Changes In Pain Threshold Research Articles

Tonic Cold Pain Temporal Summation and Translesional Cold Pressor Test-Induced Pronociception in Spinal Cord Injury: Association with Spontaneous and Below-Level Neuropathic Pain.

Background/Objectives: Although increased nociceptive excitability and deficient endogenous pain modulation are considered key features of pronociception and central sensitization, their contribution to neuropathic pain (NP) characteristics in SCI is unclear. The aim of this study was to characterize tonic cold perception and endogenous pain modulation in individuals with and without SCI-NP, considering the stage and severity of SCI and, secondarily, NP phenotype. Methods: Temporal summation of pain (TSP) and neuropathic features were assessed using the numerical rating scale (NRS) and Douleur Neuropathique 4 screening questionnaire (DN4) during the tonic cold pressor test (CPT, 12 °C 60 s) applied to the dominant hand and foot. CPT-induced pronociception was assessed as change in algometer pressure pain thresholds (PPTs) measured at the V2, C6, and L4 dermatomes. Results: A total of 72 individuals were recruited (age-sex-matched noninjured, n = 24; SCI-NP, n = 24; SCI-noNP, n = 24 [AIS A: n = 12, AIS B-D: n = 12; subacute SCI: n = 12, chronic SCI: n = 12]). TSP in response to the foot CPT was higher in subacute compared to chronic incomplete SCI-NP, while TSP to the hand CPT was significantly higher in chronic compared to the subacute complete SCI-NP group. Evoked pain intensity during the hand CPT correlated with duration of below-level SCI-NP. The hand CPT induced widespread pronociception (lower PPT), which correlated with 7-day non-evoked (spontaneous) pain intensity in individuals with incomplete SCI-NP. Individuals with below-level NP, but not at-level NP, showed higher TSP during the foot CPT and greater hand CPT-induced L4 dermatome pronociception. Conclusions: Collectively, measurements of above and below-level temporal summation of pain and translesional-induced pronociception in the SCI-NP group highlight the role of these mechanisms in widespread central sensitization, spontaneous pain intensity, and spinothalamic tract hyperexcitability, especially in individuals diagnosed with below-level NP.

Hypoalgesia and Conditioned Pain Modulation in Blood Flow Restriction Resistance Exercise.

We compared the magnitude of exercise-induced hypoalgesia and conditioned pain modulation between blood-flow restriction (BFR) resistance exercise (RE) and moderate-intensity RE. Twenty-five asymptomatic participants performed unilateral leg press in two visits. For moderate-intensity RE, subjects exercised at 50% 1RM without BFR, whereas BFR RE exercised at 30% 1RM with a cuff inflated to 60% limb occlusion pressure. Exercise-induced hypoalgesia was quantified by pressure pain threshold changes before and after RE. Conditioned pain modulation was tested using cold water as the conditioning stimulus and mechanical pressure as the test stimulus and quantified as pressure pain threshold change. Difference in conditioned pain modulation pre- to post-RE was then calculated. The differences of RE on pain modulations were compared using paired t-tests. Pearson's r was used to examine the correlation between exercise-induced hypoalgesia and changes in conditioned pain modulation. We found greater hypoalgesia with BFR RE compared to moderate-intensity RE (p=0.008). Significant moderate correlations were found between exercise-induced hypoalgesia and changes in conditioned pain modulation (BFR: r=0.63, moderate-intensity: r=0.72). BFR RE has favorable effects on pain modulation in healthy adults and the magnitude of exercise-induced hypoalgesia is positively correlated with conditioned pain modulation activation.

Spatiotemporal characterization of an experimental model of muscle pain in humans based on short-wave diathermy.

