Nitrogen dioxide exposure alters neonatal development.

Nitrogen dioxide (NO2) is one of the commonly encountered environmental contaminants. Experiments were carried out to test for neonatal behavioral alterations associated with prenatal NO2 exposure. Pregnant CD-1 mice were exposed in environmental chambers to 0, 22, or 45 ppm of NO2 in air from gestation day 7 to 18. The gas-air flow was set at 450 ml/min. Food and water were available at all times. The dams were allowed to deliver and neonatal behavioral development of the pups was studied. Nitrogen dioxide exposure did not affect the number of live pups born/litter; however, it significantly decreased their birth weight. Prenatal NO2 exposure at both levels significantly altered the righting reflex and aerial righting score of the pups on postnatal days 1 and 12, respectively. Prenatal NO2 exposure did not affect negative geotaxis and activity scores of pups on postnatal day 10 and 28, respectively. The data suggest that maternal NO2 exposure at low levels can affect neuromuscular coordination and thus produce deficits in the functional capability of the offspring.