Influence of imipramine and chloroquine on lung phospholipid content and lung structure in newborn rats

In continuation of previous experiments in adult rats the alteration in content and composition of lung phospholipids (PL) and lung structure of newborn rats of different gestational age was studied after three administrations of the amphiphilic drugs imipramine (75 mg/kg b.w.) and chloroquine (50 mg/kg b.w.). The fetuses were obtained by Cesarean section on day 20, 21, or 22 of gestation. Morphological examinations of the lungs of drug treated 21-day-old fetuses revealed a substantially better aeration than nontreated controls. 20 and 22 days old fetuses showed no differences in aeration between drug and saline treated rats. Analogous results were obtained with respect to the 1 h survival rate of newborns. Furthermore, imipramine and chloroquine cause a premature development of the pneumocytes type II as shown by electron microscopy. An increased PL content as well as disaturated phosphatidylcholine (DSPC) and phosphatidylglycerol (PG) proportion of fetal lungs, especially in animals born on day 21 of gestation, were found after drug treatment. The results suggest an acceleration of maturation of the pneumocytes type II in fetal lungs induced by amphiphilic drugs.