高压氧预适应对老龄大鼠急性全脑缺血的影响

目的 观察高压氧预适应对老龄大鼠急性全脑缺血后认知功能的影响.方法 24只老龄雄性SD大鼠分为正常对照组、高压氧组、缺血组、高压氧预适应缺血组,每组6只.缺血组、高压氧预适应缺血组采用改良Pulsinelli四血管闭塞法建立急性全脑缺血模型,高压氧组和建模前高压氧预适应缺血组给予连续5 d、每天1 h 2个标准大气压(2.0 ATA)高压氧处理,各组大鼠分别行横断位及冠状位T1WI、T2WI扫描;Morris水迷宫试验测试学习记忆功能:逃避潜伏期和目标象限游泳时间百分比.结果 正常对照组、高压氧组大鼠大脑未见明显缺血梗死灶,缺血组双侧皮质区可见明显弧形缺血梗死区,高压氧预适应缺血组双侧皮质区也可见弧形缺血梗死区,面积较缺血组小.缺血组逃避潜伏期长于高压氧预适应缺血组(P＜0.05),高压氧预适应缺血组潜伏期长于正常对照组、高压氧组(P＜0.05),后两者之间差异无统计学意义(P＞0.05).缺血组目标象限游泳时间百分比较高压氧预适应缺血组短(P＜0.05),高压氧预适应缺血组短于正常对照组、高压氧组,后两者之间差异无统计学意义(P＞0.05).结论 给予连续高压氧预适应,能减少老龄大鼠急性全脑缺血后超急性期大脑皮质缺血梗死面积,提高全脑缺血后的认知功能水平.

The effects of hyperbaric oxygen preconditioning on aged rats after acute cerebral ischemia

Objective To investigate the effects of hyperbaric oxygen preconditioning on cognitive function in aged rats after acute cerebral ischemia, and to analyze any changes in the cerebral cortex by magnetic resonance imaging (MRI). Methods Twenty-four aged male SD rats were randomly divided into a normal control group, a pure hyperbaric oxygen group, an ischemia group and an ischemia group preconditioned with hyperbaric oxygen. There were six rats in each group. A model of ischemia was induced in the ischemic group and the preconditioned ischemia group using a modified version of Pulsinelli's four-vessel occlusion method. The preconditioned ischemia group (before setting up the acute cerebral ischemia model) and the pure hyperbaric oxygen group were given hyperbaric oxygen treatment once a day for 5 days. Each group received axial line and coronal MRI scans in T1WI and T2WI. The rats' learning and memory abilities were evaluated with a Morris water maze, including escape latency and the percentage of swimming time in the platform quadrant. Results There was no obvious evidence of ischemic brain infarction in the normal control group or the pure hyperbaric oxygen group. There were clear arc-shaped bilateral cortex ischemic infarct areas in the ischemic group. The average ischemic infarct area in the preconditioned group was smaller than that in the simply ischemic group. Escape latency in the ischemia group was significantly longer than in the preconditioned group, and latency in the preconditioned group was significantly longer than that in the normal control and hyperbaric oxygen groups. The percentage of swimming time in the platform quadrant in the ischemic group was shorter than that in the preconditioned group, and that in the preconditioned group was shorter than those of the normal control group or the hyperbaric oxygen group. There was no significant difference between the normal control group and the hyperbaric oxygen group. Conclusions Continuous hyperbaric oxygen preconditioning can reduce the ischemic infarct area in aged rats after acute global cerebral ischemia and improve cognitive function.