Figure 6.

Chronic mucosal Nys treatment does not affect the bioelectric properties of primary HBE cells nor total mRNA abundance of transepithelial Na⁺ transport mediators. (A) Representative Ussing chamber tracings showing the effect of chronic Nys and KBR treatment on I_sc. The enlarged panel shows the rapid loss (completed in ∼ 15 min) of chronic Nys effect (e.g., increased I_sc) upon mounting of the cultures in a Nys-free mucosal bath. (B) Baseline I_sc values 15 minutes after mounting naïve, KBR-, and Nys-treated culture in the chambers (data are shown as mean ± SD, n = 4 individual donors, 4 to 6 cultures for each treatment; *P = 0.01 versus naïve cultures). The arrow in Figure 1A indicates the acute addition of Nys in the apical chamber. (C) ΔI_sc between peak value after acute Nys addition and baseline value (peak-basal); (D) ΔI_sc value between the I_sc value at 40 minutes and baseline value and (40min-basal). Data are expressed as mean ± SEM, n = 4 individual donors, 4 to 6 cultures for each treatment; *P < 0.05 versus naïve cultures. (E) Quantitative RT-PCR analysis of epithelial Na⁺ transport path components in naïve, KBR-, and Nys-treated cultures after 8 hours of treatment. Similar data were obtained at (F) 24 hours and (G) 96 hours of treatment. Data are shown as mean ± SEM, n = 2 individual donors, 4 cultures for each treatment. (H) Representative confocal images of naïve, KBR-, and Nys-treated HBE cultures immunostained for α₁ Na⁺/K⁺ATPase. Quantification of the α₁Na⁺/K⁺ATPase-specific signal is shown in the bar graph as mean ± SEM, n = 3 individual donors, 2 cultures for each treatment. *P < 0.05 significantly different versus naïve and KBR-treated cultures.