高压氧预处理损伤脊髓Bcl-2/Bax的表达

doi:10.3969/j.issn.2095-4344.2013.46.007

摘要/Abstract

摘要：

背景：研究表明高压氧治疗可通过减少脊髓损伤后神经细胞凋亡，促进脊髓神经功能的恢复，但其抑制凋亡的机制还不清楚。
目的：探索高压氧预处理对脊髓损伤后Bcl-2和Bax表达的影响及意义。
方法：将66只健康成年雄性SD大鼠随机分为假手术组6只、模型组和高压氧预处理组各30只。假手术组仅行椎板切除；模型组根据Allen’s打击原理制作脊髓损伤模型，不做任何治疗；高压氧预处理组在10 d内对大鼠进行5次，每次1 h的高压氧(0.25 MPa，纯氧)治疗后，再建立脊髓损伤模型。
结果与结论：免疫组化检测显示假手术组大鼠脊髓组织中Bcl-2和Bax表达较少；模型组和高压氧预处理组大鼠脊髓组织中均可见不同程度的Bcl-2和Bax阳性表达，其中Bcl-2表达高峰出现在损伤后第7天，而Bax表达高峰出现在损伤后第3天；而经高压氧预处理的大鼠脊髓组织中Bcl-2表达增加(P < 0.05)，而Bax表达减少(P < 0.05)。提示高压氧预处理能够增强Bcl-2的表达同时降低Bax的表达。

关键词: 组织构建, 组织构建与生物活性因子, 高压氧预处理, 高压氧, 脊髓损伤, Bcl-2, Bax, 免疫组化, 脊髓

Abstract:

BACKGROUND: Studies have shown that hyperbaric oxygen preconditioning can reduce neuronal apoptosis and improve neurologic dysfunction after spinal cord injury. However, the mechanism of inhibiting apoptosis is still unclear.
OBJECTIVE: To study the effect and significance of hyperbaric oxygen preconditioning on expression of Bcl-2 and Bax protein after spinal cord injury in rats.
METHODS: Sixty-six male adult Sprague-Dawley rats were divided into sham operation group, model group, treatment group at random. Animals in the sham group were six, and animals in the model and treatment groups were 30, respectively. Animals in the treatment group received hyperbaric oxygen preconditioning at 2.5 MPa (100% O₂), once for 1 hour and totally five times within 10 days before establishment of spinal cord injury models. In the sham operation group, only laminectomy was done. In the model group, a spinal cord injury model was prepared using Allen’s method.
RESULTS AND CONCLUSION: The results of immunochemistry indicated that there were few Bcl-2 and Bax-positive cells in the sham operation group; a number of Bcl-2 and Bax-positive cells were visible in the model and treatment groups. Bcl-2 and Bax expressions reached the peak at day 7 and 3, respectively, after injury. After treatment with hyperbaric oxygen preconditioning, Bcl-2 positive cells decreased significantly, while Bax-positive cells decreased significantly (P < 0.05). It indicates that the hyperbaric oxygen preconditioning can increase Bcl-2 expression but decrease Bax expression.

Key words: hyperbaric oxygenation, spinal cord injuries, apoptosis, immunohistochemistry

中图分类号:

R318

张玉强，李游，曹阳，董明岩，吕刚. 高压氧预处理损伤脊髓Bcl-2/Bax的表达[J]. 中国组织工程研究, 2013, 17(46): 8018-8023.

Zhang Yu-qiang, Li You, Cao Yang, Dong Ming-yan, Lü Gang. Effect of hyperbaric oxygen preconditioning on expression of Bcl-2 and Bax after spinal cord injury[J]. Chinese Journal of Tissue Engineering Research, 2013, 17(46): 8018-8023.

图/表（结果） 3

参考文献

[1]王晓红,邵彬,王琴,等.高压氧治疗对脊髓损伤后大鼠神经细胞凋亡及行为学评分的影响[J].重庆医学,2010,39(8):935-936.
[2]谷莉娜,郑杨,王奭骥,等.高压氧预处理对正常和糖尿病大鼠缺血再灌注心肌细胞凋亡的影响[J].中国老年学杂志,2011,31(11): 3306-3308.
[3]蔡宏斌,葛朝明,赵翀翀,等. 不同压力高压氧预处理与大鼠脑缺血灌注损伤缺血半暗带神经元细胞凋亡[J].中国康复医学杂志,2011,26(1): 50-54.
[4]张铨,陈明华,吴俊山,等.高压氧预处理对兔脊髓缺血再灌注损伤的保护机制探讨[J].现代生物医学进展,2010,10(21): 4049- 4051.
[5]徐帆,陈建敏,张晓.脊髓损伤动物模型的制备及神经功能评价[J].创伤外科杂志,2007,9(1):91-93.
[6]Fan DF, Liu K, Xu WG, et al. Hyperbaric oxygen preconditioning reduces the incidence of decompression sickness in rats via nitric oxide. Undersea Hyperb Med. 2010; 37(3):173-180.
[7]Yogaratnam JZ, Laden G, Guvendik L, et al. Pharmacological preconditioning with hyperbaric oxygen: can this therapy attenuate myocardial ischemic reperfusion injury and induce myocardial protection via nitric oxide? J Surg Res. 2008; 149(1):155-164.
[8]Gempp E, Blatteau JE. Preconditioning methods and mechanisms for preventing the risk of decompression sickness in scuba divers: a review. Res Sports Med. 2010; 18(3):205-218.
[9]Lu PG, Hu SL, Hu R, et al. Functional recovery in rat spinal cord injury induced by hyperbaric oxygen preconditioning. Neurol Res. 2012;34(10):944-951.
[10]Tai PA, Chang CK, Niu KC, et al. Attenuating experimental spinal cord injury by hyperbaric oxygen: stimulating production of vasculoendothelial and glial cell line-derived neurotrophic growth factors and interleukin-10. J Neurotrauma. 2010;27(6):1121-1127.
[11]Huang L, Mehta MP, Nanda A, et al. The role of multiple hyperbaric oxygenation in expanding therapeutic windows after acute spinal cord injury in rats. J Neurosurg. 2003;99(2 Suppl):198-205.
[12]Cheng O, Ostrowski RP, Wu B, et al. Cyclooxygenase-2 mediates hyperbaric oxygen preconditioning in the rat model of transient global cerebral ischemia. Stroke. 2011;42(2): 484-490.
[13]Liu M, Wu XP, Tong M. Effect of ultra-early hyperbaric oxygenation on spinal edema and hind limb motor function in rats with complete spinal cord transection. Nan Fang Yi Ke Da Xue Xue Bao. 2009;29(10):2014-2017.
[14]He X, Xu X, Fan M, et al. Preconditioning with hyperbaric oxygen induces tolerance against renal ischemia-reperfusion injury via increased expression of heme oxygenase-1. J Surg Res. 2011;170(2):e271-277.
[15]Li WC, Jiang DM, Hu N, et al. Lipopolysaccharide preconditioning attenuates neuroapoptosis and improves functional recovery through activation of Nrf2 in traumatic spinal cord injury rats. Int J Neurosci. 2013;123(4): 240-247.
[16]Yan W, Zhang H, Bai X, et al. Autophagy activation is involved in neuroprotection induced by hyperbaric oxygen preconditioning against focal cerebral ischemia in rats. Brain Res. 2011;1402:109-121.
[17]Ok JH, Kim YH, Ha KY. Neuroprotective effects of hypothermia after spinal cord injury in rats: comparative study between epidural hypothermia and systemic hypothermia. Spine (Phila Pa 1976). 2012;37(25):E1551-1559.
[18]Yin X, Meng F, Wang Y, et al. Effect of hyperbaric oxygen on neurological recovery of neonatal rats following hypoxic-ischemic brain damage and its underlying mechanism. Int J Clin Exp Pathol. 2013;6(1):66-75.
[19]Peng Y, Feng SF, Wang Q, et al. Hyperbaric oxygen preconditioning ameliorates anxiety-like behavior and cognitive impairments via upregulation of thioredoxin reductases in stressed rats. Prog Neuropsychopharmacol Biol Psychiatry. 2010;34(6):1018-1025.
[20]Ostrowski RP, Graupner G, Titova E, et al. The hyperbaric oxygen preconditioning-induced brain protection is mediated by a reduction of early apoptosis after transient global cerebral ischemia. Neurobiol Dis. 2008;29(1):
1-13.
[21]Liu Y, Sun XJ, Liu J, et al. Heme oxygenase-1 could mediate the protective effects of hyperbaric oxygen preconditioning against hepatic ischemia-reperfusion injury in rats. Clin Exp Pharmacol Physiol. 2011;38(10):675-682.
[22]Liu KJ, Xu J, Yang CY, et al. Analysis of olfactory ensheathing glia transplantation-induced repair of spinal cord injury by electrophysiological, behavioral, and histochemical methods in rats. J Mol Neurosci. 2010;41(1):25-29.
[23]Maybhate A, Hu C, Bazley FA, et al. Potential long-term benefits of acute hypothermia after spinal cord injury: assessments with somatosensory-evoked potentials. Crit Care Med. 2012;40(2):573-579.
[24]Hu R, Zhou J, Luo C, et al. Glial scar and neuroregeneration: histological, functional, and magnetic resonance imaging analysis in chronic spinal cord injury. J Neurosurg Spine. 2010; 13(2):169-180.
[25]Han X, Yang N, Xu Y, et al. Simvastatin treatment improves functional recovery after experimental spinal cord injury by upregulating the expression of BDNF and GDNF. Neurosci Lett. 2011;487(3):255-259.
[26]Xiong L, Zhu Z, Dong H, et al. Hyperbaric oxygen preconditioning induces neuroprotection against ischemia in transient not permanent middle cerebral artery occlusion rat model. Chin Med J (Engl). 2000;113(9):836-839.
[27]Contreras IS, Moreira LF, Ballester G, et al. Immediate ischemic preconditioning based on somatosensory evoked potentials seems to prevent spinal cord injury following descending thoracic aorta cross-clamping. Eur J Cardiothorac Surg. 2005;28(2):274-279.
[28]Lee JS, Yang CC, Kuo YM, et al. Delayed granulocyte colony-stimulating factor treatment promotes functional recovery in rats with severe contusive spinal cord injury. Spine (Phila Pa 1976). 2012;37(1):10-17.
[29]Amemori T, Jendelová P, R?zicková K, et al. Co-transplantation of olfactory ensheathing glia and mesenchymal stromal cells does not have synergistic effects after spinal cord injury in the rat. Cytotherapy. 2010;12(2): 212-225.
[30]Colak A, Antar V, Karao?lan A, et al. Q-VD-OPh, a pancaspase inhibitor, reduces trauma-induced apoptosis and improves the recovery of hind-limb function in rats after spinal cord injury. Neurocirugia (Astur). 2009;20(6):533-540.
[31]All AH, Bazley FA, Gupta S, et al. Human embryonic stem cell-derived oligodendrocyte progenitors aid in functional recovery of sensory pathways following contusive spinal cord injury. PLoS One. 2012;7(10):e47645.
[32]Colak A, Karao?lan A, Barut S, et al. Neuroprotection and functional recovery after application of the caspase-9 inhibitor z-LEHD-fmk in a rat model of traumatic spinal cord injury. J Neurosurg Spine. 2005;2(3):327-334.
[33]Zhang YP, Burke DA, Shields LB, et al. Spinal cord contusion based on precise vertebral stabilization and tissue displacement measured by combined assessment to discriminate small functional differences. J Neurotrauma. 2008;25(10):1227-1240.
[34]Jadhav V, Ostrowski RP, Tong W, et al. Hyperbaric oxygen preconditioning reduces postoperative brain edema and improves neurological outcomes after surgical brain injury. Acta Neurochir Suppl. 2010;106:217-220.
[35]Guo X, Bu X, Li Z, et al. Comparison of autologous bone marrow mononuclear cells transplantation and mobilization by granulocyte colony-stimulating factor in experimental spinal injury. Int J Neurosci. 2012;122(12):723-733.
[36]Yune TY, Kim SJ, Lee SM, et al. Systemic administration of 17beta-estradiol reduces apoptotic cell death and improves functional recovery following traumatic spinal cord injury in rats. J Neurotrauma. 2004;21(3):293-306.
[37]Kubota K, Saiwai H, Kumamaru H, et al. Myeloperoxidase exacerbates secondary injury by generating highly reactive oxygen species and mediating neutrophil recruitment in experimental spinal cord injury. Spine (Phila Pa 1976). 2012; 37(16):1363-1369.
[38]Onifer SM, Nunn CD, Decker JA, et al. Loss and spontaneous recovery of forelimb evoked potentials in both the adult rat cuneate nucleus and somatosensory cortex following contusive cervical spinal cord injury. Exp Neurol. 2007;207(2): 238-247.
[39]Martinez M, Brezun JM, Zennou-Azogui Y, et al. Sensorimotor training promotes functional recovery and somatosensory cortical map reactivation following cervical spinal cord injury. Eur J Neurosci. 2009;30(12):2356-2367.
[40]Yu CG, Jimenez O, Marcillo AE, et al. Beneficial effects of modest systemic hypothermia on locomotor function and histopathological damage following contusion-induced spinal cord injury in rats. J Neurosurg. 2000;93(1 Suppl):85-93.
[41]Chen HC, Fong TH, Hsu PW, et al. Multifaceted effects of rapamycin on functional recovery after spinal cord injury in rats through autophagy promotion, anti-inflammation, and neuroprotection. J Surg Res. 2013;179(1):e203-210.
[42]Zeng Y, Xie K, Dong H, et al. Hyperbaric oxygen preconditioning protects cortical neurons against oxygen-glucose deprivation injury: role of peroxisome proliferator-activated receptor-gamma. Brain Res. 2012; 1452:140-150.
[43]Hillard VH, Peng H, Das K, et al. Inhibition of x-irradiation-enhanced locomotor recovery after spinal cord injury by hyperbaric oxygen or the antioxidant nitroxide tempol. J Neurosurg Spine. 2007;6(4):337-343.
[44]Han X, Yang N, Cui Y, et al. Simvastatin mobilizes bone marrow stromal cells migrating to injured areas and promotes functional recovery after spinal cord injury in the rat. Neurosci Lett. 2012;521(2):136-141.
[45]Wang YC, Zhang S, Du TY, et al. Hyperbaric oxygen preconditioning reduces ischemia-reperfusion injury by stimulating autophagy in neurocyte. Brain Res. 2010;1323: 149-151.
[46]Yan W, Zhang H, Bai X, et al. Autophagy activation is involved in neuroprotection induced by hyperbaric oxygen preconditioning against focal cerebral ischemia in rats. Brain Res. 2011;1402:109-121.
[47]Zeng Y, Xie K, Dong H, et al. Hyperbaric oxygen preconditioning protects cortical neurons against oxygen-glucose deprivation injury: role of peroxisome proliferator-activated receptor-gamma. Brain Res. 2012;1452: 140-150.
[48]卢培刚,冯华,胡荣,等.高压氧预处理对脊髓损伤后轴突再生影响实验研究[J].中华神经外科疾病研究杂志, 2011,11(4):316-320.
[49]李洪鹏,巴方,白丹,等.高压氧预处理对脊髓损伤后后角神经元的保护作用[J].中国医科大学学报,2012,41(1):11-13.
[50]Li JS, Zhang W, Kang ZM, et al. Hyperbaric oxygen preconditioning reduces ischemia-reperfusion injury by inhibition of apoptosis via mitochondrial pathway in rat brain. Neuroscience. 2009;159(4):1309-1315.
[51]Wang L, Li W, Kang Z, et al. Hyperbaric oxygen preconditioning attenuates early apoptosis after spinal cord ischemia in rats. J Neurotrauma. 2009;26(1):55-66.

引言

材料方法

设计：随机分组对照实验。

时间及地点：实验于2012年11月至2013年6月在辽宁医学院附属第一医院骨组织工程实验室完成。

材料：

实验动物：6月龄雄性SD大鼠66只，体质量250- 300 g，由辽宁医学院实验动物中心(动物许可证号： SCXK(辽)2003-0007号)提供。实验符合动物伦理学的要求。

实验方法：

动物分组：66只大鼠随机分为假手术组(n=6)、模型组(n=30)和高压氧预处理组(n=30)。

高压氧预处理：根据文献[2-3]介绍的方法进行高压氧预处理。研究显示0.15-0.30 MPa间为高压氧预处理的安全有效压力，0.20 MPa和0.25 MPa下高压氧预处理减轻局灶性脑缺血-再灌注缺血损伤能力优于0.15 MPa和0.30 MPa；且0.20 MPa和0.25 MPa间，0.15 MPa和0.30 MPa间的检查结果差异无显著性意义^[2]。实验中高压氧预处理的压力选择0.25 MPa。其具体方法：用纯氧洗舱20-25 min，待舱内氧体积分数度达95%以上，缓慢加压至0.25 MPa，放入大鼠维持1 h，随后缓慢减压至常压，1次/2 d，共5次10 d，最后一次高压氧预处理后1 d，大鼠用于制作脊髓损伤模型。假手术组和模型组大鼠置于空气中常规饲养。

