ABSTRACT
In the present study we measured the lipid peroxide content in plasma and lung homogenate by Yagi's method, and analyzed the composition of surfactant phospholipid and surface activity of pulmonary surfactant by thin layer chrom-otography and by Wilhelmy's film balance.The results showed that the lipid peroxide level was increased in plasma and lung homogenate; licithine,tysopho-spholipidcholine and phosphatidylethanolamine were decreased in bronchial-alveolar lavege fluid; and pulmonary surfactant surface activity was lowered.The findings suggest that decreased surface activity may result from the decrease of disaturated phospholipidcholine, which may be due to its impaired synthesis.
ABSTRACT
Bovine pulmonary surfactant was obtained by endotracheal lavage of lungs from newly slaughtered calves followed by differential centrifugation.Lipid extracts of bovine surfactant contained 86.1?2.1% "of phospholipids (X?SD) , 1.8?1.1%of protein and smaller amounts of cholesterol, fatty acids, glycerides and carbohydrate. Phosphatidylcholine(83.4?5.6%)accounted for most of the phospholipids, of which disaturated phosphatidylcholine was 76.0? 4.7% .The physicochemical properties of bovine surfactant were measured with a modified Wilhelmy film balance made by the authors.The minimum surface tension was 2.4?1.5mN/m, stability index was 1.78?0.15, surface compresibility at 10mN/m was 0.022?0.004 m/mN, and surface concentration of phospholipids at 10mN/m was 1.112?0.283 nmol/cm2. The surfactant spread rapidly and could be quickly absorbed to the surface of the water.The results show that the bovine pulmonary surfactant we isolated is able to meet the criteria for investigations of surfactant replacement therapy.
ABSTRACT
The inhibition of bronchoalveolar surfactant function by endotoxic rat plasma was compared with that by normal rat plasma with M-8601 film balance. The results showed that endotoxic rat plasma significantly inhibited surfactant function of bronchoalveolar lavage (BAL). In the same protein concentration, the inhibition effects caused by endotoxic rat plasma were comparable with those by normal rat plasma. There were no changes of the inhibition effects after incubation of BAL with either endotoxic or normal plasma at 37℃ for 30min. These results suggest that the inhibition of surfactant function by the leakage of plasma in endotoxic lung injury is mainly due to protein components.