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背景:一氧化氮在脑缺血损伤中起着很重要的作用,而高压氧能改善缺血再灌注引起的神经损伤,高压氧的这种作用与一氧化氮是否有关联?其机制有待探讨。目的:观察一氧化氮合酶阳性细胞在大鼠急性局灶性脑缺血再灌注损伤和高压氧治疗后表达的变化。设计:随机对照动物实验。单位:解放军第四军医大学唐都医院急诊科;西安高新医院检验中心;解放军空军总医院。材料:取健康SD雄性大鼠66只,随机分为5组:假手术组5只,假手术+高压氧组5只,模型组28只,模型+高压氧组28只,后2组又分缺血后5,12,24,72h4个时间点,每个时间点7只。方法:①造模:模型组和模型+高压氧组大鼠参照Koizum方法制备大脑中动脉缺血模型,并于插入栓子造成缺血1h后抽出栓子。其他2组手术,但不插入栓子。②高压氧治疗:假手术+高压氧组和模型+高压氧组大鼠分别在缺血后2,9,21,45,69h共5次将动物置于高压氧舱内,给予高压氧(0.25MPa绝对压)治疗1h。主要观察指标:各组于相应时间点处死取脑,黄递酶-NADPH组织化学方法观察一氧化氮合酶阳性细胞在视交叉平面梗死区皮质、视前区、纹状体外侧区和纹状体内侧区域分布及形态的变化。结果:经补充后66只大鼠进入结果分析。①缺血后一氧化氮合酶阳性细胞发生形态改变,主要变化为突起减少或消失,细胞由椭圆形、三角形变成圆形,细胞皱缩,胞体着色重,胞核和胞浆均染成深蓝色;形态改变的一氧化氮合酶阳性细胞在纹状体外侧区最多,其次是视前区和纹状体内侧区,而皮质区较少。假手术组和假手术+高压氧组未见有形态改变的一氧化氮合酶阳性细胞。②模型组脑内形态有改变的一氧化氮合酶阳性细胞表达随缺血再灌注时间延长而增多,模型+高压氧组各时间点在皮质、视前区和纹状体内侧区其表达均比模型组少,但都于缺血后72h至高峰[皮质:(15.46±3.02),(30.52±4.73)个/视野;视前区:(28.56±4.05),(68.81±7.84)个/视野;纹状体内侧区:(21.09±3.83),(45.71±5.24)个/视野;P均<0.01]。结论:高压氧可明显抑制大鼠急性局灶性脑缺血再灌注损伤区一氧化氮合酶阳性细胞的变性,部位主要在皮质、视前区和纹状体内侧区。
BACKGROUND: Nitric oxide plays an important role in cerebral ischemic injury. Hyperbaric oxygen can improve nerve injury caused by ischemia-reperfusion. Is hyperbaric oxygen associated with nitric oxide? Its mechanism remains to be explored . Objective: To observe the changes of nitric oxide synthase positive cells after acute focal cerebral ischemia-reperfusion injury and hyperbaric oxygen therapy in rats. Design: Randomized controlled animal experiments. Unit: People’s Liberation Army Fourth Military Medical University Tangdu Hospital Emergency Department; Xi’an High-tech Hospital Test Center; People’s Liberation Army Air Force General Hospital. MATERIALS: Sixty-six healthy SD male rats were randomly divided into 5 groups: sham operation group (n = 5), sham operation + hyperbaric oxygen group (n = 5), model group (n = 28), model + hyperbaric oxygen group After ischemia 5,12,24,72 h4 time points, each time point 7. Methods: ①Modeling: Model group and model + hyperbaric oxygen group were given middle cerebral artery occlusion (MCAO) model according to Koizum’s method, and emboli were extracted after 1h after embolus insertion. The other 2 groups underwent surgery but did not insert emboli. ② hyperbaric oxygen therapy: sham-operated + hyperbaric oxygen group and model + hyperbaric oxygen group rats were placed in hyperbaric oxygen chamber at 2,9,21,45,69 h after ischemia for 5 times, hyperbaric oxygen (0.25 MPa absolute pressure) treatment 1h. MAIN OUTCOME MEASURES: The brain tissues were sacrificed at the corresponding time points, and the diaphorase-NADPHH histochemical method was used to observe the changes of nitric oxide synthase positive cells in the cortex, preoptic area, lateral striatum, Body area distribution and morphological changes. RESULTS: Sixty-six rats were included in the result analysis after supplementation. (1) The morphological changes of nitric oxide synthase positive cells after ischemia were mainly caused by the decrease or disappearance of protuberances, the cells changed from oval and triangle into round cells, and the cells shrank and the cell bodies were stained with heavy staining of both nucleus and cytoplasm Dark blue; morphological changes of nitric oxide synthase positive cells in the striatum lateral zone up, followed by preoptic and striatum medial area, and less cortical area. Sham-operated group and sham-operated + hyperbaric oxygen group showed no morphological changes of nitric oxide synthase positive cells. ② The expression of NOS positive cells in the model group increased with the prolongation of ischemia-reperfusion time. The expression of nitric oxide synthase positive cells in model group and hyperbaric oxygen group in cortex, preoptic area and striatum medial area (P <0.05). Compared with the model group, all of them were in the peak at 72h after ischemia [cortex: (15.46 ± 3.02), (30.52 ± 4.73) / visual field; ; The medial area of striatum: (21.09 ± 3.83), (45.71 ± 5.24) / field; P <0.01]. CONCLUSION: Hyperbaric oxygen can significantly inhibit the degeneration of nitric oxide synthase positive cells in acute focal cerebral ischemia-reperfusion injury in rats, mainly in the cortex, preoptic area and striatum medial area.