The Experimental Study On The Relationship Between Nerve Infiltration And Discogenic Pain In Rats

Objectives:To investigate the the model of low lumbar intervertebral discs innervated and nerve infiltration in painful discs。And provide clinic guideline to diagnosis and treatment to discogenic pain。Method and materials:20 adult male SD rats were randomly divided into two groups (n=10 in each group)。the control group: To adopt center approach through abdominal cavity and expose L5-6 intervertebral discs, 8 days later, Horseradish peroxidase(HRP) was injected into the L5-6 intervertebral discs from the surface of back side;operation group: After expose L5-6 intervertebral discs, prick into L5-6 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, 8 days later, Horseradish peroxidase(HRP) was injected into the L5-6 intervertebral discs from the surface of back side.The rats in both groups were killed 2 days after injected by HRP and bilateral L2 and the L5 DRG were sectioned. TMB - ST and GAP-43 immune tissue biochemical staining were adopted to observe the cross-sectional areas and the numbers of the HRP labeled cells and HRP-GAP-43 double-labeled cells .Results:the HRP labeled cells and HRP-GAP-43 double-labeled cells were found in L2,L5DRG on both sides in each group.The number of HRP-GAP-43 double-labeled cells in operated group is significantly higher than that in control group(P<0.05)。The numbers of HRP labled cells and HRP-GAP-43 double-labeled cells in L2DRG are significantly higher than that in L5DRG(P<0.05).There is no significant difference between the numbers of HRP labled cells in two groups.The diameter of HRP-GAP-43 double-labeled cells is 18～44um [average(28±12)um]。Conclusion:there are two models of innervation existing in posterior tissues of low lumbar intervertebral discs,primarily are non-segmental innervation, partly are segmental innervation;Lumbar intervertebral discs destroy can induce painful nerve fiber infiltration.