title: Delayed environmental enrichment reverses sevoflurane-induced memory impairment in rats.
abstract: BACKGROUND
  Anesthesia given to immature rodents causes cognitive decline, raising the possibility that the same might be true for millions of children undergoing surgical procedures under general anesthesia each year. We tested the hypothesis that anesthesia-induced cognitive decline in rats is treatable. We also tested if anesthesia-induced cognitive decline is aggravated by tissue injury.
  
  
  METHODS
  Seven-day old rats underwent sevoflurane anesthesia (1 minimum alveolar concentration, 4 h) with or without tail clamping. At 4 weeks, rats were randomized to environmental enrichment or normal housing. At 8 weeks rats underwent neurocognitive testing, which consisted of fear conditioning, spatial reference memory, and water maze-based memory consolidation tests, and interrogated working memory, short-term memory, and early long-term memory.
  
  
  RESULTS
  Sevoflurane-treated rats had a greater escape latency when the delay between memory acquisition and memory retrieval was increased from 1 min to 1 h, indicating that short-term memory was impaired. Delayed environmental enrichment reversed the effects of sevoflurane on short-term memory and generally improved many tested aspects of cognitive function, both in sevoflurane-treated and control animals. The performance of tail-clamped rats did not differ from those rats receiving anesthesia alone.
  
  
  CONCLUSIONS
  Sevoflurane-induced cognitive decline in rats is treatable. Delayed environmental enrichment rescued the sevoflurane-induced impairment in short-term memory. Tissue injury did not worsen the anesthesia-induced memory impairment. These findings may have relevance to neonatal and pediatric anesthesia.
authors.affiliation: Department of Anesthesia, University of California San Francisco, San Francisco, California 94143, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Shih
authors.forename: Laura D V
authors.initials: LD
authors.lastname: May
authors.forename: Heidi E
authors.initials: HE
authors.lastname: Gonzalez
authors.forename: Elaine W
authors.initials: EW
authors.lastname: Lee
authors.forename: Rehan S
authors.initials: RS
authors.lastname: Alvi
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Sall
authors.forename: Vinuta
authors.initials: V
authors.lastname: Rau
authors.forename: Philip E
authors.initials: PE
authors.lastname: Bickler
authors.forename: Gopal R
authors.initials: GR
authors.lastname: Lalchandani
authors.forename: Marianna
authors.initials: M
authors.lastname: Yusupova
authors.forename: Elliott
authors.initials: E
authors.lastname: Woodward
authors.forename: Heejae
authors.initials: H
authors.lastname: Kang
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Wilk
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Carlston
authors.forename: Mortay V
authors.initials: MV
authors.lastname: Mendoza
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Guggenheim
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schaefer
authors.forename: Allison M
authors.initials: AM
authors.lastname: Rowe
authors.forename: Greg
authors.initials: G
authors.lastname: Stratmann
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D006799:Housing, Animal; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000139:chemically induced* / Q000503:physiopathology / Q000628:therapy*; D008738:Methyl Ethers / Q000633:toxicity*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane; D013997:Time Factors
chemical_list: D008738:Methyl Ethers; D000077149:Sevoflurane