Alveolar macrophages and pulmonary surfactant of altitude-raised rats.

Alveolar macrophages and pulmonary surfactant were estimated in rates raised at high altitude (3500 m) and compared with control rats. Macrophages were obtained by washing the lungs with isotonic saline and counted in a haemocytometer to obtain the total number present. Proportions of two types of macrophages (precursor and mature) have been evaluated. Different fractions of phospholipids in lung lavage and lung tissue were separated by thin layer chromatography and estimated colorimetically. The results showed a reduction in the number of macrophages/g of lung with a corresponding a decrease in surfactant. The percentage of immature (precursor) macrophages was lower in high-altitude-raised rates. These changes observed in alveolar macrophages and lung surfactant could be due to an altered metabolism at high altitude.