There is a need to develop animal models to study
postoperative delirium. Inattention is one of the symptoms of
delirium. Increases in the levels of α-
synuclein and S100β have been reported to be associated with
delirium. Therefore, we set out to determine the effects of surgery plus
general anesthesia on the behavioral changes (including loss of attention) in mice and on the levels of α-
synuclein and S100β in the brain tissues of these mice. C57BL/6J mice (2- to 8-months-old) had a simple
laparotomy plus
isoflurane anesthesia. The behavioral changes, including attention level and the speed of movements, were determined 12, 24, and 48 h after the surgery plus
anesthesia in the mice. The levels of α-
synuclein and S100β in the cortex of these mice following the surgery plus
anesthesia were determined by Western blot analysis. We found that there was a loss of attention at 24, but not 12 or 48 h following the surgery plus
anesthesia (49% ± 5 vs. 33% ± 2.9, P = 0.011, N = 12) in the mice without significantly affecting the speed of their movements. There were increases in the levels of total α-
synuclein (139% ± 33.5 vs. 100% ± 13.7, P = 0.037, N = 6) and S100β (142% ± 7.7 vs. 100% ± 6, P = 0.002, N = 6) in the cortex of the mice 12 h following the surgery plus
anesthesia. These findings suggested that the surgery plus
isoflurane anesthesia might induce behavioral and biochemical/cellular changes associated with
delirium. We could use the surgery plus
anesthesia in mice to develop an animal model to study
postoperative delirium.