Commonly used models for eliciting muscle pain involve the injection of algesic substances or the induction of delayed onset muscle soreness. The former require invasive procedures, and the time frame for pain induction and subsidence in the latter can be inconvenient. This study presents a detailed spatiotemporal characterization of a new experimental model of muscle pain based on short-wave diathermy (SWD), developed to overcome the limitations of existing models. The shoulder was selected as target site and the effects of the model were tested in two sessions to assess its reliability. Pain intensity profiles were recorded during the application of SWD, and changes in pressure pain threshold (PPT) in the infraspinatus muscle, together with pain intensity, duration, and quality were assessed 30 min after induction. SWD-induced pain intensity scores averaged 4 points on a visual analogue scale, whereas PPT showed a consistent decrease of about 25% relative to baseline values. Pain was localized in the shoulder area, and was described as continuous, dull, well-delimited, heavy, and bearable. Pain lasted for an average of 145 min without requiring reinduction and was reliably elicited in both experimental sessions. SWD can be used to elicit experimental muscle pain in a non-invasive, long-lasting, and reliable way and allows for repeated within- and between-session testing in the shoulder. SWD produces deep heating in muscles by converting electromagnetic energy to thermal energy. It was previously shown that it can be used to elicit experimental pain in the forearm muscles, and the present study demonstrates that this can be reliably generalized to other body sites, such as the shoulder. Furthermore, SWD application is non-invasive and presents a convenient time frame for pain induction and subsidence, thus overcoming limitations associated with traditional muscle pain models.

The effect of resistance exercise on multimodal pain thresholds in local and systemic muscle sites.

Dynamic resistance exercise may produce reductions in pain locally at the exercising muscle and systemically at non-exercising sites. However, limited research has examined these changes with multiple noxious stimuli. This study examined changes in heat pain threshold (HPT) and pressure pain threshold (PPT) on different musculature after an upper and lower body exercise to compare local and systemic effects. A crossover design with 28 participants (mean age: 21 ± 4 years, 21 female) completed three sessions. Visit one included baseline quantitative sensory testing and 5-repetition maximum (RM) testing for upper (shoulder press) and lower (leg extension) body. In subsequent sessions, participants performed upper or lower body exercises using an estimated 75% 1-RM with pre/post assessment of HPT and PPT at three sites: deltoid, quadriceps, and low back. A significant three-way interaction was observed for HPT (F (1.71, 3.80) = 2.19, p = 0.036, η2p = 0.12) with significant increases in HPT over the quadriceps (p = 0.043) after leg extension and over the deltoid (p = 0.02) after shoulder press. Significant systemic changes were not observed for HPT or PPT. Local but not systemic effects were demonstrated after an acute bout of exercise. Peripheral pain sensitivity may be more responsive to heat stimuli after resistance exercise.

Inhibition of miR-199b-5p reduces pathological alterations in osteoarthritis by potentially targeting Fzd6 and Gcnt2

Osteoarthritis (OA) is a degenerative disease with a high prevalence in the elderly population, but our understanding of its mechanisms remains incomplete. Analysis of serum exosomal small RNA sequencing data from clinical patients and gene expression data from OA patient serum and cartilage obtained from the GEO database revealed a common dysregulated miRNA, miR-199b-5p. In vitro cell experiments demonstrated that miR-199b-5p inhibits chondrocyte vitality and promotes extracellular matrix degradation. Conversely, inhibition of miR-199b-5p under inflammatory conditions exhibited protective effects against damage. Local viral injection of miR-199b-5p into mice induced a decrease in pain threshold and OA-like changes. In an OA model, inhibition of miR-199b-5p alleviated the pathological progression of OA. Furthermore, bioinformatics analysis and experimental validation identified Gcnt2 and Fzd6 as potential target genes of MiR-199b-5p. Thus, these results indicated that MiR-199b-5p/Gcnt2 and Fzd6 axis might be a novel therapeutic target for the treatment of OA.

Inhibition of miR-199b-5p reduces pathological alterations in osteoarthritis by potentially targeting Fzd6 and Gcnt2.

