Maternal exposure to diesel exhaust alters placental function and induces intergenerational effects in rabbits

International audience; Airborne pollution is a rising concern in urban areas. Epidemiological studies in humans and animal experiments using rodent models indicate that gestational exposure to air- borne pollution, in particular diesel engine exhaust (DE), reduces birth weight. These effects depend on exposure duration, ges- tational window, and nanoparticle (NP) concentration. Our aim was to evaluate the effects of exposure to diluted DE on F0 on feto-placental development in a rabbit model in the F1 and F2 generations. Pregnant females were exposed to diluted (1 mg/m3), filtered DE (NP diameter ≈ 69 nm) or clean air (controls) for 2 h/day, 5 days/week by nose-only exposure (total exposure: 20 days in a 31-day gestation). DE exposure induced early signs of growth retarda- tion at mid gestation with decreased head length (p = 0.04) and umbilical pulse (p = 0.018). Near term, fetal head length (p = 0.029) and plasma insulin and IGF1 concentrations (p = 0.05 and p = 0.019) were reduced. Placental function was also affected, with reduced placental efficiency (fetal/placental weight) (p = 0.049), decreased placental blood flow (p = 0.009) and fetal vessel volume (p = 0.002). Non-aggregated and “fingerprint” NP were observed at various locations, in maternal blood space, in trophoblastic cells and in the fetal blood, demonstrating transplacental transfer. Adult female offspring were bred with control males. Although fetoplacental biometry was not affected near term, second generation fetal metabolism was modified by grand-dam exposure with decreased plasma cholesterol (p = 0.008) and increased triglyceride concentrations (p = 0.015). Repeated daily gestational exposure to DE at levels close to urban pollution can affect feto-placental development in the first and second generation.