Propyl gallate induces human pulmonary fibroblast cell death through the regulation of Bax and caspase-3

Figures & data

Figure 1. Effects of PG on cell cycle phase distributions in HPF cells. Cells in the exponential growth phase were incubated in the presence of the designated concentrations of PG for 24 h. Cell cycle phase distributions were evaluated by DNA flow cytometry. A: Each histogram shows the cell cycle distributions in PG-treated HPF cells. M1 indicates sub-G1 cells. G1, S, and G2 represent the phases of the cell cycle. B: Graph displaying the proportions of each cell cycle phase derived from A. C: Graph displaying the proportions of sub-G1 cells derived from A. *p < 0.05 as compared with untreated control cells.

Figure 2. Effects of PG on cell death and MMP (ΔΨm) in HPF cells. Exponentially growing cells were incubated in the presence of the designated concentrations of PG for 24 h. Annexin V-FITC and rhodamine staining were performed in HPF cells and were measured using a FACStar flow cytometer. A and B: Representative histograms for annexin V-FITC (A) and rhodamine staining in HPF cells (B). M1 indicates annexin V-FITC-positive (A) and rhodamine 123-negative [MMP (ΔΨ_m) loss] HPF cells (B). M2 indicates cells without MMP (ΔΨm) loss. C and D: Graphs of the percentages of M1 regions in A (C) and B (D). E: Graph displaying the proportions of MMP (ΔΨm) levels in HPF cells derived from M2 regions in B. *p < 0.05 as compared with untreated control cells.

Figure 3. Effects of caspase inhibitors on cell death and MMP (ΔΨm) in PG-treated HPF cells. Exponentially growing cells were pretreated with each caspase inhibitor (15 µM) for 1 h and then treated with 800 µM PG for 24 h. Annexin V-FITC and rhodamine staining were measured in HPF cells using a FACStar flow cytometer. A and B: Representative histograms for annexin V-FITC (A) and rhodamine staining in HPF cells (B). M1 indicates annexin V-FITC-positive (A) and rhodamine 123-negative [MMP (ΔΨm) loss] HPF cells (B). C and D: Graphs show the percentages of M1 regions in A (C) and B (D). *p < 0.05 as compared with untreated control cells.

Figure 4. Effects of apoptosis-related siRNAs on cell death in PG-treated HPF cells. HPF cells (at approximately 30%–40% confluence) were transfected with either a nontargeting control siRNA or the indicated apoptosis-related siRNAs. One day later, cells were treated with 800 µM PG for an additional 24 (A) or 48 h (B). A and B: Annexin V-FITC and PI staining in HPF cells were measured using a FACStar flow cytometer. The percentages shown in each figure represent annexin V-FITC-positive cells, regardless of PI-negative and PI-positive cells.

Figure 5. Effects of MAPK inhibitors on cell death and MMP (ΔΨm) in PG-treated HPF cells. Cells undergoing exponential growth were pretreated with each MAPK inhibitor (10 µM) for 30 min and then treated with 800 µM PG for 24 h. Annexin V-FITC and rhodamine staining in HPF cells were measured using a FACStar flow cytometer. A and B: Representative histograms for annexin V-FITC (A) and rhodamine staining in HPF cells (B). M1 indicates annexin V-FITC-positive (A) and rhodamine 123-negative [MMP (ΔΨ_m) loss] HPF cells (B). C and D: Graphs show the percentages of M1 regions in A (C) and B (D). *p < 0.05 as compared with PG-untreated control cells.

Data availability statement

Data collected during the present study are available from the corresponding author upon reasonable request.