TY - JOUR
T1 - Hyperbaric oxygen preconditioning protects rats against CNS oxygen toxicity
AU - Arieli, Yehuda
AU - Kotler, Doron
AU - Eynan, Mirit
AU - Hochman, Ayala
PY - 2014/6/15
Y1 - 2014/6/15
N2 - We examined the hypothesis that repeated exposure to non-convulsive hyperbaric oxygen (HBO) as preconditioning provides protection against central nervous system oxygen toxicity (CNS-OT). Four groups of rats were used in the study. Rats in the control and the negative control (Ctl-) groups were kept in normobaric air. Two groups of rats were preconditioned to non-convulsive HBO at 202. kPa for 1. h once every other day for a total of three sessions. Twenty-four hours after preconditioning, one of the preconditioned groups and the control rats were exposed to convulsive HBO at 608. kPa, and latency to CNS-OT was measured. Ctl- rats and the second preconditioned group (PrC-) were not subjected to convulsive HBO exposure. Tissues harvested from the hippocampus and frontal cortex were evaluated for enzymatic activity and nitrotyrosine levels. In the group exposed to convulsive oxygen at 608. kPa, latency to CNS-OT increased from 12.8 to 22.4. min following preconditioning. A significant decrease in the activity of glutathione reductase and glucose-6-phosphate dehydrogenase, and a significant increase in glutathione peroxidase activity, was observed in the hippocampus of preconditioned rats. Nitrotyrosine levels were significantly lower in the preconditioned animals, the highest level being observed in the control rats. In the cortex of the preconditioned rats, a significant increase was observed in glutathione S-transferase and glutathione peroxidase activity. Repeated exposure to non-convulsive HBO provides protection against CNS-OT. The protective mechanism involves alterations in the enzymatic activity of the antioxidant system and lower levels of peroxynitrite, mainly in the hippocampus.
AB - We examined the hypothesis that repeated exposure to non-convulsive hyperbaric oxygen (HBO) as preconditioning provides protection against central nervous system oxygen toxicity (CNS-OT). Four groups of rats were used in the study. Rats in the control and the negative control (Ctl-) groups were kept in normobaric air. Two groups of rats were preconditioned to non-convulsive HBO at 202. kPa for 1. h once every other day for a total of three sessions. Twenty-four hours after preconditioning, one of the preconditioned groups and the control rats were exposed to convulsive HBO at 608. kPa, and latency to CNS-OT was measured. Ctl- rats and the second preconditioned group (PrC-) were not subjected to convulsive HBO exposure. Tissues harvested from the hippocampus and frontal cortex were evaluated for enzymatic activity and nitrotyrosine levels. In the group exposed to convulsive oxygen at 608. kPa, latency to CNS-OT increased from 12.8 to 22.4. min following preconditioning. A significant decrease in the activity of glutathione reductase and glucose-6-phosphate dehydrogenase, and a significant increase in glutathione peroxidase activity, was observed in the hippocampus of preconditioned rats. Nitrotyrosine levels were significantly lower in the preconditioned animals, the highest level being observed in the control rats. In the cortex of the preconditioned rats, a significant increase was observed in glutathione S-transferase and glutathione peroxidase activity. Repeated exposure to non-convulsive HBO provides protection against CNS-OT. The protective mechanism involves alterations in the enzymatic activity of the antioxidant system and lower levels of peroxynitrite, mainly in the hippocampus.
KW - Central nervous system oxygen toxicity
KW - Hyperbaric oxidative stress
KW - Reactive oxygen species scavengers
UR - http://www.scopus.com/inward/record.url?scp=84899051966&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2014.03.006
DO - 10.1016/j.resp.2014.03.006
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AN - SCOPUS:84899051966
SN - 1569-9048
VL - 197
SP - 29
EP - 35
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 1
ER -