脊髓损伤模型制备：根据改良Allen’s原理制作大鼠脊髓损伤模型^[5]。大鼠麻醉利用体积分数10%的水合氯醛根据其体质量，通过腹腔注射完成，背部剪毛，常规碘伏消毒，铺无菌巾。通过计数大鼠肋骨方法，选择以T₉为中心，长度1.5-2.0 cm纵行切口，逐层切开皮肤及皮下组织，尖刀剥离椎旁肌肉，暴露棘突和椎板，用咬骨钳咬除T₈_-₁₀椎板，暴露硬脊膜。将15 g重锤自10 cm高度自由落下撞击脊髓，造成150 g•cm的损伤。以脊髓出现水肿、出血和鼠尾痉挛性摆动为造模成功标准。生理盐水冲洗后逐层缝合，再次碘伏消毒。术后腹腔注射青霉素预防感染，1次/d，连用1周。术后常规饲养，每天人工辅助排尿便3次，持续至大鼠取材的各个时间点。假手术组仅切除大鼠脊椎椎板。

脊髓的取材及标本制作：造模后8 h，造模后1，3，7和14 d。采用心脏灌注方法进行取材。其具体步骤为：大鼠用体积分数10%的水合氯醛麻醉，打开胸腔，暴露心脏，利用20号输液器针进行左心室-主动脉插管，用眼科剪剪开右心耳放血，用生理盐水灌注至右心耳流出液澄清，再用40 g/L多聚甲醛溶液灌流至大鼠四肢僵硬。沿原手术切口逐层切开，暴露损伤部位脊髓，切取损伤中心周围1.0 cm范围的脊髓组织。将切取的脊髓段浸入40 g/L多聚甲醛溶液内继续固定4 h，然后将组织转移到20%蔗糖溶液内至其沉底。采用OCT胶进行包埋，将包埋成功的组织放在冰冻切片机上进行横向连续切片，片厚8 μm，将切片放入片盒，-20 ℃冰箱保存，以备后续的Bcl-2和Bax免疫组化染色。

免疫组化染色检测损伤脊髓组织中Bcl-2和Bax的表达：免疫组化染色按SABC试剂盒说明书上步骤完成：每个时间点取10张冰冻切片，室温干燥30 min，PBS洗3次，经体积分数3%过氧化氢处理后用血清进行封闭；滴加兔抗大鼠Bcl-2和Bax(浓度均为1∶200)一抗，对照组利用PBS作为阴性对照；4 ℃孵育过夜，第2天滴加羊抗兔IgG室温孵育20 min，SABC室温孵育20 min，以上各步骤间均用PBS漂洗3次，每次5 min，进行DAB显色，复染、脱水、透明、封固。显微镜下进行观察。以细胞浆或胞膜棕黄色着色为阳性细胞，每张切片分别于灰质、白质各取5个视野(×400)，分别计数每个视野的阳性细胞数。

主要观察指标：免疫组化法测定实验大鼠脊髓中的Bcl-2和Bax表达情况。

统计学分析：数据用x(_)±s表示，利用SPSS 17.0软件包进行数据的统计分析，各组Bcl-2和Bax阳性细胞数量比较采用方差分析，P < 0.05为差异有显著性意义。

