Effect of Normobaric Oxygen Therapy in a Rat Model of Intracerebral Hemorrhage

Background and Purpose-Normobaric oxygen (NBO) therapy may be neuroprotective in acute ischemic stroke. However, how NBO may affect intracerebral hemorrhage is unclear. We tested NBO in a rat model of striatal intracerebral hemorrhage. Methods-Intracerebral hemorrhage was induced by stereotactic injection of collagenase Type VII (0.5 U) into the right striatum of male Sprague-Dawley rats. One hour later, rats were randomized into controls (n = 13) versus NBO treatment (n = 13). NBO was applied for 2 hours. Hemorrhagic blood volume, brain water content, and neurological outcomes (forelimb placement test, forelimb asymmetry, neuroscore) were quantified at 72 hours. Experiments were repeated in a second independent laboratory to assess reproducibility in neurological outcomes (n = 10 per group). Results-NBO did not worsen hemorrhage severity or brain edema. There were no significant differences in hemorrhagic blood volumes (control, 6.4 +/- 0.9 mu L versus NBO, 7.0 +/- 2.1 mu L; P = 0.18) or brain water content (control, 81.9% +/- 1.1% versus NBO, 81.6% +/- 0.5%; P = 0.58). NBO did not affect any of the neurological outcome tests in the primary or secondary studies. Conclusions-NBO therapy may not worsen outcomes in intracerebral hemorrhage. (Stroke. 2011;42:1469-1472.)