Deactivation of the pulmonary surfactant dynamics by toxic aerosols and gases.

Interactions between selected toxic aerosols and gases occurring in the air at the workplace and the pulmonary surfactant (PS) have been studied with two physicochemical techniques in vitro. The Pulsating Bubble Surfactometer (PBS) and the Langmuir-Wilhelmy Balance (LWB) have been used for measurements of dynamic interfacial properties of the PS material after its contact with several gases (sulfur dioxide, nitrogen oxides, ozone, ammonia) and liquids (sulfuric, nitric and hydrochloric acids and ammonium hydroxide), which can be brought into the alveoli with the inhaled air. Surface tension-area relationships for the interface oscillations have been analyzed using qualitative criteria of normalized hysteresis area (HA(N)) and minimum surface tension (sigma(min)). It was demonstrated that, for each analyzed compound, inactivation of the surfactant occurs, but the critical concentrations and doses are compound specific, which suggests the toxic potential of the investigated substances with respect to PS. Possible mechanisms of the interactions between the investigated substances and the surfactant components are discussed. Degradation of the PS dynamical interfacial properties (HA(N) and sigma(min)), important from the physiological viewpoint, observed in our in vitro experiments, suggests a possibility of adverse health effect in the case of a chronic inhalation of toxic gases and aerosols, even at low concentration or after a short exposure to strongly contaminated air. It results in a slowdown of the pulmonary clearance rate and increase of the lung burden for both considered cases.