The Effect of Maternal Nicotine Exposure on Fibronectin Expression in Lung Parenchyma of the Mice Newborns

Nicotine is one of the chemical substances with high level of toxicity. It crosses the placenta and accumulates in the developing organs of fetus. In this study، the effects of maternal nicotine exposure on fibronectin expression in the lungs of newborn mice were evaluated. Pregnant Balb/C mice were divided into 2 experimental and 2 control groups. The experimental group1، received 3 mg/kg intra peritoneal nicotine from day 7 of gestation to the last day of pregnancy. The experimental group 2 received the same amount of nicotine during the same gestational days as well as 2 first weeks after birth (lactation). The control groups received the same volume of normal saline during the same period s (n=6). At the end of exposure times، all of newborns were anesthetized and their lungs removed for histochemical and Immunohistochemical methods. Data were analyzed by student t-test and Mann-Whitney test. Our results indicated that ratios of lung weight and body weight in the offsprings born to the mothers with nicotine exposure compared to that of the control groups were significant. Histochemical study showed that pneumocytes type 1 differentiation and alveoli diameter were decreased in the experimental groups. Fibronectin immunoreactivity intensity was not similar in the different parts of the lungs including alveoli، bronchiole and small vessels. A significant increase in immunoreactivity showed that in alveoli experimental group 2، but in bronchioles and vessels of the experimental groups were decreased in contrast to the control groups (p<0. 05). These data also indicated that maternal nicotine exposure may induce abnormal fibronectin expression which might cause defects in lung function during life time.