High mobility group box-B1 (HMGB1) levels in the hematoma of fractured bones and in macrophage U937 cells under hypoxia. A: Enzyme-linked immunosorbent assay (ELISA) for HMGB1 in the hematoma specimens or in the fresh bleeding samples from fractured bones; B: HMGB1 level in the supernatant of macrophage U937 cells under normoxia or hypoxia for 8, 12, 24 or 48 hours; C: Western blot analysis of HMGB1 in cytosol and in nucleus in U937 cells under normoxia or hypoxia for 12, 24 or 48 hours, with tubulin as internal control; D: Relative level of HMGB1 in cytosol to in nucleus in U937 cells. The data represent three independent experiments, and shown as Mean ± SE. *P < 0.05, **P < 0.01, ***P < 0.001. ns: no significance.