Electroacupuncture relieves hyperalgesia by regulating neuronal-glial interaction and glutamate transporters of spinal dorsal horns in rats with acute incisional neck pain.

Objective: Glial cells are involved in the analgesic effect of electroacupuncture (EA) in rats with chronic neurological pain. The objective of this study was to observe the role of neuronal-glial interaction and glutamate (Glu) transporters in EA-induced acute neck pain relief in rats. Materials and methods: Male rats were placed into the following five groups: control, model, EA Futu (LI18), EA Hegu (LI4)-Neiguan (PC6), and EA Zusanli (ST36)-Yanglingquan (GB34). The incisional neck pain model was established by making a longitudinal incision along the midline of the neck. The thermal pain threshold (TPT) was measured using a radiation heat detector. The immunoactivities of glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba-1), neurokinin-1 receptor (NK-1R), Glu aspartate transporter (GLAST), and Glu transporter-1 (GLT-1) in the dorsal horns (DHs) of the cervico-spinal cord (C2-C5) were detected using immunofluorescence histochemistry. The expression levels of GFAP, Iba-1, GLAST, and GLT-1 mRNAs were determined using quantitative real-time polymerase chain reaction (PCR). Results: The TPT and levels of mRNAs expression and immunoactivity of GLT-1 and GLAST were significantly decreased, and those of Iba-1 and GFAP were significantly increased in the model group than those of the control group (P < 0.05). The activated microgliacytes were gathered around the NK-1R positive neurons, and co-expression of NK-1R and astrocytes was observed in the model group. EA LI18 significantly increased the TPT and expression of GLAST and GLT-1 mRNAs (P < 0.05) and notably decreased the number of Iba-1 positive cells and Iba-l mRNA expression (P < 0.05), whereas GLAST and GLT-1 antagonists inhibited the analgesic effect of EA LI18. However, these effects, except for the downregulation of Iba-1 mRNA, were not observed in the EA ST36-GB34 group. Fewer NK-1R-positive neurons were visible in the spinal DHs in the EA LI18 group, and the co-expression of NK-1R and astrocytes was also lower than that in the three EA groups. Conclusion: Electroacupuncture of LI18 had an analgesic effect in rats with neck incisions, which may be related to its functions in suppressing the neuronal-glial cell interaction through NK-1R and upregulating the expression of GLAST and GLT-1 in the spinal DHs.

Histochemistry of microinfarcts in the mouse brain after injection of fluorescent microspheres into the common carotid artery.

The mouse model of multiple cerebral infarctions, established by injecting fluorescent microspheres into the common carotid artery, is a recent development in animal models of cerebral ischemia. To investigate its effectiveness, mouse models of cerebral infarction were created by injecting fluorescent microspheres, 45-53 µm in diameter, into the common carotid artery. Six hours after modeling, fluorescent microspheres were observed directly through a fluorescence stereomicroscope, both on the brain surface and in brain sections. Changes in blood vessels, neurons and glial cells associated with microinfarcts were examined using fluorescence histochemistry and immunohistochemistry. The microspheres were distributed mainly in the cerebral cortex, striatum and hippocampus ipsilateral to the side of injection. Microinfarcts were found in the brain regions where the fluorescent microspheres were present. Here the lodged microspheres induced vascular and neuronal injury and the activation of astroglia and microglia. These histopathological changes indicate that this animal model of multiple cerebral infarctions effectively simulates the changes of various cell types observed in multifocal microinfarcts. This model is an effective, additional tool to study the pathogenesis of ischemic stroke and could be used to evaluate therapeutic interventions. This study was approved by the Animal Ethics Committee of the Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences (approval No. D2021-03-16-1) on March 16, 2021.

[Microstructural characteristics of lymphatic vessels in skin tissues of acupoints "Taichong" and "Yongquan" in the rat].

OBJECTIVE: To provide a new method for investigating the histological characteristics of acupoints by obser-ving the microstructure of the lymphatic vessels in the skin tissue of "Taichong" (LR3) and "Yongquan" (KI1) regions. METHODS: Six male SD rats were used in the present study. The skin tissue of LR3 and KI1 from the hind foot were taken following transcardial perfusion with 4% paraformaldehyde. The skin tissues were cut into sagittal sections with a freezing microtome and stained by fluorescent immunohistochemistry with lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), calcitonin gene-related peptide (CGRP), and phalloidin for displaying the lymphatic vessels, nerve fibers, and blood vessels, separately. The samples were viewed and recorded using fluorescent microscope and laser scanning confocal microscope. RESULTS: In the skin tissue of LR3 and KI1 regions, the lymphatic vessels, nerve fibers, and blood vessels were labeled with LYVE-1, CGRP and phalloidin, respectively. The lymphatic capillaries were found to start from the enlarged blind end and distribute in the dermis and subcutaneous tissues with various forms, crisscrossing. Abundant blood capillaries at various thickness distributed around the lymphatic capillaries in a parallel or crossed pattern, intermingled with free nerve fibers. CONCLUSION: The lymphatic capillaries, blood capillaries and nerve fibers extensively distribute in the skin tissues of LR3 and KI1 regions in rats, suggesting an involvement of the immunomodulation in the effects of acupuncture in pathological conditions, despite being not limited to the acupoint regions in the distribution of lymphatic capillaries.

