Lumbar 5 (L5) nerve compression affects adjacent DRGs and distal nerve

Painful radiculopathy, mainly caused by physical damage to spinal nerve roots, brings algesia in their innervated areas. Intriguingly, the region of paresthesia is not always limited to the injured neuron-innervated area, and abnormal activation is also frequently observed in adjacent intact nerve segments. Since injured and uninjured nerve fibers comingle in one nerve trunk, we propose a hypothesis that the compression of the spinal nerve produces a degenerative environment at the distal end of the nerve, affecting the undamaged nerve fibers. We divided the rats into two groups: Compression of L5 spinal nerve in the experimental group and sham operation in the sham group. DRGs of L4, L5 and L6, femoral nerve and sciatic nerve were collected for RNA-seq. The results showed that L5 nerve compression resulted in inflammatory response in adjacent non-injured L4 DRG. The femoral nerve and sciatic nerve showed signs of nerve damage and repair. This suggests that injured nerve fibers can influence the properties of adjacent intact fibers through the nerve trunk which they converge. Rat L5 spinal nerve was wrapped with a cannula which internal diameter is 0.5mm for 3 days or 7 days. Then DRGs of L4, L5 and L6, femoral nerve and sciatic nerve were collected from rats for RNA seq.