The effects of hyperbaric oxygen preconditioning on aged rats after acute cerebral ischemia / 中华物理医学与康复杂志

ABSTRACT

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.