Astaxanthin Can Improve Cognitive Dysfunction In Elderly Patients After Major Surgery By Inhibiting Hippocampus Oxidative Stress

[Objective]Hippocampal oxidative stress plays a key role in the pathogenesis of POCD in the elderly,and astaxanthin(ATX),as a strong antioxidant,plays a role in promoting cognitive function.Therefore,in this study,we will explore whether ATX antagonizes POCD in the elderly and whether this protective effect involves inhibition of hippocampal oxidative stress.[Methods]The model of elderly POCD rats was established in the elderly rats by exploratory laparotomy for once;The cognitive function of rats were evaluated by Y-maze,novel objective recognition(NOR),and Morris water maze(MWM);Enzyme linked immunosorbent assay(Elisa)was used to detect the oxidative stress indicators in rat hippocampal tissues[the content of Malondialdehyde(MDA)and 4-hydroxynonenal(4-HNE);the activity of glutathione peroxidase(GSH-px)and superoxide dismutase(SOD)].[Results]1.ATX improved cognitive dysfunction in the Y maze in elderly rats after surgery;ATX(30mg/kg/day,14 days)pretreatment significantly increased the spontaneous alternations rate of postoperative aged rats,and there was no significant difference in the total entries number between each group,indicating that ATX imporve the cognitive dysfunction of postoperative aged rats in Y maze.2.ATX can improve the cognitive dysfunction of NOR in elderly rats after operation;ATX(30mg/kg/day,14 days)pretreatment significantly increased the discrimination index of postoperative aged rats,and there was no significant difference in the total object exploration during training period between each group.These results suggested that ATX imporve the cognitive dysfunction of postoperative aged rats in NOR.3.ATX improved spatial learning disorders in Morris water maze in elderly rats after surgery;ATX(30mg/kg/day,14 days)pretreatment significantly reduced the escape latency to find platform during acquisition phase,increased the percentage of time expended in the target quadranand the times across platform during probe trial,in postoperative aged rats.In visible platform phase,there was no significant difference in latency and average swimming speed between each group.These data indicated ATX imporve the spatial learning and memory dysfunction of postoperative aged rats in the MWM.4.ATX antagonized the increase of hippocampal oxidative stress of postoperative aged ratsIn the hippocampus of postoperative aged rats,ATX(30mg/kg/day,14 days)pretreatment significantly reduced the content of MDA and4-HNE,increased the activity of SOD and GSH-px.These findings indicated ATX antagonized the increase of hippocampal oxidative stress of postoperative aged rats.[Conclusion] ATX improve the cognitive dysfunction of postoperative aged rats,and its mechanism involves the inhibition of hippocampal oxidative stress.