CLINICAL SURFACTANT PREPARATIONS MEDIATE SOD AND CATALASE UPTAKE BY TYPE-II CELLS AND LUNG-TISSUE

Pulmonary surfactant mixtures are rapidly taken up by alveolar type II cells and thus may serve as vectors for the pulmonary delivery of ant ioxidant enzymes to the alveolar epithelium. We prepared emulsions of Survanta with superoxide dismutase (CuZn-SOD) and catalase and quantif ied their cellular uptake both in vitro and in vivo. Incubations of fe tal lung epithelial cells with an emulsion of Survanta plus SOD and ca talase mixtures resulted in significant augmentation of SOD and catala se activities (12.8 +/- 4.6 U SOD/mu g DNA; 7.49 +/- 2.21 U catalase/m u g DNA). These numbers were significantly greater than those obtained in controls (1.8 U SOD/mu g DNA; 0.55 +/- 0.52 U catalase/mu g DNA), Survanta alone (0.43 U SOD/mu g DNA; 0.16 U catalase/mu g DNA), and SO D and catalase alone (3.47 +/- 5.2 U SOD/mu g DNA; 4.24 +/- 3.0 U cata lase/mu g DNA). Intratracheal instillation of the Survanta plus SOD an d catalase mixture resulted in significant augmentation of enzymes by the rat lung homogenates. Confocal microscopic analysis revealed the p resence of antioxidant enzymes in the cytoplasm of epithelial cells. W e concluded that Survanta supplementation, in addition to replenishing surfactant stores, can also enhance the delivery of antioxidant enzym es to alveolar epithelium both in vitro and in vivo.