ABSTRACT
Objective To investigate the effects of quercetin on glial scar formation and axonal regeneration after spinal cord injury (SCI) and its association with the p38 mitogen activated protein kinase (MAPK) signal pathway.Methods 128 female Sprague-Dawley (SD) rats were randomly divided into a control group (SCI + saline),an intervention group (SCI + quercetin + anisomycin),a treatment group (SCI + quercetin) and a sham-operation group (n =32).Basso Beattie Bresnahan (BBB) assessment and footprint analysis of the hind limb were performed on days 1,3,7,14,21 and 28 postoperation in each group.The expression levels of p38MAPK,phosphorylation p38MAPK,glial fibrillary acidic protein (GFAP) and neurofilament protein-200 (NF-200) were detected by Western blot.The numbers of GFAP and NF-200 positive staining cells in the injured spinal cord in each group were detected by immunohistochemistry.Results The BBB scores in the treatment group were significantly higher than in the intervention and control groups at each time point after SCI except on day 3 postoperation (P ＜ 0.05).The expression levels of phosphorylation p38MAPK protein in each SCI group were significantly higher than in the sham-operation group on days 3 and 7 postoperation (P ＜ 0.05).The expression levels of phosphorylation p38MAPK protein in the treatment group were significantly lower than in the control and intervention groups on days 3,7 and 14 postoperation (P ＜ 0.05),but there was no significant difference on day 28 postoperation among all the groups (P ＞ 0.05).The numbers of NF-200 and GFAP positive staining cells were significantly greater than in the sham-operation group at each time point postoperation (P ＜ 0.05);the NF-200 positive staining cells in the treatment group were significantly increased in comparison with the control and intervention groups (P ＜ 0.05);the GFAP positive staining cells in the treatment group were significandy fewer than in the control and intervention groups on days 7,14 and 28 postoperation (P ＜ 0.05).Conclusions Quercetin may have protective effects against acute SCI by decreasing glial scar formation,increasing axonal regeneration and promoting recovery of locomotor and nerve function in rats.The effects may be correlated with inhibition of the p38MAPK signal pathway.
ABSTRACT
Objective To investigate the stability of lumbar single?level dynamicly fixed by socket track pedicle screws after decompression. Methods Socket track pedicle screws are made of titanium?alloy, swing like universal screw within the scope of 18° in the sagittal plane and 8° in the horizontal plane. Motion constraints were due to the hole which the screw goes through. Six pig spines (L1-5) were tested by applying a pure moment of 4.018 Nm in 3 directions of loading. The range of motion (ROM) of the following groups underwent different surgical procedures was measured:(1) intact;(2) dynamic fixation 1 (decompres?sion by total laminectomy and instrumentation with socket track pedicle screws); (3) dynamic fixation 2 (decompression by total laminectomy and bilateral facetectomy while instrumentation with socket track pedicle screws);( 4) instability resulted from decom?pression (decompression by total laminectomy plus bilateral facetectomy without any rod);(5) hybrid fixation (decompression by to?tal laminectomy and bilateral facetectomy while instrumentation with 2 socket track pedicle screws connected with 2 unilateral pedicle screws ). Results Compared with the intact specimens (in flexion, extension, lateral bending and rotation, corresponding angular displacements were 1.84°±0.75°, 1.55°±0.34°, 2.2°±1.07°, 2.06°±0.76° respectively), the ROM of segment L3, 4 of each group were significantly restricted except for axial rotation. In flexion, extension and lateral bending, the ROM was reduced to 0.71°±0.39°, 0.46°±0.18°, 0.85°±0.66° in dynamic fixation 1 group;0.79°±0.43°, 0.71°±0.20°, 1.17°±0.48° in dynamic fixation 2 group and 0.63°±0.50°, 0.37°±0.19°, 0.54°±0.60° in hybrid fixation group. The rotation ROM of dynamic fixation 1 group and hy?brid fixation group were decreased to 1.50°±0.64° and 1.22°±0.36°, whereas the ROM of dynamic fixation 2 had a non?significant reduction to 1.85°±0.67°. The extension and rotation ROM of dynamic fixation 2 increased significantly comparing to dynamic fixa?tion 1 group; the extension, lateral bending and axial rotation ROM of hybrid fixation group were reduced comparing to the state of dynamic fixation 2 group. Conclusion The dynamic instrumentation of single?level lumbar spine with socket track pedicle screws could offer stability in all directions. The flexion, extension, lateral bending and rotation ROM of spine with dynamic instru?mentation after total laminectomy and bilateral facetectomy could be reduced.