Effect of preconditioning with different doses of emulsified isoflurane on focal cerebral ischemia-reperfusion injury in rats

Objective To investigate the effect of preconditioning with different doses of emulsified isoflurane on focal cerebral ischemia-reperfusion （I/R） injury in rats. Methods Ninety-six male SD rats were randomly divided into 6 groups （ n = 16 each）： sham operation group （group S）, I/R group, low, median and high doses of emulsified isoflurane preconditioning group （group L, M, H） and intralipid group （group IL）. Middle cerebral artery occlusion was produced by inserting a nylon thread. In group S, intraperitoneal normal saline （NS）10.5 ml/kg was injected, but the artery was only exposed 24 h later. In group I/R, intraperitoneal NS 10.5 ml/kg was injected, and the model was established 24 h later. In group L, M, H and IL, 8% emulsified isoflurane 3.5 ml/kg＋NS 7.0 ml/kg, 8% emulsified isoflurane 7.0 ml/kg ＋ NS 3.5 ml/kg, 8% emulsified isoflurane 10.5 ml/kg and 30% intralipid 10.5 ml/kg were injected intraperitoneally respectively, and then the model was established 24 h later. The temperature, HR and RR were recorded at 10 min before ischemia and at 10 min of reperfusion. The neurological deficit was scored, the cerebral infarct volume and apoptosis in neurons were detected, and microscopic examination of ischemic penumbra region was performed at 24 h of reperfusion. Results The rectal temperature and HR were significantly increased, while RR was significantly decreased duing cerebral I/R.The neurological deficit score was significantly higher, cerebral infarct volume and the number of apoptotic neurons were significantly larger in the other groups than in group S. Emulsified isoflurane preconditioning reduced neurological deficit scores, cerebral infarct volume and the number of apoptotic neurons dose-dependently. Conclusion Emulsified isoflurane preconditioning can reduce focal cerebral I/R injury in a dose-dependent manner in rats. Key words: Isoflurane;  Fat emulsions, intravenous;  Ischemic preconditioning;  Brain;  Reperfusion injury