Protein markers in cerebrospinal fluid in experimental nerve root injury. A study of slow-onset chronic compression effects or the biochemical effects of nucleus pulposus on sacral nerve roots.
METHODS
Measurement of changes in cerebrospinal fluid concentrations of nerve tissue markers, total proteins, and immunoglobulin after compression of nerve root or application of nucleus pulposus in a pig model.


OBJECTIVE
To assess whether compression or application of nucleus pulposus to spinal nerve roots may cause increased levels of cerebrospinal fluid markers of nerve tissue damage and total proteins, and whether synthesis of immunoglobulins may be induced in cerebrospinal fluid.


BACKGROUND
Previous studies have reported that there seems to be a relationship between elevated cerebrospinal fluid total protein concentrations, nerve tissue markers, clinical findings, and compression of the nerve root evaluated by radiologic changes in patients with sciatica.


METHODS
Subjects included 41 pigs, including 5 control animals. In two groups of experimental animals (n = 7; n = 5), an ameroid constrictor was slid onto the S1 nerve root. In two other groups (n = 7; n = 5), nucleus pulposus harvested from the L2-L3 disc was applied to the S1 nerve root. Two sham animal groups (n = 7; n = 5) underwent the same laminectomy. Twenty-one pigs underwent reoperation after 1 week, and 15 pigs after 4 weeks. A syringe was used to remove 3 mL of cerebrospinal fluid at L4-L5. Concentrations of total proteins, the light subunit of the neurofilament protein, S-100 protein, neuron-specific enolase, and glial fibrillary acidic protein were measured, and the presence of oligoclonal bands (immunoglobulins) were assayed in cerebrospinal fluid.


RESULTS
The pigs with compressed S1 nerve root had considerably higher neurofilament protein and total protein concentrations in their cerebrospinal fluid than the-control animals (P < 0.001 and P < 0.01, respectively) or the sham animals (P < 0.001 and P < 0.05) in the 1-week experiment. Nucleus pulposus did not induce a significant increase in concentrations of the different protein markers. The presence of oligoclonal bands in cerebrospinal fluid in the experimental groups did not differ between the control and sham animals.


CONCLUSIONS
The neurofilament protein and total protein concentrations in cerebrospinal fluid may have diagnostic importance in cases wherein clinical findings are not clearly related to the radiologic changes and vice versa. These protein markers also may be useful tools in different experimental models.
Skouen
J S
JS
University of Bergen, Section of Diagnostic Radiology, Haukeland University.
Brisby
H
H
Otani
K
K
Olmarker
K
K
Rosengren
L
L
Rydevik
B
B
D000818:Animals; D002555:Cerebrospinal Fluid / Q000737:chemistry*; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D007278:Injections, Spinal; D007403:Intervertebral Disc / Q000737:chemistry / Q000503:physiopathology* / Q000601:surgery; D007525:Isoelectric Focusing; D009408:Nerve Compression Syndromes / Q000503:physiopathology*; D016900:Neurofilament Proteins / Q000032:analysis; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D009418:S100 Proteins / Q000032:analysis; D013126:Spinal Nerve Roots / Q000737:chemistry / Q000503:physiopathology* / Q000601:surgery*; D013552:Swine
D005904:Glial Fibrillary Acidic Protein; D016900:Neurofilament Proteins; D011506:Proteins; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase