Is longer sevoflurane preconditioning neuroprotective in permanent focal cerebral ischemia?

Sevoflurane preconditioning has neuroprotective effects in the cerebral ischemia/reperfusion model. However, its influence on permanent cerebral ischemia remains unclear. In the present study, the rats were exposed to sevoflurane for 15, 30, 60, and 120 minutes, followed by induction of permanent cerebral ischemia. Results demonstrated that 30- and 60-minute sevoflurane preconditioning significantly reduced the infarct volume at 24 hours after cerebral ischemia, and 60-minute sevoflurane preconditioning additionally reduced the number of TUNEL- and caspase-3-positive cells in the ischemic penumbra. However, 120-minute sevoflurane preconditioning did not show evident neuroprotective effects. Moreover, 60-minute sevoflurane preconditioning significantly attenuated neurological deficits and infarct volume in rats at 4 days after cerebral ischemia. These findings indicated that 60-minute sevoflurane preconditioning can induce the best neuroprotective effects in rats with permanent cerebral ischemia through the inhibition of apoptosis.