Electroacupuncture improves gout arthritis pain via attenuating ROS-mediated NLRP3 inflammasome overactivation.

BACKGROUND: Gout results from disturbed uric acid metabolism, which causes urate crystal deposition in joints and surrounding tissues. Gout pain management is largely limited to colchicine and nonsteroidal anti-inflammatory drugs. Constant usage of these medications leads to severe side effects. We previously showed electroacupuncture (EA) is effective for relieving pain in animal model of gout arthritis. Here we continued to study the mechanisms underlying how EA alleviates gout pain. METHODS: Monosodium urate was injected into ankle joint to establish gout arthritis model in mice. EA or sham EA was applied at ST36 and BL60 acupoints of model animals. Biochemical assays, immunostaining, live cell Ca2+ imaging and behavioral assays were applied. RESULTS: Model mice displayed obvious mechanical allodynia, accompanied with gait impairments. EA attenuated mechanical hypersensitivities and improved gait impairments. EA reduced the overexpression of NLRP3 inflammasome signaling molecules in ankle joints of model animals. EA-induced anti-allodynia, as well as inhibition on NLRP3 inflammasome, were mimicked by antagonizing but abolished by activating NLRP3 inflammasome via pharmacological methods. EA attenuated oxidative stress, an upstream signaling of NLRP3 inflammasome in ankle joints of model mice. Exogenously increasing oxidative stress abolished EA's inhibitory effect on NLRP3 inflammasome and further reversed EA's anti-allodynic effect. EA reduced neutrophil infiltrations in ankle joint synovium, a major mechanism contributing to oxidative stress in gout. Pharmacological blocking NLRP3 inflammasome or EA reduced TRPV1 channel overexpression in dorsal root ganglion (DRG) neurons. Ca2+ imaging confirmed that EA could reduce functional enhancement in TRPV1 channel in DRG neurons during gout. CONCLUSIONS: Our results demonstrate that EA reduces gout pain possibly through suppressing ROS-mediated NLRP3 inflammasome activation in inflamed ankle joints and TRPV1 upregulation in sensory neurons, supporting EA as a treatment option for gout pain.

Electroacupuncture Ameliorates Mechanical Allodynia of a Rat Model of CRPS-I via Suppressing NLRP3 Inflammasome Activation in Spinal Cord Dorsal Horn Neurons.

Complex regional pain syndrome type-I (CRPS-I) is a chronic neurological disorder that results in severe pain and affects patients' life quality. Conventional therapies usually lack effectiveness. Electroacupuncture (EA) is an effective physical therapy for relieving CRPS-I pain. However, the mechanism underlying EA-induced analgesia on CRPS-I still remain unknown. Spinal NLRP3 inflammasome was recently identified to contribute to pain and neuroinflammation in a rat model of CRPS-I by our group. Here, we aimed to study whether EA could inhibit spinal NLRP3 inflammasome activation, thus resulting in pain relief and attenuation of spinal neuroinflammation in the rat model of CRPS-I. We established the rat chronic post-ischemic pain (CPIP) model to mimic CRPS-I. CPIP rats developed remarkable mechanical allodynia that could be relieved by daily EA intervention. NLRP3 inflammasome was activated in spinal cord dorsal horn (SCDH) of CPIP rats, accompanied with over-production of pro-inflammatory cytokine IL-1ß. Immunostaining revealed that the cellular distribution of NLRP3 was predominantly located in SCDH neurons. Pharmacological activation of NLRP3 inflammasome per se is sufficient to produce persistent mechanical allodynia in naïve animals, whereas blocking NLRP3 inflammasome attenuates mechanical allodynia of CPIP rats. EA exclusively reduced NLRP3 overexpression in SCDH neurons and attenuated spinal glial cell over-activation in CPIP rats. EA-induced anti-allodynia with attenuation of spinal glial cell over-activation were all mimicked by intrathecal blocking NLRP3 inflammasome and reversed by activating NLRP3 inflammasome, respectively, through pharmacological methods. Finally, spinal blocking IL-1ß attenuated mechanical allodynia and spinal glial cell over-activation in CPIP rats, resembling the effects of EA. In all, these results demonstrate that spinal NLRP3 inflammasome activation contributes to mechanical allodynia of the rat model of CRPS-I and EA ameliorates mechanical allodynia through inhibiting NLRP3 inflammasome activation in SCDH neurons. Our study further supports EA can be used as an effective treatment for CRPS-I.

Nrf2 Activation Mediates Antiallodynic Effect of Electroacupuncture on a Rat Model of Complex Regional Pain Syndrome Type-I through Reducing Local Oxidative Stress and Inflammation.

