IκBα worsened structural lung injury induced by prolonged pneumonia. Overexpression of IκBα worsened the decrement in alveolar airspace and the increase in alveolar tissue (A) after pneumonia-induced lung injury. (B) Image from a prolonged pneumonia-injured lung that received intratracheal vehicle, demonstrating increased wall thickness and inflammatory cell infiltrate. (C through E) Images from a pneumonia-injured lung that received increasing doses of intratracheal vector encoding the IκBα transgene. The animals that received 1 to 5 × 1010 doses demonstrated greater injury. Vehicle, animals that received intratracheal vehicle alone; IκBα 5 × 109, animals that received 5 × 109 AAV6 particles encoding IκBα; IκBα 1 × 1010, animals that received 1 × 1010 AAV6 particles encoding IκBα; IκBα 5 × 1010, animals that received 5 × 1010 AAV6 particles encoding IκBα. *Significantly different from vehicle group (P < 0.05, ANOVA). Scale bar, 200 μm.