Objective To explore the effect of sevoflurane combined with nitrous oxide on learning (short-term and long-term learning) and memory abilities in aged rats.

Methods Forty 18-month rats were randomly divided into the anesthesia group and the control group. Rats in the anesthesia group were inhaled with 1.3% sevoflurane combined with 50% nitrous oxide for 4 hours, while rats in the control group were inhaled with 50% oxygen for 4 hours. After 48 hours, spatial navigation task was took for 6 consecutive days, then the first probe test was conducted on the 7th day and the second probe test was conducted on the 14th day. Rats finished Morris water maze were decapitated and the brains were taken for detecting neuron cell apoptosis in hippocampus using Western blotting and immunohistochemical experiment.

Results Compared to the control group, the exposed rats revealed a significant deficit in spatial learning acquisition and memory retention in the first probe test (P < 0.05), while no difference in the performance of rats in the second probe test was observed between the two groups. After the first probe test, exposure to sevoflurane combined with nitrous oxide showed increased hippocampal neuronal apoptosis compared to the control group (P < 0.05), while there was no significant difference in hippocampus neuron cell apoptosis between the two groups in the second probe test.

Conclusions Spatial learning and memory dysfunction induced by 1.3% sevoflurane combined with 50% nitrous oxide in aged rats is reversible.