Nitrofen dose-dependent gestational day-specific murine lung hypoplasia and left-sided diaphragmatic hernia.

2,4-Dichlorophenyl-p-nitrophenyl ether (nitrofen) is known to induce pulmonary hypoplasia (PH) with or without diaphragmatic hernias (DH) in rats and mice. We determined the timing of administration and dose of nitrofen needed to create left-sided DH and PH in fetal mice. Time-dated pregnant CD-1 mice were gavaged with various doses of nitrofen in the later one-half of gestational days (GD) 8-11. Fetuses were removed by laparotomy at GD 14, fixed, and evaluated histologically. Fetal lung size was inversely related to nitrofen dose. Morphometric analysis of normal and nitrofen-exposed hypoplastic lungs at the pseudoglandular stage revealed significant differences in lung length, surface area, and in the number of airways. Left-sided DH were observed in a "dorsolateral" position accompanied by PH in approximately 30% of GD 14 fetuses exposed to 25 mg nitrofen on GD 8. A minimal portion of liver was present in the hernia. The lungs of fetuses exposed on GD 9, 10, and 11 progressed to near normal size. Murine fetuses exposed to 25 mg nitrofen on GD 8 resulted in PH and DH, whereas other doses created dose-dependent PH alone or none at all on GD 11. Our study established that, to create left-sided DH and PH in murine fetuses, nitrofen dose specificity and time of administration during gestation were crucial.