Objective To explore the effects of acupuncture on pruritic behaviors, expression of 5-HT neurons in medulla oblongata and 5-HTR2B on mice with chloroquine-induced pruritus; To discuss the mechanism of action of acupuncture in chloroquine-induced pruritus. Methods A non-histamine-dependent pruritus model was prepared by subcutaneous injection of chloroquine into the back of the neck. Forty C57B/6J mice were randomly divided into model-acupuncture group, model-non-acupuncture group, normal saline group and blank control group, with 10 mice in each group. After modeling, acupuncture was given in Xuehai, Quchi and Hegu on both sides. The plug and twist way was used to stimulate, once a day, three times. Model-non-acupuncture group received no acupuncture. Normal saline group received the neck injection of saline in the back. Blank control group received no treatment. Behavioral changes were observed, and immunofluorescence technique and Western blot were used to test the expression of 5-HT neurons and 5-HTR2B in medulla oblongata neurons. Results The number of scratches in model-acupuncture group and model-non-acupuncture group was obviously more than normal saline group and blank control group (P<0.05). The number of scratches in model-acupuncture group was lower than that of model-non-acupuncture group (P<0.05). The expression of 5-HT in medulla oblongata neurons was unclear in both normal saline group and blank control group. The expression of 5-HT neurons in medulla oblongata significantly increased in model group, which decreased after acupuncture. The expression of 5-HTR2B of model group was significant higher than normal saline group and blank control group (P<0.01). Compared with model-non-acupuncture group, the expression of 5-HTR2B in model-acupuncture group significant decreased (P<0.01). Conclusion Acupuncture can significantly inhibitscratching behaviors in mice induced by chloroquine, and the mechanism may be realized by decreasing the expression of 5-HT neurons and 5-HTR2B in medulla oblongata neurons.%目的 观察针刺对非组胺依赖性瘙痒模型小鼠瘙痒行为、延髓5-羟色胺(5-HT)能神经元及5-HT受体2B(5-HTR2B)表达的影响,探讨针刺在对瘙痒调控过程中的作用机制.方法 采用颈背部皮下注射氯喹方法制作非组胺依赖性瘙痒模型.40只C57B/6J小鼠随机分为造模组(针刺组、非针刺组)、生理盐水组和空白对照组,每组10只.成模后,针刺组针刺双侧"血海""曲池"及"合谷",采用提插和捻转手法刺激,每日1次,共3次,非针刺组不予针刺,生理盐水组予颈背部注射生理盐水后不做处理,空白对照组不做处理.分别观察各组小鼠行为学变化,免疫荧光和Western blot检测延髓5-HT能神经元及5-HTR2B的表达.结果 造模组小鼠搔抓次数明显高于生理盐水组和空白对照组(P<0.05),针刺组搔抓次数少于非针刺组(P<0.05),5-HT能神经元在空白对照组和生理盐水组表达均不明显,造模组小鼠5-HT能神经元表达明显增加,针刺后5-HT能神经元表达减少,针刺组和非针刺组延髓5-HTR2B表达明显高于生理盐水组和空白对照组(P<0.01),针刺组5-HTR2B表达低于非针刺组(P<0.01).结论 针刺对瘙痒模型小鼠搔抓行为具有抑制作用,其机制可能是通过下调延髓5-HT能神经元及5-HTR2B的表达发挥作用.
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