Effects Of High Mobility Group Box1Preconditioning On Spinal Cord Ischemia Reperfusion Injury In Rats

PartⅠ Effects of different doses of high mobility group box1(HMGB1)preconditioning on spinal cord ischemia-reperfusion injury (SCII) inrats.Objective: To discuss the effects of different doses of high mobilitygroup box1(HMGB1) preconditioning on spinal cord ischemia-reperfusioninjury (SCII) in rats.Methods:24male SD rats were randomly divided intoischemia/reperfusion group (group IR, n=6), preconditioning group with20ng of HMGB1(group H20, n=6), preconditioning group with50ng ofHMGB1(group H50, n=6) and preconditioning group with200ng ofHMGB1(group H200, n=6). Sterile saline or various doses of HMGB1were injected into lateral ventricle of male SD rats at18hours beforeischemia. SCII model was completed by clamping the abdominal aorta for45min. At24h after reperfusion, blood samples were collected to measurethe levels of tumor necrosis factor-α(TNF-α) and the spinal cord segmentwas harvested to observe the pathological change of spinal cord afterfunctional evaluation on hind limbs was done.Results: Compared with group IR, the hind-limb motor function scores of group H200were increased（P<0.05）.There were no significantStatistics differences between group H20, group H50and group IR in motorfunction scores.Rats in the group H50and group H200had more normalmotor neurons in the anterior of spinal cord and lower levels of TNF-α inserum in comparison with group IR（P<0.05or0.01）.Conclusions: Preconditioning with HMGB1protects spinal cordagainst ischemia-reperfusion injury in a dose-dependent manner.Part Ⅱ Role of high mobility group box1(HMGB1) preconditioningon spinal cord ischemia-reperfusion injury (SCII) in rats.Objective: To investigate the protective effect of HMGB1preconditioning on spinal cord ischemia-reperfusion injury (SCII) in rats.Methods: A total of54male SD rats were randomly divided into threegroups: sham operation group(group S, n=18), ischemia reperfusioncontrol group (group C, n=18), HMGB1preconditioning group (group H,n=18). Sterile saline or200ng rHMGB1were injected into lateralventricle of male SD rats respectively at18hours before ischemia. SCIImodel was completed by clamping the abdominal aorta for45min in groupC and group H. At6h,12h,24h after reperfusion, blood samples of sixrats in each group were collected to measure the levels of tumor necrosisfactor-α(TNF-α) and interleukin-6(IL-6) and the spinal cord segment washarvested to detect the activity of nuclear factor-κB（NF-κB）and expression of inhibitor kappa B-α(IκB-α).Results: Compared with group S，expression of TNF-α,IL-6in serum ofgroup C and group H were increased, which was accompanied with anincrease of degradation of IκB-α and activity of NF-κB in spinal cord.Meanwhile, rats in the group H had lower levels of TNF-α and IL-6inserum as well as degradation of IκB-α and activity of NF-κB in spinal cordin comparison with group C.Conclusions: Preconditioning with HMGB1protects spinal cord againstischemia-reperfusion injury by attenuating inflammatory response.