Far infrared-emitting ceramics decrease Freund's adjuvant-induced inflammatory hyperalgesia in mice through cytokine modulation and activation of peripheral inhibitory neuroreceptors

Enhanced far infrared emissivity, UV protection and near-infrared shielding of polypropylene composites via incorporation of natural mineral for functional fabric development

Far infrared radiation in the range of 4-20 µm has been showed to have biological and health benefits to the human body. Therefore, incorporating far-infrared emissivity additives into polymers and/or fabrics hold promise for the development of functional textiles. In this study, we incorporated nine types of natural minerals into polypropylene (PP) film and examined their properties to identify potential candidates for functional textiles and apparels. The addition of 2% mineral powders into PP film increased the far-infrared emissivity (5-14 µm) by 7.65%-14.48%. The improvement in far-infrared emissivity within the range of 5-14 µm, which overlaps with the peak range of human skin radiation at 8-14 µm, results in increased absorption efficiency, and have the potential to enhance thermal and biological effects. Moreover, the incorporation of mineral powders in PP films exhibited favorable ultraviolet (UV) protection and near-infrared (NIR) shielding properties. Two films, specifically those containing red ochre and hematite, demonstrated excellent UV protection with a UPF rating of 50+ and blocked 99.92% and 98.73% of UV radiation, respectively. Additionally, they showed 95.2% and 93.2% NIR shielding properties, compared to 54.1% NIR shielding properties of PP blank films. The UV protection and NIR shielding properties offered additional advantages for the utilization of polymer composite with additives in the development of sportswear and other outdoor garments. The incorporation of minerals could absorb near-IR radiation and re-emit them at longer wavelength in the mid-IR region. Furthermore, the incorporation of minerals significantly improved the heat retention of PP films under same heat radiation treatment. Notably, films with red ochre and hematite exhibited a dramatic temperature increase, reaching 2.5 and 3.2 times the temperature increase of PP films under same heat radiation treatment, respectively (46.8 °C and 59.9 °C higher than the temperature increase of 20.9 °C in the PP film). Films with additives also demonstrated lower thermal effusivity than PP blank films, indicating superior heat insulation properties. Therefore, polypropylene films with mineral additives, particularly those containing red ochre and hematite, showed remarkable heat capacity, UV-protection, NIR-shielding properties and enhanced far infrared emissivity, making them promising candidates for the development of functional textiles.

Complex Regional Pain Syndrome Type I: Evidence for the CB1 and CB2 Receptors Immunocontent and Beneficial Effect of Local Administration of Cannabidiol in Mice

Introduction: Complex regional pain syndrome type I (CRPS-I) is a debilitating neuropathic painful condition associated with allodynia, hyperalgesia, sudomotor and/or vasomotor dysfunctions, turning investigation of its pathophysiology and new therapeutic strategies into an essential topic. We aim to investigate the impact of ischemia/reperfusion injury on the immunocontent of CB1 and CB2 cannabinoid receptor isoforms in the paws of mice submitted to a chronic postischemia pain (CPIP) model and the effects of local administration of cannabidiol (CBD) on mechanical hyperalgesia. Methods: Female Swiss mice, 30-35 g, were submitted to the CPIP model on the right hind paw. Skin and muscle samples were removed at different periods for western blot analysis. Results: No changes in the immunocontent of CB1 and CB2 receptors in paw muscle tissues after ischemia-reperfusion were observed. CBD promoted an antihyperalgesic effect in both phases. AM281 reversed the effect of CBD, whereas ruthenium red abolished the late phase. Conclusion: Our results point to the possible beneficial effects of local administration of CBD in modulating CRPS-I in humans. As possible targets for CBD antihyperalgesia in this model, the contribution of cannabinoid receptor CB1, in addition to TRPM8 is suggested.

Caffeine Attenuates Electroacupuncture Effect on Pressure Pain Threshold and Tolerance in Healthy Individuals: A Randomized Controlled Trial

Introduction

The effect of caffeine on acupuncture analgesia in humans is unclear. This study aimed to investigate whether caffeine-containing beverage intake influences the effect of electroacupuncture (EA) on static quantitative sensory testing (QST) and dynamic QST in healthy subjects.

Methods

A total of 40 healthy subjects were enrolled and randomly assigned to receive coffee containing moderate doses of caffeine (coffee group) or non-caffeinated juice (juice group) for 4 weeks. The primary outcome measures were the pressure pain threshold (PPT), pressure pain tolerance (PPTo), and heat pain threshold (HPT) as static QST parameters. Numerical rating scales (NRS) of heat stimulus and nociceptive flexor reflex (RIII reflex), as parameters of dynamic QST, were also examined. EA stimulation with tolerance intensity was performed at ST36 (Zusanli)-GB34 (Yanglingquan) points at weeks 0, 2, and 4. PPT, PPTo, and HPT were detected pre- and post- EA. The NRS scores were examined pre-, during, and post-EA, and 1 min after EA was completed. The RIII reflex was examined pre- and 1–5 min post-EA.

