title: Low doses of carbon monoxide protect against experimental focal brain ischemia.
abstract: Carbon monoxide (CO) is associated with central nervous system toxicity. However, evidence also indicates that CO can be protective, depending on its concentration. To determine if CO can be neuroprotective after ischemic brain injury, we subjected mice to transient middle cerebral artery occlusion and exposed them to different concentrations of CO. We found that in mice, low CO levels protected the brain from injury following 90-min transient focal ischemia and 48 h of reperfusion. When inhalation of 125 or 250 ppm CO began immediately at the onset of reperfusion, total hemispheric infarct volume was reduced by 32.1 +/- 8.9% and 62.2 +/- 14.4%, respectively; with an extended therapeutic window of 1-3 h after ischemia, CO inhalation also attenuated infarct volume significantly. Furthermore, early CO exposure limited brain edema formation by 3.2 +/- 0.8% (125 ppm) and 2.6 +/- 0.3% (250 ppm). Finally, CO inhalation significantly improved neurological deficit scores at 48 h of survival time after ischemia. Transient elevation of carboxyhemoglobin levels returned rapidly to baseline when CO exposure was stopped. These findings suggest a potential application of CO to treat brain ischemic stroke.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 365, Baltimore, MD 21205, USA.
authors.forename: Emil
authors.initials: E
authors.lastname: Zeynalov
authors.forename: Sylvain
authors.initials: S
authors.lastname: Doré
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001929:Brain Edema / Q000209:etiology / Q000517:prevention & control; D002248:Carbon Monoxide / Q000627:therapeutic use*; D002263:Carboxyhemoglobin / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000401:mortality / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D015427:Reperfusion Injury / Q000517:prevention & control; D013997:Time Factors
chemical_list: D018696:Neuroprotective Agents; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin