title: Is glucose-6-phosphate dehydrogenase deficiency a risk factor for hyperbaric oxygen exposure?
abstract: Divers and patients lacking glucose-6-phosphate dehydrogenase (G6PD) may face a serious threat of central nervous system oxygen toxicity (CNS-OT) during exposure to hyperbaric oxygen (HBO), due to the important part played by G6PD in cellular redox balance. Our objective was to investigate G6PD deficiency as a risk factor for CNS-OT. We exposed G6PD-deficient (G6PDdef) and wild type (WT) mice to HBO at 405 kPa. Latency to CNS-OT was measured by observing the animal and monitoring the time to appearance of convulsions. Changes in glutathione peroxidase (GPx) and catalase activity were measured in red blood cells, and levels of endothelial and neuronal nitric oxide synthase (eNOS and nNOS) and 3-nitrotyrosine (NT) were measured in extracts of whole brain tissue by Western blot analysis. Unexpectedly, latency to CNS-OT was more than twice as long in G6PDdef mice compared with WT (36.9 ± 15.4 and 15.6 ± 13.2 min, respectively, P < 0.005). No significant differences were found in GPx and catalase activity or in protein levels of eNOS. However, nNOS and NT levels were lower in G6PDdef mice compared with WT (50.6%, P < 0.01 and 52.8%, P < 0.05, respectively). Our results suggest that the enhanced resistance of G6PDdef mice to HBO is due in part to a reduction in nNOS and NT levels in the brain. We conclude that G6PD deficiency at the level of the animals in the present study may not be a risk factor for developing CSN-OT, but this remains to be verified for human subjects.
authors.affiliation: Israel Naval Medical Institute, IDF Medical Corps, P.O. Box 8040, 31080, Haifa, Israel. estie@idf.gov.il
authors.forename: Mirit
authors.initials: M
authors.lastname: Eynan
authors.forename: Dimitry
authors.initials: D
authors.lastname: Tsitlovsky
authors.forename: Liron
authors.initials: L
authors.lastname: Batit
authors.forename: Ayala
authors.initials: A
authors.lastname: Hochman
authors.forename: Nitzan
authors.initials: N
authors.lastname: Krinsky
authors.forename: Amir
authors.initials: A
authors.lastname: Abramovich
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004781:Environmental Exposure / Q000009:adverse effects; D005953:Glycogen Storage Disease Type I / Q000150:complications* / Q000378:metabolism*; D006610:High Pressure Neurological Syndrome / Q000209:etiology* / Q000378:metabolism*; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D051379:Mice; D018345:Mice, Knockout; D010100:Oxygen / Q000009:adverse effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012307:Risk Factors
chemical_list: D017382:Reactive Oxygen Species; D010100:Oxygen
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