Long-term effects of prenatal 3 '-azido-3 '-deoxythymidine (AZT) exposure on intermale aggressive behaviour of mice

Rationale: AZT treatment of seropositive pregnant women and their neonates has been widely used due to its effectiveness in reducing vertical transmis sion of HIV, but medium- and long-term effects of AZT on neurobehavioural d evelopment and adult responding are still poorly described. Objective: The aim of the present study was to evaluate the long-term effects of prenatal AZT treatment on aggressive behaviour of adult male mice. Methods: Pregnant CD-1 mice were given saline vehicle, 0.4, or 0.8 mg/ml AZT in their drinki ng water from gestation day 10 to delivery. Social-aggressive types of inte raction were assessed in their male offspring following a 4-week isolation period. Two groups of subjects were used, each undergoing a different type of test: test 1 consisted of a single 20-min encounter with an isolated sam e-strain opponent on postnatal day (PND) 90, while in test 2 (PND 150) subj ects were paired for 10 min for 5 consecutive days with a non-isolated oppo nent. Results: Slight changes in both aggressive and defensive components o f the male-specific agonistic pattern were evident only in test 1, AZT mice displaying a limited increase of aggressive behaviour compared to their co ntrols. Conclusions: Although the long-term effects of prenatal AZT on soci al behaviour are limited, they may be of some relevance for paediatricians in order to plan a follow-up of infants, children and adolescents exposed i n utero to antiretroviral drugs.