Asthmalike symptoms following intratracheal exposure of Guinea pigs to sulfur mustard aerosol: therapeutic efficacy of exogenous lung surfactant curosurf and salbutamol

Abstract

The purpose of the present study was to investigate: (1) the acute effects of sulfur mustard on airway, lung, and surface tension of bronchoalveolar lavage fluid (BALfluid) in guinea pigs following intratracheal (i.t.) exposure to 1LD50 of an aerosolized solution of sulfur mustard in saline, and (2) the therapeutic efficacy of i.t. administration of the natural surfactant Curosurf and the broncholytic Salbutamol. Intratracheally aerosolized sulfur mustard solution induced two clinically relevant symptoms, that is, asthmalike symptoms reflected by an early bronchoconstriction and "late asthmatic responses" (LAR), and ARDS-like symptoms, that is, pulmonary edema and damage to the lung surfactant. The respiratory minute volume (RMV) was enhanced. Histologically, inflammation and severe epithelial injury in the upper airways were observed, whereas the lungs were homogeneously affected. The surface tension of BAL fluid derived at 24 h after sulfur mustard exposure was much higher (20 +/- 1 mN/m) than that of unexposed control animals (about 1.0 +/- 0.5 mN/m), indicating that the lung surfactant had been altered, and justifying treatment with exogenous surfactant. Intratracheal nebulization of a Salbutamol solution (10 microg/kg), or i.t. bolus administration of Curosurf (62.5 or 125 mg/kg), tended to reduce mortality, although Salbutamol appeared to be more effective than Curosurf in this respect. Although the present study does not give a definite answer to the question of whether the animal model used would be the most relevant for humans, a number of considerations in favor of i.t. aerosolization of sulfur mustard are discussed. Since it was noticed that sulfur mustard exposure induced damage to the lung surfactant, severe bronchoconstriction, and inflammation of the respiratory tract, the effectiveness of a combined treatment consisting of exogenous surfactant, anti-inflammatory drugs, and broncholytics is recommended to be further investigated.