Fig. 3

Azithromycin enhanced early apoptosis in IPF fibroblasts compared to controls. a No cytotoxicity was measured by LDH release in cell supernatant in control fibroblasts (n = 4). b Most IPF fibroblasts (n = 5) showed increased cytotoxicity after AZT (50 μM and 500 μM) treatment in the presence or absence of TGF-β. No statistical difference was reached. c Significant increase of early apoptosis (A+/PI-) in both control (n = 4, ***p-value ≤0.001) and IPF fibroblasts (n = 4, ****p-value ≤0.0001) is observed after co-stimulation with TGF-β and AZT. IPF fibroblasts had significantly higher early apoptosis level after costimulation compared to controls (*p-value ≤0.05). Data represent fold increases relative to the negative control (RM). One-way ANOVA followed by Tukey’s post test was used for statistical analysis. d Bcl-xL protein expression was assessed by western blot analysis in whole cell lysates from control or IPF fibroblasts. Bcl-xL protein expression was significantly reduced after additional AZT treatment in IPF fibroblasts when directly compared to controls (paired students t-test; **p-value ≤0.01). Normalized fold decrease of Bcl-xL expression of TGF-β and AZT relative to TGF-β is shown (n = 3). At least three independent experiments were performed