Tobacco smoke-induced clastogenicity in mouse fetuses and in newborn mice

The clastogenic activity of tobacco smoke (TS) was established in mouse fetuses employing the micronucleus test. A 1-h exposure of pregnant mice BDF1 (C57Bl x DBA2) to TS (600 cm3 TS in a 14-l glass chamber, 4 exposures of 15 min each with 1 min intervals during which a total air change was made) on day 16/17 caused a 2-3-fold increase in the number of micronucleated polychromatic erythrocytes (MN PCEs) in fetal liver as well as in the liver of newborn mice (1-5 h after birth). A similar, although slightly greater micronucleus response occurred in fetuses obtained from pregnant mice treated repeatedly with TS (60 min/day in total) starting on day 11 of gestation. The in vivo clastogenic activity of TS was also established by evaluating the MN PCE level in the peripheral blood of newborn mice (1-5 h after birth and during the first several days of life) treated transplacentally with TS during the last third of pregnancy. The young animals (1-3 weeks old) were more sensitive to the clastogenic activity of TS as compared to their 6-month-old mothers but no data were obtained showing a possible passing of the TS-contained clastogens from 'smoking' lactating mothers to their suckling offspring. The combined application of micronucleus test proved to be very convenient and useful when studying the different aspects of TS-induced genotoxicity.