Immature and mature neurons coexist among glial scars after rat traumatic brain injury
Tatsuki Itoh1, Takao Satou, Shozo Nishida
1Department of Pathology, Kinki University School of Medicine, Osaka, Japan. tatsuki@med.kindai.ac.jp
Objectives:
Glial scars around a damaged area after brain injury inhibit neurite elongation from surviving neurons and axonal plasticity, and thus prevent neural network regeneration. However, the generation, differentiation and maturation of neural stem cells (NSCs) among glial scars after brain injury have not yet been reported.
Methods:
In the present study, we investigated the chronological relationship between gliosis and maturation of new neurons around a damaged area using a rat traumatic brain injury (TBI) model.
Results:
Between 1 and 7 days after injury, many nestin-positive cells were observed around the damaged area. Three days after injury, many small nestin-positive cells showed an astrocytic morphology. Between 1 and 30 days after injury, doublecortin (DCX)-positive cells were present around the damaged area. Three and 7 days after injury, a small number of nestin-positive cells were immunopositive for glial fibrillary acidic protein (GFAP). Seven days after injury, there were DCX-positive cells in the gliosis occurring in the lesion. Thirty days after injury, DCX-positive cells were observed near and among the glial scars and a small number of these cells were immunopositive for NeuN.
Discussion:
These results suggest that DCX-positive cells were present near and among the glial scars after brain injury, and that these cells changed from immature to mature neurons. It is considered that promotion of the maturation and differentiation of newly formed immature neurons near and among glial scars after injury may improve the brain dysfunction induced by glial scars after brain injury.