Osteoarthritis (OA) is a degenerative disease with a high prevalence in the elderly population, but our understanding of its mechanisms remains incomplete. Analysis of serum exosomal small RNA sequencing data from clinical patients and gene expression data from OA patient serum and cartilage obtained from the GEO database revealed a common dysregulated miRNA, miR-199b-5p. In vitro cell experiments demonstrated that miR-199b-5p inhibits chondrocyte vitality and promotes extracellular matrix degradation. Conversely, inhibition of miR-199b-5p under inflammatory conditions exhibited protective effects against damage. Local viral injection of miR-199b-5p into mice induced a decrease in pain threshold and OA-like changes. In an OA model, inhibition of miR-199b-5p alleviated the pathological progression of OA. Furthermore, bioinformatics analysis and experimental validation identified Gcnt2 and Fzd6 as potential target genes of MiR-199b-5p. Thus, these results indicated that MiR-199b-5p/Gcnt2 and Fzd6 axis might be a novel therapeutic target for the treatment of OA.

The Effect of Myofascial Stretching on Mechanical Nociception and Contributing Neural Mechanisms.

Myofascial stretching is often prescribed in the management of musculoskeletal pain. However, the neural mechanisms contributing to a decrease in pain are unknown. Stretching produces a sensation that may act as a conditioning stimulus in a conditioned pain modulation response. The purpose of this study was to compare immediate changes in pressure pain thresholds (PPTs) during a low-intensity stretch, moderate-intensity stretch, and cold water immersion task. A secondary purpose was to examine if personal pain sensitivity and psychological characteristics were associated with the responses to these interventions. Twenty-seven (27) healthy participants underwent a cross-over study design in which they completed a cold water immersion task, upper trapezius stretch to the onset of the stretch sensation, and a moderate-intensity stretch. A significant condition x time effect was observed (F (8,160) = 2.85, p < 0.01, partial eta2 = 0.13), indicating reductions in pain sensitivity were significantly greater during a cold water immersion task compared to moderate-intensity stretching at minutes two and four. Widespread increases in heat pain threshold and lower pain-related anxiety were moderately correlated with the response to the cold water immersion task but not stretching. Moderate-intensity stretching may not elicit a conditioned pain modulation response possibly because the stretch was not intense enough to be perceived as painful.

MiR-21-5p alleviates trigeminal neuralgia in rats through down-regulation of voltage-gated potassium channel Kv1.1.

