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The role of complement C3 in intracerebral hemorrhage-induced brain injury

Shuxu Yang1, Takehiro Nakamura, Ya Hua

  • 1Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan 48109-0532, USA.

Journal of Cerebral Blood Flow and Metabolism : Official Journal of the International Society of Cerebral Blood Flow and Metabolism
|March 23, 2006
PubMed

Insights

Complement C3 deficiency reduces brain injury after intracerebral hemorrhage (ICH). C3-deficient mice showed less brain edema and inflammation, suggesting C3 aggravates ICH-related brain damage.

Area of Science:

  • Neuroscience
  • Immunology
  • Biochemistry

Background:

  • Complement cascade activation contributes to brain injury following intracerebral hemorrhage (ICH).
  • Previous studies indicated complement C5 deficiency exacerbated ICH-induced brain injury.
  • The role of upstream complement component C3 in ICH remained unclear.

Purpose of the Study:

  • To investigate the specific role of complement C3 in the pathogenesis of ICH-induced brain injury.
  • To determine if complement C3 deficiency impacts brain edema, inflammation, and functional outcomes after ICH.

Main Methods:

  • Intracerebral hemorrhage was induced in male complement C3 deficient and sufficient mice via autologous whole blood infusion.
  • Brain tissue was analyzed for edema, hemeoxygenase-1 levels, microglial activation, and neutrophil infiltration.
  • Behavioral tests, including forelimb use asymmetry and corner turn, assessed functional deficits.

Main Results:

  • Complement C3 deficient mice exhibited significantly reduced brain edema compared to sufficient controls.
  • Lower levels of hemeoxygenase-1, decreased microglia activation, and reduced neutrophil infiltration were observed in C3 deficient mice.
  • C3-deficient mice demonstrated improved forelimb use asymmetry following ICH compared to C3-sufficient mice.

Conclusions:

  • Complement C3 plays a critical role in exacerbating brain injury after ICH.
  • Complement C3 activation influences heme metabolism and the inflammatory response post-ICH.
  • Targeting complement C3 may represent a therapeutic strategy for mitigating ICH-induced brain damage.

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