Functional, biochemical, and morphologic changes in alveolar macrophages following thoracic x-irradiation.

Alveolar macrophages lavaged from mice at various times after 1800 rads of thoracic x-irradiation were compared to control mice. Determination of their numbers, size distribution, glass adherence, latex particle uptake, cytochemistry, morphology, protein, phospholipid, and hydrolytic enzyme composition showed that defective bacterial uptake and clearance, which has been demonstrated by other workers, may be related to a transient decrease in their numbers rather than activity. A decrease in numbers is explainable on the basis of a population of radiosensitive precursors in the lung interstitium. The work load in the alveolar space may prolong the duration of their residence in the alveoli as well as increase their size and content of hydrolytic enzymes and ingested surfactant components.