Effect of electroacupuncture at "Neiguan" (PC6) on pain and brain orexin 1 receptor in mice with inflammatory pain. / 电针"å† å ³"å¯¹ç‚Žæ€§ç—›å°é¼ è„‘å† é£Ÿæ¬²ç´ 1受体的影响.

OBJECTIVES: To observe the effect of electroacupuncture (EA) at "Neiguan" (PC6) on pain response in mice injected with complete Freund's adjuvant (CFA) in the hind paw, so as to investigate the mechanism of orexin 1 receptor (OX1R) -endogenous cannabinoid 1 receptor (CB1R) pathway in acupuncture analgesia. METHODS: A total of 48 male C57BL/6 mice were used in the present study. In the first part of this study, 18 mice were randomized into control, model and EA groups, with 6 mice in each group. In the second part of this study, 30 mice were randomized into control, model, EA, EA+Naloxone, EA+OX1R antagonist (SB33486) groups, with 6 mice in each group. Inflammatory pain model was established by subcutaneous injection of 20 µL CFA solution in the left hind paw. EA (2 Hz, 2 mA ) was applied to bilateral PC6 for 20 min, once a day for 5 consecutive days. The mice in the EA+Naloxone and EA+SB33486 groups were intraperitoneally injected with naloxone (10 mg/kg) or SB33486 (15 mg/kg) 15 min before EA intervention on day 5, respectively. Tail-flick method and Von Frey method were used to detect the thermal pain threshold and mechanical pain threshold of mice. Quantitative real-time PCR was used to detect the expression level of ß-endorphin mRNA in periaqueductal gray (PAG) of mice. The expression of OX1R positive cells in the lateral hypothalamic area (LH) and CB1R positive cells in the ventrolateral periaqueductal gray (vlPAG) were detected by immunofluorescence. RESULTS: Compared with the control group, the thermal pain threshold and mechanical pain threshold of the model group were decreased (P<0.001), the expression level of ß-endorphin mRNA in PAG was decreased (P<0.001), and the numbers of OX1R positive cells in LH and CB1R positive cells in vlPAG were decreased (P<0.05, P<0.001). Compared with the model group, the thermal pain threshold and mechanical pain threshold of the EA group were significantly increased (P<0.001), and the numbers of OX1R positive cells in LH and CB1R positive cells in vlPAG were increased (P<0.01, P<0.001). Compared with the EA group, the mechanical pain threshold in the EA+SB33486 group was significantly decreased (P<0.01), but there was no significant difference in the mechanical pain threshold between the EA+Naloxone group and EA group, and the numbers of OX1R positive neurons in LH and CB1R positive neurons in vlPAG were decreased in the EA+SB33486 group (P<0.001). CONCLUSIONS: EA at PC6 can achieve analgesic effect on CFA mice by activating the OX1R-CB1R pathway in the brain, and this effect is opioid-independent.

Effect of electroacupuncture on inflammatory response and immune cells in mice with chronic inflammatory pain. / ç”µé’ˆå¯¹æ ¢æ€§ç‚Žæ€§ç—›å°é¼ ç‚Žæ€§ååº”å’Œå ç–«ç»†èƒžçš„å½±å“.

OBJECTIVES: To observe the effects of electroacupuncture(EA) on local inflammatory mediators and macrophage polarization, and immune cells in the spleen of mice with chronic inflammatory pain induced by complete Freund's adjuvant (CFA) in the hind paw, so as to investigate the immunoinflammatory regulatory mechanisms of EA in relieving pain and swelling in mice with chronic inflammatory pain. METHODS: Thirty C57BL/6 mice were randomly divided into control, model, and EA groups, with 10 mice in each group. Chronic inflammatory pain model were established by subcutaneous injection of 20 µL CFA solution in the left hind paw for 7 consecutive days. After modeling, mice in the EA group received EA at bilateral "Zusanli"(ST36) for 20 min (2 Hz/100 Hz, 1 mA) once a day for 18 consecutive days. Mechanical pain threshold, heat pain thresholds, and paw thickness were measured before and after mode-ling, and after interventions. Western blot was used to detect the expression of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1ß, and NOD-like receptor protein 3 (NLRP3) in the paw tissue. Immunohistochemistry was used to detect the positive expression of M1-type macrophage marker inducible nitric oride synthase (iNOS) and M2-type marker CD206 in the paw, and flow cytometry was used to detect the proportion of F4/80+ CD11b+ macrophages, Ly6G+ CD11b+ neutrophils, and CD25+ Foxp3+ regulatory T cells (Treg) in the spleen. RESULTS: Compared with the control group, mechanical pain and heat pain thresholds were significantly reduced(P<0.000 1), while paw thickness, expressions of IL-1ß, TNF-α, and NLRP3 in the paw, and positive expression of M1 macrophage marker iNOS in the paw, the proportions of macrophages and neutrophils in the spleen were significantly increased (P<0.000 1, P<0.001) in the model group. Compared with the model group, mechanical pain threshold and heat pain thresholds, CD206 positive expression in the paw, and Treg cell proportion in spleen were significantly increased (P<0.01), while paw thickness, the expressions of IL-1ß, TNF-α and NLRP3 in the paw, as well as the positive expression of M1 macrophage marker iNOS in the paw, the proportions of macrophages and neutrophils in the spleen were significantly reduced (P<0.001, P<0.01, P<0.05)in mice of the EA group after intervention. CONCLUSIONS: EA may alleviate pain and swelling in mice with chronic inflammatory pain by regulating the numbers of macrophages, neutrophils, and Treg cells, as well as promoting M2 polarization of local macrophages and inhibiting the release of pro-inflammatory cytokines.

[Effect of different electrical current intensities of electroacupuncture preconditioning on cardiac function and macrophage polarization in mice with acute myocardial ischemia].

OBJECTIVE: To observe the effect of different intensities of electroacupuncture (EA) preconditioning on car-diac function and polarization state of macrophages in mice with acute myocardial ischemia (AMI), so as to explore its possible mechanism underlying improvement of AMI. METHODS: A total of 50 male C57BL/6J mice were randomly divided into sham ope-ration, AMI model, and EA pretreatment groups (0.5 mA, 1 mA, 3 mA subgroups), with 10 mice in each group/subgroup. The mice in the EA pretreatment groups were subjected to EA stimulation of bilateral "Neiguan"(PC6) with 0.5, 1.0 and 3 mA respectively and frequency of 2 Hz/15 Hz for 20 min, once a day, for 3 days. The acute myocardial ischemia model was established by ligating the anterior descending branch (ADB) of the left coronary artery, while the sham operation only had a surgical suture trans-passed below the ADB but without ligation. The myocardial infarction area was measured after TTC staining, and the cardiac function ï¼»left ventricular ejection fraction (EF), short-axis contraction rate (FS)ï¼½ was detected by using echocardiography. The M1 macrophages were labeled with CD11b+F480+CD206low, M2 macrophages were labeled with CD11b+F480+CD206high and detected by using flow cytometry, and the expression levels of myocardial interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), Toll-like receptor-4 (TLR4) proteins were detected by using Western blot. RESULTS: Compared with the sham operation group, the model group had a significant increase in the infarction area (P<0.000 1), number of cardiac macrophages and percentage of M1 type macrophages (P<0.000 1), and the expression levels of myocardial IL-1ß, TNF-α, TLR4 proteins (P<0.001, P<0.01), and a remarkable decrease in the levels of EF, FS and the percentage of M2 type macrophages (P<0.000 1). In contrast to those of the model group, the area of myocardial infarction (P<0.000 1, P<0.01), expression levels of myocardial IL-1ß, TNF-α, TLR4 proteins (P<0.01, P<0.05, P<0.001) in the 0.5 mA, 1 mA and 3 mA groups, number of macrophages and percentage of M1 macrophages (P<0.05) in the 1 mA group were significantly decreased, while the levels of EF and FS (P<0.000 1, P<0.05, P<0.001) in the 3 EA groups, and percentage of M2 macrophage (P<0.05) in the 1 mA group were significantly increased. Comparison among the 3 EA groups displayed that the effects of 1 mA group were significantly superior to those of 0.5 and 3 mA groups in up-regulating EF and FS (P<0.01, P<0.001), and in down-regulating the area of infarct myocardium (P<0.01, P<0.000 1), and the expression of TLR4 protein (P<0.01), and 0.5 mA group in the expression of IL-1ß and TNF-α proteins (P<0.05). CONCLUSION: EA preconditioning with electrical current intensities of 0.5 mA, 1 mA and 3 mA can effectively reduce myocardial infarction size, improve cardiac function in mice with AMI, which may be related with its effects in reducing the number of cardiac macrophages and down-regulating the expression of myocardial IL-1ß, TNF-α and TLR4 proteins. The therapeutic effect of 1 mA is better than that of 0.5 and 3 mA.