| Objective:. To study the different atmosphere absolute effectiveness of hyperbaric oxygen preconditioning on the neurological deficits, cerebral infarction volume, the level of oxidative stress and neuron apoptosis in ischemic penumbra after transient cerebral ischemia-reperfusion injure via established middle cerebralartery ocelusion(MCAO)model deseribed initially by Zea-Longa with some modifications in Wister rats.Methods: 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 Wister rats in the trial group were again divided as,1.5ATA HBO-PC group (0.15MPa),2.0ATA (0.2 MPa) group HBO-PC,2.5ATA group (0.25MPa) HBOP, and 3. OATA group (0.3MPa) HBO-PC. with 8 rats in each. HBO-PC was administered by using 100% oxygen at different ATA for 60 minute at 24 hours interval for five times in 10 days. The last HBO-PC was performed at 24 hours before middle cerebral artery occlusion produced by the filament model initially reported by Zea-Longa with some modifications. A sign of success for the anesthesia of conscious rats Zea-Longa scale score greater than 2 points, score less than or equal to 2 points were removed and immediately added. The samples of each group underwent TUNEL reaction to detected the apoptosis of the neurons, immunohistochemistry staining to measure the expression of Caspase-3 and bcl-2 and Malondialdehyde (MDA) content, activity of catalase (CAT)and superoxide dismutase(SOD) sampled from the cerebral cortex ischemia penumbra. Sham group and MCAO group was not HBO or normobaric oxygen preconditioning, post 10 days treatment eaqeal to the trial group.Results:HBO-PC with 1.5ATA,2. 0ATA,2.5ATA and 3.0ATA all decreased infarction volume, improved neurological recovery, meanwhile decreased caspase-3 enzyme activity, upregulated the expression of bcl-2, abated the apoptosis of ischemic tissue, and reduced the level of MDA as well as increased the antioxidant activity of CAT and SOD. In all trial groups, above index, showed significant difference as compared with that in the control group (P＜0. 05), however, HBO-PC with 2. OATA and 2.5ATA were superior to HBOP with 1.5ATA and 3. OATA (P＜0.05).Conclusion: HBO-PC protects brain tissues from ischemia-reperfusion injury by up-regulating antioxidant enzyme and down-regulating free radical injury and neuronal apoptosis activities in cerebral cortex penumbra after focal ischemia-reperfusion. And hyperbaric oxygen preconditiong with 2. OATA and 2.5ATA were superior to with 1.5ATA and 3. OATA. |
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