CD163/Hemoglobin Oxygenase-1 Pathway Regulates Inflammation in Hematoma Surrounding Tissues after Intracerebral Hemorrhage

Background The aim of the present study was to investigate changes in the expression of CD163 and hemoglobin oxygenase-1 (HO-1) in brain tissue surrounding hematomas after intracerebral hemorrhage (ICH), and correlations with other factors. Materials and methods Brain tissues in the close surrounding of ICH hematomas (n = 27, ICH group) were collected at 6 hours or less, 6-24 hours, 24-72 hours, and more than 72 hours after bleeding onset, and more distant tissues (n = 12, control group) were histologically analyzed with hematoxylin and eosin staining and transmission electron microscopy. Interleukin (IL)-1, IL-10, and tumor necrosis factor-alpha, as well as the expression of CD163 and HO-1, were assessed using immunochemistry, Western blotting, and reverse transcription–polymerase chain reaction. Apoptosis rates were determined with terminal deoxynucleotidyl transferase dUTP nick end labeling assays. Results The expressions of the inflammatory cytokines IL-1 and tumor necrosis factor-alpha were increased at 6-24 hours ( P  .05), reached a peak at 24-72 hours ( P  .001 and P  .01), at which time histopathological changes became most obvious and apoptosis rates were highest, but diminished for more than 72 hours after ICH onset. The anti-inflammatory cytokine IL-10 peaked at 6-24 hours ( P P  .05). CD163 and HO-1 expressions gradually increased from 6 to 24 hours to peaks at more than 72 hours after ICH onset ( P  .001). Conclusion The highest inflammation level in tissues surrounding ICH hematomas occurred 2-3 days after bleeding onset, but was accompanied by an anti-inflammatory factor IL-10 expression enhancement. In the period of more than 72 hours after ICH onset, CD163 and HO-1 expressions reached peaks and inflammatory cytokine expressions dropped.