七氟烷对大鼠海马Tau蛋白基因的调控作用及其对认知的影响

Effects of sevoflurane anesthesia on Tau mRNA expression in rat hippocampus and the cognition

目的探讨新生期大鼠重复七氟烷麻醉后海马内Tau蛋白mRNA表达水平的改变程度及其对认知功能的影响。方法 SPF级7日龄健康SD大鼠36只,体重15~18 g,雌雄不拘。首先随机分为两个组:2.6%七氟烷组(Sev2.6组,n=18)和对照组(Con组,n=18)。于大鼠出生后第7天(P7)、第14天(P14)和第21天(P21)进行重复七氟烷吸入麻醉处理及对照处理,Sev2.6组吸入2.6%七氟烷2 h,Con组吸入O_21 L/min+Air 1 L/min的混合气体。再据大鼠生长的不同时期随机分为3个亚组(新生期、幼年期、成年期),于幼年期、成年期大鼠行Morris水迷宫实验检测大鼠行为学变化。水迷宫实验结束后立即取海马组织,采用RT-q PCR法测定Tau蛋白mRNA的表达水平。结果随测试天数的增加,两组大鼠在幼年期、成年期逃避潜伏期均呈缩短趋势,并且在第3、4、5天之间比较差异无统计学意义(P>0.05)。在幼年期和成年期两组大鼠逃避潜伏期、原平台象限滞留时间、原平台象限路程、平均速度、经过平台次数等指标组间比较差异无统计学意义(P>0.05)。幼年期Sev2.6组大鼠海马中Tau蛋白mRNA表达量为1.44±0.43,较Con组Tau蛋白mRNA表达量(0.93±0.13)明显增加,差异有统计学意义(P<0.05),而在新生期、成年期两组大鼠海马中Tau蛋白mRNA表达量差异无统计学意义(P>0.05)。结论新生期重复2.6%七氟烷吸入麻醉后可导致大鼠海马Tau蛋白mRNA表达的一过性上调,但不引起认知功能的损害。

Objective To study the effects of repeated sevoflurane anesthesia on Tau mRNA expression in hippocampus and investigate the relationship between the Tau mRNA expression and the ability of learning and memory in neonatal rats.Methods Thirty-six healthy Sprague-Dawley rats were randomly divided into two groups,control group （n=18） and sevoflurane group （n=18）.The sevoflurane group was given 2.6% sevoflurane inhalation anesthesia for 2 h at the postnatal 7th days,14th days and 21st days （P7,P14 and P21）.Control group was given mixed carrier gas （the proportion of 1∶1 oxygen and air） for 2 h at the same days.The behavior was tested through Morris water maze test in two groups at juvenile and adult period.After the behavior test,hippocampal specimens were obtained for determination of the expression of Tau mRNA by RT-qPCR.Results In juvenile and adult periods,the escape latency in two groups became shorter over time,and there was no statistical difference between two groups at the 3,4 and 5 d （P〉0.05）.No significant change was found between two groups in the escape latency,the time of staying at the original platform quadrant,the distance of swimming in the original platform,the average speed of swimming and the frequency of crossing the original platform during juvenile and adult period （P〉0.05）.In the juvenile period,the expression of Tau mRNA in the hippocampus of sevoflurane group was higher than that in the control group （P〈0.05）.No difference of Tau mRNA expression between neonatal and adult periods was shown （P〉0.05）.Conclusion The repeated 2.6% sevoflurane inhalation in the neonatal period could increase the expression of Tau mRNA in the hippocampus of juvenile rats with no behavior changes in juvenile and adult periods.