CHANGES IN SURFACTANT PROTEIN OF THE LUNG FOLLOWING OXYGEN-TOXICITY IN PROTEIN MALNOURISHED RATS

This study was carried out on 30 rats divided into three equal groups. Rats in Group 1, taken as controls, were fed a normal protein diet. A nimals in Groups 2 and 3 were maintained on rations deficient in prote in; each group was subdivided into two subgroups. Animals in the first subdivision of each group were placed in an environment of 100% O-2 f or 24 h while those in the second breathed normal air. The protein con tent of surfactant and the apparent molecular weights of the different protein bands were determined. Both quantitative and qualitative chan ges in surfactant-associated proteins were observed. These changes app eared secondary to protein malnutrition as well as hyperoxic exposure of the lung. The reduction in total protein of the lung surfactant was proportional to the degree of protein deficiency in the diet. There w as a further decrease following exposure to 100% oxygen for 24 h. Thes e changes may lead to surfactant dysfunction as the surfactant apoprot ein is important for the functional integrity of the surfactant.