Figure 4. CFTR^–/–;TgFABP>pCFTR pigs lack CFTR-mediated electrolyte transport in the airways.

(A) Microscopic images of trachea from a CFTR^–/–;TgFABP>pCFTR newborn pig. The tracheas were irregularly shaped, had cartilage ring defects in the anterior trachea (top panel, arrow), and areas of abnormal-appearing airway smooth muscle bundles (bottom panel, arrows) (30). Scale bars: 820 μm (top panel); 82 μm (bottom panel). (B) Changes in short-circuit current (Isc) following addition of forskolin/IBMX (ΔIsc_F&I) to freshly excised tracheal segments from newborn CFTR^+/+, CFTR^–/–, and CFTR^–/–;TgFABP>pCFTR piglets. (C) ΔIsc_F&I in cultured tracheal epithelia from newborn CFTR^+/+, CFTR^–/–, and CFTR^–/–;TgFABP>pCFTR piglets (no sample was available for line d). Prior to forskolin/IBMX treatment, tissues were sequentially exposed to amiloride and DIDS. Symbols represent individual animals. Line represents mean ± SEM. Data for lines b, d, and e in B and line e in C did not differ significantly from data for CFTR^–/–.