摘要
目的:探讨高压氧处理对慢性脑灌注不足(CCH)大鼠神经的保护作用及其作用机制。方法:采用随机数字表法将28只SD大鼠分为假手术组、模型组、常压氧组和高压氧组,每组7只。采用改良的两步法双侧颈总动脉阻断术(mBCCAO)建立CCH大鼠模型,常压氧组CCH大鼠给予常压吸纯氧,高压氧组CCH大鼠给予0.2 MPa高压氧治疗,2组处理均为1 h/次,1次/d,连续吸纯氧4周;假手术组不结扎或离断颈总动脉,假手术组和模型组每天放置在氧舱内,不吸氧,不加压,放置时间与常压氧组和高压氧组相同。1周后,采用激光散斑成像仪和水迷宫实验观察各组大鼠局部脑血流量(rCBF)和学习记忆功能的变化,并验证CCH大鼠模型构建是否成功。干预4周后,对各组大鼠进行苏木精-伊红(HE)、尼氏(Nissl)染色观察大鼠海马神经细胞的形态、细胞中Nissl小体数量的变化;免疫荧光染色检测各组大鼠大脑海马组织微血管内皮相关蛋白claudin-5、ZO-1和CD31的表达水平。结果:mBCCAO手术1周后,与假手术组相比,模型组rCBF明显降低(P<0.01);模型组和假手术组大鼠每日游泳速度比较差异无统计学意义(P>0.05),模型组的逃避潜伏期较假手术组明显更长(P<0.01);移除平台后,模型组大鼠比假手术组大鼠逃避潜伏期的时间更长,同时穿过平台次数更少(均P<0.01),表明模型组大鼠大脑组织rCBF下降及认知功能缺陷,已成功建立CCH大鼠模型。处理4周后,与假手术组相比,模型组大鼠海马组织结构层数减少、排列紊乱、细胞松散、细胞间隙增大、Nissl小体数量减少,染色较淡;海马微血管内皮相关蛋白claudin-5、ZO-1和CD31的表达水平明显降低(均P<0.05)。与模型组大鼠相比较,常压氧组和高压氧组大鼠的海马组织结构层数增多,排列较整齐、紧密,细胞形态较完整、Nissl小体数量明显增多,染色较深;海马微血管相关蛋白claudin-5、ZO-1和CD31的表达水平明显提高,且以高压氧组改善或提高最明显(均P<0.05)。结论:高压氧处理可明显减轻CCH大鼠大脑海马区神经元的损伤,从而改善大鼠的认知障碍,其作用机制可能与其上调CCH大鼠海马微血管内皮细胞的相关蛋白表达水平有关。
Objective To investigate the neuroprotective effects of hyperbaric oxygen(HBO)treatment on rats with chronic cerebral hypoperfusion(CCH)and its underlying mechanisms.Methods Twenty-eight SD rats were divided into four groups(n=7 per group)according to the random number table method:sham-operation group,model group,normobaric oxygen(NBO)group,and HBO group.The CCH rat model was established using a modified two-step bilateral common carotid artery occlusion(mBCCAO)method.The NBO group received normobaric pure oxygen,while the HBO group was treated with 0.2 MPa HBO,each was treated for one hour daily for four weeks.The sham-operation group underwent no carotid artery ligation or disconnection,and both the sham-operation and model groups were placed in the oxygen chamber without oxygen or pressure treatment for the same duration.After one week,changes in regional cerebral blood flow(rCBF)and learning-memory functions were assessed using laser speckle imaging and the Morris water maze test to validate the CCH model.After four weeks of intervention,hematoxylin-eosin(HE)and Nissl staining were performed to observe hippocampal neuronal morphology and Nissl body counts.Immunofluorescence staining was used to detect the expression levels of microvascular endothelial-related proteins(claudin-5,ZO-1,and CD31)in the hippocampal tissue.ResultsOne week post-mBCCAO,rCBF in the model group was significantly lower than in the sham-operation group(P<0.01);daily swimming speeds showed no significant difference between the model and sham-operation groups(P>0.05);the escape latency in the model group was significantly longer than in the sham-operation group(P<0.01);after platform removal,the model group exhibited longer escape latency and fewer platform crossings compared with the sham-operation group(all P<0.01),indicating that the model group of rats exhibited a decrease in rCBF and cognitive function impairment,thus confirming successful CCH model establishment.After four weeks treatment,compared with those in the sham-operation group,the model group showed reduced hippocampal layers,disordered arrangement,loose cells,enlarged intercellular spaces,decreased Nissl body counts,and lighter staining;the expression levels of claudin-5,ZO-1,and CD31 were significantly lower in the model group(all P<0.05).Compared with the model group,both the NBO and HBO groups exhibited increased hippocampal layers,more orderly and compact cell arrangement,intact cell morphology,increased Nissl body counts,and darker staining;the expression levels of claudin-5,ZO-1,and CD31 were significantly higher in the NBO and HBO groups,with the HBO group showing the most pronounced improvement(all P<0.05).ConclusionHBO treatment can significantly alleviate hippocampal neuronal damage in CCH rats,thereby improving cognitive impairment.The mechanism may be related to the upregulation of microvascular endothelial-related protein expression in the hippocampus.
作者
邝英
李航
潘树义
Kuang Ying;Li Hang;Pan Shuyi(School of Medicine,South China University of Technology,Guangzhou 510006,China;Department of Hyperbaric Oxygen,The Sixth Medical Center of PLA General Hospital,Beijing 100048,China)
出处
《中华航海医学与高气压医学杂志》
2025年第5期456-464,共9页
Chinese Journal of Nautical Medicine and Hyperbaric Medicine
基金
海军后勤科研重点项目(BLB19J014)
关键词
慢性脑低灌注
大鼠
高压氧
微血管内皮细胞
Chronic cerebral hypoperfusion
Rat
Hyperbaric oxygen
Microvascular endothelial cell