Results

At week 0, both groups showed increased PPT and PPTo and decreased NRS scores of heat stimuli and RIII reflex after EA, but HPT was not affected. After 4 weeks, the effects of EA on PPT and PPTo were attenuated in the coffee group compared to the juice group, whereas the effect of EA on the NRS scores and RIII reflex were not influenced. There was no significant difference found at week 2 for these indications. EA also did not affect the HPT in both groups at week 4.

Conclusion

Moderate caffeine intake reduced the effects of EA on PPT and PPTo in healthy subjects.

Decrease of IL-1β and TNF in the Spinal Cord Mediates Analgesia Produced by Ankle Joint Mobilization in Complete Freund Adjuvant-Induced Inflammation Mice Model

Objective

This study aims to investigate the effects of ankle joint mobilization (AJM) on mechanical hyperalgesia and peripheral and central inflammatory biomarkers after intraplantar (i.pl.) Complete Freund’s Adjuvant (CFA)-induced inflammation.

Methods

Male Swiss mice were randomly assigned to 3 groups (n = 7): Saline/Sham, CFA/Sham, and CFA/AJM. Five AJM sessions were carried out at 6, 24, 48, 72, and 96 h after CFA injection. von Frey test was used to assess mechanical hyperalgesia. Tissues from paw skin, paw muscle and spinal cord were collected to measure pro-inflammatory (TNF, IL-1β) and anti-inflammatory cytokines (IL-4, IL-10, and TGF-β1) by ELISA. The macrophage phenotype at the inflammation site was evaluated by Western blotting assay using the Nitric Oxide Synthase 2 (NOS 2) and Arginase-1 immunocontent to identify M1 and M2 macrophages, respectively.

Results

Our results confirm a consistent analgesic effect of AJM following the second treatment session. AJM did not change cytokines levels at the inflammatory site, although it promoted a reduction in M2 macrophages. Also, there was a reduction in the levels of pro-inflammatory cytokines IL-1β and TNF in the spinal cord.

Conclusion

Taken together, the results confirm the anti-hyperalgesic effect of AJM and suggest a central neuroimmunomodulatory effect in a model of persistent inflammation targeting the pro-inflammatory cytokines IL-1β and TNF.

Infrared radiation from cage bedding moderates rat inflammatory and autoimmune responses in collagen-induced arthritis

The development of collagen type II (CII)-induced arthritis (CIA), a model of rheumatoid arthritis, in rats housed in cages with bedding composed of Celliant fibres containing ceramic particles, which absorb body heat and re-emit the energy back to the body in the form of infrared radiation (+IRF rats), and those housed in cages with standard wooden shaving bedding (-IRF control rats) was examined. The appearance of the first signs of CIA was postponed, while the disease was milder (judging by the arthritic score, paw volume, and burrowing behaviour) in +IRF compared with -IRF rats. This correlated with a lower magnitude of serum anti-CII IgG antibody levels in +IRF rats, and lower production level of IL-17, the Th17 signature cytokine, in cultures of their paws. This could be partly ascribed to impaired migration of antigen-loaded CD11b + dendritic cells and their positioning within lymph nodes in +IRF rats reflecting diminished lymph node expression of CCL19 /CCL21. Additionally, as confirmed in rats with carrageenan-induced paw inflammation (CIPI), the infrared radiation from Celliant fibres, independently from immunomodulatory effects, exerted anti-inflammatory effects (judging by a shift in pro-inflammatory mediator to anti-inflammatory/immunoregulatory mediator ratio towards the latter in paw cultures) and ameliorated burrowing behaviour in CIA rats.

ET-B receptors involvement in peripheral opioid analgesia induced by light-emitting diode photobiomodulation in male and female mice

Currently, photobiomodulation therapy (PBMT) is gaining space in the scientific and clinical environment. To help elucidate the importance of irradiance, this study evaluated the effect of two different PBMT irradiances (3.5 and 90 mW/cm²), given a fixed wavelength of 630 nm and a dose of 2 J/cm², on mechanical hyperalgesia following Complete Freund's Adjuvant (CFA) intraplantar (i.pl.) injection in mice. Additionally, we investigated the role of peripheral opioid and endothelin-B receptors (ET_B-R), as well as sex differences in treatment outcome. Different groups of male or female mice were evaluated 6 and 96 h after CFA. Mechanical hyperalgesia was evaluated 30 min after treatments. Naloxone or Bq-788 administration, fifteen minutes before PBMT or Sarafotoxin S6c, helped determine the involvement of peripheral opioid and ET_B-Rs on PBMT. Lastly, ET_B-Rs skin immunocontent in both sexes was quantified after PBMT consecutive daily treatments. PBMT at an irradiance of 90 mW/cm², was more effective than 3.5 mW/cm². Bq-788 and naloxone administration prevented the effects of PBMT and SRTX S6c; however, PBMT did not influence peripheral ET_B-Rs immunocontent. The results suggest that irradiance influences PMBT effect; and that activation of ET_B-R play a role in peripheral PBMT opioid induced analgesia. Lastly, PMBT effects do not appear to be sex-dependent.

