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.

Electrical Stimulation of the Auricular Branch Vagus Nerve Using Random and Alternating Frequencies Triggers a Rapid Onset and Pronounced Antihyperalgesia via Peripheral Annexin A1-Formyl Peptide Receptor 2/ALX Pathway in a Mouse Model of Persistent Inflammatory Pain.

This study evaluated the antihyperalgesic and anti-inflammatory effects of percutaneous vagus nerve electrical stimulation (pVNS) by comparing the effects of alternating and random frequencies in an animal model of persistent inflammatory hyperalgesia. The model was induced by Freund's complete adjuvant (CFA) intraplantar (i.pl.) injection. Mice were treated with different protocols of time (10, 20, or 30 min), ear laterality (right, left or both), and frequency (alternating or random). Mechanical hyperalgesia was evaluated, and some groups received i.pl. WRW4 (FPR2/ALX antagonist) to determine the involvement. Edema, paw surface temperature, and spontaneous locomotor activity were evaluated. Interleukin-1ß, IL-6, IL-10, and IL4 levels were verified by enzyme-linked immunosorbent assay. AnxA1, FPR2/ALX, neutrophil, M1 and M2 phenotype macrophage, and apoptotic cells markers were identified using western blotting. The antihyperalgesic effect pVNS with alternating and random frequency effect is depending on the type of frequency, time, and ear treated. The pVNS random frequency in the left ear for 10 min had a longer lasting antihyperalgesic effect, superior to classical stimulation using alternating frequency and the FPR2/ALX receptor was involved in this effect. There was a reduction in the levels of pro-inflammatory cytokines and an increase in the immunocontent of AnxA1 and CD86 in mice paw. pVNS with a random frequency in the left ear for 10 min showed to be optimal for inducing an antihyperalgesic effect. Thus, the random frequency was more effective than the alternating frequency. Therefore, pVNS may be an important adjunctive treatment for persistent inflammatory pain.

Effects of the application of a food processing-based classification system in obese women: A randomized controlled pilot study.

Background: Obesity is one of the major public health problems worldwide and contributes to the onset of many diseases, especially the ones related to the metabolic syndrome. The new Dietary Guidelines for the Brazilian population bring a new food classification based on food processing and prioritizes the consumption of fresh or minimally processed foods. Aim: This study analyzed the effects of an educational intervention on obese women, on their weight loss, quality of life, components of the metabolic syndrome and pain. Methods: Randomized controlled pilot study, including 40 obese women, randomized into 2 groups: control group and intervention group. An educational intervention with 5 biweekly meetings of 90 min based on the Dietary Guidelines for the Brazilian population (2014) was carried out involving the intervention group. Parameters related to weight loss, quality of life (SF-36), pain (McGill), bioelectrical impedance analysis, cardiorespiratory fitness, and serum and clinical components of metabolic syndrome, as well as serum concentrations of cytokines were assessed. Results: Significantly decrease of body mass, waist and hip circumferences, basal metabolic rate, extracellular water, body capacitance, and body cell mass were observed in the intervention group after 3 months. Reduction of pain and improvement in quality of life and cardiorespiratory fitness were also observed in the intervention group. There were reductions in waist circumference and glycemia, components of metabolic syndrome. Conclusions: This study showed that the educational intervention can be associated with weight loss, increase in quality of life, reduction of pain, and better metabolic syndrome parameters in obese women.

Contribution of plasma, placental, inflammatory and pro-resolving mediators in labor induction.

INTRODUCTION: The onset of labor is regulated by endocrine, nervous and immunological factors. This study was designed to determine the inflammatory and pro-resolving mediator levels in plasma and placenta of women undergoing labor induction in late-term pregnancy. METHOD: Healthy pregnant women admitted for delivery or labor induction were included. TNF, IL-1ß, IL-6, IL-8, and IL-10 were quantified by ELISA in plasmatic and placental samples and Annexin A1 (ANXA1) in the placenta by Western Blotting, and immunofluorescence to CD15+ antibody. The data were analyzed using the Wilcoxon test and Spearman correlation. The p-value was significant when <0.05. RESULTS: There was a higher concentration of IL-8 was found in the amniotic plaque (p = 0.042) and IL-10 (p < 0.001) in the trophoblast of patients with spontaneous labor. Greater ANXA1 density in the trophoblast was also observed in those with induction failure. There was a positive correlation of ANXA1 density in trophoblast induction duration with (r = 0.580) and with the IL-6 level in amniotic plaque (r = 0.517), and a positive correlation between labor duration and density of ANXA1 was identified in the trophoblast (r = 0.419). An increase was identified in CD15+ cell immunocapturing among the groups with spontaneous labor compared to the group with induction failure (p < 0.001). DISCUSSION: The inflammatory process in labor involves both maternal and fetal participation. Induction failure is associated with higher levels of ANXA1 in the trophoblast.

