Objective: To study the protection of different atmosphere absolute (ATA) hyperbaric oxygen preconditioning (HBO-PC) on neurons against free radical injury in rats with cerebral ischemia-reperfusion.Method: Totally 48 Wistar rats were randomly assigned to the following three groups: sham group (n=8), MCAO group (control group, n=8), and HBO-PC plus MCAO group (trial group, n=32). The rats in trial group were sub-divided as, 1.5ATA (0.15MPa) sub-group, 2.0ATA (0.20MPa) sub-group, 2.5ATA (0.25MPa) sub-group, and 3.0ATA (0.30MPa) sub-group, with 8 rats in each. HBO-PC was administered by using 100% oxygen at different ATA for 60min with 24h interval for 5 times in lOd. The last times of HBO-PC was performed at 24h before middle cerebral artery occlusion (MCAO) produced by the filament mothod initially reported by Zea-Longa with some modifications. After ischemia 2h and reperfusion 24h, the samples of each group were detected with TU-NEL reaction to observe the apoptosis of neurons in ischemic penumbra, and content of malondialdehyde(MDA) activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) sampled from the ischemia penumbra were measured.Result: After HBO-PC with 1.5ATA, 2.0ATA, 2.5ATA and 3.0ATA the apoptosis of ischemic penumbra tissue decreased, and the level of MDA reduced and the antioxidant activities of CAT and SOD increased. In all trial groups, above indexes, showed significantly different as compared with that in control group (P<0.05), but there was no significant effect on the activity of GSH-px(P > 0.05). However, the effect of HBO-PC with 2.0ATA and 2.5ATA were superior to those with 1.5ATA and 3.0ATA (P<0.05).Conclusion: These observations demonstrated that HBO-PC played an important role in the upregulations of antioxidant enzyme activities against free radical injury and neuron apoptosis after brain ischemia-reperfusion, and the effects of HBO-PC with 2.0ATA and 2.5ATA against free radieal injury were superior to that with 1.5ATA and 3.0ATA.Author's address Department of Neurology, The Second Hospital of Lanzhou University, Lanzhou, 730000%观察不同压力高压氧预处理(HBO-PC)对大鼠脑缺血-再灌注缺血半暗带氧化应激平衡的调节及对自由基损伤的脑保护作用,选择恰当的预处理压力窗.方法:将46只SD大鼠随机分为3组:假手术组(n=6)；左侧大脑中动脉闭塞(MCAO)组(n=8)；HBO-PC+MCAO组(n=32).HBO-PC+MCAO组按不同的HBO-PC压力分为1.5ATA(0.15MPa)组、2.0ATA(0.20MPa)组、2.5ATA(0.25MPa)组和3.0ATA(0.30MPa)组4个亚组,每组8只.按不同治疗压力,每次吸氧1h、隔日1次,共5次,10d完成.最后一次HBO-PC后24h根据Zea-Longa线栓法制作MCAO再灌注损伤模型,缺血2h再灌注24h后检测缺血半暗带神经元凋亡水平、丙二醛(MDA)含量、同时检测总超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化酶(GSH-px)的抗氧化酶活力.假手术组和对照组不进行HBO/常压氧治疗,10天后处理同实验组.结果:实验组中各亚组缺血半暗带凋亡细胞数和MDA含量均不同程度下降,总SOD和CAT活动水平均不同程度的增高,与MCAO组比较差异有显著性意义(P＜0.05)；各预处理亚组GSH-px表达无明显变化,与MCAO组比较差异无显著性意义(P＞0.05).预处理组内比较,上述指标(除GSH-px)在2.0ATA和2.5ATA组间,1.5ATA和3.0ATA组间差异均无显著性意义(P＞0.05)；但是,2.0ATA和2.5ATA组比较1.5ATA和3.0ATA组差异有显著性意义(P＜0.05).结论:HBO-PC可能通过上调抗氧化酶活性减轻局灶性脑缺血-再灌注缺血半暗带的自由基损伤和神经元凋亡,1.5ATA-3.0ATA间为HBO-PC的安全有效压力,发现2.0ATA和2.5ATA压力下HBO-PC抗自由基损伤能力优于1.5ATA和3.0ATA.
展开▼
