Electrophysiological properties of the airway: epithelium in the murine, ovalbumin model of allergic airway disease

Abstract

The electrophysiological properties of cultured tracheal cells (CTCs) were examined in a murine (C57BL/6J), ovalbumin (OVA)-induced model of allergic airway disease (AAD) at early (3-day OVA-aerosol) and peak (10-day OVA-aerosol) periods of inflammation. Transepithelial potential difference, short-circuit current (Isc), and resistance (RT) were lower in CTCs from 10-day OVA-aerosol animals compared to CTCs from naïve mice. In cells cultured for 5 weeks, RT was greater in naive CTCs than in 10-day OVA-aerosol CTCs at all times (P < 0.01). The Isc response to mucosal amiloride (10(-4) mol/L) was increased in CTCs from 10-day OVA-aerosol mice compared to naïve mice (6.0 +/- 0.37 microA/cm2 versus 1.8 +/- 0.56 microA/cm2; P < 0.001) with intermediate values for CTCs from 3-day OVA-aerosol mice. The cAMP-induced increase in Isc was blunted in 10-day OVA-aerosol animals compared to CTCs from naïve mice (9 +/- 12% versus 39 +/- 7%; P < 0.01) with intermediate values for CTCs from 3-day OVA-aerosol mice. There was no difference in mannitol flux in naïve compared to 10-day OVA-aerosol CTCs. Similar results were found using intact tracheas mounted in a perfusion chamber. These data demonstrate changes in airway epithelial cell function in the OVA-induced model of AAD that may contribute to the pathogenesis of airway inflammation.

Figure 1

Representative fluorescent immunohistochemical photo of mouse tracheal cells in culture with pancytokeratin staining demonstrating the typical cobblestone appearance. A: Cells in culture from naïve animals 10 days after creating an air-liquid interface. B: Cells in culture from 10-day OVA-aerosol animals 10 days after creating an air-liquid interface. Scale bars, 10 μm.

Figure 2

Tissue resistance in tracheal cells from naïve animals (squares) and 10-day OVA-aerosol animals (diamonds) cultured on transwell filters with an air-liquid interface. The air-liquid interface was established on day 4 in culture. Each point represents the mean ± SEM of a minimum of 10 observations. The resistance of the transwell filter has been subtracted from the reported values. At every time point, the resistance of the 10-day OVA-aerosol tracheal cell cultures was lower than the resistance of the naïve tracheal cell cultures.

Figure 3

The short circuit current (Isc) response to amiloride and cAMP in CTCs from naïve (white bars), 3-day OVA-aerosol (gray bars), and 10-day OVA-aerosol (black bars) animals grown on transwells and mounted in Ussing chambers. Data are presented as the mean ± SEM of 10 to 28 transwells/condition.

Figure 4

Typical recording from naïve trachea mounted in perfusion chamber. Amiloride (10⁻⁴ mol/L) was added at the first arrow. A cAMP cocktail was added at the second arrow.