Lavandula angustifolia essential oil inhalation reduces mechanical hyperalgesia in a model of inflammatory and neuropathic pain: The involvement of opioid and cannabinoid receptors.

Lavandula angustifolia (LaEO) essential oil has been widely used by aromatherapy in the treatment of various clinical conditions, with evidence of its analgesic and anti-inflammatory potential. Our results demonstrate that sixty-five substances were identified in LaEO. Among the compounds found, the major ones were linalool (30.61%) and linalyl acetate (20.36%). We found that LaEO inhalation reduces mechanical hyperalgesia in conditions of chronic inflammatory and neuropathic pain. Furthermore, this effect seems to be mediated by peripheral and central opioid and cannabinoid 2 receptors. The findings of the present study suggests that the LaEO inhalation is effective on the chronic pain treatment.

The role of the endocannabinoid system in the antihyperalgesic effect of Cedrus atlantica essential oil inhalation in a mouse model of postoperative pain.

ETHNOPHARMACOLOGICAL RELEVANCE: Cedar is part of the phylum of conifers, and it's essential oil has been used for therapeutic purposes since ancient times. In our previous study, we have demonstrated that the inhalation of the Cedrus atlantica essential oil (CaEO) induces an antihyperalgesic effect in a model of postoperative pain. But the mechanism that underlies this effect is not yet fully known. AIM OF THE STUDY: This study investigates the involvement of the endocannabinoid system in the antihyperalgesic effect produced by the inhalation of CaEO in a post operative pain model. MATERIALS AND METHODS: Male Swiss mice (25-35±2g) were subjected to plantar incision. To assess the involvement of the endocannabinoid system, two different approaches were made: (1) by administering antagonists to the CB1 and CB2 receptors in different sites (intraperitoneal [i.p.], intraplantar [i.pl.] and intrathecal [i.t.]) and (2) by assessing the synergic effect of the inhalation of sub-effective doses of CaEO, Fatty acid hydrolase (FAAH) and Monoacylglycerol lipase (MAGL), and endocannabinoid degradation inhibitors (URB937 and JZL184, respectively). RESULTS: The antihyperalgesic effect of CaEO inhalation was prevented by pretreatment with AM281 or AM630 given by i.p. and i.t., but not i.pl. Additionally, in mice pretreated with FAAH or the MAGL inhibitors, the antihyperalgesic effect of CaEO inhalation was significantly longer, which demonstrates the involvement of the endocannabinoid system in the antihyperalgesic effect of CaEO inhalation in a preclinical model of postoperative pain. CONCLUSIONS: The present study shows that CaEO inhalation exerts an antihyperalgesic effect, possibly by the activation of the endocannabinoid system in a preclinical model of postoperative pain. It could be a new alternative to treat pain in a clinical environment.

Inhalation of Cedrus atlantica essential oil alleviates pain behavior through activation of descending pain modulation pathways in a mouse model of postoperative pain.

ETHNOPHARMACOLOGICAL RELEVANCE: Cedrus atlantica essential oil (CaEO) presents analgesic and anti-inflammatory sedative properties. However, it remains unknown whether CaEO alleviates acute postoperative pain. MATERIALS AND METHODS: Here, we investigated the effect of CaEO on postoperative pain and its mechanisms related to the descending pain control in Swiss males mice induced by a plantar incision surgery (PIS) in the hindpaw. RESULTS: Inhalation of CaEO (5', 30' or 60') markedly reduced mechanical hypersensitivity. This effect was prevented by pre-treatment with naloxone or p-chlorophenylalanine methyl ester (PCPA, 100mg/kg, i.p.)-induced depletion of serotonin. In addition, p-alpha-methyl-para-tyrosin (AMPT, 100mg/kg, i.p.)-induced depletion of norepinephrine, intraperitoneal injection of the α2-adrenergic receptor antagonist yohimbine (0.15 mg/kg, i.p.) or haloperidol (1mg/kg, i.p.) an antagonist of dopaminergic (D1 and D2) receptors prevented the effect of CaEO on hypersensitivity. CONCLUSIONS: These findings suggest that CaEO alleviates postoperative pain by activating the descending pain modulation pathways on the opioidergic, serotonergic, noradrenergic (α2-adrenergic) and dopaminergic (dopamine D1 and D2 receptors) systems.