Morphometric aspects of the articular cartilage of rats treated with low-level laser therapy and exercise in a rheumatoid arthritis model

INTRODUCTION: Rheumatoid arthritis (RA) is classified as an autoimmune, chronic disease affecting diarthrodial joints and periarticular structures. OBJECTIVE: To evaluate whether low-intensity laser treatment (LLLT) and/or exercise reduce the deleterious effects of tissue in a rheumatoid arthritis model. METHODS: 128 rats were divided into two inflammatory periods: acute (7 days) and chronic (28 days) and subdivided into control, injury and treatment. The protocol with Freund's Complete Adjuvant was used in two inoculations, one intradermal and one intraarticular in the tibiofemoral joint, the control animals received saline solution. For treatment, LLLT 660 nm, 5 J/cm² was used in the sensitized joint and climbing exercise in stairways with an overload of 100 grams. After the experimental period, the animals were euthanized and the joints were prepared for morphometric analysis of the total thickness, superficial, deep, and cellular density of the articular cartilage. Generalized Linear Models with Sidak post-test were chosen. RESULTS: The control group was found to be different from the lesion group with greater joint cartilage thickness, andthe animals treated with exercise alone increased the joint cartilage compared to thecontrol group. CONCLUSION: The animals treated with laser association and exercise showed improvement in the morphometric aspects of the articular cartilage.

Research progress of new vaccine adjuvants / 生物工程学报

In recent years, the development of new vaccines such as nucleic acid vaccines, genetically engineered vaccines, and synthetic peptide vaccines has achieved rapid development. However, compared with traditional inactivated or live vaccines, these vaccines often have problems such as poor immunogenicity. Therefore, an adjuvant is needed to enhance its effect, and adjuvants have proven to be a key component in vaccines. There are many types of adjuvants, while currently no unified standard for the classification. At present, the most commonly used adjuvants are Aluminum adjuvant and Freund's adjuvant, but new generation vaccines will probably need new generation adjuvants. Thus, this review aims to showcase the current status of immune adjuvants, with the focus on immunomodulatory molecular adjuvant, antigen delivery adjuvant and compound adjuvant. This review provides new insights for the development of novel vaccine adjuvants.

Evolution of mirror-image pain in temporomandibular joint osteoarthritis mouse model

Abstract Mirror-image pain is a kind of pain that occurs on the contralateral side, but its pathogenesis remains unclear. Objective To develop an osteoarthritis mouse model for investigating mirror-image pain through observing nocifensive behaviors, histological changes, and nociceptive activity at days 3, 7, 14, 21, and 28 after the chemical induction of unilateral temporomandibular joint (TMJ) osteoarthritis. Methodology We randomly divided 6-week-old mice into sham and complete Freund adjuvant groups. To induce nocifensive behaviors, we applied 0.04 g of von Frey filament, 10 psi of air puff, and cold acetone on both sides of whisker pads at different days. The histology of TMJ on both sides was observed by hematoxylin/eosin staining and microcomputed tomography scanning. Furthermore, the nociceptive activity was evaluated using the phosphorylated cyclic AMP response element binding protein (pCREB) and a microglia marker at different days in the trigeminal subnucleus caudalis. Results Nocifensive behaviors against mechanical and temperature stimuli on the contralateral side became stronger than the baseline on day 28, in agreement with the elevation of the pCREB and the microglia marker in the trigeminal subnucleus caudalis. Thus, hypernociception on the contralateral side occurred at day 28. Conclusions Clearly, the TMJ model with unilateral osteoarthritis exhibited mirror-image pain. Therefore, this model is useful in investigating the pathogenesis of pain and in developing treatments.

Analgesic effect of Fengshi Qutong Capsules on mice with chronic inflammatory pain caused by complete Freund's adjuvant / 中国中药杂志

