Normobaric hyperoxia reduces MRI diffusion abnormalities and infarct size in experimental stroke.

Abstract

BACKGROUND:

Hyperbaric oxygen therapy is considered an important stroke treatment strategy.

BACKGROUND:

To determine whether normobaric oxygen is neuroprotective, and, if so, what the therapeutic time window is.

METHODS:

Experiment 1-Serial diffusion- and perfusion-weighted MRI (DWI and PWI) was performed after middle cerebral artery filament occlusion (MCAO) in rats randomized to FiO(2) 30% (normoxia) or FiO(2) 100% (hyperoxia). Experiment 2-48-hour lesion volumes were analyzed in rats subjected to 2-hour MCAO and randomized to normoxia or hyperoxia starting 15, 30, or 45 minutes after MCAO and ending 15 minutes after reperfusion.

RESULTS:

Experiment 1-Lesion apparent diffusion coefficient (ADC) values were persistently low in normoxic animals. In hyperoxia-treated rats, ADC values in cortical border zones showed progressive recovery from 66 +/- 3% of contralateral before hyperoxia, to 104 +/- 20% at approximately 2 hours. Striatal ADC values showed early but ill-sustained improvement. ADC lesion volumes increased progressively in the normoxia group. In the hyperoxia group, ADC lesion volumes tended to decrease after starting hyperoxia; however, lesions later increased in size, and 2-hour lesion volumes were not significantly different from baseline. PWI showed stable right MCA hypoperfusion in all animals. Experiment 2-Hyperoxia within 30 minutes significantly reduced total and cortical lesion volumes at 48 hours after stroke. Striatal lesion volumes were significantly reduced in the hyperoxia-15 group.

CONCLUSION:

In rats subjected to transient stroke, 100% oxygen administered within 30 minutes salvages ischemic brain tissue, especially in the cerebral cortex. Reducing the time to treatment enhances the degree of neuroprotection.

• Authors: Aneesh B Singhal, Rick M Dijkhuizen, Bruce R Rosen, Eng H Lo
• Journal: Neurology (Neurology) Vol. 58 Issue 6 Pg. 945-52 (Mar 26 2002) ISSN: 0028-3878 [Print] United States
• PMID: 11914413 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Topics

• Animals
• Brain Ischemia (pathology, physiopathology, therapy)
• Cerebral Cortex (blood supply, pathology, physiopathology)
• Corpus Striatum (blood supply, pathology, physiopathology)
• Hyperoxia (pathology)
• Infarction, Middle Cerebral Artery (pathology, physiopathology, therapy)
• Magnetic Resonance Imaging (statistics & numerical data)
• Male
• Oxygen Inhalation Therapy (methods, statistics & numerical data)
• Rats
• Rats, Sprague-Dawley