Trigeminal neuralgia (TN) is a common neuropathic pain. Voltage-gated potassium channel (Kv) has been confirmed to be involved in the occurrence and development of TN, but the specific mechanism is still unclear. MicroRNA may be involved in neuropathic pain by regulating the expression of Kv channels and neuronal excitability in trigeminal ganglion (TG). This study aims to explore the relationship between Kv1.1 and miR-21-5p in TG with a TN model, evaluate whether miR-21-5p has a regulatory effect on Kv1.1, and to provide a new target and experimental basis for the treatment of TN. A total of 48 SD rats were randomly divided into 6 groups: 1) a sham group (n=12), the rats were only sutured at the surgical incision without nerve ligation; 2) a sham+agomir NC group (n=6), the sham rats were microinjected with agomir NC through stereotactic brain injection in the surgical side of TG; 3) a sham+miR-21-5p agomir group (n=6), the sham rats were microinjected with miR-21-5p agomir via stereotactic brain injection in the surgical side of TG; 4) a TN group (n=12), a TN rat model was constructed using the chronic constriction injury of the distal infraorbital nerve (dIoN-CCI) method with chromium intestinal thread; 5) a TN+antagonist NC group (n=6), TN rats were microinjected with antagonist NC through stereotactic brain injection method in the surgical side of TG; 6) a TN+miR-21-5p antagonist group (n=6), TN rats were microinjected with miR-21-5p antagonist through stereotactic brain injection in the surgical side of TG. The change of mechanical pain threshold in rats of each group after surgery was detected. The expressions of Kv1.1 and miR-21-5p in the operative TG of rats were detected by Western blotting and real-time reverse transcription polymerase chain reaction. Dual luciferase reporter genes were used to determine whether there was a target relationship between Kv1.1 and miR-21-5p and whether miR-21-5p directly affected the 3'-UTR terminal of KCNA1. The effect of brain stereotaxic injection was evaluated by immunofluorescence assay, and then the analogue of miR-21-5p (agomir) and agomir NC were injected into the TG of rats in the sham group by brain stereotaxic apparatus to overexpress miR-21-5p. The miR-21-5p inhibitor (antagomir) and antagomir NC were injected into TG of rats in the TN group to inhibit the expression of miR-21-5p. The behavioral changes of rats before and after administration were observed, and the expression changes of miR-21-5p and Kv1.1 in TG of rats after intervention were detected. Compared with the baseline pain threshold, the facial mechanical pain threshold of rats in the TN group was significantly decreased from the 5th to 15th day after the surgery (P<0.05), and the facial mechanical pain threshold of rats in the sham group was stable at the normal level, which proved that the dIoN-CCI model was successfully constructed. Compared with the sham group, the expression of Kv1.1 mRNA and protein in TG of the TN group was down-regulated (both P<0.05), and the expression of miR-21-5p was up-regulated (P<0.05). The results of dual luciferase report showed that the luciferase activity of rno-miR-21-5p mimics and KCNA1 WT transfected with 6 nmol/L or 20 nmol/L were significantly decreased compared with those transfected with mimic NC and wild-type KCNA1 WT, respectively (P<0.001). Compared with low dose rno-miR-21-5p mimics (6 nmol/L) co-transfection group, the relative activity of luciferase in the high dose rno-miR-21-5p mimics (20 nmol/L) cotransfection group was significantly decreased (P<0.001). The results of immunofluorescence showed that drugs were accurately injected into TG through stereotaxic brain. After the expression of miR-21-5p in the TN group, the mechanical pain threshold and the expression of Kv1.1 mRNA and protein in TG were increased. After overexpression of miR-21-5p in the sham group, the mechanical pain threshold and the expression of Kv1.1 mRNA and protein in TG were decreased. Both Kv1.1 and miR-21-5p are involved in TN and miR-21-5p can regulate Kv1.1 expression by binding to the 3'-UTR of KCNA1.

Temporal summation does not predict the acupuncture response in patients with chronic non-specific low back pain.

Previously, we had observed that immediate pain reduction after one acupuncture treatment was associated with high temporal summation of pain (TS) at a pain free control site and younger age in a mixed population of chronic pain patients. The aim of the present study was to verify these results in chronic non-specific low back pain (LBP) and to collect pilot data on the association between TS and the response to an acupuncture series. TS at a pain free control site (back of dominant hand) and at the pain site was quantified by the pin-prick induced wind-up ratio (WUR) in 60 LBP patients aged 50 years or younger. Response to one acupuncture treatment was assessed by change in pain intensity and pressure pain threshold (PPT) at the pain site. The primary hypothesis was that a high TS (WUR > 2.5) would be associated with a clinically relevant reduction in pain intensity of at least 30%. In study part two, 26 patients received nine additional treatments. Response to the acupuncture series was assessed by the pain intensity during the last week, the PPT and the Hannover functional ability questionnaire (FFbH-R). An immediate reduction in pain intensity of at least 30% was frequent irrespective of TS at the control site (low vs. high TS 58% vs. 72%, p = 0.266). High TS at the pain site was also not significantly associated with a clinically relevant immediate reduction in pain intensity (low vs. high TS 46% vs. 73%, p = 0.064). The PPT was not changed after one acupuncture treatment. Study part two did not reveal a consistent association between TS at the control site and any of the outcome measures but also a trend toward a higher chance for a clinically relevant response along with low TS at the pain site. Our results do not suggest an important role of TS for predicting a clinically important acupuncture effect or the response to a series of 10 acupuncture treatments in patients with chronic non-specific LBP. Overall high response rates imply that acupuncture is a suitable treatment option for LBP patients irrespective of their TS.

