Objective To evaluate the effect of hyperoxygenated solution on myocardial injury in the rats with acute carbon monoxide (CO) poisoning.Methods Thirty pathogen-free adult male SpragueDawley rats,weighing 250-300 g,were randomly divided into 5 groups (n=6 each) using a random number table:control group (C group),acute CO poisoning group (ACP group),and different doses of hyperoxygenated solution groups (HP1-3 groups).CO 120 ml/kg was injected intraperitoneally to establish the model of acute CO poisoning.Hyperoxygenated solution 10,15 and 20 ml/kg were infused via the caudal vein at 1 h after intraperitoneal injection of CO in HP1-3 groups,respectively.At 24 h after intraperitoneal injection of CO,blood samples were collected from the caudal vein for determination of plasma creatine kinase (CK),creatine kinase-MB (CK-MB),lactic dehydrogenase (LDH) and alpha-hydroxybutyrate acid dehydrogenase (α-HBDH) activities using the automatic biochemical analyzer.The rats were then sacrificed,and myocardial specimens were obtained for examination of the pathological changes with a light microscope.Results Compared with group C,the plasma LDH,α-HBDH,CK and CK-MB activities were significantly increased in ACP and HP1-3 groups (P＜0.01).Compared with group ACP,the plasma LDH,α-HBDH,CK and CK-MB activities were significantly decreased in HP1-3 groups (P＜0.05 or 0.01).Compared with group HP1,the plasma LDH,α-HBDH,CK and CK-MB activities were significantly decreased in HP2,3 groups (P＜0.05).The pathological changes of myocardium were significantly attenuated in HP1-3 groups as compared with group ACP.Conclusion Hyperoxygenated solution can attenuate myocardial injury in the rats with acute CO poisoning.