| Objective:To observe the effects of sevoflurane anesthesia on cognitive function and the expressive level ofα4,β2,α3,α7 n Ach R in adult rats.Methods:One hundred and forty-four Sprague-Dawley adult rats of either gender,aged 3 to 4 months,weighing 220 to 270g,were randomly divided into4 groups（n=36）:the control group（C）,and other groups were exposed to sevoflurane for 1h（S1）,3h（S2）,5h（S3）,respectively.Adult rats in control group inhaled air,3%sevoflurane was inhaled for 1h,3h,5h in S1,S2 and S3 groups,respectively.All rats were trained by the orientation navigation experiment before anesthesia.12 rats in each group were tested by space exploration experiment at 1 and 7 days after anesthesia.12 rats in each group were sacrificed immediately after anesthesia and at 1 and 7 days after anesthesia,the hippocampal tissue was removed.Morris water maze was performed to assess cognitive function,recording escape latency,the duration of staying in the target quadrant,the swimming distance in target quadrant,total distance,number of crossing platforms,and calculating the ratio of the duration in the original platform quadrant to the total duration and the ratio of the distance in the original platform quadrant to the total distance.The hippocampal tissue were obtained for detecting the protein and gene expressive level ofα4,β2,α3,α7 n Ach R by Western blot（WB）,immunohistochemistry（IHC）and fluorescent quantitative real-time reverse transcriptase polymerase chain reaction.Results:Compared with C group,no significant differences of escape latency were observed in S1,S2 and S3 groups（P>0.05）,the duration of staying in the target quadrant,the ratio of the duration in the original platform quadrant to the total duration and the ratio of the distance in the original platform quadrant to the total distance were significantly decreased in S1,S2 and S3 groups（P<0.05）,the swimming distance in target quadrant was significantly shortened at 1 day after anesthesia in S3 group,the expressive level ofα4、β2、α7 n Ach R protein and m RNA was down-regulated,the number ofα4 positive cells was reduced and the expressive level ofα3 n Ach R protein was down-regulated in S1,S2 and S3 groups（P<0.05）,the expressive level ofα3 n Ach R m RNA was down-regulated at 7 days after anesthesia in S2 and S3 groups（P<0.05）.Compared with S1 and S2 groups,the duration of staying in the target quadrant,the ratio of the duration in the original platform quadrant to the total duration and the ratio of the distance in the original platform quadrant to the total distance were significantly decreased at 1 day after anesthesia in S3 group（P<0.05）.Compared with S1 group,the expressive level ofα7 n Ach R protein was down-regulated immediately after anesthesia in S3 group,the expressive level ofα3 n Ach R m RNA was down-regulated at 7 day after anesthesia in S2 and S3groups（P<0.05）.Conclusion:Exposed to 3%sevoflurane anesthesia for 1h,3h,5h can lead the cognitive function to decline in adult rats and exposed to 3%sevoflurane anesthesia for 5h has more significant effects on cognitive decline at 1 day after anesthesia,which may be associated with the down-regulating expression ofα4,β2,α3,α7 n Ach R. |
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