Methylphenidate attenuates signs of evoked neuropathic pain in animal model.

Methylphenidate is a psychostimulant that increases dopamine and noradrenaline levels. Recent studies have shown that methylphenidate potentiates the effect of morphine and together suppress acute and chronic pain. In clinical practice, methylphenidate has been used as a treatment for ADHD and changes of pain threshold have been noted in these patients. The aim of this study was to determine the effect of methylphenidate in an animal model of peripheral neuropathic pain. Neuropathic pain was modeled by the chronic constriction of the sciatic nerve (CCI) in Wistar rats. We evaluated the effect of methylphenidate (1 mg/kg, s.c.) on evoked pain (reflex tests - plantar test, vonFrey test and operant test - thermal place preference) and on spontaneous pain (conditioned place preference). CCI induced thermal, mechanical and cold hyperalgesia/allodynia. Methyphenidate suppressed mechanical and cold hyperalgesia/allodynia, while had no effect on thermal one. Therefore, methylphenidate seems to be a new potential pharmacotherapy for the treatment of neuropathic pain.

The effectiveness of using pulsed electromagnetic fields for osteoarthritis of the knee joint

BACKGROUND: Osteoarthritis is one of the most common forms of pathology of the musculoskeletal system with significant impairment of motor function, which is one of the main causes of disability in the population.&#x0D; AIM: This study was aimed at testing the effectiveness of the portable device "ALMAG+" with pulsed electromagnetic fields in the treatment of pain in patients with osteoarthritis of the knee joint.&#x0D; MATERIALS AND METHODS: This randomized, double-blind, placebo-controlled clinical trial included patients with radiographic evidence of knee osteoarthritis and persistent pain greater than 40 mm on a visual analogue scale (VAS). The study included daily treatment with pulsed electromagnetic fields from the ALMAG+ device for 1 month in 60 patients with knee osteoarthritis. The primary outcome measure was reduction in pain intensity assessed by VAS and WOMAC scales. Secondary outcomes included the 36-item Short Form Medical Outcomes Study version 2 (SF-36 v2) quality of life, pressure pain threshold, and changes in non-steroidal anti-inflammatory drug/analgesic use.&#x0D; RESULTS: Sixty-six patients were enrolled in the study, and 60 completed the study. After 1 month of treatment, pulsed electromagnetic fields caused a significant reduction in pain VAS and WOMAC scores compared to placebo. In addition, patients receiving pulsed electromagnetic fields improved pain tolerance, which was reflected in changes in pain threshold, and physical condition. We obtained a significant and statistically significant effect of the organized pulsed electromagnetic fields factor on VAS pain scores (F=47.6; p=0.00006); assessments of the severity of pain, joint function and stiffness on the scales of the WOMAC questionnaire also significantly changed under the influence of the pulsed electromagnetic fields factor (F=14.7; p=0.001). 26% of patients in the pulsed electromagnetic fields group discontinued non-steroidal anti-inflammatory drug/analgesic therapy. No adverse events were identified during treatment.&#x0D; CONCLUSION: These results suggest that pulsed electromagnetic fields therapy is effective in relieving pain in patients with knee osteoarthritis and also affects pain threshold, stiffness, and physical functioning. In the future, it is desirable to conduct larger studies, including those comparing the effectiveness of pulsed electromagnetic fields therapy with standard pharmacological approaches for osteoarthritis.

