BDA-labeling of CST originating from the contralesional intact hemisphere.

Representative images from the cervical spinal cord show BDA-labeled CST axons crossing the midline (arrows in B) and sprouting into the denervated side of the ventral gray matter in a rat after TBI. tPA treatment significantly increased the axon midline crossing (arrows in C). There were no obvious BDA-labeled axons observed in the opposite side of the cervical spinal cord in sham rats (A). Quantitative data (D) show that the number of contralesional CST in the denervated cervical gray matter was increased significantly by traumatic injury (p<0.05 vs. Sham+tPA) and tPA treatment (p<0.05 vs. TBI+Saline). Scale bar  = 50 µm. Data represent mean ± SD. n = 8 (rats/group).