Fig. 4.

HMGB1 facilitates NET formation ex vivo. A: neutrophils in bronchoalveolar lavages (BALs) were collected 24 h after intratracheal administration of LPS (1 mg/kg) or LPS and HMGB1 (300 ng), and free DNA was determined in BAL neutrophils that were immediately incubated after isolation for 15 or 60 min followed by addition of Sytox probe for 5 min. Means ± SD, n = 3; *P < 0.05 or ***P < 0.001 compared with BALs of mice that were not subjected to HMGB1 administration. B: representative images show NET formation ex vivo (arrows) in BALs obtained from mice treated with LPS or LPS/HMGB1 as indicated in A. BAL neutrophils were incubated immediately after isolation for 15 and 60 min and then DNA stained with DAPI.