Unilateral L4-dorsal root ganglion stimulation evokes pain relief in chronic neuropathic postsurgical knee pain and changes of inflammatory markers: part II whole transcriptome profiling.

BACKGROUND: In our recent clinical trial, increased peripheral concentrations of pro-inflammatory molecular mediators were determined in complex regional pain syndrome (CRPS) patients. After 3 months adjunctive unilateral, selective L4 dorsal root ganglion stimulation (L4-DRGSTIM), significantly decreased serum IL-10 and increased saliva oxytocin levels were assessed along with an improved pain and functional state. The current study extended molecular profiling towards gene expression analysis of genes known to be involved in the gonadotropin releasing hormone receptor and neuroinflammatory (cytokines/chemokines) signaling pathways. METHODS: Blood samples were collected from 12 CRPS patients for whole-transcriptome profiling in order to assay 18,845 inflammation-associated genes from frozen blood at baseline and after 3 months L4-DRGSTIM using PANTHER™ pathway enrichment analysis tool. RESULTS: Pathway enrichment analyses tools (GOrilla™ and PANTHER™) showed predominant involvement of inflammation mediated by chemokines/cytokines and gonadotropin releasing hormone receptor pathways. Further, screening of differentially regulated genes showed changes in innate immune response related genes. Transcriptomic analysis showed that 21 genes (predominantly immunoinflammatory) were significantly changed after L4-DRGSTIM. Seven genes including TLR1, FFAR2, IL1RAP, ILRN, C5, PKB and IL18 were down regulated and fourteen genes including CXCL2, CCL11, IL36G, CRP, SCGB1A1, IL-17F, TNFRSF4, PLA2G2A, CREB3L3, ADAMTS12, IL1F10, NOX1, CHIA and BDKRB1 were upregulated. CONCLUSIONS: In our sub-group analysis of L4-DRGSTIM treated CRPS patients, we found either upregulated or downregulated genes involved in immunoinflammatory circuits relevant for the pathophysiology of CRPS indicating a possible relation. However, large biobank-based approaches are recommended to establish genetic phenotyping as a quantitative outcome measure in CRPS patients. Trial registration The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267.

3-(4-Chlorophenylselanyl)-1-methyl-1H-indole promotes recovery of neuropathic pain and depressive-like behavior induced by partial constriction of the sciatic nerve in mice.

3-(4-Chlorophenylselanyl)-1-methyl-1H-indole (CMI) is an organoselenium compound that presents antioxidant activity, antinociceptive, anti-inflammatory and antidepressive-like effect in mice in previous studies conducted by our research group. In this study, we evaluate the anti-allodynic, anti-hyperalgesic and antidepressant-like effects of CMI on partial sciatic nerve ligation (PSNL) in male adult Swiss mice (25-35 g) as well as the involvement of oxidative stress in these effects. Mice underwent PSNL surgery and after 4 weeks they were treated with CMI (10 mg/kg, intragastric route [i.g.]) or vehicle. The treatment with CMI (10 mg/kg, i.g.) reversed the increased the percentage of response to Von-Frey Hair (VFH) stimulation, decreased the latency time to nociceptive response in the hot-plate test, increased immobility time in the forced swimming test (FST) and decreased groomings activity in the splash test, all induced by PSNL. Additionally, CMI also reversed increased the levels of reactive oxygen species (ROS) and lipid peroxidation in cortex and hippocampus and plasmatic levels of corticosterone in mice, induced by PSNL. Results demonstrate that CMI reversed behavioral and biochemical alterations in the dyad pain-depression induced by PSNL and possibly modulation of oxidative system.

[Resuscitation acupuncture for thalamic pain:a randomized controlled trial].

