Abstract: Abstract: Mesenchymal stem cells (MSCs), which are regarded as the promising option of cell replacement therapy, are able to regulate immune response after tissue damage caused by traumatic brain injury (TBI). Secondary neuroinflammation following the mechanical injury is the essential factor of neural cell necrosis and apoptosis, even after the intracranial pressure has returned to normal. Their immune environments caused by neuroinflammtary response determine the outcome and long-term behavior function of TBI in survivors directly. MSCs modulate macrophage/microglia, drive them to polarize into alternative M2-like cells through releasing soluble cytokines, such as prostaglandin E2 (PGE2), tumor necrosis factor- stimulated gene 6 protein (TSG-6), IL-1 and TGF-β, which limits the progression of inflammation and maintain micro- environment stable. Meanwhile, macrophage/microglia exerts significant effects in MSCs survival, proliferation, differentiation and activation. It provides a novel approach as a practical anti-inflammatory therapy in clinical treatment.

Key words:  mesenchymal stem cells, craniocerebral trauma, macrophages, microglia, inflammation, immunity, review, macrophage polarization