Tensiometric study of surface activity and halothane impact on biosurfactant production of lung cells

Alveolar pneumocytes type II produce in vivo surface-active components, called lung surfactant (LS), which functions at the alveolar air/water interface are very important for the lung mechanics. LS exists in vivo as a colloid-dispersed phospholipid system and its deficiency or inactivation caused by inhalation toxins leads to severe respiratory problems, which are widely studied from the point of view of surface and colloid chemistry, biophysics, biochemistry and medicine.

In this work we investigated the biosurfactant (phospholipids) production by A 549 cells (which originate from the alveolar pneumocytes type II) by measuring the decrease of surface tension in the medium where the cells were grown. Also we studied the effects of halothane on the surfactant production, its accumulation in the cell culture medium and the cell adhesive properties.

Our results showed that there was significant increase of the phospholipid content in the cell culture medium and its surface activity during time of cell growth, detected by surface tension measurements. It was shown that the equilibrium surface tension values of the medium with cells decreased with ca. 4.5 mN/m at 24 h and with 12.0 mN/m at 48 h in comparison with the medium without cells. The effects of halothane on the surfactant production and cell adhesive properties were proved to be time- and concentration-dependent.

Our results demonstrate the opportunity of the interfacial tensiometry to monitor the production of biosurfactants in the field of cell culturing and in colloid systems where biosurfactants exist in vivo and that the tensiometric measurements have potential for use as diagnostic tools in medical applications.