OBJECTIVE: To compare the effects between resuscitation acupuncture and pregabalin for thalamic pain and their impacts on plasma P substance (SP) and ß-endorphin (ß-EP). METHODS: Sixty-four patients were randomly assigned into an acupuncture group and a western medication group, 32 cases in each one. Based on conventional western methods, pregabalin capsule was used orally in the western medication group, 75 mg a time,twice a day; resuscitation acupuncture was applied in the acupuncture group. The main acupoints were Shuigou (GV 26), Neiguan (PC 6), Sanyinjiao (SP 6). Patients with upper limb pain were attached affected Jiquan (HT 1), Chize (LU 5), and Hegu (LI 4); lower limb pain, affected Weizhong (BL 40), Zusanli (ST 36); hea-dache, bilateral Fengchi (GB 20), Wangu (GB 12), and Yifeng (TE 17), twice a day. Treatment was given 6 d a week for 8 weeks in the two groups. The changes of simplified McGill pain questionnaire (SF-MPQ), plasma SP and ß-EP were observed before and after 4-week, 8-week treatment, as well as at follow-up, namely, 3 months after treatment. Also, clinical effects were evaluated. RESULTS: The total effective rate of the acupuncture group was 50.0% (16/32) after 4-week treatment, which was similar to 46.9% (15/32) in the western medication group (P>0.05). While after 8-week treatment and at follow-up, the total effective rates of the acupuncture group were 90.6% (29/32) and 84.4% (27/32), which were better than 65.6% (21/32) and 40.6% (13/32) of the western medication group correspondingly (both P<0.05). After 4-week, 8-week treatment and at follow-up, the pain scores of the acupuncture group were lower than that before treatment (all P<0.05). After 4-week and 8-week treatment, the pain scores of the western medication group were lower than that before treatment (both P<0.05). After 8-week treatment and at follow-up, the pain scores of the acupuncture group were superior to thoseof the western medication group (both P<0.05). After 4-week and 8-week treatment,the contents of plasma SP reduced compared with those before treatment in the two groups (all P<0.05), and plasma ß-EP increased (all P<0.05). After 8-week treatment, SP content of the acupuncture group was apparently lower than that of the western medication group (P<0.05), and ß-EP increased more obviously (P<0.05). CONCLUSIONS: Resuscitation acupuncture can effectively relieve the symptoms of thalamic pain with stable and long-term effect, and it is better than pregabalin. Meanwhile, the acupuncture can increase ß-EP and reduce SP.

NK cells mediate the cumulative analgesic effect of electroacupuncture in a rat model of neuropathic pain.

BACKGROUND: Cumulating evidence has revealed the effectiveness of acupuncture therapy in relieving pain via immunoregulation. However, its underlying mechanism remains unknown. The present study was designed to determine the changes of immunogenic responses at different time-points of electroacupuncture (EA) interventions in neuropathic pain rats. METHODS: The neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury (CCI). EA was applied at Zusanli (ST36) and Yanglingquan (GB34) for the EA groups. The thermal pain threshold was detected with an algesia-detector. The subgroups of plasma and splenic lymphocytes were determined via fluorescence-activated cell sorting. Specific inflammatory cytokines were assayed using an ELISA-based bead multiplex assay. The activities of splenic natural killer (NK) cells and cytotoxic T lymphocytes were detected by methyl thiazolyl tetrazolium colorimetric method. For confirming the involvement of NK cell in EA-analgesia, anti-asialo-ganglio-N-tetraosylceramide (anti-asialo-GM1) antibody was given to CCI rats before EA. RESULTS: Following CCI, the thermal pain threshold of the affected hind footpad was significantly decreased, and increased from the 3rd day to the 12th day after EA interventions, presenting a time-dependent tendency from the 5th day on. From day 3 to 5 of EA interventions, the percentages and activity of splenic NK cells, concentrations of splenic interleukin-2 (IL-2) and beta-endorphin (ß-EP) were significantly increased. Meanwhile, the concentrations of plasma IL-2, IL-1ß and gamma-interferon (IFN-γ) were significantly decreased and returned to the normal level on day 12 following EA. Plasma transforming growth factor-ß (TGF-ß) levels were considerably upregulated on day 5 and 12 following EA. The CD4+/CD8+ T cell ratio was markedly downregulated compared with the control and CCI groups on day 5 and returned to the normal level on day 12 following EA. After depleting NK cells by anti-asialo-GM1 antibody, the increased thermal pain threshold following EA intervention was obviously reduced. CONCLUSIONS: Repeated EA interventions have a time-dependent cumulative analgesic effect in neuropathic pain rats, which is closely associated with its regulatory effects on NK cells, splenic IL-2, ß-EP, and plasma IL-2, IL-1ß, IFN-γ and TGF-ß levels.