Complex regional pain syndrome type-I (CRPS-I) represents a type of neurovascular condition featured by severe pain in affected extremities. Few treatments have proven effective for CRPS-I. Electroacupuncture (EA) is an effective therapy for pain relief. We explored the mechanism through which EA ameliorates pain in a rat CRPS-I model. The chronic postischemic pain (CPIP) model was established using Sprague-Dawley rats to mimic CRPS-I. We found that oxidative stress-related biological process was among the predominant biological processes in affected hindpaw of CPIP rats. Oxidative stress occurred primarily in local hindpaw but not in the spinal cord or serum of model rats. Antioxidant N-acetyl cysteine (NAC) attenuated mechanical allodynia and spinal glia overactivation in CPIP model rats, whereas locally increasing oxidative stress is sufficient to induce chronic pain and spinal glia overactivation in naive rats. EA exerted remarkable antiallodynia on CPIP rats by reducing local oxidative stress via enhancing nuclear factor erythroid 2-related factor 2 (Nrf2) expression. Pharmacological blocking Nrf2 abolished antioxidative and antiallodynic effects of EA. EA reduced spinal glia overactivation, attenuated the upregulation of inflammatory cytokines, reduced the enhanced TRPA1 channel activity in dorsal root ganglion neurons innervating the hindpaws, and improved blood flow dysfunction in hindpaws of CPIP rats, all of which were mimicked by NAC treatment. Thus, we identified local oxidative injury as an important contributor to pathogenesis of animal CRPS-I model. EA targets local oxidative injury by enhancing endogenous Nrf2-mediated antioxidative mechanism to relieve pain and inflammation. Our study indicates EA can be an alternative option for CRPS-I management.

[Determination of seven ingredients of different grades Alismatis Rhizoma by QAMS method].

The present study is to establish a quantitative analysis of multi-components by single marker(QAMS) for determining contents of seven compositions in Alismatis Rhizoma, alismoxide, alisol C 23-acetate, alisol A, alismol, alisol B, alisol B 23-acetate and 11-deoxy-alisol B. Six relative correction factors(RCFs) of alismoxide, alisol C 23-acetate, alisol A, alismol, alisol B and 11-deoxy-alisol B were established in the UPLC method with alisol B 23-acetate as the internal standard, which was to calculate the mass fraction of each. The mass fraction of seven effective constituents in Alismatis Rhizoma was calculated by the external standard method(ESM) at the same time. Compared with the content results determined by the ESM and QAMS, the feasibility and accuracy of QAMS method were verified. Within the linear range, the RCFs of alismoxide, alisol C 23-acetate, alisol A, alismol, alisol B, 11-deoxy-alisol B were 0.946, 4.183, 0.915, 1.039, 0.923 and 1.244, respectively, with good repeatability in different experimental conditions. There was no significant difference between the QAMS method and ESM method. Then, QAMS method was applied to determination of the different degree Alismatis Rhizoma from different areas. As a result, the concentrations of 7 components have differences in different areas, but no significant differences in different grades. The QAMS method is feasible and accurate for the determination of the seven chemical compositions, and which can be used for quality control of Alismatis Rhizoma.

Electroacupuncture Alleviates Pain Responses and Inflammation in a Rat Model of Acute Gout Arthritis.

Acute gout arthritis is one of the most painful inflammatory conditions. Treatments for gout pain are limited to colchicine, nonsteroidal anti-inflammatory drugs, and corticosteroids, which oftentimes result in severe adverse effects. Electroacupuncture (EA) has been proved to be effective in relieving many inflammatory pain conditions with few side effects. Here, we aim to investigate the therapeutic potentials of EA on pain and inflammation of a rat model of acute gout arthritis and underlying mechanisms. We found that 2/100 Hz EA produced the most robust analgesic effect on mechanical hyperalgesia of acute gout arthritis rat model compared with 2 and 100 Hz. EA produced similar analgesic effect compared with indomethacin. 2/100 Hz EA also significantly alleviates the ongoing pain behavior, thermal hyperalgesia, and ankle edema. Locally applied µ and κ-opioid receptor antagonists but not adenosine A1 receptor antagonist significantly abolished the analgesic effect of EA. Locally applied µ and κ-opioid receptor agonists produced significant antiallodynia on acute gout arthritis rats, mimicking EA. Furthermore, 2/100 Hz EA upregulated ß-endorphin expression in inflamed ankle skin tissue. Our results demonstrated, for the first time, that EA can be used for relieving acute gout arthritis with effect dependent on peripheral opioid system and comparable with the one obtained with indomethacin.

[Synergistic antileukemic effect of phytoestrogens and chemotherapeutic drugs on leukemic cell lines in vitro].

Natural phytoestrogens such as the isoflavones genistein and daidzein, and the flavones quercetin exhibit anti-cancer properties. This study was purpose to investigate the anti-proliferative effect of phytoestrogens on acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) cells, and their synergistic antileukemic effect in combination with chemotherapeutic drugs. Optimal dosage of genistein, quercetin and in combination with chemicals for leukemia cells were determined by experiments. Cell viability, apoptosis induction and cell cycle arrest were detected by trypan blue staining, MTT assay, optical microscopy, flow cytometry (FCM). The schedule treatment of combination of genistein and chemicals was determined. The results showed that genistein exhibited a dose- and time-dependent inhibitory effect on cell proliferation in NB4 and HL-60 cells, induced apoptosis and cell cycle arrest in G2/M phase. Quercetin had evident inhibitory effect on the proliferation of K562 and K562/A cells. The combination of genistein and chemicals exerted a synergistic effect on cell growth inhibition. In conclusion, this study demonstrated the synergistic antileukemic effect of genistein with chemotherapeutic drugs on leukemic cells. This combination appears to be a new idea for the clinical novel treatment of leukemia.