Abstract
Aim: Tracheal injury is a frequent occurence in individuals that smoke. Recent evidence show that current and ex smokers exhibit tracheal and systemic dysfunction of CFTR rendering a phenotype of "acquired cystic fibrosis". Thus, elucidation of the effects of smoking on tracheal ion transporters is of great clinical value. Our aim was to develop an ex vivo sheep model for the electrophysiological study of trachealENaC sodium transporter, the main airway sodium channel, after the effect of cigarette smoke extract (CSE).
Materials and method: Tracheas were isolated from healthy sheep and the tracheal epithelium was surgically excised. Tissues were mounted in Ussing chambers and Short Circuit Current (ISC) was measured after incubation with for 5% CSE in PBS or PBS alone for 30 min. Function of ENaC was investigated by addition of amiloride (10-5M) apically. Also some specimens were stained with H&E for detection of histological alterations.
Results: The amiloride effect on normal epithelium led to a significant decrease of ISC [ΔΙ=33±5.92 μA/cm2; p<0.001 compared to control experiments (ΔΙ=1.44±0.71 μA/cm2)]. After incubation with CSE, ENaC Isc was significantly reduced (ΔΙ=14.80±1.96 μA/cm2; p<0.001). Histological images post CSE incubation revealed decreases in the height of the epithelium.
Conclusions: ENaC inhibition by amiloride shows that it is functional in normal sheep tracheal epithelium. After CSE incubation ENaC currents are significantly reduced. This could be due to the observed reduction in the tracheal epithelium height. Further validation of the ex vivo model is needed.
- Copyright ©ERS 2015