Effects of isoflurane on spatial reference memory and changes of Caspase-3 expression and apoptosis in brain of aged mice

Objective To investigate the effect of isoflurane on the spatial learning and memory in aged mice,and whether this is associated with the changes of Caspase-3 expression and apoptosis in brain.Methods Twenty-four CO57BL/6 aged mice(16 months)were randomly divided into isoflurane treatment group(Iso Group,n=12) and sham control group (Con Group,n=12).Mice in Iso group were exposed to 1% isoflurane in carrying gas of 30% oxygen,balance nitrogen in a warmed,humidified chamber for4 h per day for2 days.For Con group,animals were treated at the same condition with only carrying gas.After anesthetic exposures,behavioral testing was performed using the Morris water maze(MWM),and then changes of Caspase-3 expression and apoptosis in hippocampus CAI,dentate gyrus(DG) and cortex(CX) in brain were determined by using immunofluorecence staining and TUNEL staining.Results In hidden-platform training of MWM,the mean escape latency to platform showed no significant difference between the two groups (F=0.007,P=1.235),but the mice in Iso group showed obviously impaired retention of memory by spending more percentage of time swimming in the probe quadrant as compared to the control animals in the probe test((34.5±5.0)%vs(45.1±4.9)%.P 0.05).Conclusion 1% isoflurane repeatedly exposure significantly impaires the spatial reference memory in aged mouses,however does not significantly change the expression of easpase-3 and apoptosis in brain. Key words: Isoflurane; Reference Memory; Mouse; Aged; Caspuse-3