At the termination of the experiments, all rats were sacrificed for histological confirmation of lesions. All lesions were confirmed by toluidine blue stain. The animals were perfused with phosphate-buffered saline (PBS) and then with 4% paraformaldehyde. The brains and spinal cords were removed, post-fixed in 4% paraformaldehyde and cryoprotected in 30% sucrose. The tissue was then sectioned into 30 μm-thick sections using a cryostat (Leica CM 1850; Leica Biosystems, Germany) and stained with toluidine blue. Only those rats with histologically-verified lesions were included in the data analysis.