A MODEL FOR ACUTE CARBON-MONOXIDE POISONING IN CONSCIOUS RATS

These experiments were designed to establish an animal model of acute carbon monoxide (GO) poisoning in awake habituated rats. On the day be fore exposure, under a brief anesthesia, a Levine preparation (unilate ral common carotid artery occlusion) was performed on group 1 (n=8) an d 2 (n=28), but not on group 3 rats (n=8). Group 1 rats were exposed t o air as control. Groups 2 and 3 rats were exposed to 0.27% CO in air for 60 min [carboxyhemoglobin (HbCO) = 70%] followed by a 2-day recove ry in air. The Levine preparation per se did not induce any detectable physiologic effects on group 1 rats. Identical cardiovascular and met abolic responses to CO occurred in groups 2 and 3. After the CO exposu re, all group 3 rats lived for 2 days with normal neurologic index (NI ). In group 2 (n = 25 post-CO), 84% of the rats showed increased NI an d edema of the ipsilateral cerebral hemisphere, and 76% of the rats di ed 8.7 +/- 1.7 h after the CO exposure. NI correlated with the brain e dema (r(s) =0.748,P < 0.001) and inversely correlated with the surviva l time after the CO exposure (r(s) = -0.777, P < 0.001). We therefore may conclude that exposure of the Levine-prepared rats to 0.27% CO in air for 60 min will provide a valuable model for testing of different treatments for CO poisoning.