The Establishment Of Animal Model For Discogenic Low Back Pain And Its Behavioral Test

Objective: To establish animal model of discogenic low back pain, investigate its pathogenesis, observe the behavioral manifestation of animals who suffered from discogenic low back pain.Methods and research contents: 96 male SD rats were randomly divided into three groups: sham, the first and second operation groups. The rats were taken supine position after general anaesthesia, to adopt center approach through abdominal cavity and expose L6-7 intervertebral discs, to prick into L6-7 intervertebral discs at ventral center of intervertebral discs by specially made pinhead which diameter is 0.2 mm, which depth were controlled 3 mm reaching the sites below posterior outer annular fibrosus(the first operation group), or prick into the sites below posterior outer annular fibrosus, which were intersected 30 degrees with the first pin hole(the second operation group). To observe the spontaneous behavioral manifestation at various intervals and the pathological changes of L6-7 intervertebral discs, to examine the expression of CD34 IL-1β和COX-2 in intervertebral discs adopting immunohistochemical methods. Main results:1.There are cells which are interlaced reticulately and similar to fibrous tissue cells in the nucleus pulposus of intervertebral discs. There are hyaloid degeneration in these cells, which are interlaced with gelatum-like substance. The fibrocartilage cells degenerate in the inner annular fibrosus. 2.There are fissures from front to rear in the operated intervertebral discs. The posterior outer annular fibrosus do not rupture, these changes are accorded with the pathological manifestation of discogenic low back pain. 3. There are sporadic CD34 positive cells in the inner intervertebral discs after operation, indicating that vascular endothelial cells have formed.4. There are sporadic IL-1 P positive cells in many sites of the inner intervertebral discs after operation, which are distributed in ring form., there are no or a trifle of positive cells in the outer intervertebral discs.5. There are sporadic COX-2 positive cells in many fibrous tissue-like cells in nucleus pulposus after operation, there are sparse positive cells in a few fibrocartilage cells of inner annular fibrosus.6.For experimental rats in the the second operation groups, the time of immobility prolongs, the time of locomotion decreases, there is statistical significance compared with the rats of sham group.