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letter
. 2018 Sep 1;198(5):672–674. doi: 10.1164/rccm.201805-0827LE

Figure 1.

Figure 1.

CFTR (cystic fibrosis transmembrane conductance regulator) dysfunction in tracheas from Day 0 neonatal rats born from cigarette smoke–exposed mothers. Tracheas were excised, opened longitudinally along the dorsal surface, and microscopically dissected to remove extraneous connective tissue. Segments were mounted as flat sheets in modified Ussing chambers. Short-circuit current (Isc) measurements were performed under voltage-clamp conditions before and after addition of channel modulators in symmetrical chloride solutions as described previously (12). (A) Representative Isc tracing of neonatal rats from cigarette smoke–exposed mothers compared with air control mothers, demonstrating a depressed forskolin-sensitive and CFTRInh-172 (selective CFTR inhibitor 172) response. (B) Mean neonatal tracheal Isc treated with sequential addition of Ringer’s solution (baseline), amiloride (100 μM), forskolin (10 μM) + IBMX (100 μM), and CFTRInh-172 (10 μM). Tracings were normalized to postamiloride Isc for clarity of comparisons. After a delay (baseline), a subset of tracings were subjected to ATP (10 μM) and bumetanide (100 μM). n = 20 smoke pups from 5 litters; n = 32 control pups from 7 litters. The results were analyzed by two-way ANOVA with Bonferroni multiple comparisons. (C) Forskolin + IBMX–dependent change in tracheal Isc to detect cAMP-dependent ion channel function. (D) CFTRInh-172 (10 μM)-dependent changes in Isc; n = 20 smoke and 32 control. (E) Normalized tracheal CFTR mRNA levels as compared with the internal β-actin control; n = 8 smoke and n = 8 control. The results were analyzed by unpaired t test. (F) Body weights at Day 0 and Day 3 of neonates. Day 0: n = 115 smoke and n = 107 control. Day 3: n = 27 smoke and n = 20 control. Smoke pups from 12 litters; control pups from 10 litters. (G) CFTR-dependent changes in tracheal Isc as reflected by changes with forskolin + IBMX, as also shown in C. Day 0: n = 20 smoke and n = 32 control. Day 3: n = 13 smoke and n = 9 control. Symbols with error bars in B, F, and G represent mean ± SEM. Horizontal bars in C–E represent mean. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. IBMX = 3-isobutyl-1-methylxanthine.