Mechanism of isoflurane preconditioning's neuroprotection against global cerebral ischemia in rat

Objective To investigate mechanism of isoflurane preconditioning's neuroprotection against global cerebral ischemia in rat.Methods Global cerebral ischemia was induced by occlusions of bilateral common carotid and vertebral arteries (four vessels).Seventy-eight male healthy Wistar rats (weighing 250～300g) were selected according to model criteria and randomly divided into four groups:sham operation group (SH),ischemia group (ISC),ischemia preconditioning group (IPC),and isoflurane preconditioning(ISOPC).Each group was divided into three subgroups according to reperfusion time:6h,24h and 72h.Every cerebrum was resected and stained using hematoxylin-eosin (HE) and immunohistochemical method to evaluate the expression of Bcl-2 protein.Results Bcl-2 protein expressed in CA1 after 72h reperfusion in ISC,IPC and ISOPC group.There was almost no expression of Bcl-2 protein in SH group.Bcl-2 protein expressed in part of survival pyramidal neuron cell in ISC.Whereas in IPC and ISOPC group,Bcl-2 protein expression immunoreactivity significantly increased;and also expressed in endothelial cell of vessel.Conclusion The expression of Bcl-2 protein in the CA1 area following preconditioning is closely related to the acquisition of suppressing the apoptosis of neural cells.Isoflurane preconditioning can mimic the role of IPC to suppress the apoptosis of neural cells following ischemia and induce neuroprotection.