Maternal titanium dioxide nanomaterial inhalation exposure compromises placental hemodynamics.

ABSTRACT: The fetal consequences of gestational engineered nanomaterial (ENM) exposure are unclear. The placenta is a barrier protecting the fetus and allowing transfer of substances from the maternal circulation. The purpose of this study was to determine the effects of maternal pulmonary titanium dioxide nanoparticle (nano-TiO2) exposure on the placenta and umbilical vascular reactivity. We hypothesized that pulmonary nano-TiO2 inhalation exposure increases placental vascular resistance and impairs umbilical vascular responsiveness. Pregnant Sprague-Dawley rats were exposed via whole-body inhalation to nano-TiO2 with an aerodynamic diameter of 188?±?0.36?nm. On gestational day (GD) 11, rats began inhalation exposures (6?h/exposure). Daily lung deposition was 87.5?±?2.7??g. Animals were exposed for 6?days for a cumulative lung burden of 525?±?16??g. On GD 20, placentas, umbilical artery and vein were isolated, cannulated, and treated with acetylcholine (ACh), angiotensin II (ANGII), S-nitroso-N-acetyl-DL-penicillamine (SNAP), or calcium-free superfusate (Ca2+-free). Mean outflow pressure was measured in placental units. ACh increased outflow pressure to 53?±?5?mmHg in sham-controls but only to 35?±?4?mmHg in exposed subjects. ANGII decreased outflow pressure in placentas from exposed animals (17?±?7?mmHg) compared to sham-controls (31?±?6?mmHg). Ca2+-free superfusate yielded maximal outflow pressures in sham-control (63?±?5?mmHg) and exposed (30?±?10?mmHg) rats. Umbilical artery endothelium-dependent dilation was decreased in nano-TiO2 exposed fetuses (30?±?9%) compared to sham-controls (58?±?6%), but ANGII sensitivity was increased (-79?±?20% vs -36?±?10%). These results indicate that maternal gestational pulmonary nano-TiO2 exposure increases placental vascular resistance and impairs umbilical vascular reactivity.

SUBMITTER: Abukabda AB 

PROVIDER: S-EPMC6422339 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature