Effects of sevoflurane preconditioning on postoperative cognitive dysfunction in aged rats

Abstract

Objective To evaluate the effects of sevoflurane preconditioning on postoperative cognitive dysfunction in aged rats.Methods One hundred and twenty healthy male Sprague-Dawley rats,aged 18 months,weighing 400-450 g,were randomly divided into 3 groups (n =40 each) using a random number table:control group (group C),operation group (group O),and sevoflurane preconditioning group (group Sev).In group C,the rats were only anesthetized with pentobarbital sodium and did not undergo operation.In group O,the rats were anesthetized with pentobarbital sodium and underwent 30 min of exploratory laparotomy.In group Sev,the rats inhaled 2.4％ sevoflurane for 30 min and then inhaled air for 30 min,and the other procedures were similar to those previously described in group O.At 30 min before operation and on 1st,3rd,5th and 7th days after operation,Morris water maze test was performed to record the escape latency,time of staying at the original platform quadrant and frequency of crossing the original platform.At 30 min before operation and on 1st and 7th days after operation,10 rats in each group were sacrificed and hippocampi were isolated to detect the apoptotic rate and intracellular [Ca2 +] i (using flow cytometry) and the ultrastructure of hippocampal neurons was observed with transmission electron microscope.Results Compared with group C,the escape latency was significantly prolonged,the time of staying at the original platform quadrant was shortened,the frequency of crossing the original platform was decreased,and the apoptotic rate and intracellular [Ca2 +] i were increased after operation in O and Sev groups (P ＜0.05).Compared with group O,the escape latency was significantly shorten,the time of staying at the original platform quadrant was prolonged,the frequency of crossing the original platform was increased,and the apoptotic rate and intracellular [Ca2+]i were decreased after operation in group Sev (P ＜ 0.05).Microscopic examination showed no abnormality in the ultrastructure of hippocampal neurons in group C,and the pathological changes of the ultrastructure of hippocampal neurons were obvious in group O,and were significantly attenuated in group Sev.Conclusion 2.4％ sevoflurane preconditioning can reduce postoperative cognitive dysfunction in aged rats,and regulation of imbalance of calcium homeostasis and reduction of cell apoptosis are involved in the mechanism. Key words: Anesthetics, inhalation ; Brain; Cognition disorders; Postoperative complications ; Aged