Heat acclimation prolongs the time to central nervous system oxygen toxicity in the rat: Possible involvement of HSP72

Yehuda Arieli, Mirit Eynan, Hanan Gancz, Ran Arieli, Yechezkel Kashi

Research output: Contribution to journalArticlepeer-review

Abstract

Oxygen toxicity of the central nervous system (CNS-OT) can occur during diving with oxygen-enriched gas mixtures, or during hyperbaric medical treatment. CNS-OT is characterised by convulsions and sudden loss of consciousness, which may be fatal in diving. Heat acclimation is known to provide cross-tolerance to various forms of stress in different organs, including the brain. We hypothesised that heat acclimation may delay the onset of CNS-OT in the rat. Male Sprague-Dawley rats were acclimated to an ambient temperature of 32°C for 4 weeks. Rats in the control group were kept at 24°C. Both groups were exposed to oxygen at 608 kPa. EEG was recorded continuously until the appearance of the first electrical discharge preceding clinical convulsions. CO2 production was measured simultaneously with the EEG. Latency to CNS-OT was measured and brain samples were taken for evaluation of heat shock protein 72 (HSP72) levels by Western blot analysis at the end of the acclimation period and during 4 weeks of deacclimation. Latency to CNS-OT was twice as long in the heat-acclimated rat, with insignificant changes in CO2 production. This prolongation continued for 2 weeks during deacclimation. There was a significant increase in the level of HSP72 following heat acclimation, with a subsequent decrease during deacclimation. We conclude that heat acclimation prolongs latency to CNS-OT in a way that does not involve changes in metabolic rate. During deacclimation there was a linear relationship between latency to CNS oxygen toxicity and the level of HSP72. A possible beneficial effect of HSP72 is discussed.

Original languageEnglish
Pages (from-to)15-20
Number of pages6
JournalBrain Research
Volume962
Issue number1-2
DOIs
StatePublished - 7 Feb 2003
Externally publishedYes

Keywords

  • CO production
  • Convulsion
  • Deacclimation
  • Heat shock protein

ASJC Scopus subject areas

  • Clinical Neurology
  • Molecular Biology
  • General Neuroscience
  • Developmental Biology

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