The Changes of PKCγ in the Protective Effect of Isoflurane Preconditioning Against Cerebral Ischemic Reperfusion Injury in Rats

Objective To explore the changes with time in the distribution and levels of protein kinase Cγ(PKCγ) in cytosolic and cell membrane fractions in the course of isoflurane preconditioning's neuroprotection.Methods Seventy-two rats were randomly allocated to three experiment groups: sham-operated,ischemia-reperfusion and isoflurane-preconditioning(n=24 for each).The rats in sham-operated were divided into three different sub-groups: reperfusion at 4,24,72 h(n=8 for each).The rats in ischemia-reperfusion and isoflurane-preconditioning groups were divided respectively into three different sub-groups: ischemia-reperfusion at 4,24,72 h(n=8 for each).The focal cerebral ischemic-reperfusion rat model was established with thread ligation method.The rats in sham-operated group were killed at 4,24 and 72 hour after reperfusion respectively,and samples of frontal cortex were taken.After 2 hours of ischemia,the rats in ischemic-reperfusion group were killed at 4,24 and 72 hour after reperfusion respectively,and samples of frontal cortex were taken.The concentration of PKCγ in cytosolic and cell membrane fractions in the frontal cortex of the brain was examined by western blot analysis.In the isoflurane-preconditioning group,1.5% isoflurane was administered at 90 min before the onset of ischemia and last for 60 min.The rats' vessels were dissected but the suture was not introduced into the lumen of the internal carotid artery in sham-operated group.Results The levels of PKCγ in isoflurane-preconditioning and ischemia-reperfusion groups increased in membrane but decreased in cytosolic fractions after 4,24,72 hour reperfusion compared with that in sham-operated group(all P0.05).The levels of PKCγ in isoflurane-preconditioning group were higher in membrane and lower in cytosolic fractions than those in ischemia-reperfusion group at 4,24 and 72 hour of reperfusion respectively(all P0.05).And the amount of translocated PKCγ reached the peak at 24 hour after reperfusion in isoflurane-preconditioning group.Conclusion Isoflurane-preconditioning enhances the translocation of PKCγ from the cytosol to the membrane fraction,thereby preventing beneficial cell signaling possibly during reperfusion injury.