The aim was to observe the analgesic effect of Fengshi Qutong Capsules(FSQTC) on chronic inflammatory pain in mice, and investigate its effect on p-ERK/COX-2 signal molecular activity. A model of chronic inflammatory pain was induced in mice by complete Freund's adjuvant(CFA). The mice were divided into normal control group, model group, model+FSQTC 0.3, 0.6 and 1.2 g·kg~(-1 )groups, model+positive control drug ibuprofen(IBP, 0.34 mg·kg~(-1)·d~(-1)) group, and normal control+ FSQTC 1.2 g·kg~(-1)group. FSQTC or IBP was given once a day by oral administration. Standard Von Frey fiber was used to evaluate the mechanical pain threshold, and the acetone stimulation was used to induce inflammatory plantar and observe the cold pain reaction scores. The mechanical pain threshold and cold pain reaction scores were observed before administration and 1, 2, 3, 4, 6 h after administration on the first day, as well as 3 h after administration on the 3 rd to 7 th day. The protein levels of PGE_2, COXs-1,2 and p-ERK in the spinal cord of the inflammatory foot and lumbar 4-5 were detected by enzyme-linked immunosorbent assay, Western blot, immunohistochemistry and immunofluorescence. The results showed that the mechanical pain threshold of the model group decreased and the cold pain reaction score increased as compared with the normal group. FSQTC application could dose-dependently increase the mechanical pain threshold and decrease the cold pain reaction score. The effect lasted for 6 h, most significant at 3 h. The effect of ibuprofen was similar to that of the 0.6 g·kg~(-1) dose group. In addition, FSQTC could reduce the abnormally increased protein content of PGE_2, COX-2 and p-ERK in the inflammatory foot and/or spinal cord of the model group, and the effect was most significant in middle and high dose groups. However, it had no effect on COX-1 in the inflammatory foot and spinal cord of mice. The results suggest that FSQTC has ob-vious analgesic effect on chronic inflammatory pain in mice, which may be related to inhibition of p-ERK/COX-2 signaling pathway.

Evaluation of antiarthritic activity of ginkgolic acid against Freund's adjuvant induced arthritic rat model

This study aimed to analyze the antiarthritic activity of ginkgolic acid against the Complete Freund's Adjuvant (CFA)-induced arthritis in rats. Arthritis was induced through an intradermal injection of CFA (0.1 mL) at the right hind footpad of adult Wistar Albino rats. Ginkgolic acid was administered orally at doses of 25 mg/kg and 50 mg/kg, respectively, once daily via gavage for 25 days upon inducing arthritis. Indomethacin was administered orally at a dose of 3 mg/kg twice in a week which served as positive control group. The animals were sacrificed and subjected to biochemical and histopathological analysis upon completion of treatment. Ginkgolic acid was able to reverse the arthritic effect (p < 0.01) induced by CFA in a dose dependent manner. Swelling of paw, thymus and spleen index, serum biomarker levels, and pro-inflammatory cytokines were significantly reduced (p < 0.01) by the acid whereas the antioxidant enzyme activities were remarkably restored. The histopathological findings were in agreement with the biochemical results. The results indicate that the antioxidant and anti-inflammatory properties of ginkgolic acid can be credited to the antiarthritic effects, and it can be promoted as a potential agent for therapeutic use against osteoarthritis

Rhoifolin regulates oxidative stress and proinflammatory cytokine levels in Freund's adjuvant-induced rheumatoid arthritis via inhibition of NF-κB

Rheumatoid arthritis (RA) is an autoimmune disease of knee joints involving pain and inflammation. Rhoifolin is a plant flavonoid known to have antioxidant and anti-inflammatory properties. This study was taken to identify the effect of rhoifolin on complete Freund's adjuvant (CFA)-induced arthritis in the rat model. Treatment with rhoifolin (10 and 20 mg/kg) showed a significant improvement in the overall health parameters such as paw edema and weight loss. This improvement in morphological parameters corroborated the findings with gross morphological changes observed in the histopathological analysis. Rhoifolin treatment also caused a significant decrease in oxidative stress, evident from changes in intracellular levels of glutathione, glutathione peroxidase, malondialdehyde, and superoxide dismutase in the articular cartilage tissue. Moreover, proinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin(IL)-1β, and IL-6 showed a significant downregulation of gene expression and intracellular protein concentration levels. The NF-κB pathway showed a significant attenuation as evident in the significant reduction in the levels of NF-κB p65 and p-IκB-α. These results indicated that rhoifolin can be a natural therapeutic alternative to the extant regimens, which include non-steroidal anti-inflammatory drugs and immunosuppressants. Additionally, the antioxidant and anti-inflammatory action of rhoifolin was probably mediated by the NF-κB pathway. However, the exact target molecules of this pathway need to be determined in further studies.

Evaluation of the effects of autohemotransfusion in arthritic rats induced by two doses of complete Freund's adjuvant

The aim the study was to evaluate the effects of autohemotransfusion in adjuvant-induced arthritis model by injections of high and low doses of Complete Freund ́s Adjuvant (CFA). Male Holtzman rats (200-230g) were distributed in six groups: control (C); control treated by autohemotransfusion (CT); CFA induced arthritis 0.5% w/v (AIA); CFA induced arthritis 0.5% w/v treated with autohemotransfusion (AIAT); CFA induced arthritis 0.1% w/v (AS) and CFA induced arthritis 0.1% w/v treated with autohemotransfusion (AST). The number of leukocytes, the weight of different organs and the paw volume were analyzed. The autohemotransfusion without erythrocytes promoted a reduction in the number of leukocytes in AIAT and AST when compared to AIA (p 0.05). The autohemotransfusion used in this work presented positive effects on AIA as they promoted a reduction in the number of leukocytes and an increase in thymus weight and body growth. However, other types of autohemotransfusion must be tested to determine the true efficacy of this alternative method of treatment.

