Effect of 8% emulsified isoflurane postconditioning on focal cerebral ischemia-reperfusion injury in rats

Objective To investigate the effect of postconditioning with 8 % emulsified isoflurane (EI) on focal cerebral ischemia-reperfusion (I/R) injury in rats. Methods Forty-eight male SD rats weighing 260-300 g were randomly divided into 6 groups ( n = 8 each): group Ⅰ sham operation (group S); group Ⅱ I/R; group Ⅲ,Ⅳ, Ⅴ 3 different doses of EI (group L-EI, M-EI, H-.EI) and group Ⅵ lipid emulsion (group LE). Right middle cerebral artery occlusion (MCAO) was induced by inserting a nylon thread 0.24 mm in diameter into right internal carotid artery. The thread was threaded cranially until resistance was met. MCAO was maintained for 2 h followed by 24 h reperfusion in group Ⅱ-Ⅵ. In group Ⅲ-Ⅴ EI 3.5, 7.0 and 10.5 ml/kg were injected intraperitoneally (IP) immediately before reperfusion respectively. In group LE 30% lipid emulsion 10.5 ml/kg was given instead of EI. The neurologic deficit was assessed and scored (0 = normal, 4 = unable to move and unconscious). The animals were then killed and infarct size was measured. Results IP 8% emulsified isoflurane 7.0 and 10.5 ml/kg injected before reperfusion significantly reduced neurologic deficit scores and infarct size in group M-EI and H-EI as compared with group I/R. Conclusion Postconditioning with 8% emulsified isoflurane can protect the brain against focal cerebral I/R injury. Key words: Isoflurane; Lipid emulsions, intravenous; Reperfusion injury; Brain; Ischemic postconditioning