电针对不同时程焦虑样行为大鼠海马神经元型一氧化氮合酶的影响

Effects of Electroacupuncture on Hippocampal nNOS Expression in Rats with Anxiety-like Behavior

目的:探讨电针对不同时程——应激中和应激后焦虑样行为大鼠海马神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)的影响。方法:SD大鼠随机分为正常1组和正常2组、应激1组和应激2组、电针预处理组和电针后处理组,采用足底电击结合孤养的方法制备焦虑样模型。电针预处理组造模同时电针"百会"和"印堂"穴,电针后处理组造模后电针"百会""印堂"穴,每次均刺激20min,每日1次,连续治疗7d。采用高架十字迷宫实验(EPM评分)评价焦虑样行为,逆转录聚合酶链反应(RT-PCR)和免疫组化方法分别检测各组大鼠海马CA 1、CA 3区nNOS mRNA和蛋白的表达。结果:大鼠足底电击7d后开臂/(开臂+闭臂)的时间百分比和次数百分比较正常组显著降低(P<0.01,P<0.05),不同时间电针干预均能够使其显著升高(P<0.05);应激1组和应激2组大鼠海马nNOS mRNA表达高于正常组,电针处理均能降低其表达(P<0.05);应激1组和2组大鼠海马CA 1区nNOS平均吸光度值显著降低,而CA 3区显著升高(P<0.01),电针处理可以使其逆转(P<0.01)。结论:电针预处理和后处理对不同时程——应激中和应激后焦虑样行为大鼠均具有明显抗焦虑作用,可能与其对海马内nNOS的表达调节相关。

Objective To compare the effects of electroacupuncture（EA）preconditioning and post-conditioning on hippocampal neuronal nitric oxide synthase（nNOS）expression in rats with anxiety-like behavior,so as to explore the reasonable EA intervention time.Methods Forty-two SD rats were randomly divided into 6 groups：normal 1,normal 2,anxiety model 1,anxiety model 2,EA-pre-conditioning and EA-post-conditioning.The anxiety model was established by giving the rats with repeated foot shock stimulation（0.8mA,2-25s/time,10 times in 5min）combined with isolation-raising.Before or after modeling,EA stimulation was applied to＂Baihui＂（GV 20）and ＂Yintang＂（GV 29）for 20 min,once a day for 7 days.Elevated plus maze（EPM）tests were performed to determine the percentages of time spent in the open arms and the percentages of entries into the open arms in 5min for evaluating the animals＇ anxiety-like behavioral activities.The reverse transcriptase polymerase chain reaction（RT-PCR）was used to detect hippocampal nNOS mRNA expression and the immunohistochemical staining adopted to detect the expression of nNOS protein in the hippocampal CA 1and CA 3areas,respectively.Results Compared with their own normal control group 1 and 2,both the percentage of time spent in the open arms and the percentage of entries into the open arms were significantly decreased in model group 1 and 2（P〈0.05,P〈0.01）.After pre-and post-conditioning of EA,the decreased proportions of time spent and entries into the open arms were considerably increased（P〈0.05）,suggesting an improvement of anxiety-like behavior activities after EA intervention.The expression levels of hippocampal nNOS mRNA and nNOS protein in the hippocampal CA 3region were significantly higher in the model group 1 and 2 than in their own normal control group 1 and 2（P〈0.01）,but those of nNOS protein in the CA 1 area were markedly lower in the model group 1and 2than in their own normal control group 1 and 2（P〈0.01）.Following pre-and post-conditioning of EA,the increased expression levels of nNOS mRNA and protein of CA 3 area and the decreased level of nNOS protein of CA 1 area were all notably reversed（P〈0.05,P〈0.01）.Conclusion Both pre-and post-conditioning of EA can improve anxiety-like behavior in anxiety rats,which may be associated with its effects in down-regulating hippocampal nNOS expression.