“…Attempts to enhance innate post-PNX responses using individual growth promoters in rodent models led to mixed cellular and structural effects (14,24,25,40,57) and few studies assessed the functional outcome on gas exchange. In our earlier canine studies (4,6,34,51,54), oral all-trans retinoic acid significantly enhanced active alveolar re-growth after right PNX (34,51) 54) and abrogated oxidative stress damage ( 6), but exerted only minor effects on extravascular alveolar tissue compartments.…”