七氟醚麻醉对大鼠中枢神经系统金属硫蛋白mRNA表达的影响

Effects of sevoflurane anesthesia on the metallothionein mRNA expression in central nervous system of neonatal rats

目的探讨七氟醚麻醉对新生大鼠神经系统内金属硫蛋白（MT）mRNA表达水平的影响。方法新生大鼠36只随机均分为三组，七氟醚组：新生大鼠依次吸入8％、5％、3％七氟醚3min、1min、4h，70％氧气作为载气；氧气组：大鼠吸入70％氧气4h；对照组：大鼠不给予任何处理。分别于吸入2h（T1）、4h（T2）和停止吸入后2h（T3）处死大鼠，每个时点处死4只。剖取前额叶皮层（PFC）和海马组织，应用Real-timePCR测定MTⅠ、MTⅡ、MTⅢmRNA的表达水平。结果T1～T3时七氟醚组大鼠前额叶皮层中MTⅠ、MTⅡmRNA的相对表达量明显高于对照组和氧气组（P〈0．05）。七氟醚组MTⅡmRNA的相对表达量不同时点间比较T3〉T2〉T-（P〈0．05）。三组间MT Ⅲ mRNA的相对表达量差异无统计学意义。T1～T3时七氟醚组大鼠海马组织内MTⅡ mRNA的相对表达量明显高于对照组和氧气组，且不同时点间比较T3〉T2〉T1（P〈0．05）。三组间MTⅠ、MTⅢ mRNA的相对表达量差异无统计学意义。结论七氟醚麻醉可较长期上调新生大鼠前额叶皮层MTⅠ和MTⅡmRNA的表达，以及海马组织中MTⅡmRNA的表达，该作用可能是抵抗七氟醚损害发育期中枢神经功能的机制。

Objective To investigate the effects of sevoflurane anesthesia in metallothionein （MT） mRNA expression in central nervous system of neonatal rats. Methods Thirty six neonatal （P8） rats were randomly divided into three groups. In thesevoflurane treatment group, twelve rats were exposed to 8%, 5%, 3% sevoflurane for 3 rain,1 min and 4 h separately with 70% oxygen as a carrier. In the oxygen treatment group, twelve rats were exposed to 70% oxygen for 4 h. There is no treatment was given to the twelve rats in the control group. Rats were sacrificed at 2 h（T1 ）, 4 h（T2 ） during anesthesia and 2 h after anesthesia （T2） separately in sevoflurane treatment group （n = 4）. Prefrontal cortex （PFC） and hippocampus were removed for determination of MT Ⅰ , MT Ⅱ, MTⅢ mRNA expression by Real-time PCR. The oxygen treatment group and control group were given the same treatment at the same time points. Results In PFC, the expression of MT Ⅰ and MT Ⅱ mRNA in sevoflurane treatment group was up-regulated at T1, T2, T3 compared with oxygen treatment group and control group（P〈0.05）. The results of comparison between different time points in MT Ⅱ mRNA expression was T3 〉T2〉T1 （P〈0. 05）. No significant difference was found in MTⅢ mRNA expression between three groups. In hippocampus, the expression of MT Ⅱ mRNA in sevoflurane treatment group was up-regulated at T1, T2, T3 compared with oxygen treatment group and control group. The results of comparison between different time points in MT Ⅱ mRNA expression was T3 T2〉T1 （P〈0.05）. No significant difference was found in MT Ⅰ and MTUI mRNA expression between three groups. Conclusion Sevoflurane anesthesia can up-regulate MT Ⅰ and MT Ⅱ mRNA expression in PFC, and MT Ⅱ mRNA expression in hippocampus for a long time, which may result in the protection effect during the development of central nervous systerm.