Penetrating spinal cord injury transiently inhibits responsiveness to touch in mice

Spinal cord injury (SCI) is a devastating mechanical trauma of the spinal cord. We recently showed that penetration of fine needles from dorsal to ventral regions in the spinal cord disturbed spontaneous locomotion in mice. However, it has not been verified if penetrating SCI at the dorsal side of the spinal cord, responsible regions for sensory functions, changes movements after sensory stimulation. In this study, penetration into the dorsal midline or dorsolateral regions was separately applied to mice. Using these mice, we evaluated withdrawal movements after tactile and thermal stimulations as well as locomotion. Penetrating SCI at midline and dorsolateral regions exhibited normal Basso Mouse Scale for Locomotion (BMS) and beam walking test scores. In addition, locomotion in open field was not affected in these mice. Also, we showed that responses after thermal stimulation on hot plate was not changed in mice with midline and dorsolateral penetrations. However, paw withdrawal after both static and dynamic touches were transiently inhibited in mice after both midline and dorsolateral penetrations. This model is a valuable tool for examining the functional and pathological consequences of damage to specific, discrete regions or tracts within the spinal cord.