Effects of hyperbaric oxygen on learning and memory ability in VPA autism and on the morphology of pyramidal cells in the CA1 region of the hippocampus / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effects of hyperbaric oxygen on learning and memory ability in rats with a model of VPA autism and on the pyramidal cells in the CA1 region of the hippocampus.Methods An animal model of autism was established in the offspring of Wistar rats which had received a single intraperitoneal injection of sodium valproate at the 12.5th day of pregnancy.A total of 48 male VPA autism model rats were randomly divided into the hyperbaric oxygen group,a high pressure air group,a normal pressure high oxygen group and a normal pressure air group (each group with 12 rats).A normal control group was obtained by injecting physiological saline.The autism model rats of the hyperbaric oxygen group were treated with high pressure oxygen in an animal experiment cabin which was cleaned with pure oxygen for 10 min,pressurized for 15 min,held at 2.0 atmospheres absolute (ATA) for 45 min and then had the pressure relieved over 15 min.For the high pressure air group the cabin was pressurized with air for 15 min,held at 2.0 ATA for 45 min and the pressure was relieved over 15 min.For the normal pressure,high oxygen group the cabin was cleaned for 10 min with pure oxygen,then pure oxygen was supplied for 1 hour with the cabin door open.The normal pressure air group rats were placed in the open cabin with no pressure or additional oxygen.The testing lasted 7 days for 1 hour per day.The normal control group rats were placed in ordinary cages.Learning and memory were evaluated using the Y electric maze test before and after the interventions.Any changes in the pyramidal cells in the CA1 region of the hippocampus were observed after hematoxylin and eosin (HE) staining.Results The average number of tries of the hyperbaric oxygen group after treatment was significantly less than before treatment and memory retention times were increased.The number was also less in the normobaric hyperoxia group and memory retention times again improved.The number of apoptotic cells was reduced and the number of normal form cells in the CA1 region increased after the hyperbaric oxygen intervention.Conclusions The learning and memory abilities of the autistic rats improved after the hyperbaric oxygen intervention.Pyramidal cells in the CA1 region proliferated and the number of apoptotic cell decreased.This may be the mechanism by which hyperbaric oxygen intervention treats autism.