Figure 7.

Neutrophil activation triggered by mtDNA and fMLF. (A-C) C57BL/6 mice were instilled with normal saline, fMLF (1 µM, 200 µl), mtDNA (2.5 µg) and mitochondria (200 µg), and were sacrificed 24 h after instillation. n = 3 per group. (A) The representative lung sections of HE staining are shown. Scale bar = 20 µm. (B) Influx of neutrophils in whole lungs was detected with flow cytometry by labelling CD45, CD11b and Ly-6G. (C) The percentages of CD11b+Ly-6G+ neutrophils in CD45+ cells of the lungs are shown. (D-E, G) Isolated murine neutrophils (5 × 10⁶) were incubated with fMLF (1 µM), mtDNA (2.5 µg/ml) and mitochondria (200 µg/ml) for 2 h in vitro. n = 3 per group. The release of MPO (D) and elastase (E) in the supernatant of neutrophils was determined. (F) Neutrophil chemotaxis assays were performed with fMLF (1 µM) and mtDNA (2.5 µg/ml) for 4 h and the number of migrated cells was counted in five HPFs. (G) Western blotting was performed to confirm the activation of p38 MAPK in neutrophils induced by fMLF and mtDNA. Data are mean ± SEM; *P < 0.05, **P < 0.01, ***P < 0.001 compared with the control group by Student's t-test.