Previous study in an ovine model of
smoke inhalation and
burn (S + B) injury has shown distal migration of upper airway mucus. This study examines the localization of an upper airway gland specific mucus,
mucin 5B (MUC5B) in lung autopsy tissues of
burn-only injury and in victims of S + B injury. We hypothesize that victims with S + B injury would exhibit increased distal migration of MUC5B than that seen in victims of
burn-only injury. Autopsy lung tissue from victims of
burn injury alone (n = 38) and combined S + B injury (n = 22) were immunostained for MUC5B. No normal lung tissues were included in the study. Semiquantitative analysis of the extent of MUC5B in bronchioles and parenchyma was performed on masked slides. Irrespective of injury conditions, all victims showed MUC5B in bronchioles.
Mucin 5B was seen in the parenchyma except in two
burn victims. No statistically significant difference was seen in the mean bronchiolar and parenchyma MUC5B scores between S + B and
burn-only victims (P > 0.05). No strong statistical correlation of MUC5B scores with days postinjury or to the number of ventilatory days was evident. The percentage of
pneumonia, identified histologically, was also similar between study groups. This study did not confirm our results in an ovine model of S + B injury. In contrast, virtually all pediatric
burn victims, regardless of concomitant inhalation injury, showed MUC5B in their bronchioles and parenchyma. Increased mucus synthesis and/or impaired mucociliary function may contribute to the pulmonary pathophysiology associated with
burn injury.