barrier creams before UGEO application, but were washed at one or eight hours after the oil was applied. Another group was treated with UGEO five times but was never washed; other groups consisted of barrier cream and commercial cleaner controls. Skins and lungs were harvested 24 hours after the final exposure and DNA isolated. Carcinogen-DNA adduct levels were determined by 32P-postlabelling followed by thin-layer chromatography to separate the adducts and scintillation counting to quantify the adduct level. Pre-application of barrier cream reduced markedly the carcinogen-DNA adduct levels in both skin and lung tissue of mice treated with UGEO and washed at eight hours. In the lung, this reduction was statistically significant. Adduct levels in both tissues were approximately the same in the groups washed at one hour, indicating that if the skin is washed promptly after exposure, barrier cream application is unnecessary. If, however, washing does not take place until several hours after exposure, the pre-application of barrier cream appears to significantly reduce the DNA adduct levels. These data are of practical importance to mechanics who may be working with oily parts for extended periods.