Gestation stage-specific oxidative deoxyribonucleic acid damage from sidestream smoke in pregnant rats and their fetuses.

Transplacental exposure to environmental tobacco smoke (ETS) is a possible cancer risk factor in offspring. The authors exposed pregnant Sprague-Dawley rats to a relevant dose of ETS (1 mg/m3) from gestation day 4 to days 16 or 21. They then assayed tissues for levels of 8-oxo-2'-deoxyguanosine (8-oxo-dG), a marker of oxidative deoxyribonucleic acid damage. ETS exposure ending on gestation day 16 resulted in statistically significant increases in 8-oxo-dG in maternal liver and kidney and in fetal kidney. On gestation day 21, there were significant 8-oxo-dG increases in fetal liver and brain. These gestational stage- and tissue-specific increases of 1.2- to 1.4-fold are similar to the putative relative increases in risk of human cancers related to ETS.