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Neck pain and low back pain are two of the major diseases, which causes patients a low quantify of life and a heavy economic burden, intervertebral disc degeneration (IDD) contributes to them, and the mechanism is not totally clear. The increased inflammatory cytokines including interleukin (IL)-1β and tumor necrosis factor (TNF)α and downstream signaling pathways are involved. Inositol requiring enzyme 1 (IRE1) is a crucial enzyme that regulates endoplasmic reticulum (ER) stress. It is reported that IRE1 plays an important role in the activation of NF-κB, PI3K/Akt and MAPK signaling pathways. Considering this, we performed a series of experiments in vitro and in vivo to evaluate the role of IRE1 in the progress of IDD. We demonstrated that IRE1 pathway was induced by IL-1β, inhibition of IRE1 suppressed the matrix degeneration of NP cells and ameliorated IDD grade in the punctured rat model. Further results indicated that inhibition of IRE1 suppressed HO induced cell senescence, IL-1β-induced cellular reactive oxygen species (ROS) level and the activation of NF-κB, PI3K/Akt and MAPK signaling pathways. It also played a crucial role in the apoptosis of NP cells and the progress of macrophage polarization. Our findings demonstrated that inhibition of IRE1 could suppress the degeneration of NP cells and prevent IDD in vivo. IRE1 may be a potential target for IDD treatment.
Learn More >Opioids are commonly prescribed for pain despite growing evidence of their low efficacy in the treatment of chronic inflammatory pain and the high potential for misuse. There is a clear need to investigate non-opioid alternatives for the treatment of pain. In the present study, we tested the hypothesis that acute and repeated dopamine agonist treatment would attenuate mechanical hypersensitivity in male Long-Evans rats experiencing chronic inflammatory pain. We used two clinically available therapeutics, l-DOPA (precursor of dopamine biosynthesis) and pramipexole (dopamine D2/3 receptor agonist), to examine the functional role of dopamine signaling on mechanical hypersensitivity using an animal model of chronic inflammatory pain (complete Freund's adjuvant, CFA). We found that both acute and repeated pramipexole treatment attenuated hyperalgesia-like behavior in CFA-treated animals but exhibited no analgesic effects in control animals. In contrast, there was no effect of acute or repeated l-DOPA treatment on mechanical hypersensitivity in either CFA- or saline-treated animals. Notably, we discovered some extended effects of l-DOPA and pramipexole on decreasing pain-like behavior at three days and one week post-drug treatment. We also examined the effects of pramipexole treatment on glutamatergic and presynaptic signaling in pain- and reward-related brain regions including the nucleus accumbens (NAc), dorsal striatum (DS), ventral tegmental area (VTA), cingulate cortex (CC), central amygdala (CeA), and periaqueductal gray (PAG). We found that pramipexole treatment decreased AMPA receptor phosphorylation (pGluR1845) in the NAc and DS but increased pGluR1845 in the CC and CeA. A marker of presynaptic vesicle release, pSynapsin, was also increased in the DS, VTA, CC, CeA, and PAG following pramipexole treatment. Interestingly, pramipexole increased pSynapsin in the NAc of saline-treated animals, but not CFA-treated animals, suggesting blunted presynaptic vesicle release in the NAc of CFA-treated animals following pramipexole treatment. To examine the functional implications of impaired presynaptic signaling in the NAc of CFA animals, we used ex vivo electrophysiology to examine the effects of pramipexole treatment on the intrinsic excitability of NAc neurons in CFA- and saline-treated animals. We found that pramipexole treatment reduced NAc intrinsic excitability in saline-treated animals but produced no change in NAc intrinsic excitability in CFA-treated animals. These findings indicate alterations in dopamine D2/3 receptor signaling in the NAc of animals with a history of chronic pain in association with the anti-hyperalgesic effects of pramipexole treatment.
Learn More >Malfunctioning synaptic plasticity is one of the major mechanisms contributing to the development of chronic pain. We studied spike-timing dependent depression (tLTD) in the ACC of male mice, a brain region involved in processing emotional aspects of pain. tLTD onto layer 5 pyramidal neurons depended on postsynaptic calcium-influx through GluN2B-containing NMDARs and retrograde signaling via nitric oxide to reduce presynaptic release probability. After chronic constriction injury of the sciatic nerve, a model for neuropathic pain, tLTD was rapidly impaired; and this phenotype persisted even beyond the time of recovery from mechanical sensitization. Exclusion of GluN2B-containing NMDARs from the postsynaptic site specifically at projections from the anterior thalamus to the ACC caused the tLTD phenotype, whereas signaling downstream of nitric oxide synthesis remained intact. Thus, transient neuropathic pain can leave a permanent trace manifested in the disturbance of synaptic plasticity in a specific afferent pathway to the cortex.Synaptic plasticity is one of the main mechanisms that contributes to the development of chronic pain. Most studies have focused on potentiation of excitatory synaptic transmission, but very little is known about the reduction in synaptic strength. We have focused on the ACC, a brain region associated with the processing of emotional and affective components of pain. We studied spike-timing dependent LTD, which is a biologically plausible form of synaptic plasticity, which depends on the relative timing of presynaptic and postsynaptic activity. We found a long-lasting and pathway-specific suppression of the induction mechanism for spike-timing dependent LTD from the anterior thalamus to the ACC, suggesting that this pathology might be involved in altered emotional processing in pain.
