【Objective】 To investigate the effects of isoflurane and sevoflurane at the same depth of anesthesia on apoptosis of neuron in the parietal cortex and the expression of Akt and Bcl-xl/Bad proteins of cortex in neonatal rats. 【Methods】 Five litters of neonatal rats at postnatal day 7

eleven rats in each litter

(altogether fifty-five rats) were involved in this study. Rats in each litter were assigned randomly into three groups: 4 rats in isoflurane group (I group)

4 rats in sevoflurane group (S group) and 3 rats in control group (C group). The rats in I group

S group

or C group were separately exposed to 1.1% isoflurane or 1.8% sevoflurane (equivalent to 0.5 MAC for neonatal rats) or air for 4 h. One neonatal rat in each group each litter was punctured though heart at the end of anesthesia and blood was get to measure its pH and blood glucose(n = 5). One neonatal rat in each litter was perfused at 2 h after isoflurane or sevoflurane exposure and their brain were embedded by paraffin. Caspase-3 positive expression in the parietal cortex of brain were detected by immunohistochemistry staing (n = 5). Besides

the fresh cortex were dissected at 0 h in C group and at 2 h

4 h in I group and S group

phospho-Akt

Akt

Bcl-xl

and Bad protein expression were detected by Western blot (n = 5). One way ANOV were used for data analysis among groups.【Result】 The numbers of caspase-3 positive cells in the parietal cortex in I group were (27.12±5.22) per mm2

which increased by 751.11% when compared with C group [(3.15±0.59)per mm2

P<0.001] and increased by 199.67% when compared with S group [(9.05±1.76) per mm2

P <0.01]

but there were no significant difference between C group and S group. The expression of phospho-Akt protein in the cortex decreased by 66.31% (P < 0.01) at 2 h and recovered at 4 h in I group when compared with C group

while there were no significant difference at 2 h and 4 h between S group and C group. The expression of Bad protein in the cortex increased by 162.2%(P<0.05) at 2 h in I group when compared with C group

there were no significant difference at 2 h and 4 h between S group and C group. There was no significant difference of expression of Bcl-xl among I group

S group and C group. The ratio of Bcl-xl/Bad of cortex decreased by 42.85% (P < 0.01) at 2 h in I group when compared with C group

while there were no significant difference between S group and C group. 【Conclusion】 0.5 MAC isoflurane induced more cells to develop apoptosis in parietal cortex brain in the neonatal rats at postnatal day 7 than 0.5 MAC sevoflurane. Isoflurane inhibited Akt phosphorylation and increased Bad expression

decreased the ratio of Bcl-xl/Bad

which may be one of the mechanisms of that isoflurane induced apoptosis. While sevoflurane did not significantly inhibit Akt phosphorylation and decrease the ratio of Bcl-xl/Bad.