title: Hyperbaric oxygen preconditioning attenuates postoperative cognitive impairment in aged rats.
abstract: Cognitive decline after surgery in the elderly population is a major clinical problem with high morbidity. Hyperbaric oxygen (HBO) preconditioning can induce significant neuroprotection against acute neurological injury. We hypothesized that HBO preconditioning would prevent the development of postoperative cognitive impairment. Elderly male rats (20 months old) underwent stabilized tibial fracture operation under general anesthesia after HBO preconditioning (once a day for 5 days). Separate cohorts of animals were tested for cognitive function with fear conditioning and Y-maze tests, or euthanized at different times to assess the blood-brain barrier integrity, systemic and hippocampal proinflammatory cytokines, and caspase-3 activity. Animals exhibited significant cognitive impairment evidenced by a decreased percentage of freezing time and an increased number of learning trials on days 1, 3, and 7 after surgery, which were significantly prevented by HBO preconditioning. Furthermore, HBO preconditioning significantly ameliorated the increase in serum and hippocampal proinflammatory cytokines tumor necrosis factor-α, interleukin-1 β (IL-1β), IL-6, and high-mobility group protein 1 in surgery-challenged animals. Moreover, HBO preconditioning markedly improved blood-brain barrier integrity and caspase-3 activity in the hippocampus of surgery-challenged animals. These findings suggest that HBO preconditioning could significantly mitigate surgery-induced cognitive impairment, which is strongly associated with the reduction of systemic and hippocampal proinflammatory cytokines and caspase-3 activity.
authors.affiliation: aDepartment of Anesthesia and Operation Center, Chinese People's Liberation Army General Hospital bDepartment of Anesthesiology, Beijing Military Region General Hospital, Beijing cDepartment of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Institute of Anesthesiology, Tianjin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Keliang
authors.initials: K
authors.lastname: Xie
authors.forename: Changsheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Song
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control*; D006624:Hippocampus / Q000276:immunology / Q000378:metabolism; D006931:Hyperbaric Oxygenation / Q000379:methods*; D007249:Inflammation / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D011183:Postoperative Complications / Q000517:prevention & control*; D051381:Rats; D017207:Rats, Sprague-Dawley