The effect of titanium dioxide nanoparticles on pulmonary surfactant function and ultrastructure

• Published in: Respiratory research 2009-09, Vol.10 (1), p.90-90, Article 90
• Main Authors: Schleh, Carsten, Mühlfeld, Christian, Pulskamp, Karin, Schmiedl, Andreas, Nassimi, Matthias, Lauenstein, Hans D, Braun, Armin, Krug, Norbert, Erpenbeck, Veit J, Hohlfeld, Jens M
• Format: Article
• Language: English
• Subjects: Adsorption; Animals; Asthma; Automobile engines; Disease; Dose-Response Relationship, Drug; Female; Health aspects; Inhalation Exposure; Lungs; Medical research; Microscopy, Electron, Transmission; Mortality; Nanoparticles; Oxidative stress; Particle Size; Physiological aspects; Proteins; Pulmonary Alveoli - diagnostic imaging; Pulmonary Alveoli - drug effects; Pulmonary Alveoli - metabolism; Pulmonary surfactant; Pulmonary Surfactant-Associated Proteins - drug effects; Pulmonary Surfactant-Associated Proteins - metabolism; Pulmonary Surfactant-Associated Proteins - ultrastructure; Quartz - pharmacology; Rats; Rats, Wistar; Surface active agents; Surface area; Surface Tension; Surfactants; Swine; Titanium - pharmacology; Titanium dioxide; Transmission electron microscopes; Ultrasonography
• ISSN: 1465-993X; 1465-9921; 1465-993X; 1465-9921
• DOI: 10.1186/1465-9921-10-90

Pulmonary surfactant reduces surface tension and is present at the air-liquid interface in the alveoli where inhaled nanoparticles preferentially deposit. We investigated the effect of titanium dioxide (TiO(2)) nanosized particles (NSP) and microsized particles (MSP) on biophysical surfactant function after direct particle contact and after surface area cycling in vitro. In addition, TiO(2) effects on surfactant ultrastructure were visualized. A natural porcine surfactant preparation was incubated with increasing concentrations (50-500 microg/ml) of TiO(2) NSP or MSP, respectively. Biophysical surfactant function was measured in a pulsating bubble surfactometer before and after surface area cycling. Furthermore, surfactant ultrastructure was evaluated with a transmission electron microscope. TiO(2) NSP, but not MSP, induced a surfactant dysfunction. For TiO(2) NSP, adsorption surface tension (gammaads) increased in a dose-dependent manner from 28.2 + or - 2.3 mN/m to 33.2 + or - 2.3 mN/m (p < 0.01), and surface tension at minimum bubble size (gammamin) slightly increased from 4.8 + or - 0.5 mN/m up to 8.4 + or - 1.3 mN/m (p < 0.01) at high TiO(2) NSP concentrations. Presence of NSP during surface area cycling caused large and significant increases in both gammaads (63.6 + or - 0.4 mN/m) and gammamin (21.1 + or - 0.4 mN/m). Interestingly, TiO(2) NSP induced aberrations in the surfactant ultrastructure. Lamellar body like structures were deformed and decreased in size. In addition, unilamellar vesicles were formed. Particle aggregates were found between single lamellae. TiO(2) nanosized particles can alter the structure and function of pulmonary surfactant. Particle size and surface area respectively play a critical role for the biophysical surfactant response in the lung.