Experimental study on the abnormal autoimmunity in the model of ruptured lumbar disc herniation

English Keywords:Sciatica model without mechanical pressure  Abnormal autoimmunity  Antigen-antibody complexes  Cytokine

English Abstract:

  【Abstract】 Objectives: To investigate the abnormal autoimmunity in the model of ruptured lumbar disc herniation. Methods: 20 SD rats were divided into experimental group and control group, a lumbar disc herniation model without mechanical pressure(sciatica model) was established on Sprague Dawley rat by putting nucleus pulposus near the nerve root. The mechanical withdrawal thresholds of posterior limbs and slope-climbing test were measured at preoperation and 1, 2, 3 weeks after operation. 3 weeks later, the rats were sacrificed, and the immunoglobulin G(IgG) and immunoglobulin M(IgM) in serum were examined by turbidimetry. The presence and distribution of antigen-antibody complexes in nucleus pulposus were examined by immunohistochemical method. And the levels of cytokine TNF-α, IL-6, IL-12 were detected by enzyme linked immunosorbent assay, and the BCA method was used to analyze the activity of PLA2 in the sciatic nerve. Results: Before model establishment, all rats had IV grade slope-climbing, after surgery, the rats in experimental group had Ⅲ grade slope-cimbing, while the rats in control group maintained IV grade slope-climbing. After the model establishment, the mechanical withdrawal thresholds of posterior limbs significantly decreased (from 40.7±5.3mmHg to 90.4±5.0mmHg, P<0.01), the levels of IgG and IgM in serum elevated significantly(4.98±0.96g/L and 1.45±0.37g/L respectively, P<0.05), meanwhile the levels of cytokine TNF-α, IL-6, IL-12 elevated remarkably(205.77±46.32pg/L, 186.4±87.3pg/L and 69.23±27.46pg/L, P<0.05). There was positive presence of antigen-antibody complexes in the nucleus pulposus(P<0.01), and obvious inflammatory lesion in the sciatic nerve was observed after model establishment. Conclusions: There is abnormal autoimmunity in the sciatica model induced with no mechanical pressure, which may lead to pain.