针刺对肥胖大鼠下丘脑穹隆周核的作用

Effects of Electroacupuncture on Electrical Activity of Neurons of Hypothalamic Perifornical Nucleus and on Hypothalamic and Plasma Leptin and Insulin Levels in Obesity Rats

目的 :探讨针刺对肥胖机体下丘脑穹隆周核神经功能的作用机制。方法 :将实验大鼠随机分为正常组、对照组和针刺组 ,应用放免、神经细胞微电极和脑立体定位技术 ,观察针刺对肥胖大鼠体重、Lee’s指数、体脂、中枢和外周瘦素 (LP)和胰岛素 (INS)水平以及下丘脑穹隆周核 (PeF)神经细胞自发放电频率的影响。结果 :肥胖大鼠体重、Lee’s指数、体脂、血清中LP和INS水平以及PeF神经细胞自发放电频率均显著高于正常大鼠水平 ,而下丘脑LP和INS水平均显著低于正常大鼠水平 ;PeF神经细胞自发放电与肥胖指标、血清LP和INS水平均呈正相关 ,而与下丘脑LP和INS水平呈负相关。针刺治疗在取得良好减肥疗效的同时 ,肥胖大鼠血清LP和INS以及PeF神经细胞自发放电水平均显著回降 ,而下丘脑LP和INS水平却显著回升。结论 :肥胖机体LP和INS血脑转运异常以及PeF神经功能亢奋可能是产生肥胖的重要原因。针刺对肥胖机体中枢和外周LP和INS水平以及PeF神经功能的良性调整可能是针刺减肥的作用机制之一。

Objective:To explore the effect of electroacupuncture (EA) on the nervous function of hypothalamic perifornical nucleus (PeF) in obesity rats.Methods: Thirty-six SD male rats were randomly and evenly divided into normal control group, model group and acupuncture group. Changes of body weight, Lee’s index, body fat, hypothalamic and serum leptin (LP) and insulin (INS) contents as well as spontaneous discharges of neurons in hypothalamic PeF were observed in obesity rats. EA (10 Hz, 1.5 V and continuous waves) was applied to “Zusanli”(ST 36) and “Neiting”(ST 44) for 10 min, once daily and continuously for 14 days. Hypothalamic tissue and serum LP and INS contents were assayed with radioimmunoassay. Electrical activity of PeF neurons were recorded by using micro-electrodes. Results: The body weight, Lee’s index, body fat, the levels of serum LP and INS as well as the discharge rate of PeF neurons in obesity rats were all markedly higher than those in normal rats, while the levels of hypothalamic LP and INS in obesity rats were strikingly lower than those in normal rats (P<0.05～0.01). Compared with model group, the body weight, Lee’s index, body fat, serum LP and INS as well as the discharge rate in acupuncture group all lowered significantly (P< 0.05～0.01); while hypothalamic LP and INS increased remarkably (P<0.01). There were positive interrelations between the spontaneous discharge rate of PeF neurons and the obesity index, between the discharge rate and the serum LP and INS levels (P<0.05～0.01). There were negative interrelations between the spontaneous discharge rate of PeF neurons and the levels of hypothalamic LP and INS. It indicated that acupuncture treatment could induce weight loss, lower serum LP and INS as well as the spontaneous discharges of PeF neurons, and raise hypothalamic LP and INS contents markedly. Conclusion: Acupuncture treatment induced decrease of peripheral LP and INS levels and reduction of the activity of PeF neurons and increase of central LP and INS contents may be responsible for the effect of acupuncture in antiobesity.