RESUMO
OBJECTIVE: To investiage the effect of electroacupuncture (EA) at a single acupoint of Shenmen (HT7), Baihui (GV20), Sanyinjiao (SP6) and at combined acupoints of Shenmen (HT7) and Baihui (GV20) and Sanyinjiao (SP6) on the PKA/CREB and BDNF/TrkB signaling, as well as neuroapoptosis and neurogenesis in hippocampus and elucidate the underlying mechanism of single and combined acupoints on ameliorating spatial learning and memory deficits in a rat model of primary insomnia. METHODS: Primary insomnia was modeled by intraperitoneal injection of para-chlorophenylalanine (PCPA) once daily for 2 d. EA was applied at Shenmen (HT7), Baihui (GV20), Sanyinjiao (SP6), or Shenmen (HT7) + Baihui (GV20) + Sanyinjiao (SP6) (combined) for 30 min daily for 4 d. Spatial learning and memory function was evaluated by the Morris water maze (MWM) test. Protein expressions of hippocampal cAMP-dependent protein kinase (PKA)-Cß, phosphorylated cAMP-responsive element-binding protein (p-CREB), brain-derived neurotrophic factor (BDNF), and tyrosine kinase receptor B (TrkB) were evaluated by Western blotting. Neuronal apoptosis in the hippocampus was detected with the transferase-mediated dUTP-X nick end labeling assay. Endogenous neurogenesis was examined with bromodeoxyuridine staining. The MWM test and hippocampal p-CREB, BDNF, and TrkB protein levels in the combined acupoints group were evaluated after the administration of a PKA-selective inhibitor (H89). RESULTS: Spatial learning and memory were significantly impaired in rats with insomnia. The spatial learning deficits were ameliorated in the Shenmen (HT7), Baihui (GV20), Sanyinjiao (SP6), and combined groups; this improvement was significantly greater in the combined group than the single acupoint groups. The spatial memory impairment was improved in the combined, Baihui (GV20), and Shenmen (HT7) groups, but not the Sanyinjiao (SP6) group. The expressions of PKA-Cß, p-CREB, BDNF, and TrkB were decreased in rats with insomnia. All these proteins were significantly upregulated in the combined group. PKA/p-CREB protein levels were elevated in the Baihui (GV20) and Shenmen (HT7) groups, whereas BDNF/TrkB expression was upregulated in the Sanyinjiao (SP6) group. The staining results showed significant attenuation of hippocampal cell apoptosis and increased numbers of proliferating cells in the combined group, whereas the single acupoint groups only showed decreased numbers of apoptotic cells. In the combined group, the PKA inhibitor reversed the improvement of spatial memory and upregulation of p-CREB expression caused by EA, but did not affect its activation of BDNF/TrkB signaling. CONCLUSIONS: EA at the single acupoints Baihui (GV20), Shenmen (HT7), or Sanyinjiao (SP6) had an ameliorating effect on the spatial learning and memory deficits induced by insomnia. EA at combined acupoints exerted a synergistic effect on the improvements in spatial learning and memory impairment in rats with insomnia by upregulating the hippocampal PKA/CREB and BDNF/TrkB signaling, facilitating neurogenesis, and inhibiting neuronal apoptosis. These findings indicate that EA at combined acupoints [(Baihui (GV20), Shenmen (HT7), and Sanyinjiao (SP6)] achieves a more pronounced regulation of hippocampal neuroplasticity than EA at single acupoints, which may partly explain the underlying mechanisms by which EA at combined acupoints exerts a better ameliorative effect on the cognitive dysfunction caused by insomnia.
Assuntos
Eletroacupuntura , Distúrbios do Início e da Manutenção do Sono , Ratos , Animais , Ratos Sprague-Dawley , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Pontos de Acupuntura , Fenclonina/metabolismo , Aprendizagem Espacial , Hipocampo/metabolismoRESUMO
<p><b>OBJECTIVE</b>To observe the impacts of electroacupuncture (EA) on microgliacytes and astrocytes of cervical spinal cord in rats with thyroid incisional pain and explore the mechanism of acupuncture anesthesia in thyroid surgery.</p><p><b>METHODS</b>Sixty Wistar male rats were randomized into a normal group, a model group, a Futu (LI 18) group, a Hegu (LI 4)-Neiguan (PC 6) group and a Zusanli (ST 36)-Yanglingquan (GB 34) group, 12 rats in each one. Except the normal group, a longitudinal incision, about 1.5 cm in length was done along the neck midline in the rats of the rest groups to prepare the model of thyroid incisional pain. In the Futu (LI 18) group, the Hegu (LI 4)-Neiguan (PC 6) group and the Zusanli (ST 36)-Yanglingquan (GB 34) group, after modeling for 4 h, 24 h and 48 h, EA was applied to bilateral "Futu" (LI 18), "Hegu" (LI 4) "Neiguan" (PC 6) and"Zusanli" (ST 36) "Yanglingquan" (GB 34) separately, once a day, continuously for 3 days. In the normal group and the model group, no any intervention was applied. The thermal radiant apparatus was used to detect the thermal pain threshold (PT). The fluorescence quantitative RT-PCR and the Western blotting (WB) were used to determine the expressions of protein and gene of microglia activation markers Iba1 and CD11b and the astrocyte specific protein marker, glial fibrillary acid protein (GFAP) in cervical spinal cord (Cto C) after intervention in the rats of each group.</p><p><b>RESULTS</b>After intervention, as compared with the normal group, in the model group, the neck PT was reduced apparently (<0.05), the expressions of Iba1 and CD11b and GFAP mRNA as well as the protein expressions in the spinal cord of Cto Cwere up-regulated apparently (<0.05,<0.01). As compared with the model group, in the Futu (LI 18) and the Hegu (LI 4)-Neiguan (PC 6) group, PT was increased significantly (both<0.05) and that did not change apparently in the Zusanli (ST 36)-Yanglingquan (GB 34) group (>0.05). In the Futu (LI 18) group, the protein and gene expressions of Iba1, CD11b and GFAP were lower than those in the model group (all<0.05). In the Hegu (LI 4)-Neiguan (PC 6) group, the expressions of Iba1 mRNA, CD11b protein, GFAP mRNA and protein were all lower apparently than those in the model group (all<0.05). In the Zusanli (ST 36)-Yanglingquan (GB 34) group, the expressions of Iba1, CD11b and GFAP proteins were not different significantly as compared with the model group (all>0.05). In the Zusanli (ST 36)-Yanglingquan (GB 34) group, the expressions of Iba1 mRNA and CD11b mRNA and protein expressions in the spinal cord of Cto Cwere higher apparently than those in the Futu (LI 18) group (<0.01,<0.05); the expressions of Iba1 mRNA and CD11b protein expressions were higher than those in the Hegu (LI 4)-Neiguan (PC 6) group (all<0.05); GFAP mRNA and protein expressions were higher apparently than those in the Futu (LI 18) group and the Hegu (LI 4)-Neiguan (PC 6) group (all<0.05).</p><p><b>CONCLUSIONS</b>EA at "Futu" (LI 18) or "Hegu" (LI 4), "Neiguan" (PC 6) relieves the acute neck incisional pain in the rats and its effect may be closely relevant with the down-regulation of the activities of microgliacytes and astrocytes in the spinal cords.</p>