小鼠磨牙区咀嚼刺激的改变对焦虑情绪的影响

Chewing Stimulation Alteration of Molars Increases Anxiety in Mice

目的:建立小鼠磨牙区咀嚼刺激改变的实验模型,并观察小鼠在短期及长期内焦虑情绪的改变以及小鼠皮层和海马区单胺类神经递质的改变。方法:将2月龄C57BL/6雄性小鼠随机分成3组:对照组、磨牙磨除组(磨牙咀嚼刺激减少组)和磨牙拔除组(磨牙咀嚼刺激消除组),分别于处理后1周及2个月时进行旷场实验和高架十字迷宫实验,实验结束后处死小鼠,通过液相色谱-串联质谱法检测小鼠皮层和海马区单胺类神经递质的改变。结果:磨牙磨除组和磨牙拔除组小鼠在处理后1周及2个月内的自发活动能力都没有改变,并且1周内咀嚼刺激的改变不会对焦虑情绪产生影响,而2个月后咀嚼刺激的改变会增加小鼠的焦虑情绪。磨牙磨除组和磨牙拔除组小鼠海马区的多巴胺、肾上腺素和去甲肾上腺素的水平显著高于对照组,磨牙拔除组小鼠海马区的5-羟色胺水平显著高于对照组。结论:小鼠磨牙区长期咀嚼刺激的改变会增加小鼠的焦虑情绪并且会增加小鼠海马区单胺类神经递质的水平。

Objective： To investigate the influence of chewing stimulation alteration of molars on anxiety in mice. Methods： 2-month-old C57BL/6 male mice were divided into three groups, which included the control group, molarless group and tooth extraction group. The anxiety-related behaviors were detected by the open field and elevated plus maze experiments one week and two months after treatment. After that, monoamine neurotransmitters in the cortex and hippocampus were detected using liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Results： The locomotor activity levels were not changed either in one week or in two months after chewing stimulation alteration in three groups. There was no significant difference in anxiety-related behaviors among the control group, molarless group, and tooth extraction group one week after the treatment. Two months after treatment more anxiety-related behaviors were observed in the molarless group and tooth extraction group. The results of LC-MS/MS showed that the molarless group and tooth extraction group exhibited higher dopamine （DA）, epinephrine （E） and norepinephrine （NE） in the hippocampus compared to the control group. And the tooth extraction group exhibited higher 5-hydroxytryptamine （5-HT） in the hippocampus compared to the control group. Conclusion： Two months after chewing stimulation alteration of molars in mice, more anxiety-related behaviors were observed and monoamine neurotransmitters in the hippocampus were increased in the molarless group and tooth extraction group.