GABAergic Inhibition of Spinal Cord Dorsal Horns Contributes to Analgesic Effect of Electroacupuncture in Incisional Neck Pain Rats.

BACKGROUND: Acupuncture has shown to be effective in relieving post-surgical pain. Nonetheless, its underlying mechanisms remain largely unknown. In the present study, we investigated the effect of electroacupuncture (EA) on the expression of GABA, GABA-A receptor (R) and GABA-BR in the spinal cord dorsal horns (DHs), and the involved neural cells in rats with incisional neck pain. MATERIALS AND METHODS: Male SD rats were randomly divided into control, model, Futu (LI18), Hegu-Neiguan (LI4-PC6), and Zusanli-Yanglingquan (ST36-GB34) groups. The incisional neck pain model was established by making a longitudinal incision and repeated mechanical separation along the thyroid gland region. EA (2Hz/100Hz, 1mA) was applied to LI18, LI4-PC6, ST36-GB34 separately for 30min, once at 4, 24 and 48h after incision. The local thermal pain threshold (TPT) of the focus was measured and the expression of GABA, and GABAR proteins and mRNAs detected by immunofluorescence stain and quantitative RT-PCR, respectively. RESULTS: The analgesic effect of LI18 and LI4-PC6 was superior to that of ST36-GB34 in incisional neck pain rats. Moreover, the EA stimulation of LI18 or LI4-PC6 increased the expression of GABA and GABA-Aα2 and GABA-Aß3, GABA-B1, and GABA-B2 mRNAs in spinal DHs 4h after surgery, while GABA-A and GABA-B antagonists inhibited the analgesic effect of LI18. Immunofluorescence double staining showed that GABA was expressed on astrocytes and neurons, and GABA-B expressed only on neurons. CONCLUSION: EA of both LI18 and LI4-PC6 has a good analgesic effect in incisional neck pain rats, which is closely related to their effects in upregulating the expression of GABA and its receptors in spinal DHs. The effects of LI18 and LI4-PC6 EA are obviously better that those of ST36-GB34 EA, and GABA is expressed on neurons and astrocytes.

[High Mobility Group Box 1/ CD 24 Receptor/ß-EP Signaling in "Zusanli" (ST 36) Region Contributes to Electroacupuncture Analgesia in Rats with Neuropathic Pain].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the expression of high mobility group box 1 (HMGB 1) and its receptor CD 24 proteins and ß-endorphin (ß-EP) content in "Zusanli" (ST 36) region in rats with chronic constriction injury (CCI), so as to explore its mechanisms underlying pain relief. METHODS: Thirty male Wistar rats were rando-mized into control, CCI model and EA groups (n＝ 10 rats in each). The neuropathic pain model was established by ligature of the left sciatic nerve to induce CCI in the model and EA groups, and sham operation was performed in rats of the control group. Paw with drawal latency (PWL, thermal pain threshold) of the bilateral hind-limbs was detected by using an algesia-detector. Eight days after CCI operation, EA was applied to bilateral "Zusanli" (ST 36) and "Yanglingquan" (GB 34) for 30 min, once daily for 5 days. The acetylated-HMGB 1 expression was determined by immunoprecipitation, and the expression of HMGB 1 and toll like receptor 4 (TLR 4) proteins and CD 24 mRNA were detected using Western blot and fluorescent quantitative real time-PCR, respectively, and the content of ß-EP in the acupoint region was assayed by enzyme linked immunosorbent assay (ELISA). Anti-CD 24 neutralizing antibody (200 µL, 100 µg/mL) was injected into ST 36 region once daily for 3 days for verifying the involvement of HMGB 1/CD 24 signaling in EA analgesia. RESULTS: Compared with the control group, the bilateral PWL difference values in the other two groups were significantly increased (P<0.05), meaning an occurrence of hyperalgesia after CCI. In comparison with the CCI model group, the hyperalgesia in the EA group was obviously decreased (P<0.05). After CCI, the expression levels of HMGB 1 and TLR 4 proteins were considerably increased compared with those in the control group (P<0.05). After 5-times' EA, the acetylated-HMGB 1, the expression of CD 24 mRNA, and the content of ß-EP were notably up-regulated (P<0.05), and there were no obvious changes in the expression levels of HMGB 1 and TLR 4 proteins (P>0.05). After local injection of anti-CD 24 antibody, EA-induced increases of ß-EP content and reduction of thermal pain threshold were significantly suppressed (P<0.05). CONCLUSION: EA of ST 36 and GB 34 can alleviate neuropathic pain in CCI rats, which is associated with its effects in up-regulating ß-EP content, and HMGB 1 protein and CD 24 mRNA expression levels in ST 36 region. The activated HMGB 1/CD 24/ß-EP signaling contributes to EA-ST 36 induced analgesia.

Impact of long-term potassium supplementation on thiazide diuretic-induced abnormalities of glucose and uric acid metabolisms.

