Perinatal exposure to low levels of carbon monoxide impairs neurobehavior in adult mice

Maternal smoking is associated with several adverse neurological outcomes including increased risk for SIDS and attention deficit disorder. Perinatal exposure to carbon monoxide (CO) disrupts development of brain structures and associates with neurological disorders. OBJECTIVE: to uncover age and sex differences in neurobehavioral phenotype of perinatally CO-exposed mice. Pregnant mice were exposed to 0, 75, and 150 ppm of CO approximating levels found in smokers from embryonic day 0 until weaning. We utilized the Open Field Test (OFT), Acoustic Startle Response/Prepulse Inhibition (ASR/PPI), and the Neurobehavioral Severity Scale Revised (NSS-R) to evaluate changes in neurological and behavioral functioning in rodents. Animals were evaluated at 14 and 60 days of life (do). RESULTS: At 14 do: (1) NSS-R increased (0.33(plus or minus)0.22, 1.56(plus or minus)0.19 and 1.27(plus or minus)0.23 at 0, 75 and 150 ppm respectively) indicating decreased sensory-motor function after exposure to CO, with females showing greater sensitivity; (2) males and females exposed to CO showed decreased startle with and without pre-pulse. RESULTS: at 60 do: (1) OFT-horizontal activity decreased without sexual preference; (2) CO-exposed animals showed some enhanced startle with PPI. We conclude that perinatal exposure to CO is associated with mild neurological impairment in 14 do mice that persists to 60 days.