Lung growth induced by prenatal instillation of perfluorocarbon into the fetal rabbit lung.

Abstract

The study's aim was to evaluate whether prenatal instillation of perfluorooctylbromide (PFOB, a perfluorocarbon) into the lungs of fetal rabbits leads to increased lung growth. Hysteroamniotomy was performed in eight pregnant New Zealand white rabbits on gestational day 27. In each mother, four fetuses were randomized to undergo either 1) endotracheal intubation and intrapulmonary instillation of 1 ml PFOB, 2) intrapulmonary instillation of 1 ml 0.9% NaCl solution (saline), 3) no fetal manipulation (control), or 4) tracheal occlusion (TO). The distribution of PFOB was documented radiographically. The fetuses were born by cesarean section after 48 h, sacrificed, weighed, and their lungs excised. Fetal lung to body weight ratios (FLBW) were determined, and the lungs were snap frozen for histomorphologic analysis and lung tissue distillation. On macroscopic inspection, PFOB-filled and tracheally-occluded lungs were markedly larger than saline-filled and control lungs. Mean FLBW was higher in fetuses treated with intrapulmonary instillation of PFOB (0.037+/-0.009), compared with fetuses receiving saline (0.027+/-0.008) or the unmanipulated controls (0.028+/-0.008). FLBW was highest after TO (0.049+/-0.008). After 48 h, in-vivo radiographs did not demonstrate any residual PFOB. Average dry fetal left lung weight (in g) was much higher in the TO (0.064+/-0.029) and PFOB (0.062+/-0.016) fetuses compared with the saline (0.054+/-0.017) and control (0.043+/-0.012) groups. Alveolar architecture on microscopy was similar between all groups, although the alveolar septae appeared thicker and more cellular after PFOB treatment and TO. We concluded that prenatal intrapulmonary PFOB instillation leads to increased lung growth in the late gestation rabbit model. Although PFOB instillation resulted in lower wet FLBW than TO, the increase in dry lung weight is comparable. This novel technique may be a less invasive and less noxious treatment strategy for pulmonary hypoplasia associated with diaphragmatic hernia.