Learn More >Bone cancer pain (BCP) is the most frequently observed chronic cancer pain, and its development remains largely unexplored. Dysregulation of non-coding RNAs greatly contributes to the pathogenesis of BCP. In the present study, we found a new long noncoding RNA (lncRNA), NONRATT009773.2, and investigated its role in the spinal cord of BCP rats. Our results showed that NONRATT009773.2 was significantly up-regulated in BCP model rats, while depletion of NONRATT009773.2 attenuated BCP. In contrast, overexpression of NONRATT009773.2 triggered pain-like symptoms in normal animals. Moreover, NONRATT009773.2 functioned as a microRNA (miRNA) sponge to absorb miR-708-5p and up-regulated miRNA downstream target CXCL13, which plays fundamental roles in the initiation and maintenance of neuroinflammation and hyperalgesia. Collectively, our current findings indicated that NONRATT009773.2 could be employed as a new therapeutic target for BCP.
Learn More >To evaluate the effectiveness of telemedicine psychoeducational interventions (PIs) in adult patients on the clinical management of chronic non-oncological diseases compared with another therapeutic option or no treatment.
Learn More >Migraine affects more than a billion people all over the world and requires critical employment of healthcare resources. Telemedicine could be a reasonable tool to manage people suffering from headaches, and it received a big push from the COVID-19 pandemic.
Learn More >This study retrospectively studied the incidence of chronic post-surgical pain (CPSP) following single-stage implant-based breast reconstruction (IBBR) and evaluated the possible risk factors. This was a retrospective cohort study, involving all patients undergoing single-stage IBBR between January and December 2019. The follow-up was completed between January and March 2021. The scores for satisfaction (SS) were based on the BREAST-Q, while the pain burden index (PBI) was used to assess the degree of CPSP. The questionnaires were completed by 159 patients. CPSP occurred in 48.43% of the patients, 2.52% of them being severe cases. Significant predictors for the development of CPSP in the univariate analysis included severe acute postoperative pain (PP), a history of preoperative chronic pain, psychological disorders, SS with the reconstructed breasts, and whether there were any regrets about having had the reconstruction. Multivariate analysis identified severe acute PP (odds ratio (OR) = 2.80, 95% confidence interval (CI) = 1.16-6.79, p = 0.023), a history of preoperative chronic pain (OR = 3.39, 95% CI = 1.42-8.10, p = 0.006), and the SS (OR = 0.86, 95% CI = 0.75-0.99, p = 0.034) as being independently associated with the development of CPSP. In subgroup analysis, the PBI of the patients in the SS < 12 group (p < 0.001), the bilateral group (p < 0.01), and the severe acute PP group (p < 0.005) was significantly higher than the PBI of those in the control groups. This study demonstrated a significant incidence of CPSP following single-stage IBBR, and the patients with lower SS of their reconstructed breasts developed more CPSP. Lower SS, bilateral procedures, and severe acute PP were predictors of higher PBI.Trial registration: Registered in Chictr.org.cn registry system on 24 February 2020 (ChiCTR2000030139).
Learn More >As the relay centre for processing sensory information, the thalamus may involve in the abnormal sensory procedure caused by cortical spreading depression (CSD). However, few studies have focused on the transient response of thalamus during CSD. Our study aimed to investigate the neuronal activity of mouse thalamus ventral posteromedial nucleus (VPM) during CSD by in vivo micro-endoscopic fluorescence imaging of the genetic calcium probe GCaMP6s expressed in excitatory glutamatergic neurons.
Learn More >Interoception is the sensation of the physiological state inside one's body. Growing evidence suggests that visual feedback of interoception improves body self-consciousness (BSC) and reduces pain perception among patients with chronic pain. However, whether the integration of exteroception and interoception influences pain processing in healthy individuals remains largely unknown. To examine this question, we combined the rubber hand illusion (RHI) paradigm with visualized interoception -flashing of an LED light on the rubber hand synchronously or asynchronously with participants' real-time heartbeats. Under these conditions, we tested pain thresholds and corresponding event-related potentials. The interoceptive visual feedback inhibited the P2 component of pain, and the RHI inhibited pre-stimulus alpha-band brain activity. BSC had no significant effect on the processing of pain. These findings demonstrate that interoceptive signals with visual feedback inhibit pain processing, and that this psychophysiological process is largely independent of reported self-consciousness, in healthy individuals.
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