Degeneration of peripheral nerves and expression changes of microtubule-associated protein 1B in rats after chronic spinal cord compression / 中华神经医学杂志

ABSTRACT

Objective To observe the morphological changes of the peripheral nerves,the expression changes of microtubule-associated protein 1B (MAP1B) and the changes of motor function in rats after chronic spinal cord compression.Methods A total of 50 female Wistar rats were randomly divided into normal control group (n=10),sham-operated group (n=10) and chronic compressive groups (n=30).The rats in the chronic compressive groups were given gradual compression on the posterior spinal cord using blunt plastics screw; compression degree reached 20％ (n=10),40％ (n=10) and 60％ (n=10),respectively,after 2 months.Rats in the normal control group did not receive any treatment and rats in the sham-operated group was only given removal of the L5 spinous process and part of the vertebral plate.Following sacrifice of the rats,cells from sciatic nerves were removed for HE staining;light microscopy and electron microscopy were employed to observe the changes; immunohistochemical staining of MAP1B was performed.Results Hypokinesia,and decreased Tarlov scores,Ramp test scores and BBB-21 scores in the chronic compressive groups were noted as compared with those in the normal control group (P＜0.05).Peripheral nerve degeneration was noted in all the chronic compressive groups; the more severe the compression,the more significant the degeneration.Expression of MAP1B in the peripheral nerves of the chronic compressive groups was significantly down-regulated as compared with that in the normal control group (P＜0.05).Conclusion Spinal cord compressive injury can lead to peripheral nerve degeneration; and neuronal apoptosis and necrosis lead to rare axonal regeneration,which may be one of the important reasons that influences the neural function recovery after chronic spinal cord compression.