讨论

高压氧预处理有助于脊髓损伤后神经功能的恢复。高压氧预处理增加了脊髓组织中一氧化氮水平，缩短了脊髓损伤后运动诱发电位和感觉诱发电位的潜伏期，激活了神经元和神经胶质细胞的自噬作用，减轻了脊髓损伤后的氧化应激反应，减少神经细胞的凋亡，促进脊髓损伤后轴突再生^[6-48] 。高压氧预处理可减少了心、肾、脑和脊髓损伤后的细胞凋亡。不同压力下高压氧预处理均可不同程度降低脑损伤后脑缺血半暗带凋亡细胞数和Caspase-3阳性细胞数，其Bcl-2表达水平不同程度增高；他们认为高压氧预处理通过上调抗氧化酶活性，从而减轻局灶性脑皮质缺血-再灌注缺血半暗带的自由基损伤和神经元凋亡；高压氧预处理可能通过下调皮质缺血半暗带神经元线粒体水平的凋亡反应减轻大鼠脑缺血-再灌注损伤^[3] 。高压氧预处理与低氧预处理显著改善了脊髓损伤后的神经功能。脊髓损伤后运动诱发电位和感觉诱发电位的潜伏期显著延长，但高压氧预处理与低氧预处理组的潜伏期缩短。与对照组相比，高压氧预处理与低氧预处理明显减少了凋亡细胞数量，增加了nestin阳性细胞数量，从而增强脊髓损伤后轴突再生，Lu等^[9]认为高压氧预处理通过抑制脊髓损伤后细胞凋亡促进神经功能恢复。李洪鹏等^[49]报道高压氧预处理5 d的脊髓全横断模型，术后8 h和术后1 d高压氧预处理组脊髓后角神经元凋亡细胞数较对照组明显减少，认为高压氧预处理保护了损伤脊髓后角神经元，且术后1 d内的效果明显最显著。
Bcl-2和Bax是参与凋亡调控的重要因子，Bcl-2抑制细胞凋亡，而Bax促进细胞凋亡；高压氧预处理对Bax和Bcl-2表达影响的研究是目前的研究热点。谷莉娜等[2]在研究高压氧预处理对正常和糖尿病大鼠缺血再灌注心肌细胞凋亡及Bcl-2和Bax蛋白的影响时发现高压氧预处理后正常大鼠和糖尿病大鼠的凋亡指数均明显降低，Bax蛋白表达均明显降低，而Bcl-2蛋白表达均显著升高；他们认为高压氧预处理对正常及糖尿病大鼠均有抗心肌细胞凋亡的作用，但对正常大鼠保护作用更强，其保护机制可能与下调Bax蛋白表达，上调Bcl-2蛋白表达有关。Li等^[50]研究发现脑的缺血再灌注损伤前高压氧预处理可减轻脑水肿，减少脑梗死面积，促进神经功能的恢复。高压氧预处理降低了细胞色素C水平，降低了caspase酶的活性，增大了Bcl-2/Bax比值，减少了缺血组织的凋亡。高压氧预处理通过抑制线粒体的细胞凋亡途径保护脑组织免于缺血再灌注损伤。高压氧预处理增加了脊髓缺血再灌注损伤后组织中过氧化物酶和过氧化氢酶活性，增强了线粒体中Bcl-2的表达，引起线粒体中的过氧化物和过氧化氢减少，再灌注1 h后细胞色素C释放进入细胞液减少，随后激活了caspase-3和caspase-9。高压氧预处理提高了神经功能的评分，减少了脊髓缺血1 d后腰段脊髓灰质前中后部的神经细胞凋亡，高压氧预处理同时增加了一氧化氮的产生。他们认为高压氧预处理通过增加过氧化物酶，过氧化氢酶和Bcl-2抑制线粒体凋亡途径减轻了脊髓缺血再灌注损伤，同时一氧化氮也参与脊髓的神经功能保护^[51] 。
实验结果显示高压氧预处理组Bcl-2蛋白表达在脊髓损伤后显著升高，伤后8 h可见Bcl-2阳性细胞，伤后第1，3天时Bcl-2阳性细胞明显增多，伤后第7天Bcl-2表达达高峰，伤后第14天仍可见大量Bcl-2阳性细胞，其各时间点Bcl-2阳性细胞数量较假手术组和模型组显著增加(P < 0.05)。而高压氧预处理组Bax蛋白表达在脊髓损伤后明显降低，脊髓损伤后8 h即可见Bax阳性细胞，伤后第1天Bax阳性细胞数显著增加，伤后第3天时Bax阳性表达到高峰，伤后第7天开始逐渐下降，伤后第14天仍有阳性表达，但在伤后各个时间点高压氧预处理组脊髓灰质和白质内Bax阳性细胞数均少于对照组(P < 0.05)。说明高压氧预处理增加了损伤脊髓组织中Bcl-2蛋白表达，减少了Bax蛋白表达，抑制了损伤脊髓组织中的细胞凋亡，从而减轻了脊髓的继发性损伤。因此，推测脊柱手术术前进行高压氧预处理可能对减少手术导致的脊髓或神经损伤起到一定的保护作用。