Chronic maternal nicotine exposure during gestation and lactation and the development of the lung parenchyma in the offspring

THE AIM OF THIS STUDY WAS TO INVESTIGATE THE EFFECT OF MATERNAL NICOTINE EXPOSURE DURING GESTATION AND LACTATION ON: (1) the development of the gas exchange area of the lungs of the offspring; and (2) to determine whether these effects are reversible. Pregnant rats received daily nicotine (subcutaneously 1mgkg(-1) body weight) during gestation and lactation. Nicotine administration started 1 day after mating and lasted until weaning on postnatal day 21. The offspring were exposed to nicotine via the placenta and mother's milk only. The lung tissue of the neonates was collected on postnatal days 14, 21, 35 and 42 and prepared for morphometry. The results obtained show that maternal nicotine exposure resulted in bigger alveolar volumes and suppressed alveolarisation in the lungs of the offspring. Flattening of the alveoli occurred as the animals aged and as a consequence the internal surface area available for gas exchange decreased; a condition that resembles panlobular emphysema. It is unlikely that these effects of maternal nicotine exposure during gestation and lactation on lung development in the offspring was due to a lower birth weight, or a reduction in the period of gestation, or a poor supply of nutrients to the offspring. The changes in the gas-exchange region of the nicotine-exposed rat pups appear to be irreversible.