Antinociceptive curcuminoid, KMS4034, effects on inflammatory and neuropathic pain likely via modulating TRPV1 in mice.

BACKGROUND: Curcumin, the active ingredient of turmeric (Curcuma longa), has a wide range of beneficial effects including anti-inflammation and analgesia. However, poor bioavailability of curcumin hinders its clinical application. To overcome this limitation, we modified the structure of curcumin and synthesized new derivatives with favourable pharmacokinetic profiles. Recently, curcumin has been shown to have an antagonizing effect on transient receptor potential vanilloid type 1 (TRPV1) ion channels. We investigated the antinociceptive activity of KMS4034 which had the most favourable pharmacokinetics among the tested curcumin derivatives. METHODS: To evaluate the mechanism of the antinociceptive effects of KMS4034, capsaicin (I(CAP))- and heat (I(heat))-induced currents in TRPV1 expressing HEK293 cells were observed after the application of KMS4034. Nociceptive behavioural measurement using the hot-plate test, formalin test, and chronic constriction injury (CCI) model were evaluated in mice. Also, calcitonin gene-related peptide (CGRP) was stained immunohistochemically in the L4/5 dorsal horns in mice with neuropathic pain. RESULTS: I(CAP) (P<0.01) and I(heat) (P<0.05) of TRPV1 were significantly blocked by 10 µM KMS4034. Behaviourally, noticeable antinociceptive effects after 10 mg kg(-1) of KMS4034 treatment were observed in the first (P<0.05) and second phases (P<0.05) of the formalin and hot-plate tests. The mechanical threshold of CCI mice treated with 10 mg kg(-1) KMS4034 was significantly increased compared with control. Immunohistochemical CGRP expression was decreased in the lamina I-II of the lumbar dorsal horns in KMS4034-treated CCI mice compared with the control (P<0.05). CONCLUSIONS: KMS4034 may be an effective analgesic for various pain conditions.

Altered thyroid hormones and behavioural change in a sub-population of rats following chronic constriction injury.

Hypothyroidism is associated with a disturbance of behaviour and mood. There are also individuals, not classified as hypothyroid, with low to 'low normal' thyroid hormone levels and normal thyroid-stimulating hormone (TSH) levels who have mood and behavioural changes. As the peripheral thyroid hormones decrease, TSH is expected to increase. However, there are a number of physiological mechanisms known to suppress TSH. In the present study, we report on thyroid hormone regulation in a rat model of neuropathic pain and altered social behaviour that is usually transient, but is persistent in a sub-group of the population. Following ligation of the sciatic nerve, male Sprague-Dawley rats were assessed for social dominance towards an intruder: 20% showed persistently decreased social dominance. Plasma levels of thyroid hormones, TSH and corticosterone were measured before and on days 2, 3, 4, 5 and 6 after injury in 21 rats. The mean plasma thyroxine (T4), free thyroxine (fT4) and triiodothyronine (T3) levels decreased significantly post-injury in rats with persistently changed behaviour compared to rats with unchanged behaviour (P < or = 0.002). There was no significant difference between groups for mean change in free triiodothyronine (fT3) or TSH. There was a correlation between decreased dominance behaviour and decrease in both T4 (r = 0.62, P = 0.009) and fT4 (r = 0.71, P = 0.001), but no correlation with TSH. In a sub-population of rats, decreased thyroid hormones did not result in the expected increased levels of TSH to restore pre-injury levels, nor did they show increased hypothalamic thyrotrophin-releasing hormone mRNA expression, indicating altered hypothalamic-pituitary-thyroid axis regulation. Because T3 availability to the brain is dependent on both circulating T3 and T4, decreased peripheral thyroid hormones may result in changed neural function, as expressed in altered complex behaviours in this sub-population of rats.