Clinical effects of different virtual reality presentation content on anxiety and pain: a randomized controlled trial

Many patients are frightened of or anxious about dental treatment. We have recently reported our use of virtual reality (VR) to alleviate the fear and anxiety experienced during oral surgical procedures However, the effectiveness of VR in alleviating anxiety varies greatly between individuals. We therefore investigated whether the content of the VR presentation made any difference to its effect in alleviating anxiety, and whether it had any analgesic effect. The study subjects experienced one of two different types of VR presentation and were asked to complete a questionnaire about any changes in their anxiety during the procedure, including a visual analog scale (VAS) score. As an objective evaluation, changes in pain threshold during the VR presentation were investigated using PainVision. For those patients who experienced a presentation showing a natural landscape, the change in VAS score was − 13.3 ± 28.7 mm, whereas for those who experienced a presentation showing a video game the change was − 22.2 ± 32.1 mm, an even greater reduction. In a pain questionnaire completed by individuals who had experienced the video game presentations, approximately 70% reported that their pain had diminished. An objective evaluation of pain threshold also showed that the pain threshold of individuals increased by around 3% while experiencing the natural landscape VR presentation, but that while experiencing the video game presentation, it increased significantly by around 15% compared with baseline. These results show that the content of the presentation affected not only the rate of decrease in anxiety, but also the pain threshold.

The hypoalgesic effects of wrist extensors training with blood flow restriction in patients with lateral elbow tendinopathy: a study protocol for a cross-over randomized controlled trial

Background: Lateral elbow tendinopathy (LET) is a disabling overuse injury with a significant healthcare burden. Despite the fact that exercise interventions are considered the best recommended treatment option of LET, their effectiveness in reducing pain and improving function remains debatable. The aim of our study is to evaluate the immediate effects of a new method of exercise using blood flow restriction (BFR) on pain perception and pain-free grip strength in patients with LET. Methods: This study was designed as a cross-over randomized controlled trial. We will compare an intervention using wrist extensors training with (WET-BFR) to a control intervention using WET-without-BFR in patients with LET. All measurements will be taken by a blinded assessor pre- and post-intervention. Primary outcome measures will be the changes in pressure pain thresholds at the lateral epicondyle, extensor carpi radialis brevis, C4 vertebra and tibialis anterior. Secondary outcome measure will be the changes in pain-free grip strength ratio. Conclusions: New approaches are needed to improve the treatment outcomes in LET. Although BFR training was found more effective in improving function and treatment success than conventional training, the effects on pain intensity were poor. Our hypothesis is that using the best BFR practice guidelines for wrist extensors training might be more effective to reduce pain sensitivity compared with non-BFR training in patients with LET. The trial will provide new research data to inform clinical practice regarding the effects of using BFR training in the current patient group. Trial registration: University of West Attica ethics committee: 9150/01-02-2023, ClinicalTrials.gov: NCT05919914

Reliability of quantitative sensory testing in the assessment of somatosensory function after high-frequency stimulation-induced sensitisation of central nociceptive pathways.

The high frequency stimulation (HFS) model can be used alongside quantitative sensory testing (QST) to assess the sensitisation of central nociceptive pathways. However, the validity and between-session reliability of using QST z -score profiles to measure changes in mechanical and thermal afferent pathways in the HFS model are poorly understood. In this study, 32 healthy participants underwent QST before and after HFS (5× 100 Hz trains; 10× electrical detection threshold) in the same heterotopic skin area across 2 repeated sessions. The only mechanical QST z -score profiles that demonstrated a consistent gain of function across repeated test sessions were mechanical pain threshold (MPT) and mechanical pain sensitivity (MPS), which were associated with moderate and good reliability, respectively. There was no relationship between HFS intensity and MPT and MPS z -score profiles. There was no change in low intensity, but a consistent facilitation of high-intensity pin prick stimuli in the mechanical stimulus response function across repeated test sessions. There was no change in cold pain threshold (CPT) and heat pain threshold (HPT) z -score profiles across session 1 and 2, which were associated with moderate and good reliability, respectively. There were inconsistent changes in the sensitivity to innocuous thermal QST parameters, with cool detection threshold (CDT), warm detection threshold (WDT), and thermal sensory limen (TSL) all producing poor reliability. These data suggest that HFS-induced changes in MPS z -score profiles is a reliable way to assess experimentally induced central sensitisation and associated secondary mechanical hyperalgesia in healthy participants.

