Hyperbaric
oxygen has been found to be beneficial in treating
heatstroke animals. We attempted to further assess the possible mechanism of therapeutic protection offered by hyperbaric
oxygen in experimental
heatstroke. Anesthetized rats, immediately after the onset of
heatstroke, were randomized into the following groups and given: a) hyperbaric
oxygen (100% O(2) at 253 kPa for 1 h); or b) normal air. They were exposed to 43 degrees C temperature to induce
heatstroke. When the untreated rats underwent heat stress, their survival time values were found to be 20-24 min.
Resuscitation with hyperbaric
oxygen increased the survival time to new values of 152-176 min. All untreated
heatstroke rats displayed cerebrovascular dysfunction (evidenced by
hypotension, intracranial hypertension, and cerebral hypoperfusion,
hypoxia, and
ischemia), hypercoagulable state (evidenced by increased levels of activated partial thromboplastin time, prothrombin time, and
D-dimer, but decreased values of platelet count and
protein C in plasma), and tissue
ischemia/injury (evidenced by increased levels of
creatinine, serum
urea nitrogen,
aspartate aminotransferase,
alanine aminotransferase, and
alkaline phosphatase in plasma, and dihydrobenzoic
acid, lipid peroxidation, and oxidized-form
glutathione/reduced-form of
glutathione ratio in hypothalamus). The cerebrovascular dysfunctions, hypercoagulable state, tissue
ischemia/injury, and brain oxidative stress that occurred during
heatstroke were all suppressed by
hyperbaric oxygen therapy. The current results indicate that
hyperbaric oxygen therapy may resuscitate rats that had a
heatstroke by decreasing multiple organ dysfunction and brain oxidative stress.