The Pulmonary Macrophage Response to Irritants

Abstract

Relatively large dust burdens were imposed on the lungs of rats and hamsters by inhalation and by intratracheal injection, respectively. Three dusts with an average diameter of about 1μ were employed with and without mineral oil injected intratracheally subsequently: silicon dioxide (SiO₂ [quartz]), ferric oxide (Fe₂O₃), and antimony trioxide (Sb₂O₃). Pulmonary macrophage counts by the saline washout method were made prior to and immediately following the imposition of the lung dust burden, as well as 1, 4, 7, 14, and 30 days later. Many of the recovered cells were leukocytes. After a statistical evaluation of the results, it was concluded that the number of lung macrophages recoverable by the saline washout method is dependent upon factors that cannot be regulated, nor can their effects be estimated, and that interpretations based upon the numbers of lung macrophages so obtained are, therefore, subject to pitfalls.