Abstract: Objective To explore the change rules of behavioral characteristics, survival time and saturation of carboxyhemoglobin （HbCO） in different CO concentration to provide experimental basis for the cases of CO poisoning death in forensic practice. Methods Total 160 SD rats were randomly divided into four groups. CO with the concentration of 1 250 mg/m3, 3 750 mg/m3, 6 250 mg/m3 were continuously and respectively replenished in a self-made toxicant exposure equipment until rats died from poisoning. In different CO concentration, the behavioral characteristics and survival time of poisoning rats were observed and recorded. The saturation of HbCO in heart blood was detected by spectrophotometric method. Organs such as brain, heart, lung and liver, and heart blood were obtained via autopsy and histopathological observation was performed. Results The behavioral characteristics of CO poisoning rats were limp and slow response. There were a gradual decrease of survival time and an increase of HbCO saturation in rats with the increase of CO concentration. Three rats in CO concentration of 1 250 mg/m3 group showed lower saturations of HbCO than the lethal dose and this situation hasn’t been found in other groups. Conclusion The animal model of CO poisoning established under different CO concentration has the advantages such as simplicity and good repeatability, which lays a foundation to the further study for CO and other inhaled toxic gas in the research of forensic sciences.

Key words: forensic pathology, carboxyhemoglobin, carbon monoxide poisoning, models, animal, rats