Effects of high-mobility group box1 on cerebral angiogenesis and neurogenesis after intracerebral hemorrhage.

Neural stem cells, which reside mainly in the subventricular and subgranular zones of the hippocampus, can regenerate new neuroblasts after various brain insults. Aided by vascular remodeling, these new neuroblasts migrate long distances to injured brain regions. Studies have suggested that high-mobility group box1 (HMGB1), a nonhistone nuclear DNA-binding protein, may stimulate such remodeling in the late phase of some types of brain injury, but it is unclear whether this is true for intracerebral hemorrhage (ICH). Here we used a rat model of collagenase-induced ICH to determine whether HMGB1 can promote neurogenesis and angiogenesis in the late phase of injury. Daily administration of ethyl pyruvate, which inhibited HMGB1 expression, reduced the recovery of neurological function, decreased vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) levels in the ipsilateral striatum, and decreased the numbers of 5-bromo-2-deoxyuridine (BrdU)- and doublecortin (DCX)-positive cells around the hematoma. These findings suggest that HMGB1 may promote angiogenesis and neurogenesis in the late phase of ICH.