ABSTRACT
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.