Manual Acupuncture Stimulation of Paired Acupoints Can Relieve Sleep Disorder Possibly by Upregulating Pineal Melatonin Protein and Its Receptor mRNA Levels in the Suprachiasmatic Nucleus in Insomnia Rats

Abstract

To observe the effect of manual acupuncture stimulation of paired "Baihui" (GV 20)+ "Shenmen" (HT 7), GV 20+ "Sanyinjiao" (SP 6), and GV 20+ non-acupoint on expression of melatonine (MT) and suprachiasmatic melatonin receptor 1 (MT1) and melatonin receptor 2 (MT2) mRNAs in insomnia rats, so as to explore their action difference and the underlying mechanism in improving insomnia. Male SD rats were randomly divided into normal control (n=12), mo-del (n=8), GV 20+HT 7(n=12), GV 20+SP 6(n=11), and GV 20+ non-acupoint (n=10) groups. The insomnia model was established by intraperitoneal injection of Para-chlorophenylalanine suspension (50 mg/mL, 50 mg/100 g), once daily for 2 days. The abovementioned acupoints GV 20, bilateral HT 7, SP 6 and non-acupoints (the midpoint between the elbow-tip and armpit on the medial side of the upper-arm) were punctured with filiform needles and manipulated by rotating the needle for about 1 min which was repeated once again every 10 min during 30 minutes' needle-retaining. The treatment was conducted once daily for 7 days. The expression levels of MT immunoactivity in the conarium tissue, and MT1 and MT2 mRNAs of the suprachiasmatic nucleus (SCN) region were detected using immunohistochemistry and fluorescence quantitative real time-PCR, respectively. After modeling, the expression levels of pineal MT (an increase of gray value means a decrease of immunoactivity), SCN MT1 and MT2 mRNAs were notably down-regulated in the model group relevant to the normal control group (P<0.05, P<0.01). Following the treatment, the down-regulated expression levels of MT protein, and MT1 and MT2 mRNAs were obviously reversed in the GV 20 + HT 7, GV 20 + SP 6 groups relevant to the model group (P<0.05, P<0.01). The therapeutic effect of GV 20+ HT 7 was superior to that of GV 20+ non-acupoint in up-regulating the expression of MT1 mRNA (P<0.01), and markedly superior to that of GV 20+ SP 6 and GV 20+ non-acupoint in increasing the sleep duration and in up-regulating the expression of MT2 mRNA (P<0.01). No significant differences were found among the 3 treatment groups in up-regulating the expression of MT (P>0.05). Manual acupuncture stimulation of GV 20+ HT 7 and GV 20+ SP 6 can improve the sleep disorder in insomnia rats, which may be related to its effects in increasing the levels of pineal MT protein, and MT1 and MT2 mRNAs in hypothalamic SCN.