Role and anti-inflammatory mechanisms of acupuncture and moxibustion therapy on pain relief through NOX-ROS-NLRP3 pathway in CCI rats models.

To observe the effects of acupuncture and moxibustion therapy on pain relief in sciatica rats and to explore the mechanism of its anti-inflammatory effect. SPF grade 4-6-week-old Kunming rats were randomly divided into 5 groups including a blank group, sham-operated group, model group, acupuncture, and moxibustion (AnM) group, and positive group. A total of 10 rats were included in each group. The model group, the AnM group, and the positive group were prepared by ligating the left sciatic nerve. AnM group was used for acupuncture and moxibustion therapy intervention, and the positive group was rendered to quick-acting sciatica pills once a day for 7 days (3 courses of treatment). The blank group, sham-operated group, and model group were not treated. The changes in thermal and mechanical pain thresholds were observed before and after the operation, and the morphological changes of the dorsal horn of the spinal cord in the lumbosacral region of the rats in each group were observed by HE staining after the courses of treatment finished. The contents of IL-1β, IL-6, IL-18, and TNF-α were measured by ELISA and the expressions of NOX1, NOX2, NOX4, and NLRP3 genes were detected by RT-qPCR while the protein expressions of NOX1, NOX2, NOX4 and NLRP3 were analyzed by Western blotting. The AnM and positive group showed a significant increase in thermal and mechanical pain thresholds after treatment, while there was no significant change in the model group. As compared to the control group, the contents of IL- 1β, IL-6, IL-18, and TNF-α, as well as the relative expressions of NOX1, NOX2, NOX4, and NLRP3 genes were significantly increased in the model group (P < 0.05 or P < 0.01). As compared to the model group, the contents of IL-1β, IL-6, IL-18, and TNF-α, as well as the relative expressions of NOX1, NOX2, NOX4, and NLRP3 genes significantly decreased in the AnM and positive groups (P < 0.05 or P < 0.01). The pathological changes of inflammatory infiltration of tissue cells in the dorsal horn of the lumbosacral spinal cord were slowed in the AnM group. Acupuncture and moxibustion therapy have a positive effect on pain relief and anti-inflammatory effects in CCI sciatica rats, which may point to the regulation of NOX1, NOX2, NOX4, and NLRP3 expressions, and inhibition of ROS.

Wistar Rat Parietal Lobe Cell And Pain Perception Changes After Frequent Of Mobile Phone Electromagnetic Wave Expose

Background: The increasing number of mobile phone users raises concerns about the effects. Mobile phone electromagnetic wave radiation harms pain perception due to granular cell changes in the cerebral parietal cortex. Objective: To determine the effect of exposure to electromagnetic waves mobile phone on pain perception due to changes in the granular cells of the cerebral parietal cortex Wistar rats. Methods: Experimental research using randomized posttest with control group design. Samples were 28 rats divided into 4 groups. The control group was not exposed, the treatment group was exposed to 2100 MHz electromagnetic waves for 2 hours/day with a distance of 3 cm for 15 days in treatment group 1, for 30 days in treatment group 2, and 45 days in treatment group 3. Measurement of pain onset using the hot method. Changes in pain threshold were taken from the difference in pain onset after exposure to before exposure. Granular cell changes in the cerebral parietal cortex were assessed from the total score with the provisions of normal cells (sumx0), hydropic degenerated cells (sumx1), and necrotic cells (sumx2). Results: The longer the exposure to mobile phones, the higher the pain threshold and the cerebral parietal cortex granular cell damage score. There was a significant difference in pain threshold and changes in cerebral parietal cortex granular cells between groups (p=0.000). There was a significant relationship between changes in the parietal cerebral cortex granular cells and pain threshold in Wistar rats exposed to electromagnetic waves (p=0.000). Conclusion: Exposure to mobile phone electromagnetic waves affects pain perception due to changes in the granular cells of the cerebral parietal cortex in wistar rats.

