Figure 1

Morphologic changes in the lung at PN15 after hormonal treatments. (A). A simplified distal architecture was seen in DEX-treated animals. RA-treated animals had smaller and more numerous alveoli. Concomitant DEX and RA administration resulted in septation similar to that of controls. Vehicle (saline or CSO) treatment alone had no effects on lung histology. Control: same handling, no injections. DEX: Dexamethasone. RA: all-trans-retinoic acid. CSO: cottonseed oil. (B). Radial Alveolar Counts confirm the decreased septation seen with DEX treatment (*p < 0.001 DEX vs. control), the increased septation seen with RA (*p < 0.001 RA vs. control), and the resolution of DEX effects by concomitant RA administration (**p < 0.001 DEX vs. DEX+RA). Data are representative of at least 6 rats per treatment group. All images 40× magnification.