电针对焦虑大鼠胸腺组织形态、心钠肽和利钠肽受体-A表达的影响

Effect of Acupuncture on Histology of Thymus and Expressions of ANP and NPR-A in Anxiety Rats

目的通过观察电针对焦虑模型大鼠胸腺组织形态、胸腺心钠肽(atrial natriuretic peptide,ANP)和利钠肽受体-A(natriuretic peptide receptor type A,NPR-A)表达的影响,探讨针刺调节焦虑障碍免疫功能的可能机制。方法将34只健康SD大鼠随机分为空白组(10只)、模型组(12只)和电针组(12只)。模型组和电针组大鼠均采用慢性不可预见性应激刺激方法复制焦虑模型。电针组运用电针刺激内关和神门穴,隔日1次,每次留针15 min,持续15日。其余两组在同一时间以相同方法固定15 min,未予电针治疗。运用高架十字迷宫实验测试大鼠焦虑行为;光学显微镜观察胸腺组织病理改变;免疫组化法观察胸腺ANP、NPR-A的表达。结果模型组大鼠胸腺组织形态发生重度萎缩,胸腺小叶结构不清,胸腺皮髓界限不清,淋巴细胞排列疏松,胸腺小体体积明显增大。电针组大鼠胸腺轻度萎缩,胸腺小叶结构存在,皮髓分界清楚,皮质区淋巴细胞稠密,髓质区增宽。与空白组比较,模型组大鼠在开臂的次数(open-arms entries,OE)占进入开闭臂总次数的百分比(OE%)明显下降(P<0.05),ANP表达升高(P<0.05),NPR-A表达降低(P<0.01);与模型组比较,电针组OE%值明显升高(P<0.05),ANP表达降低(P<0.05),NPR-A表达升高(P<0.01)。结论电针除具有降低大鼠焦虑情绪的作用外,还可通过干预胸腺ANP的合成和分泌及其特异性受体NPR-A的表达,改善由于慢性应激所致的胸腺受损。

Objective To explore possible mechanism of electroacupuncture（EA） for regulating immune function in anxiety disorder（AD） rats by observing the effect of acupuncture on the histology of thymus and expressions of atrial natriuretic peptide（ANP） and natriuretic peptide receptor type A（NPRA） in thymus.Methods Totally 34 SD healthy rats were randomly divided into the blank control group（n=10）,the model group（n=12）,the EA group（n=12）.Anxiety model was established in rats of the model group and the EA group by using chronic unpredictable stress（CUS） stimulation.EA（15/25 Hz）at Neiguan（PC6） and Shenmen（HT7） was performed in the EA group,with 15-min needle retaining,once every other day,15 days in total.Needle was fixed at same acupoints for 15 min without electric stimulus in the other two groups.Anxiety-like behavior was measured by elevated plus-maze（EPM） test.Pathological changes of thymus tissue were observed by optical microscope.Expressions of ANP and NPR-A in thymus were measured by immunohistochemical assay.Results The thymus tissue in the model group was severely atrophied,with unclear structure of thymic lobules,unclear margin of thymic medulla,loosely arranged lymphocytes,and obviously enlarged volume of thymic corpuscle.The thymus tissue in the EA group was mildly atrophied,with existent structure of thymic lobules,clear margin of thymic medulla,densely arranged lymphocytes in cortical region,and widened medullary area.Compared with the blank control group,the percentage of open-arms entries（OE%） in the total OE times obviously decreased in the model group（P 〈0.05）,ANP expression obviously increased（P 〈0.05）,and NPR-A expression obviously decreased（P 〈0.01）.Compared with the model group,OE%was obviously elevated（P 〈0.05）,ANP expression obviously decreased（P 〈0.05）,and NPR-A expression obviously increased（P〈0.01） in the EA group.Conclusion EA not only could reduce anxiety of rats,but also could improve chronic stress induced thymus injury through intervening synthesis and secretion of ANP,as well as the expression of NPR-A（a specific receptor of ANP）.