Aim: 

Hyperosmolar expsoure is a model of exercise-induced changes in the airways of athletes (Anderson et al, JACI 2008). Hyperosmolarity was shown to activate bronchial epithelial cells (BEC) to release interleukin 8 (IL-8) (Hashimoto et al, AJRCCM 1999); however, other studies suggest that may exert an anti-inflammatory action on neutrophils (Rizzoli et al, J Immunol 1998) or alveolar epithelial cells (Lee et al, ATS 200t, A122).

Methods: 

We examined the effects of hyperosmolar stimulation on IL-8 release in two different BEC lines, BEAS-2B, a normal human BEC line, and NCl-H292, a cell line derived from a pulmonary mucoepidermoid carcinoma. Both BEC lines were exposed to increasing concentrations of NaCl or Mannitol (320, 640, 960, 1280 mOsm/Kg H₂O) in culture medium for 5, 10 or 40 min; at 24 h after exposure, supernatants were collected for subsequent determination of IL-8 concentration. (ELISA; R&D System, UK).

Results: 

Similar to previuos results, IL-8 concentration increased significantly in NCl-H292 cells exposed for 40 min to NaCl or Mannitol medium at osmolarity 640 mOsm/Kg H₂O (p<0.01, ANOVA), whereas lower NaCl/Mannitol concentrations or shorter exposure times did not affect IL-8 release. Conversely, IL-8 release in the BEAS-2B line was not affected by any concentration of, or exposure time to, hyperosmolar NaCl or Mannitol. Cell viability measured by Trypan Blue exclusion was >90% in all experiments.

Conclusion: 

These preliminary data indicate that normal human BEC may not be activated by hyperosmolar exposure in vitro, suggesting a sgnificant viability of BEC response to hyperosmolarity dependent on the BEC model used.