title: Expression of c-Fos and c-Jun in adjacent cervical spinal cord segments following C7nerve root rhizotomy in rats: Indication of a neural pathway between adjacent cervical spinal cord segments.
abstract: Cervical radiculopathy is a common disease in clinical practice. However, the symptoms are not confined to the affected spinal cord segment indicated by magnetic resonance imaging (MRI) findings. In the present study, we measured c-Fos and c-Jun expression in ipsilateral and adjacent cervical spinal cord segments following C7nerve root rhizotomy, to determine whether there is a neural pathway between adjacent cervical spinal cord segments. Forty-eight adult male Wistar rats were randomly divided into two groups: the C7rhizotomy group (rhizotomy group, n=24) and the sham-operated group (sham group, n=24). The right C7nerve root was completely cut off in the rhizotomy group, while it was exposed but not cut in the sham group. The expression of c-Fos and c-Jun in cervical spinal cord segments was detected by immunohistochemistry at 2 and 4 h after surgery. We observed that the number of c-Fos- and c-Jun-positive neurons in ipsilateral C5-7segments were significantly increased at 2 and 4 h after C7nerve root rhizotomy (P<0.05 vs. the sham group). The location of c-Fosand c-Jun-positive neurons in C5-7gray matter was similar in the rhizotomy and sham groups, which was mainly in lamina IX of the anterior horn and laminae I-II of the dorsal horn of the spinal cord. However, the number of c-Fos- and c-Jun-positive neurons in the C5-7gray matter was significantly reduced at 4 h after surgery compared with the number 2 h after surgery. The location of c-Fos- and c-Jun-positive neurons at 4 h was similar with that at 2 h. Therefore, there may be a neural pathway between ipsilateral adjacent cervical spinal cord segments. This may be one possible explanation as to why the radicular symptoms of cervical radiculopathy are not confined to the affected spinal cord segment shown by MRI.
authors.affiliation: Department of Orthopedic Surgery, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Keliang
authors.initials: K
authors.lastname: Xie
authors.forename: Shiqing
authors.initials: S
authors.lastname: Feng
authors.forename: Pei
authors.initials: P
authors.lastname: Wang
authors.forename: Xinlong
authors.initials: X
authors.lastname: Ma
keywords: c-Fos; c-Jun; cervical radiculopathy; neural pathway; spinal cord