乙酸致内脏痛模型小鼠杏仁中央核c-fos表达和动物焦虑样行为的影响

摘要

目的 探讨乙酸所致内脏痛小鼠杏仁中央核(CeA)c-fos的表达时程变化及其与小鼠焦虑样行为的关系.方法 将雄性昆明小鼠随机分为生理盐水组、乙酸致内脏痛1 h组、乙酸致内脏痛2 h组以及乙酸致内脏痛24 h组,观察各组动物1 h内腹壁收缩次数,采用旷场实验对生理盐水组、乙酸致内脏痛2 h组及乙酸致内脏痛24 h组动物焦虑样行为进行检测,行为学检测结束后,采用免疫组织化学法分别检测此3组动物杏仁中央核c-fos的表达变化.结果 内脏痛评分表明,与生理盐水组比较,乙酸致内脏痛1 h组动物腹壁收缩次数明显增加(P＜0.001),而乙酸致内脏痛2 h组及乙酸致内脏痛24 h组动物腹壁收缩次数无明显变化(P＞0.05);旷场实验结果表明,与生理盐水组比较,乙酸致内脏痛2 h组和乙酸致内脏痛24 h组中央格停留时间及穿越中央格子数均明显减少(P＜0.001),而三组动物活动度间差异无统计学意义(P＞0.05).免疫组化结果表明,与生理盐水组比较,乙酸致内脏痛2 h组及乙酸致内脏痛24 h组动物杏仁中央核c-fos表达增加(P＜0.05).结论 乙酸致内脏痛小鼠焦虑情绪持续的时间远远长于疼痛本身,其机制可能与杏仁中央核神经元过度活化有关.%Objective To explore the expression of c-fos in the central nucleus of amygdala (CeA) and its relationship with acetic acid-elicited visceral pain (AAVP)related anxiety behavior in mice.Methods Male Kunming mice were randomly divided into normal saline (NS)group and one hour after acetic acid-elicited visceral pain (AA-1h)group,two hours after acetic acid-elicited visceral pain (AA-2 h)group and twenty-four hours after acetic acid-elicited visceral pain (AA-24 h)group,visceral pain behaviours of all animals were measured by Writhing test while the anxiety-like behavior of NS group and AA-2 h group and AA-24 h group animals were determined by open field test (OFT).After the behavior test,the three group animals were scarified for the determination of c-fos in the CeA by immunohistochemistry.Results Compared to NS group, AA-1h group animals showed significantly increased number of writhes(P＜0.001),while no statistics difference between NS group and AA-2 h or AA-24 h group(P＞0.05,respectively).In the OFT,AA-2 h or AA-24 h group showed significantly decreased time and number of crossing in the center compared with the NS group(P＜0.001,respectively),while no difference in the locomotive activity was found among the three groups(P＞0.05,respectively).The results of immunohistochemistry showed that compared to NS group,AA-2 h or AA-24 h group showed significantly increased number of c-fos positive cell in the CeA(NS vs AA-2 h,P＜0.001,NS vs AA-24 h,P＜0.05).Conclusion AA treatment leads to anxiety-like behavior in the mice even after the visceral pain disappeared,which might be due to the over-activated neuron in the CeA.