Figure 5.

The effect of the CCSP-rtTA transgene and doxycycline treatment on alveolar histology. Double transgenic tetO-muPA:CCSP-rtTA, single transgenic CCSP-rtTA, and nontransgenic wild-type mice were maintained on regular water until 6 wk of age. Thereafter, the mice were placed on doxycycline treatment for 24 wk. At 30 wk of age, the lungs were removed, inflation fixed at 25 cm H₂O pressure, sectioned, stained with hematoxylin and eosin, and photographed at ×40 magnification. Representative photomicrographs from each genotype have been included.