Systemic complement depletion diminishes perihematomal brain edema in rats.
OBJECTIVE
The complement cascade is activated after experimental intracerebral hemorrhage (ICH). It remains unclear, however, whether depleting the complement system will improve injury resulting from ICH. This study investigated the effects of systemic complement depletion on brain edema formation after ICH.


METHODS
Fifty-six pentobarbital-anesthetized Sprague-Dawley rats were used. Treatment animals were complement-depleted with cobra venom factor (CVF) (intraperitoneally). Control rats received an equal volume of saline injection (intraperitoneally). In both treatment and control rats, autologous blood (100 microL) was infused stereotaxically into the right basal ganglia. Rats were killed 2, 24, or 72 hours later for brain water, ion, and tumor necrosis factor-alpha (TNF-alpha) measurements, for Western blot analysis, and for immunohistochemical studies. Brain edema was quantitated by wet/dry weight. TNF-alpha levels were measured by enzyme-linked immunosorbent assay. Western blot analysis was applied for C9 semiquantification. Immunohistochemistry was used to detect complement C3d, C5a, C9, and myeloperoxidase.


RESULTS
Perihematomal brain edema was reduced by systemic complement depletion at 24 hours (78.8+/-0.6% versus 81.5+/-0.8% in control, P:<0.01) and 72 hours (81.5+/-1.5% versus 83.6+/-0.9% in control, P:<0.05), while cerebellar water content was unaffected (78.2+/-0.3% versus 78.0+/-0. 1%). Complement depletion reduced TNF-alpha production 2 hours after ICH. Immunocytochemistry showed that complement depletion significantly reduced perihematomal C9 deposition, C3d production, and the number of C5a- and myeloperoxidase-positive cells.


CONCLUSIONS
Complement depletion by CVF attenuates brain edema in ICH, indicating that complement activation plays an important role in ICH-induced brain edema. Preventing complement activation may be effective in the treatment of ICH.
Xi
G
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Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor 48109-0532, USA.
Hua
Y
Y
Keep
R F
RF
Younger
J G
JG
Hoff
J T
JT
D000818:Animals; D001784:Blood Gas Analysis; D001786:Blood Glucose; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001929:Brain Edema / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D002543:Cerebral Hemorrhage / Q000150:complications*; D015933:Complement C3d / Q000378:metabolism; D015936:Complement C5a / Q000378:metabolism; D003186:Complement C9 / Q000378:metabolism; D003165:Complement System Proteins / Q000172:deficiency*; D004195:Disease Models, Animal; D004546:Elapid Venoms / Q000008:administration & dosage*; D004797:Enzyme-Linked Immunosorbent Assay; D006461:Hemolysis; D007150:Immunohistochemistry; D007274:Injections, Intraperitoneal; D008297:Male; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014867:Water / Q000032:analysis / Q000378:metabolism
D001786:Blood Glucose; D003186:Complement C9; D004546:Elapid Venoms; D014409:Tumor Necrosis Factor-alpha; C016310:cobra venom factor; D014867:Water; D015933:Complement C3d; D015936:Complement C5a; D003165:Complement System Proteins; D009195:Peroxidase