title: Protective effects of exogenously administered or endogenously produced melatonin on hyperbaric oxygen-induced oxidative stress in the rat brain.
abstract: 1. Hyperbaric oxygen (HBO) is a widely used treatment modality in many diseases. A known side-effect of HBO is the production of reactive oxygen species (ROS). Many anti-oxidants, such as vitamins C and E, riboflavin and selenium, have been used successfully to scavenge the ROS produced by HBO administration. 2. The aim of the present study was to determine whether melatonin, a newly discovered anti-oxidant, has a protective effect against the overproduction of ROS produced by HBO in rat brain tissue. 3. Seventy male Sprague-Dawley rats were divided into seven groups as follows: 1, daytime control; 2, daytime HBO; 3, melatonin; 4, daytime HBO plus melatonin; 5, night-time control; 6, night-time HBO; and 7, night-time HBO under light exposure. 4. Hyperbaric oxygen was administered at 303 kPa for 120 min. Melatonin was injected at a dose of 10 mg/kg, i.p. Brain malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels were measured to elucidate oxidant status. 4. The MDA and SOD levels of groups 2 and 7 increased significantly. Exogenous (group 4) and endogenous (group 6) melatonin protected against HBO-induced lipid peroxidation. Exogenously administered melatonin (groups 3 and 4) had increased levels of the anti-oxidant enzymes SOD and GPx. 5. In conclusion, HBO caused oxidative stress and melatonin exhibited protective effects. Both endogenously produced and exogenously administered melatonin were found to be effective.
authors.affiliation: Department of Undersea and Hyperbaric Medicine, Gulhane Military Medical Academy, Ankara, Turkey.
authors.forename: Kadir
authors.initials: K
authors.lastname: Dundar
authors.forename: Turgut
authors.initials: T
authors.lastname: Topal
authors.forename: Hakan
authors.initials: H
authors.lastname: Ay
authors.forename: Sukru
authors.initials: S
authors.lastname: Oter
authors.forename: Ahmet
authors.initials: A
authors.lastname: Korkmaz
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000201:enzymology; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005979:Glutathione Peroxidase / Q000378:metabolism; D006931:Hyperbaric Oxygenation; D007274:Injections, Intraperitoneal; D008027:Light; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D008550:Melatonin