Treatment of hypertension with thiazide diuretics may trigger hypokalemia, hyperglycemia, and hyperuricemia. Some studies suggest simultaneous potassium supplementation in hypertensive patients using thiazide diuretics. However, few clinical studies have reported the impact of long-term potassium supplementation on thiazide diuretic-induced abnormalities in blood glucose and uric acid (UA) metabolisms. One hundred hypertensive patients meeting the inclusion criteria were equally randomized to two groups: IND group receiving indapamide (1.25-2.5 mg daily) alone, and IND/KCI group receiving IND (1.25-2.5 mg daily) plus potassium chloride (40 mmol daily), both for 24 weeks. At the end of 24-week follow-up, serum K+ level in IND group decreased from 4.27 ± 0.28 to 3.98 ± 0.46 mmol/L (P < 0.001), and fasting plasma glucose (FPG) and UA increased from 5.11 ± 0.52 to 5.31 ± 0.57 mmol/L (P < 0.05), and from 0.404 ± 0.078 to 0.433 ± 0.072 mmol/L (P < 0.05), respectively. Serum K+ level in IND/KCl group decreased from 4.27 ± 0.36 to 3.89 ± 0.28 mmol/L (P < 0.001), and FPB and UA increased from 5.10 ± 0.41 to 5.35 ± 0.55 mmol/L (P < 0.01), and from 0.391 ± 0.073 to 0.457 ± 0.128 mmol/L (P < 0.001), respectively. The difference value between the serum K+ level and FPG before and after treatment was not statistically significant between the two groups. However, the difference value in UA in IND/KCl group was significantly higher than that in IND group (0.066 (95% confidence interval (CI): 0.041-0.090) mmol/L vs. 0.029 (95% CI: 0.006-0.058) mmol/L, P < 0.05). The results showed that long-term routine potassium supplementation could not prevent or attenuate thiazide diuretic-induced abnormalities of glucose metabolism in hypertensive patients; rather, it may aggravate the UA metabolic abnormality.

Repeated electroacupuncture treatment attenuated hyperalgesia through suppression of spinal glial activation in chronic neuropathic pain rats.

BACKGROUND: Cumulated evidence reveals that glial cells in the spinal cord play an important role in the development of chronic neuropathic pain and are also complicated in the analgesic effect of EA intervention. But the roles of microgliacytes and astrocytes of spinal cord in the process of EA analgesia remain unknown. METHODS: A total of 120 male Wistar rats were used in the present study. The neuropathic pain model was established by chronic constrictive injury (CCI) of the sciatic nerve. The rats were randomly divided into sham group, CCI group, and sham CCI + EA group, and CCI + EA group. EA was applied to bilateral Zusanli (ST36)-Yanlingquan (GB34). The mechanical (both time and force responses) and thermal pain thresholds (PTs) of the bilateral hind-paws were measured. The number of microgliacytes and activity of astrocytes in the dorsal horns (DHs) of lumbar spinal cord (L4-5) were examined by immunofluorescence staining, and the expression of glial fibrillary acidic protein (GFAP) protein was detected by western blot. RESULTS: Following CCI, both mechanical and thermal PTs of the ipsilateral hind-paw were significantly decreased beginning from the 3rd day after surgery (P < 0.05), and the mechanical PT of the contralateral hind-paw was considerably decreased from the 6th day on after surgery (P < 0.05). CCI also significantly upregulated the number of Iba-1 labeled microgliacytes and the fluorescence intensity of glial fibrillary acidic protein (GFAP) -labeled astrocyte in the superficial laminae of DHs on bilateral sides (P < 0.05). After repeated EA, the mechanical and thermal PTs at bilateral hind-paws were significantly relieved (P < 0.05). The increased of number of microgliacytes was markedly suppressed by 2 days' EA intervention, and the average fluorescence intensity was suppressed by 2 weeks' EA. The expression of GFAP protein were down-regulated by 1 and 2 weeks' EA treatment, respectively (P < 0.05). CONCLUSIONS: Repeated EA can relieve neuropathic pain and mirror-image pain in chronic neuropathic pain rats, which is probably associated with its effect in downregulating glial cell activation of the lumbar spinal cord, the microgliacyte first and astrocyte later.

[Effect of Electroacupuncture Intervention on Expression of Synaptic Plasticity-related Molecules in Amygdala in Chronic Pain-negative Affection Rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on expression of synaptic plasticity-related glutamate N-methyl-D-aspartate (NMDA) receptor subunit NR 1, gamma-aminobutyric acid (GABA) receptor subunits (Aß 2, B 1), etc. in the amygdala in chronic neuropathic pain negative affection (CNPPNA) rats, so as to reveal its mechanism underlying pain relief. METHODS: Male Wistar rats were randomized into normal control, CNPPNA model, EA, and anesthesia+EA (AEA)groups (n=14 in each group, 8 for quantitative RT-PCR and 6 for immunofluorescence staining). The CNPPNA model was established by ligation of the left sciatic nerve and repeated electrical stimulation of the hindpaw plantar skin in the pain-paired compartment. EA was applied to bilateral "Zusanli"(ST 36)and "Yanglingquan"(GB 34)for 30 min, once daily for 7 days.Thermal pain threshold (paw withdrawal latency, PWL)of the bilateral paws was measured by using a Tail-Flick Unit. The conditioned place aversion (CPA) was determined by using a CPA-paired compartment. The expression levels of GABAAß 2, GABAB 1, NMDA receptor subunit NR 1, postsynaptic density-95 protein(PSD-95), Piccolo genes in the right amygdala area were determined using quantitative RT-PCR, and the immunoactivity of metabotropic glutamate receptor subunit 1 (mGluR 1) and GABAB 2 in the basolateral amygdala (BLA) nucleus was detected using immunofluorescence staining. RESULTS: After modeling, PWL difference (PWLD) values of the model group were significantly increased (P<0.001),and the time spent in the CPA-paired compartment was considerably decreased compared with the control group (P<0.001).After EA intervention for 3 and 7 days, the PWLD levels of both EA and AEA groups were apparently decreased(P<0.05),and the time spent in the CPA-paired compartment was apparently increased in the EA and AEA groups(P<0.05),suggesting a pain relief and an improvement of the negative affection after EA intervention. Additionally, following EA, the apparently-decreased expression levels of GABAAß 2,GABAB 1,PSD-95,Piccolo genes and the reduced numbers of GABAB 2 positive cells and NMDA-NR 1 mRNA as well as mGluR 1 positive fiber numbers were remarkably increased in the EA group (P<0.05, P<0.001).The expression levels of Piccolo gene, GABAB 2 and mGluR 1 positive cells/fiber numbers were apparently lower in the AEA group than in the EA group (P<0.001). No significant differences were found between the EA and AEA groups in the PWLD, time spent in the CPA-paired compartment, and the expression levels of NMDA-NR 1, GABAAß 2, GABAB 1 and PSD-95 genes (P>0.05). CONCLUSIONS: Repeated EA stimulation of ST 36-GB 34 has a role in relieving both sensory and affection dimensions of chronic pain in CNPPNA rats, which Feb be respectively related to its effects in up-regulating the expression of GABAAß 2, GABAB 1, NMDA-NR 1, PSD-95 and Piccolo genes, and in promoting the expression of mGluR 1 and GABAB 2 proteins and Piccolo gene in the amygdala.

Electroacupuncture Reduces the Effects of Acute Noxious Stimulation on the Electrical Activity of Pain-Related Neurons in the Hippocampus of Control and Neuropathic Pain Rats.

To study the effects of acupuncture analgesia on the hippocampus, we observed the effects of electroacupuncture (EA) and mitogen-activated protein kinase (MEK) inhibitor on pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal area CA1 of sham or chronic constrictive injury (CCI) rats. The animals were randomly divided into a control, a CCI, and a U0126 (MEK1/2 inhibitor) group. In all experiments, we briefly (10-second duration) stimulated the sciatic nerve electrically and recorded the firing rates of PENs and PINs. The results showed that in both sham and CCI rats brief sciatic nerve stimulation significantly increased the electrical activity of PENs and markedly decreased the electrical activity of PINs. These effects were significantly greater in CCI rats compared to sham rats. EA treatment reduced the effects of the noxious stimulus on PENs and PINs in both sham and CCI rats. The effects of EA treatment could be inhibited by U0126 in sham-operated rats. The results suggest that EA reduces effects of acute sciatic nerve stimulation on PENs and PINs in the CA1 region of the hippocampus of both sham and CCI rats and that the ERK (extracellular regulated kinase) signaling pathway is involved in the modulation of EA analgesia.

[Effect of Electroacupuncture Intervention on Expression of Pain Sensory and Affective Proce- ssing-related µ-opioid Receptor, etc. in the Amygdala in Chronic Neuropathy Pain Rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on expression of pain sensory and affective processing-related µ-opioid receptor (MOR), glutamatergic AMPA receptor subunit GIuA 1, extracellular signal-regulated kinase (ERK 1/2), cAMP response element binding protein(CREB) in the amygdala in chronic constrictive injury (CC) + negative affection(NA) rats, so as to reveal its mechanism underlying pain relief. METHODS: A total of 32 male Wistar rats were randomized into normal control, model, EA, and anesthesia+ EA (AEA) groups (n = 8 in each group). The neuropathic pain NA model was established by ligation of the left sciatic nerve and repeated electrical stimulation of the paw-bottom in the pain-paired compartment. EA was applied to bilateral "Zusanli" (ST 36) and "Yanglingquan" (GB 34) for 30 min, once daily for 7 days. Thermal pain threshold (paw withdrawl latency, PWL) of the bilateral paws was measured by using a Tail-Flick Unit. The expression levels of MOR and p-CREB in the central amygdala (CeA) and those of MOR, GluA 1, p-ERK 1/2 and p-CREB in the right amygdala area were determined using immunofluorescence and Western blot, respectively. RESULTS: in comparison with the normal group, PWL difference (PWLD) values of the model group were significantly increased (P < 0.001), and the time spent in the CPA-paired. compartment was considerably decreased (P < 0.001). After EA, the PWLD levels of both EA and AEA groups were apparently decreased (P < 0.05), showing a pain relief; and the time spent in the CPA-paired compartment was apparently increased in the EA group (P < 0.05) , rather than in the AEA group (P > 0.05). Additionally , compared to the normal group, the expression level of MOR protein in the amygdala was remarkably increased (P < 0.05) and those of GIuA 1, p-ERK 2 and p-CREB proteins were apparently decreased (P < 0.05). After EA intervention for 7 days, the expression levels of these four proteins in the EA group, and those of MOR, p-ERK 2 and p-CREB in the AEA group were significantly up-regulated (P < 0.001, P < 0.01, P < 0.05). The expression level of GIuA 1 was significantly higher in the EA group than in the AEA group (P < 0.05). CONCLUSION: Repeated EA stimulation of ST 36-GB 34 has a definite effect in relieving both sensation and affection dimensions of pain in NA rats, which may be related to its effect in up-regulating the expression of GIuA 1 in the amygdala, but the effects of MOR, p-ERK 2 and p-CREB need being researched further.

Involvement of hippocampal acetylcholinergic receptors in electroacupuncture analgesia in neuropathic pain rats.

BACKGROUND: Cumulating evidence has shown a close correlation between electroacupuncture stimulation (EAS) frequency-specific analgesic effect and central opioid peptides. However, the actions of hippocampal acetylcholinergic receptors have not been determined. This study aims to observe the effect of different frequencies of EAS on the expression of hippocampal muscarinic and nicotinic acetylcholinergic receptors (mAChRs, nAChRs) in neuropathic pain rats for revealing their relationship. METHODS: Forty male Wistar rats were randomly and equally divided into sham, CCI model, 2, 2/15 and 100 HzEA groups. The neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury (CCI). EAS was applied to bilateral Zusanli (ST36) and Yanglingquan (GB34) for 30 min, once daily for 14 days except weekends. The mechanical pain thresholds (withdrawal latencies, PWLs) of bilateral hindpaws were measured. The expression levels of hippocampal M1 and M2 mAChR, and α4 and ß2 nAChR genes and proteins were detected by quantitative RT-PCR and Western blot, separately. The involvement of mAChR and nAChR in the analgesic effect of EAS was confirmed by intra-hippocampal microinjection of M1mAChR antagonist (Pirenzepine) and α4ß2 nAChR antagonist (dihydro-beta-erythroidine) respectively. RESULTS: Following EAS, the CCI-induced increase of difference values of bilateral PWLs on day 6 and 14 was significantly reduced (P < 0.05), with 2/15 Hz being greater than 100 Hz EAS on day 14 (P < 0.05). After 2 weeks' EAS, the decreased expression levels of M1 mAChR mRNA of both 2 and 2/15 Hz groups and M1 mAChR protein of the three EAS groups, α4 AChR mRNA of the 2/15 Hz group and ß2 nAChR protein of the three EAS groups were considerably increased (P < 0.05), suggesting an involvement of M1 mAChR and ß2 nAChR proteins in EAS-induced pain relief. No significant changes were found in the expression of M2 mAChR mRNA and protein, α4 nAChR protein and ß2 nAChR mRNA after CCI and EAS (P > 0.05). The analgesic effect of EAS was abolished by intra-hippocampal microinjection of M1mAChR and α4ß2 nAChR antagonists respectively. CONCLUSIONS: EAS of ST36-GB34 produces a cumulative analgesic effect in neuropathic pain rats, which is frequency-dependent and probably mediated by hippocampal M1 mAChR and ß2 nAChR proteins.

Effect of Repeated Electroacupuncture Intervention on Hippocampal ERK and p38MAPK Signaling in Neuropathic Pain Rats.

Results of our past studies showed that hippocampal muscarinic acetylcholine receptor (mAChR)-1 mRNA and differentially expressed proteins participating in MAPK signaling were involved in electroacupuncture (EA) induced cumulative analgesia in neuropathic pain rats, but the underlying intracellular mechanism remains unknown. The present study was designed to observe the effect of EA stimulation (EAS) on hippocampal extracellular signal-regulated kinases (ERK) and p38 MAPK signaling in rats with chronic constrictive injury (CCI) of the sciatic nerve, so as to reveal its related intracellular targets in pain relief. After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05). Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05). Correspondingly, CCI-induced decreased expression levels of Ras, c-Raf, ERK1 and p-ERK1/2 proteins, and p38 MAPK mRNA and p-p38MAPK protein in the hippocampus tissues were reversed by EA2W (P < 0.05). The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

[Effect of electroacupuncture intervention on expression of pain sensory and affection processing related corticotropin-releasing factor receptor mRNA, etc. in the amygdala in neuropathic pain and negative affection rats].

OBJECTIVE: To observe the effect of electroacupuncture .(EA) stimulation of "Zusanli" (ST 36)-"Yang- lingquan" (GB 34) on expression of pain sensory and affection processing-related corticotropin-releasing factor (CRF) receptor, glutamatergic NMDA receptor and GABA receptor subtype genes in the amygdala in chronic constrictive injury (CCI) of the sciatic nerve rats, so as to reveal its mechanism underlying pain relief. METHODS: Experiments were separately performed in 36 male Wistar rats which were randomized into normal control, CCI model and EA + CCI; normal control, CCI + negative affection (NA) model and CCl+ NA+ EA groups (n =6 in each group). Neuropathic pain model was established by ligature of the left sciatic nerve, and NA model established by ligation of the left sciatic nerve and repeated skin stimulation (acupuncture needle pricking + direct current stimulation) of the paw-bottom, once daily for 3 days. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral ST 36-GB 34 for 30 min, once daily for 7 days. Thermal pain threshold (paw withdrawal latency, PWL) of the bilateral paws was measured by using a Tail-Flick Unit 37360. Expression levels of CRF-1 R, CRF-2 R, NR 2 A,NR 2 B,GABAaR and GABAcR genes in the amygdala were determined using quantitative RT-PCR. RESULTS: In comparison with the normal control groups, PWL difference (PWLD) values of the bilateral paws of CCIl model and CCI+NA model groups were significantly increased (P<0. 05). In comparison with the model group, following 7 days' EA stimulation, PWLD were considerably decreased (P<0. 05), showing a pain relief. RT-PCR results indicated that compared to the normal control group, the expression levels of CRF-1 R, CRF-2 R, NR 2 A and NR 2 B genes were apparently increased in the CCI model group (P<0. 01, P<0. 001), and those of CRF-1 R, CRF-2 R, NR 2 A, NR 2 B, GABAaR and GABAcR genes were remarkably down-regulated in the CCI + NA model group (P<0. 05, P<0. 01, P<0. 001). After EA intervention for 7 days, CRF-2 R, NR 2 A and NR 2 B were significantly down-regulated in the CCI + EA group, and CRF-1 R, CRF-2 R, NR 2 B,GABAaR and GABAcR genes were obviously up-regulated in the CCI + NA + EA group (P<0. 01, P<0. 001). CONCLUSION: Repeated EA stimulation of ST 36-GB 34 has a definite analgesic effect in neuropathic pain and negative affection rats, which may be respectively related to its effects in down-regulating expression of CRF-2 R, NR 2 A and NR 2 B genes, and up-regulating expression of CRF-1 R, CRF-2 R, NR 2 B,GABAaR and GABAcR genes in the amyg- dala.

Effect of Electroacupuncture Intervention on Expression of CGRP, SP, COX-1, and PGE2 of Dorsal Portion of the Cervical Spinal Cord in Rats with Neck-Incision Pain.

The present study was aimed to determine if cervicospinal substance P (SP) and its neurokinin-1 receptor (NK-1R), calcitonin gene-related peptide (CGRP), cyclooxygenase-1 (COX-1), and prostaglandin E2 (PGE2) were involved in electroacupuncture (EA) analgesia in neck-incision pain rats. EA intervention was applied to bilateral Futu (LI18), Hegu (LI4)-Neiguan (PC6), and Zusanli (ST36)-Yanglingquan (GB34) for 30 min. Cervicospinal SP and CGRP immunoactivity was detected by immunofluorescence technique, NK-1R and COX-1 protein and mRNA expression levels were determined using Western blot and real-time PCR, respectively, and PGE2 content was measured using ELISA. Outcomes indicated that EA of EA-LI18 and LI4-PC6 (not ST36-GB34) significantly suppressed neck-incision induced decrease of thermal pain threshold (P < 0.05). EA stimulation of LI18 and LI4-PC6 markedly inhibited neck-incision induced upregulation of SP and CGRP immunoactivity, NK-1 R and COX-1 mRNA and protein expression levels, as well as the increase of PGE2 content in the dorsal cervicospinal cord (P < 0.05). These findings showed that LI18 and LI4-PC6 EA stimulation-induced downregulation of SP, CGRP, NK-1R, COX-1, and PGE2 levels in the dorsal cervicospinal cord may contribute to their effects in relieving neck-incision pain. This study highlights the targets of EA intervention for reducing post-thyroid-surgery pain for the first time.

[Involvement of hippocampal NO/PKG signaling pathway in the accumulative analgesic effect of electroacupuncture stimulation of "Zusanli" (ST 36)-"Yanglingquan"(GB 34) in chronic neuropathic pain rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli"(ST 36)-"Yanglingquan"(GB 34) on pain behavior and expression of hippocampal neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase(iNOS)and cGMP-dependent protein kinase (PKG) mRNA in rats with chronic neuropathic pain so as to analyze its mechanism underlying analgesia. METHODS: Forty male Wistar rats were randomly divided into control, CCI model, EA-2 Hz, EA-2 Hz/15 Hz, EA-100 Hz groups, with 8 cases in each group. Chronic neuropathic pain model was established by ligature of the left sciatic nerve under anesthesia (Urethane + Alpha-Chloralose) except rats in the control group. EA(2 Hz, 2 Hz/15 Hz, 100 Hz, 1 mA) was applied to bilateral "Zusanli"(ST 36)-"Yanglingquan"(GB 34) for 30 min, once each day for 2 weeks. The thermal and mechanical paw withdrawal latencies (pain thresholds) of the bilateral limbs were detected before and after EA interventions. The hippocampal tissue of the rat was collected for detecting the expression levels of nNOS, INOS and PKG genes using quantitative real-time-PCR technique. RESULTS: In comparison with the control group, the thermal and mechanical pain thresholds of the model group were decreased obviously (P<0. 05).Compared with the model group, both thermal and mechanical pain thresholds of the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups were markedly increased after EA intervention for 3, 7, 10 and 14 days (P<0. 05). Compared with the control group, the expression levels of hippocampal nNOS and PKG mRNA were significantly and moderately up-regulated in the model group (P<0. 05). While in comparison with the model group, the expression levels of hippocampal nNOS and PKG mRNA in the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups were markedly down-regulated (P<0. 05). No significant differences were found among the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups in the analgesic effect and in down-regulating hippocampal nNOS and PKG mRNA expression (P>0.05). However, the recovery state of the pain reaction of both EA-2 Hz and EA-2 Hz/ 15 Hz groups was relatively better than that of the EA-100 Hz group from day 3 to 10 after EA intervention. CONCLUSION: EA stimulation of "Zusanli"(ST 36)-"Yanglingquan"(GB 34) at 2 Hz, 2 Hz/15 Hz and 100 Hz can significantly suppress chronic neuropathic pain induced in CCI rats, which may be closely associated with its effects in down-regulating hippocampal nNOS and PKG mRNA expression levels.

Observation of Pain-Sensitive Points along the Meridians in Patients with Gastric Ulcer or Gastritis.

This study aims to investigate the sensitization of human skin points along certain meridians related to visceral disease by using the pressure-pain threshold (PPT) as an indicator. We detected and compared the PPTs of people with and without gastric ulcer or gastritis on the related acupoints, abdomen area, and back area with von Frey detector and observed the similarities and differences under their respective physiological and pathological states. The results showed that (1) the PPTs of patients with gastric ulcer on related acupoints decreased significantly compared with the control group; (2) there was no significant difference in PPT between the chosen points of the measured meridian and the adjacent nonacupoints; (3) there was an apparent distribution of tender points on the relevant abdomen and back regions of patients with gastric ulcer or gastritis, but none was found on the control group; (4) the pain-sensitive points of gastric ulcer and gastritis patients were BURONG (ST19), LIANGMEN (ST21), and HUAROUMEN (ST24) of the stomach meridian on the abdominal region and PISHU (BL20), WEISHU (BL21), and WEICANG (BL50) on the back, among others The results suggest that the practical significance of acupoints may lie in its role as a relatively sensitive functional area. In a pathological state, the reflex points on the skin which are related to certain visceral organs become sensitive and functionally intensify.

[Effects of electroacupuncture at "Futu"(LI 18), etc. on pain threshold and cervico-spinal mGlu receptor 5/cAmp/CREB signaling in rats with neck incision pain].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Futu" (LI 18),etc. on the pain threshold and expression of metabotropic glutamate receptor subtype 5 (mGluR 5), cyclic adenosine monophosphate (cAMP), mitogen-activated protein kinase (MAPK), cAMP responsive element binding protein (CREB) genes in the cervico-spinal dorsal region in rats with neck incision pain so as to analyze its underlying analgesic mechanism in performing thyroid surgery. METHODS: Forty male Wistar rats were randomly divided into control, model, Futu (LI 18), Hegu (LI 4)-Neiguan (PC 6), Zusanli (ST 36)-Yanglingquan (GB 34) groups, with 8 cases in each group. Neck-incision pain model was established by making a longitudinal incision along the midline of the neck under anesthesia (isoflurane) except rats in the control group. EA(2 Hz/15 Hz, 1-2 mA) was applied to bilateral LI 18, LI 4-PC 6 and ST 36-GB 34 for 30 min, 4 h, 24 h and 48 h after modeling, respectively. The thermal pain threshold was detected before modeling, and before and after each treatment. After removing the ventral part, the spinal tissue of the cervical 1 -4 segments was collected for detecting the expression of mGluR 5, cAMP, MAPK, CREB genes by using quantitative real-time-PCR technique. RESULTS: In comparison with the control group, the pain threshold of the model group was decreased obviously (P<0.05). Compared with the model group, the pain thresholds of the LI 18 and LI 4-PC 6 groups were upregulated markedly after treatment (P<0.05). No significant differences were found between the LI 18 and LI 4-PC 6 groups, and between the model and ST 36-GB 34 groups in pain thresholds (P>0.05). Compared with the control group, the expression le-vels of mGluR 5 mRNA, cAMP mRNA and CREB mRNA in the cervico-spinal cord were upregulated significantly in the model group (P<0.05). While in comparison with the model group, cervico-spinal cAMP mRNA, and CREB mRNA were down-regulated markedly (P<0.05) and mGluR 5 mRNA was down-regulated moderately (P>0.05) in the LI 18 group, rather than in the LI 4-PC 6 and ST 36-GB 34 groups (P>0.05). CONCLUSION: EA-LI 18 can significantly suppress neck incision pain induced pain reaction, which may be closely associated with its functions in down-regulating expression levels of intracellular cAMP mRNA and CREB mRNA in the cervico-spinal cord.