The Influence of Visual Feedback-based Eccentric Pulley Training on Motion Speed and Pressure Pain Threshold Changes in Low Back Pain Patient

The Influence of Visual Feedback-based Eccentric Pulley Training on Motion Speed and Pressure Pain Threshold Changes in Low Back Pain Patient

Reduction of Pain After Laparoscopic Bariatric Surgery by Personalized Checkpoint Acupuncture—Data of a STRICTA Conform Pilot Study

BackgroundItremains challenging in clinical practice to perform optimal pain management following bariatric surgeries. Acupuncture (AC) is an effective method of postoperative pain management, but its clinical efficacy depends on the rationale used to select AC points.MethodsWe developed a method to identify individual patterns of pain and a corresponding set of acupoints (corrAC) based on the relative pressure sensitivity of six abdominal visceral pressure points, i.e., the gastrointestinal (GI) checkpoints (G1–G6). Patients with moderate to severe pain were included and received a single AC treatment following surgery. The visual analog scale (VAS) score, pain threshold, and skin temperature were assessed before AC and at 5 min, 1 h, and 24 h following AC. AC was performed with 1-mm-deep permanent needles.ResultsFrom April 2021 to March 2022, 72 patients were included in the analysis. Fifty-nine patients received corrAC, whereas 13 received a noncorresponding AC (nonAC) as an internal control. Patients receiving corrAC showed a significant reduction (74%) in pain at 5 min after treatment (p < 0.0001) and a significant increase (37%) in the pain threshold (p < 0.0001). In this group, a significant increase in skin temperature above G1, G3, G4, and G5 was observed. Patients receiving nonAC showed neither significant pain reduction nor significant changes in pain threshold. The skin above G3 and G4 did not reveal temperature changes.ConclusionCheckpoint AC may be an effective tool in postoperative pain therapy after bariatric surgery. Vegetative functional involvement might be associated with pain relief.Graphical

An investigation of the change in facial pain threshold after auricular acupuncture in healthy volunteers: a pilot study

Auricular Acupuncture (AA) is both a diagnostic method and a treatment used to relieve pain and alleviate addictions. The effects and biological mechanisms of AA on the human body have been increasingly observed in clinical and experimental studies based on the gate control theory and the endogenous opioids theory. The purpose of this study was to investigate changes in facial pain thresholds among healthy volunteers after applying AA to acupoints on both auricles. This was a pilot study with a crossover randomized controlled trial design. 66 healthy volunteers with normal hemodynamic indexes were randomly assigned to one of two groups to receive AA treatment at the Shenmen point, Sympathetic point, Adrenal gland point, Jaw point, and Tooth point of either the left or right auricle (phase 1). 7 days later, participants received sham acupuncture at the same points (phase 2). In phase 1, the results showed that AA at these points in either auricle increased the pain threshold of the facial skin statistically significantly (p&lt;0.05). No statistically significant difference was detected in the sham acupuncture phase. This suggests that AA can be used as a non-pharmacological adjunct to facial pain relief.

An illusion of disownership over one’s own limb is associated with pain perception

Viewing one’s body and even a fake/virtual body experienced as one’s own has been suggested to modulate pain perception. However, what happens to pain perception when one’s own body part is felt as not belonging to one? We designed a paradigm to induce an illusory feeling of disownership regarding one’s limb, investigating whether the feeling affects pain threshold. Participants observed right-side images of their bodies from a third-person perspective via a head-mounted display in real-time. Following instructions, they moved their left hand while keeping their left elbow behind the upper body, so that the connection of their arm to the torso was not visible (test condition), or in front of it, so they could see the arm being part of them (control condition). Then, pain threshold was tested with a thermal stimulator. We found a significantly higher strength of disownership in the test condition than in the control condition. While there was no pain modulation within and between conditions, disownership ratings negatively correlated with pain-threshold changes, where the participants reporting explicit disownership showed lower pain-threshold changes than the others. The finding suggests that while multisensory disintegration had no modulatory effect, the individual sense of disownership was associated with pain perception.