Serum S100B, brain edema, and hematoma formation in a rat model of collagenase-induced hemorrhagic stroke

S100B, a 21-kD Ca2+ binding protein expressed in Schwann cells and astroglia, has often been reported as a promising biomarker for ischemic stroke. In addition to ischemic stroke, the peripheral S100B level may also be useful as a biomarker for intracerebral hemorrhage (ICH). However, the kinetics and characterization of peripheral S100B in patients or experimental animal models with ICH have not been carefully examined. The present study investigated the kinetics and characteristics of the serum S100B level in a rat collagenase-induced ICH model. The serum S100B kinetics and the time-course of brain edema and hematoma formation were examined. Then, the correlations between the elevated serum S100B level and brain edema or hematoma formation were investigated. A transient elevation of serum S100B that peaked at 6 h after ICH induction was observed. The single measurement of serum S100B at 6 h after ICH induction was significantly correlated with brain edema formation and the maximal extent of the hematoma volumes. These results suggest the significance of serum S100B as a biomarker of brain damage resulting from ICH.