title: [Effects of toxic gases and phagocytic defense of the respiratory system. "In vitro" approach].
abstract: A new technique of cell culture in gas phase may be used for the "in vitro" study of the effects of toxic gases on the alveolar macrophages responsible for phagocytic defence of the respiratory system. Macrophage cells deposited on a porous membrane applied to the surface of a reservoir filled with nutrient fluid, survive in direct contact with the atmosphere, retaining normal metabolic and functional activities for several days. It is then possible to analyse the effects exerted on these cells by various types of gaseous aerocontaminants. This "in vitro" technique is highly sensitive. Nitrogen dioxide and ozone have cytotoxic effects after 30 minutes exposure at concentrations at less than 1 p.p.m. Acrolein has a harmful effect only at concentrations of 8 to 35 p.p.m. A mixture of oxygen (95 p. cent) and of CO2 (5 p. cent) causes much slower cell destruction, in a period varying from 2 to 6 days. Information provided by this method must be interpreted taking two concepts into account: 1--"in vitro" cytotoxicity explores only one aspect of the harmfulness of a gas, since the latter may have pathological effects by other mechanisms: irritant action on the respiratory mucosa resulting in hypersecretion and bronchospasm, ciliary paralysis or destruction, changes in the alveolar wall also capable of disturbing the phagocytic intervention of alveolar macrophages; 2--"in vitro", certain gaseous aerocontaminants are fixed or neutralised in part in the upper airway or by secretions lining the respiratory mucosa. In addition, the constant supply of new cells from the interstitium or pulmonary capillaries, limits the consequence of any possible destruction of phagocytic cells exposed to toxic gases. However, these reservations are compensated by the new possibilities offered by the "in vitro" study of the cytotoxicity of gases in the following areas: establishment of a hierarchy of gaseous pollutants, evaluation of their mechanism of action and determination of methods of protection against their harmful effects.
mesh_terms: D000171:Acrolein / Q000633:toxicity; D001424:Bacterial Infections / Q000503:physiopathology; D005740:Gases / Q000633:toxicity*; D006801:Humans; D066298:In Vitro Techniques; D009585:Nitrogen Dioxide / Q000633:toxicity; D010126:Ozone / Q000633:toxicity; D010587:Phagocytosis; D011650:Pulmonary Alveoli / Q000187:drug effects; D012137:Respiratory System / Q000503:physiopathology*
chemical_list: D005740:Gases; D010126:Ozone; D000171:Acrolein; D009585:Nitrogen Dioxide
vernacular_title: Agressions par gaz toxiques et défense phagocytaire de l'appareil respiratoire. Approche "in vitro".