Antihyperalgesic effect of exercise is augmented by the oral pretreatment with extract of Casearia sylvestris in an animal model of osteoarthritis

Background/Purpose:

Osteoarthritis (OA) is the main orthopedic disease to cause pain and edema in humans. This study evaluated the influence of complementary medicine on the hyperalgesia and edema induced by exercise in an animal model of OA as well as possible role for interleukin (IL)-1β to these outcomes.

Methods:

Mice (25–35 g) were subjected to intraplantar injection of Freund’s complete adjuvant and were subjected to exercise and oral treatment with ethanolic crude extract of Casearia sylvestris (ECE-CS) or vehicle (alone or in combination) and evaluated through behavioral and biochemical tests.

Results:

At day 5, exercise and ECE-CS alone did not reduce hyperalgesia, while the combination of both enhanced this effect. In muscle and skin tissues from the treated paw of mice, both treatments alone or in combination reduced in similar extent the levels of IL-1β in relation to the control group.

Conclusion:

Association of both complementary therapies may bring benefits on pain associated with OA in humans.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Antiedematous Effect Promoted by Occlusion of Legs with Compressive Socks Containing Infrared-Emitting Ceramic Particulates

Background: Published literature reports significant improvements in pathological conditions, such as pain, blood dyscrasias, and cellulite, after using topical occlusive accessories containing particulate ceramic materials. Objective: In this study, we investigated whether the use of a topical occluding garment made with synthetic fibers embedded with powdered ceramic materials could be beneficial to patients suffering from edema of lower limb extremities. Materials and methods: The cohort comprised 30 volunteers of both genders who were divided into two study groups. The bioceramic (BC) group wore compressive socks made of fabrics with embedded ceramic powder for 8 h a day for 28 days. The placebo group wore compressive socks of the same material without ceramic powder. The efficacy of the treatment was quantified through weekly plethysmographic measurements. In addition, pain relief was evaluated through a visual analog scale (VAS). Results: Data showed a statistically significant reduction in the edema volume for the BC group compared with the placebo group: 78.9 ± 10.7 mL versus 41.3 ± 5.6 mL, p = 0.003. Further, there was also greater pain relief for the BC group when compared with the placebo group, with a pain decrease of 7.0 ± 0.2 U versus 3.3 ± 0.2 U, respectively, on the VAS from 0 to 10 (p = 0.024). Conclusions: The topical occlusive therapy with compressive socks containing infrared-emitting ceramic particulate in its fabrics showed that they were more beneficial than the placebo garment in the treatment of edema of the inferior member extremities as well as in relief of associated pain.

Analgesic Effect of Zanthoxylum nitidum Extract in Inflammatory Pain Models Through Targeting of ERK and NF-κB Signaling

Background

Zanthoxylum nitidum (Roxb.) DC., also named Liang Mianzhen (LMZ), one kind of Chinese herb characterized with anti-inflammatory and relieving pain potency, which is widely used to treat injuries, rheumatism, arthralgia, stomach pain and so on in China. But its mechanism related to the anti-hyperalgesic has not been reported. The aim of this study was to investigate the analgesic activity of Liang Mianzhen on mice with Complete Freund adjuvant (CFA)-induced chronic inflammatory pain. Meanwhile, the peripheral and central mechanisms of analgesic effect of Liang Mianzhen were further examined via observing the effects of Liang Mianzhen on the signal pathway associated with inflammatory induced hyperalgesia.

Methods

The inflammatory pain model was established by intraplantar injection of CFA in C57BL/6J mice. After 1 day of CFA injection, the mice were treated with LMZ (100 mg/kg) for seven consecutive days, and the behavioral tests were measured after the daily intragastric administration of LMZ. The morphological changes on inflamed paw sections were determined by hematoxylin eosin (HE) staining. Changes in the mRNA expression levels of tumor necrosis factor (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nuclear factor κB p65 (NF-κBp65) were measured on day seven after CFA injection by using real-time quantitative PCR analysis and enzyme linked immunosorbent assay (ELISA) method, respectively. Moreover, immunohistochemistry and western blotting were used to detect extracellular regulated protein kinases 1/2 (ERK1/2) and NF-κB signal pathway activation.

Results

The extract of LMZ (100 mg/kg) showed a significant anti-inflammatory and analgesic effect in the mice model. The paw edema volume was significantly reduced after the administration of LMZ compared to CFA group, as well as the paw tissues inflammatory damage was relived and the numbers of neutrophils in mice was reduced significantly. The CFA-induced mechanical threshold and thermal hyperalgesia value were significant improved with LMZ treatment at day three to day seven. We also found the mRNA levels of TNF-α, IL-1β, IL-6 and NF-κBp65 were down-regulate after 7 days from the LMZ treatment compared to CFA group. Meanwhile, LMZ significantly suppressed over-expression of the phosphorylation of ERK1/2 and NF-κBp65 in peripheral and central.

Conclusion

The present study suggests that the extract of LMZ attenuates CFA-induced inflammatory pain by suppressing the ERK1/2 and NF-κB signaling pathway at both peripheral and central level.