Particulate Material Effects on Pulmonary Surfactant Models

Abstract

IntroductionPulmonary Surfactants (PS) are present in the air-liquid interface of lung alveoli. Its main function is to enhance the alveoli dilatational properties by lowering the surface tension of the system, as well as to prevent the collapse during the respiration process1. Particulate Material (PM) are exogenous particles which are related to some respiratory problems2. In the present work is reported the effects of those particles in system models of PS.MethodologyDipalmitoylphosphatidylcholine (DPPC) is the major component of PS and Cholesterol (Chol) is the most abundant neutral lipid. DPPC monolayers are used as models and the effects of PM and Chol were evaluated by using Oscillating Drop System (ODS) and Atomic Force Microscopy (AFM) techniques.ResultsChol brought the Dilatational Elastic Modulus (E) to higher values evidencing an increase in the rigidity of the monolayers. Such effect is explained by the fact that Chol molecules act as space fillers turning the monolayers into more rigid structures. PM showed two different effects. The first one being the decrease of E at low PM concentration. The second one is the increase in E values which is believed to be a result of the adsorption of the particles to the monolayers.ConclusionsPM and Chol were observed to provoke changes in some physicochemical properties of DPPC monolayers. PM as exogenous structures may cause problems to the regular functions of the PS as already reported.References1) Goerke, J. Biochim Biophys Acta 1998, 19, 79-89.2) Arbex, M. A. et al. Jornal brasileiro de pneumologia 2004, 158-175.