1319 VITAMIN E DOES NOT PREVENT OXYGEN-INDUCED LUNG INJURY IN LAMBS

Abstract

Lung microvascular permeability to protein increases in lambs that breathe 100% O2 for 3-5 days. We tried to prevent this injury by giving vitamin E to 6 lambs. After 4 h in air, the lambs breathed 100% O2 continuously. They received vitamin E, 20 mg/kg/d IM for 2 days before and throughout the study. To assess lung fluid filtration and microvascular permeability to protein, we measured pulmonary arterial (PA) and left atrial (LA) pressures, lung lymph flow, and concentrations of protein in lymph and plasma. Before and 3 days after starting O2, we gave 125I-albumin IV to 4 lambs and determined the time at which specific activity in lymph reached 1/2 that in plasma (T½). Results (X ± sx): *=per g dry lung underline=significant difference, p< .05 Despite a 10-fold increase in plasma tocopherol levels, lymph flow tripled, the concentration of protein in lymph increased, and T½ decreased. These results show that pulmonary microvascular permeability to protein increased during O2 breathing. All lambs died of respiratory failure within 4 days. Postmortem lung water was 25% greater than that of normal lambs, and lung histology showed extensive pulmonary edema. We conclude that vitamin E was ineffective in preventing or lessening lung injury from O2.