[Prophylactic effect of ambroxol on acute hydrochloric acid aspiration - induced lung injury]

To evaluate the protective effect of ambroxol, a muco-active drug, on acute hydrochloric acid-induced lung injury in rats.

Thirty pathogen-free SD rats were randomly divided into three groups: group A (n=10) and group B (n=10) were injected normal saline (NS) intraperitoneally (6.7 ml/kg), and group C with ambroxol (50 mg/kg), once a day for 3 consecutive days. Then animals received in tracheal instillation of NS (group A, pH 5.3, 1.2 ml/kg) or hydrochloric acid/NS (group B and C, pH 1.25, 1.2 ml/kg). Five hours after instillation of the injury vehicle, the arterial gas was determined, and the extent of lung injury was assessed by measuring the ratio of wet to dry weight (W/D) and evaluation of pathological change in lung tissue.

(1)Partial pressure of oxygen in arterial blood (PaO(2)) was significantly lower in group B than in groups A and C, although pH and partial pressure of carbon dioxide in arterial blood (PaCO(2)) in three groups showed little difference (all P<0.01). (2)The W/D was the highest in group B and the lowest in group A. (3)Severe acute lung injuries were detected in group B by pathological examination, the extent of injury was less in group C than in group B, but more severe than in group A (group A vs. B and B vs. C in mean pathologic score, P<0.01 and P<0.05, respectively).

Hydrochloric-acid aspiration may induce an acute and diffuse lung injury, with manifestations of hyperpnea, lower PaO(2) and severe pathological changes in lung tissues. Ambroxol may have a protective effect against lung injury induced by hydrochloric acid.