Research Paper Volume 10, Issue 4 pp 549—560

Unrepaired DNA damage in macrophages causes elevation of particulate matter- induced airway inflammatory response

Figure 2. Particulate matter (PM) exposure induces DNA damage response (DDR) signaling in macrophages. C57/BL6 mice (n=3) were instilled intratracheally with PM at 100 μg·d-1 for 2 days in vivo. After 24 hours lung tissues were collected, and DNA damage response was analysed. (A) Representative image of γH2AX (red) in lung tissues. The average percentage of γH2AX positive cells to the total lung tissue cells with DAPI staining were quantified. (B) Analysis of RPA (red) in lung tissues. The average percentage of RPA positive cells to the total lung tissue cells with DAPI staining were quantified. (C) Representative immunofluorescence images of γH2AX (red) in bone marrow–derived macrophages (BMDMs) stimulated with PM at 100 μg·mL-1 for 24 hours. Cells with 5 or more foci were counted as positive. (D) Analysis of 53BP1 (red) in BMDMs treated with PM at 100 μg·mL-1 for 24 hours. Cells with 5 or more foci were counted as positive. All experiments were repeated at least 3 times, and data are presented as means ± SEMs. *p < 0.05; **p < 0.01; ***p < 0.001.