Morphological Changes And Function Of Microglia After Embryonic Cortical Tissue Transplantation

Trauma brain injury is a common disease of central nervous system,and there is no effective treatment in clinic.Embryonic cortical tissue transplantation is an effective method to repair CNS injury and provides a new way to supplement the lost neurons after brain injury and reconstruct the original neural circuits.It has a great influence on the recovery of trauma brain injury when brain produces immune responses after trauma brain injury.Microglia is an essential immune cells in the central nervous system,its morphological changes and function in embryonic cortical tissue is not clear.In this study,two kinds of transgenic mice,THY1-YFP H-line,CX3CR1GFP/+,and a C57BL/6 wild-type mice were used to establish the model of embryonic cortical tissue transplantation,and GW2580 was given to inhibit proliferation of microglia in mouse brains.The morphological changes and function of microglia were evaluated by immunofluorescence staining,confocal laser scanning and two-photon imaging in vivo.The results show that the recovery of motor function was significantly improved after transplantation by rotarod test and forelimb grip strength test.Our data suggested that axons in the graft projected into the host brain 60 days after the fetal mouse cortical tissue of THY1-YFP H-line mouse was transplanted into the lesion cavity of C57BL/6 wild-type mice The results of TUNEL staining combined with in vivo two-photon imaging showed that the microglia in the graft tissue underwent apoptosis and gradually disappear within 24 h after transplantation.Subsequently,microglia in the host brain migrated to the graft.At the same time,microglia in the transplanted tissue experienced dramatic morphological changes.The survival area of grafts decreased significantly when the proliferation of microglia were inhibited by using GW2580.These results suggest that the proliferation of microglia after transplantation is beneficial to the survival of the graft.The study here provide a theoretical basis and new ideas for the clinical treatment in traumatic brain injury.