Effect of Acupuncture Stimulation of Different Acupoint Combinations on Sleep and Expression of Circadian Clock and Bmal 1 Genes in Hypothalamus of Insomnia Rats / 针刺研究

ABSTRACT

OBJECTIVE: To observe the effect of manual acupuncture stimulation (MAS) of "Baihui"(GV 20)-"Shenmen"(HT 7)or GV 20-"Sanyinjiao"(SP 6) on sleep and expression of circadian rhythm genes (Clock and Bmal 1) in the hypothalamus in insomnia rats, so as to select a better acupoint group for insomnia. METHODS: A total of 53 SD rats were randomly divided into normal control (n=12),insomnia model (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 p-chlorophenylalanine (PCPA,500 mg/kg,100 mg/mL) once daily for 2 days. The MAS (uniform reinforcing-reducing needling) was applied to GV 20-HT 7, GV 20-SP 6 or GV 20-non-acupoint for 30 min,once daily for 7 days. The sleep onset latency and sleep duration were gauged after intraperitoneal injection of pentobarbital sodium (35 mg/kg). The expression levels of Clock mRNA and Bmal 1 mRNA in the hypothalamic tissues containing ventrolateral preoptic area (VLPO) and suprachiasmatic nucleus (SCN) region were detected by fluorescence quantitative real-time PCR. RESULTS: Following administration of pentobarbital sodium,the sleep latency was significantly prolonged and the sleep duration was considerably shortened in rats of the model group(P<0.05). After the treatment, the increased sleep latencies in the GV 20-HT 7, GV 20-SP 6 and GV 20-non-acupoints were all significantly down-regulated (P<0.05), and the decreased sleep duration was significantly increased only in the GV 20-HT 7 group relevant to the model group (P<0.05), but not in the GV 20-SP 6 and GV 20-non-acupoint groups (P<0.05). There were no significant differences in the sleep latency among the 3 treatment groups (P<0.05). The sleep duration was obviously prolonged in the GV 20-HT 7 group than in the GV 20-SP 6 and GV 20-non-acupoint groups (P<0.05). After modeling, the expression levels of Clock mRNA and Bmal 1 mRNA in hypothalamic VLPO and SCN regions were significantly down-regulated relevant to the normal control group (P<0.01). Following the treatment, the expression levels of Clock mRNA in the VLPO and SCN regions of the GV 20-SP 6 and GV 20-HT 7 groups, and those of Bmal 1 mRNA in the VLPO and SCN regions of the 3 treatment groups were considerably increased relevant to the model group (P<0.05, P<0.01). The effects of GV 20-HT 7 were significantly superior to those of GV 20-SP 6 and GV 20-non-acupoint (and also the action of GV 20-SP 6 was evidently superior to that of GV 20-non-acupoint) in up-regulating the expression of Clock mRNA and Bmal 1 mRNA in both VLPO and SCN regions (P<0.05, P<0.01). CONCLUSIONS: Manual acupuncture stimulation of GV 20-HT 7 can improve the sleep latency and duration in insomnia rats,which may be associated with its effects in up-regulating the expression levels of circadian Clock mRNA and Bmal 1 mRNA in hypothalamic VLPO and SCN regions, and the efficacy of GV 20-HT 7 is obviously better than that of GV 20-SP 6 and GV 20-non-acupoint.