EFFECTS OF EXOGENOUS TRANSFORMING GROWTH-FACTOR-BETA-1 ON SPINAL-CORDINJURY IN RATS

This study was undertaken to examine the effect of transforming growth factor-beta 1 (TGF-beta 1) administered into the subarachnoid space a fter spinal cord injury (SCI) on the increased production of inducible -nitric oxide synthase (i-NOS) in the injured spinal cord in rats. The expression of i-NOS mRNA after SCI was remarkably down-regulated by T GF-beta 1 in vivo. Rats treated with TGF-beta 1 showed a better outcom e regarding hindlimb motor dysfunction in the first 5 days after injur y compared to the saline-treated rats. However, the final outcome was not better and fibrous scar formation in the injured spinal cord was m ore evident, which was demonstrated as increased immunoreactivity of f ibronectin in the later stage after SCI. These results provide evidenc e of both positive and negative contributions of TGF-beta 1 to the pat hology associated with SCI.