O. Elidemir et al., A novel diagnostic method for pulmonary aspiration in a murine model - Immunocytochemical staining of milk proteins in alveolar macrophages, AM J R CRIT, 161(2), 2000, pp. 622-626
Aspiration of foreign material into the lungs has been implicated in the et
iology of a variety of pulmonary disorders. Although aspiration is a common
clinical problem, its diagnosis represents a major challenge due to the la
ck of sensitive and/or specific tests. In this study, we evaluated the sens
itivity and specificity of a novel diagnostic method in a murine model of m
ilk aspiration, Under light anesthesia, BALB/c mice received either single
or repeated intranasal instillation of milk. Control animals received steri
le physiologic saline or were infected with respiratory pathogens in a simi
lar manner, After isolation and cannulation of the trachea, mouse lungs wer
e lavaged with PBS at various time points after the last aspiration event.
Cells were recovered for Oil Red O (ORO) staining as well as immunocytochem
istry for milk proteins: alpha-lactalbumin and beta-lactoglobulin. After si
ngle aspiration of milk, a large number of alveolar macrophages displayed a
strong immunoreactivity for alpha-lactalbumin for 2-96 h. After single and
repeated aspiration, the percentage of positive cells for alpha-lactalbumi
n was significantly higher when compared with ORO staining at 24, 48, and 7
2 h (p < 0.05). No immunoreactivity for milk proteins was found in alveolar
macrophages obtained from our control groups. These findings demonstrate t
hat immunocytochemical staining of milk proteins within alveolar macrophage
s represents a novel, sensitive, and specific test for the diagnosis of asp
iration In a murine model.