Abstract: Objective To explore pathological characteristics of different white matter tracts at core of the spinal cord injury (SCI) in adult rats. Methods 21 adult female Wistar rats were divided into normal group (n=3), sham group (n=3) and lesion group (n=15). The rats of the lesion group were severely injured at T7-8 using the NYU impactor of 10 g×50 mm. The pathology of spinal cord injury was detected using Luxol fast blue (LFB) staining and NF200 immunohistochemistry staining 1 day, 3 days, 7 days, 14 days and 28 days after injury, while the hindlimbs behavior of rats was rated with Basso-Beattie-Bresnahan (BBB) scores of open-field. Results The BBB scores recovered 3 days after injury and reached a platform from 14 to 28 days after injury. LFB showed that there were spared white matters on ventral white matter (VWM) and lateral white matter (LWM). The percentage of spared white matters area decreased to the lowest 3 days after injury, and reached a platform from 7 to 28 days after injury. The number of NF200-IR axons reduced significantly in white matter tracts after SCI. Conclusion Ventral spared white matters plays a key role in the recovery of motor function in rat with SCI, and the first 3 days was a time window to protect the white matters from injury.

Key words: spinal cord injury, function recovery, spared white matter, axon degeneration