Changes of gene expression after cell transplantation. Gene expression of IL-1β, IL-6, and BAD in host brain were examined by (A) RT-PCR and (B) quantitative analysis. Although IL-1β gene expression is not statistically different after cell transplantation, IL-6 gene expression significantly decreased in the pericontusional regions of the co-transplantation group at 7 days compared with OEC only grafts (P <0.05). Moreover, BAD gene expression decreased significantly in the NSC + OEC group when compared with that of the TBI, NSC, and OEC groups (P <0.05). *Statistical significance of P <0.05. NSC, neural stem cell; OEC, olfactory en sheathing cell; TBI, traumatic brain injury.