Effects of emulsified isoflurane preconditioning on expression of platelet-activating factor and its receptor in brain during focal cerebral ischemia-reperfusion in rats

Abstract

Objective To investigate the effects of emulsified isoflurane preconditioning on the expression of platelet-activating factor (PAF) and PAF receptor during focal cerebral ischemia-reperfusion (I/R) in rats.Methods Thirty-two healthy adult male SD rats weighing 250-300 g were randomly divided into 4 groups ( n =8each):group sham operation (group S); group I/R; group emulsified isoflurane preconditioning( group EI) and group lipid emulsion (group LE).Focal cerebral I/R was induced by 2 h occlusion of middle cerebral artery followed by reperfusion in groups I/R,EI and LE.8％ emulsified isoflurane 10.5 ml/kg and 30％ lipid emulsion 10.5 ml/kg were injected intraperitoneally at 24 h before cerebral ischemia in groups EI and LE respectively.The neurologic deficit score (NDS) (0 =no deficit,4 =unable to control) was evaluated at 12 h of reperfusion.Venous blood samples were collected for measurement of plasma PAF concentration.The animals were then sacrificed and their brains removed for determination of infarct size (by TTC staining) and PAF receptor expression in hippocampus and cerebral cortex (by Western blot).Results Focal cerebral I/R significantly increased NDS,the infarct size,plasma PAF concentration and PAF receptor expression in cerebral cortex and hippocampus in group I/R as compared with group S.Emulsified isoflurane preconditioning significantly attenuated the focal cerebral I/R induced above changes in group EI as compared with group I/R,but there was no significant difference between groups I/R and LE.Conclusion Emulsified isoflurane preconditioning can attenuate focal cerebral I/R injury by inhibiting PAF and PAF receptor expression. Key words: Isoflurane; Fat emulsions, intravenous; Reperfusion injury; Platelet activating factor; Receptors, cell surface; Brajn