Effect of metformin on weight gain during antihypertensive treatment with a beta-blocker in Chinese patients.

BACKGROUND: Overweight and obesity are associated with cardiovascular disease (CVD). This study was designed to investigate whether combined use of nitrendipine and atenolol has any effect on body weight (BW) and whether metformin can prevent antihypertensive medication-induced weight gain and has any effect on blood glucose (BG). METHODS: Included in the present study were 94 hypertensive patients with a body mass index (BMI) > or =25 kg/m(2), of whom 45 patients were treated with nitrendipine plus atenolol (N/A group), and the remaining 49 patients were treated with nitrendipine, atenolol, and metformin (N/A/M group). The mean follow-up duration was 14 months. BW and glucose tolerance were measured. RESULTS: In N/A group, BW and fasting BG significantly increased from 73.5 +/- 9.6 kg to 74.2 +/- 9.7 kg (P < 0.05) and from 94.2 +/- 10.5 mg/dl to 97.9 +/- 11.3 mg/dl (P < 0.01), respectively, whereas postprandial BG did not change significantly. In N/A/M group, BW slightly decreased from 72.7 +/- 10.1 kg to 72.3 +/- 10.2 kg (P = 0.30), and fasting BG did not change significantly (93.5 +/- 10.4 mg/dl vs. 92.7 +/- 10.2 mg/dl, P = 0.59), whereas 2-h postprandial BG significantly decreased from 133.7 +/- 30.5 mg/dl to 124.0 +/- 29.6 mg/dl (P < 0.05). Furthermore, a significant difference was observed in difference value of BW before and after treatment between the two groups (0.7 (95% confidence interval, 0.1-1.3) kg in N/A group vs. -0.4 (95% confidence interval, -1.3 to 0.4) kg in N/A/M group, P < 0.05). CONCLUSIONS: Combination therapy of nitrendipine and atenolol may significantly increase BW and fasting BG in overweight or obese patients with hypertension. Metformin may prevent BW gain and improve BG levels in hypertensive patients who received combination therapy of nitrendipine and atenolol.

[Treatment of severe acute biliary pancreatitis in the elderly by integrated traditional Chinese and Western medicine].

OBJECTIVE: To summarize the therapeutic effect of integrated traditional Chinese and Western medicine (ICWM) on severe acute biliary pancreatitis (SABP), and to discuss the opportunity of operation. METHODS: The hospitalization duration, incidence of complications, operation transmitting rate and mortality were analyzed in 96 senile SABP patients (Group A) treated by ICWM, and 32 senile SABP patients treated by conventional Western medicine, they were hospitalized from January 2000 to December 2007. RESULTS: (1) The average hospitalization duration in Group A and B was 28.2 +/- 11.3 days and 32.7 +/- 14.3 days respectively, showing insignificant difference between them (P>0.05); (2) The early stage incidence of complications being 29.2% (28/96) in Group A and 34.4% (11/32) in Group B, no significant difference between groups was shown, but a significant difference did show at the late stage, 36.5% (35/96) vs 53.1% (17/32), the incidence in Group A was lower significantly (P<0.05). (3) The two groups were not different in operation transmitting rate 36.4% (35/96) vs 43.8% (14/32), P>0.05. (4) The mortality in Group A, 21.9% (21/96) was lower than that in Group B, 37.5% (12/32), P <0.05. CONCLUSION: ICWM has good effect in treating SABP, and the opportunity of operation transmitting should be decided according to whether there obstruction of biliary tract exists or not.

Effect of electroacupuncture on thalamic neuronal response to visceral nociception.

The thalamus has been shown to play an important role in somatovisceral integration. This study set out to examine thalamic neuronal responses to visceral nociception when electrical stimulation was applied to the skin receptive field (RF) or to ST(36), an acupoint most frequently used for abdominal pain conventionally. Single neuronal recordings were carried out extracellularly in the thalamic ventrobasal nucleus of anaesthetized rats. Among numerous neurons responding to tactile stimulation, 72 units were found responsive not only to innocuous stimulation on skin RF (60 activated, 12 inhibited) but also to noxious colorectal distension (CRD). Electrical stimulation (2 Hz, 1 mA) of the neuronal somatic receptive field center reduced the subsequent neuronal responses to CRD in 40 neurons tested. High frequency stimulation (100 Hz) produced stronger inhibition than low frequency (2 Hz) stimulation at RF. The inhibition on visceral nociceptive response occurred immediately after the stimulation. In comparison with the effect of RF stimulation, the inhibitory effect was less at either ipsilateral or contralateral ST(36). Our data suggest that, at single thalamic neuron level, stimulation at conventional acupoint is not necessarily as effective as stimulation at neuronal skin receptive field, and high frequency is more effective than low frequency stimulation for the inhibition of visceral nociception.