The Expression Of Autophagy And Tis Changes By Hyperbaric Oxygen After Spinal Cord Injury In Rat:an Experiment Study

Object: To assess autophagy expression after rat spinal cord injury (SCI) andinvestigate the effect of hyperbaric oxygen treatment on autophagy.Methods: Seventy-five adult Sprague-Dawley rats were used for the experimentalprocedure and were randomly divided into sham operation group(n=25),spinal cord injurygroup(n=25), hyperbaric oxygen group(n=25).In the SCI group, laminectomy at T10wereperformed, followed by clamp force of the spinal cord. In the sham group, only alaminectomy was performed without contusion.In the HBO group, was treated byHyperbaric oxygen after SCI. BBB function score evaluation test was carried out every dayafter the operation. Hematoxylin-Eosin (HE) staining of objective spinal cord was done.Cellular localization and ultrastructural changes after spinal cord injury were comparedwith those sham-operated rats using Western-blotting and TEM, at6hours,1days,3days,7days and14days after SCI，respectively. We also used Western-blot andimmunofluorescent double labeling to investigat the effect of hyperbaric oxygen onautophagy expression of contused spinal cord.Data from the Western-blot and BBB wereanalyzed using a nonparametric T-test with P<0.05being considered significant.Results: BBB score was significantly higher in the HBO group than the SCI groupand sham group (P<0.05). The existence of autophagy and progress of autophagic celldeath after SCI were confirmed by TEM.We detected significantly elevated level ofBeclin-1and LC3at6hours after SCI, and then the level declined until2week after SCI.Hyperbaric oxygen induced Beclin-1and LC3expression at6hours after SCI. Beclin-1and LC3positive cells were colocalized with neuronal nuclei and glialfibrillary acidicprotein. Conclusion: Through observing the enhanced autophagy expression in neurons soonafter spinal cord injury by clamping force and the induced effect of hyperbaric oxygentreatment, this study demonstrates the characteristics of autophagy expression after SCIand suggests that autophagic cell death may play a role in neuronal death after spinal cordtrauma.