Transplantation of neural stem cells enhances expression of synaptic protein and promotes functional recovery in a rat model of traumatic brain injury.

Transplantion of neural stem cells (NSCs) has shown promise for the treatment of traumatic brain injury (TBI). Although the functional mechanisms underlying transplant‑mediated recovery following TBI have yet to be determined, previous studies demonstrated that transplanted NSCs may respond to the release of specific neurotransmitters, and/or the production of factors that promote neuronal growth. Therefore, we hypothesize that the direct transplantation of NSCs into the injured brain enhanced the expression of synaptic protein and regeneration-associated protein, which may be responsible for promoting functional recovery in a rat model of TBI. Our results showed that NSC transplant significantly improved neurological motor function in selected behavioral tests compared to saline control rats. Our data showed that the number of surviving cells engrafted into the rats was 4.1±0.9% of engrafted cells at 8 weeks post‑transplantation, with 11.4±1.6% βⅢ-tubulin-immunopositive cells of these cells. RT-PCR and Western blot analysis demonstrated that the expression of synaptophysin (SYP) and regeneration‑associated protein (GAP43) in the injured brain of NSC-transplanted rats was significantly increased compared to the saline control rats during the experimental period. These data suggest that NSCs transplanted directly into the injured brain are capable of surviving, differentiating into neurons and promoting functional recovery in a rat model of TBI. Engrafted NSCs increase the expression of SYP and GAP43 in the injured brain of NSC-transplanted rats, which is suggested as one of the mechanisms underlying the improved functional recovery on motor behavior due to the transplantation of NSCs following TBI.