Oxidative stress and antioxidant status in patients undergoing prolonged exposure to hyperbaric oxygen.
OBJECTIVE
To evaluate the condition of oxidative stress in patients undergoing prolonged exposure to hyperbaric oxygen (HBO) and the possible modifications of the antioxidant defense systems in the absence of antioxidant supplementation.


METHODS
Twelve patients exposed to 15 HBO treatments for pathological conditions related to hypoxia were included in the study. Oxidative stress indices as well as plasma and erythrocyte antioxidant levels were measured in blood samples collected both at the 1st and 15th HBO session.


RESULTS
The repeated exposures to HBO led to a significant accumulation of plasmatic reactive oxygen metabolites (ROM) and malondialdehyde (MDA). After 15 HBO sessions, no relevant differences were detected for reduced glutathione (GSH), alpha-tocopherol, and retinol plasma levels; however, a significant decrease in erythrocyte superoxide dismutase (SOD) and catalase (CAT) activity was observed when compared to the 1st HBO exposure; glutathione peroxidase (GPx) activity remained almost unchanged.


CONCLUSIONS
In the absence of antioxidant supplementation, the prolonged HBO treatment leads to a condition of oxidative stress that seems to affect in particular the response of the enzymatic antioxidant defense system; the possible relationship between the chemical modifications of the enzymes caused by oxygen reactive species and the consequent inactivation of the proteins is under investigation.
Institute of Biological Chemistry G.Fornaini, University of Urbino Carlo Bo, 2-61029 Urbino (PU), Italy. s.benedetti@uniurb.it
Serena
S
Benedetti
Antonio
A
Lamorgese
Michele
M
Piersantelli
Silvia
S
Pagliarani
Francesca
F
Benvenuti
Franco
F
Canestrari
D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000097:blood / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood / Q000378:metabolism; D006801:Humans; D006931:Hyperbaric Oxygenation; D000860:Hypoxia / Q000097:blood / Q000201:enzymology / Q000378:metabolism / Q000628:therapy; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000097:blood; D013482:Superoxide Dismutase / Q000097:blood / Q000378:metabolism
D000975:Antioxidants; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase