Effects of normobaric hyperoxia on the learning and memory abilities of valproic acid autism model rats and the morphology of pyramidal cells in hippocampal CA1 region / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the effects of normobaric hyperoxia intervention on learning and memory abilities of valproic acid(VPA) autism model rats and the morphology of pyramidal cells in hippocampus CA1 area.Methods Animal model groups of autism were obtained in male offspring of the Wistar rats that received intraperitoneal injection of 600 mg/kg VPA at the 12.5 day after pregnancy.According to the eye opening time,behavior,weaning weight and the learning and memory abilities which were evaluated by the Y electricity maze test at the 28th day after birth,40 male VPA autism model rats were randomly selected 20 only and divided into normobaric hyperoxia model group (group A,n =10),atmospheric air model group (group B,n =10).Normal control groups were obtained in male offspring of Wistar rats that received intraperitoneal injection of equivalent physiological saline at the same period pregnancy.(group C,n =10).Rats in group A were treated with oxygen for 1 h per day and lasted 1 week;group B and C were treated with normal air.The learning and memory abilities of three groups were assessed at the 35th day after birth.The immunohistochemistry methods and image analysis were used to observe the pyramidal cells of autism model rats in hippocampal CA1 region.The effect of normobaric hyperoxia therapy on pyramidal cell of autism model rats in hippocampal CA1 region were evaluated by HE staining technique.Results The trying times of group A after treatment were less than those before treatment (31.15 ± 0.99 vs 31.54 ± 0.97,t =2.739,P =0.018).The memory times were more than those before treatment (3.00± 0.58 vs 2.69 ± 0.48,t =-2.309,P =0.040).The trying times of group A after treatment were less than those in group B after treatment (P =0.016).The memory times of group A were not different from that in group B after treatment(P=0.810).The morphology of pyramidal cells in hippocampal CA1 region showed that the pyramidal cells of the autism model rats had apoptosised.The number of apoptotic cells reduced and the number of normal form cells increased after the normobaric hyperoxia intervention compared with the autism model rats.Conclusion Normobaric hyperoxia intervention can improve the learning and memory abilities of the autism model rats.The apoptosis of the pyramidal neurons in hippocampal CA1 might be reduced after the normobaric hyperoxia intervention.