HMGB1 and brain injury: Our collective results support a previously described mechanism of a crosstalk between astrocytes and NS/PCs, and provide an experimental basis that reactive astrocyte-derived HMGB1 can promote NS/PC proliferation, which may be one of the reasons that NS/PCs spontaneously proliferate following brain injuries, and suggest that HMGB1 may be a very important factor for the regeneration of injured brain tissue.