Long-term effects of developmental exposure to zidovudine on exploratory behavior and novelty discrimination in CD-1 mice.

Long-term changes in exploratory, social and agonistic behavior have been reported in rodents following developmental exposure to zidovudine (AZT), an agent commonly administered to pregnant seropositive women and their neonates to prevent HIV-1 transmission. The present study evaluates the effects of either prenatal or prolonged AZT treatment on spatial and nonspatial novelty discrimination in mice, using an open-field test with four objects, in which responses to both spatial rearrangement of familiar objects and object novelty are assessed. AZT (160 mg/kg) or Saline was given orally twice daily to pregnant mice from gestational days (GD) 10 to 19 (Experiment 1) or from GD 10 to lactation day 10 (Experiment 2). Offspring of both sexes were tested on postnatal day (PND) 28, 45 or 70. Depending on treatment schedule, AZT altered different behavioral responses, males being more affected than females. The prenatal treatment (Experiment 1) reduced exploration of the objects at all ages considered and increased wall and top rearing at ages 45 and 70. Following prolonged treatment (Experiment 2), AZT offspring were markedly more active than controls and displayed more wall rearing at age 70 while showing lower grooming frequency at all ages. Both AZT and control mice failed to respond to object rearrangement at adulthood, a discrepancy from previous data, which is discussed in relation to perinatal stress effects.