Gait Assessment of Pain and Analgesics: Comparison of the DigiGait™ and CatWalk™ Gait Imaging Systems / 神经科学通报·英文版

Investigation of pain requires measurements of nociceptive sensitivity and other pain-related behaviors. Recent studies have indicated the superiority of gait analysis over traditional evaluations (e.g., skin sensitivity and sciatic function index [SFI]) in detecting subtle improvements and deteriorations in animal models. Here, pain-related gait parameters, whose criteria include (1) alteration in pain models, (2) correlation with nociceptive threshold, and (3) normalization by analgesics, were identified in representative models of neuropathic pain (spared nerve injury: coordination data) and inflammatory pain (intraplantar complete Freund's adjuvant: both coordination and intensity data) in the DigiGait™ and CatWalk™ systems. DigiGait™ had advantages in fixed speed (controlled by treadmill) and dynamic SFI, while CatWalk™ excelled in intrinsic velocity, intensity data, and high-quality 3D images. Insights into the applicability of each system may provide guidance for selecting the appropriate gait imaging system for different animal models and optimization for future pain research.

Chronic inflammation deteriorates structure and function of collagen fibril in rat temporomandibular joint disc / 国际口腔科学杂志·英文版

Collagen is the building component of temporomandibular joint (TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inflammation. However, the mechanism by which inflammation influences disc function remains unknown. The relationship between the ultrastructure and nanomechanical properties of collagen in inflamed discs should be clarified. Seven-week-old female Sprague-Dawley rats were randomly divided into two groups. Chronic TMJ inflammation was induced by intra-articular injection of complete Freund's adjuvant, and samples were harvested after 5 weeks. Picrosirius staining revealed multiple colours under polarized light, which represented alternative collagen bundles in inflamed discs. Using atomic force microscopy scanning, the magnitude of Young's modulus was reduced significantly accompanied with disordered collagen fibril arrangement with porous architecture of inflamed discs. Transmission electron microscopy scanning revealed a non-uniform distribution of collagen fibres, and oversized collagen fibrils were observed in inflamed discs. Fourier transform infrared microspectroscopy revealed a decrease in 1 338 cm/amide II area ratio of collagen in different regions. The peak positions of amide I and amide II bands were altered in inflamed discs, indicating collagen unfolding. Our results suggest that sustained inflammation deteriorates collagen structures, resulting in the deterioration of the ultrastructure and nanomechanical properties of rat TMJ discs.

Chemokine Receptor CXCR3 in the Spinal Cord Contributes to Chronic Itch in Mice / 神经科学通报·英文版

Recent studies have shown that the chemokine receptor CXCR3 and its ligand CXCL10 in the dorsal root ganglion mediate itch in experimental allergic contact dermatitis (ACD). CXCR3 in the spinal cord also contributes to the maintenance of neuropathic pain. However, whether spinal CXCR3 is involved in acute or chronic itch remains unclear. Here, we report that Cxcr3 mice showed normal scratching in acute itch models but reduced scratching in chronic itch models of dry skin and ACD. In contrast, both formalin-induced acute pain and complete Freund's adjuvant-induced chronic inflammatory pain were reduced in Cxcr3 mice. In addition, the expression of CXCR3 and CXCL10 was increased in the spinal cord in the dry skin model induced by acetone and diethyl ether followed by water (AEW). Intrathecal injection of a CXCR3 antagonist alleviated AEW-induced itch. Furthermore, touch-elicited itch (alloknesis) after compound 48/80 or AEW treatment was suppressed in Cxcr3 mice. Finally, AEW-induced astrocyte activation was inhibited in Cxcr3 mice. Taken together, these data suggest that spinal CXCR3 mediates chronic itch and alloknesis, and targeting CXCR3 may provide effective treatment for chronic pruritus.

Spinal CCL2 Promotes Central Sensitization, Long-Term Potentiation, and Inflammatory Pain via CCR2: Further Insights into Molecular, Synaptic, and Cellular Mechanisms / 神经科学通报·英文版

Mounting evidence supports an important role of chemokines, produced by spinal cord astrocytes, in promoting central sensitization and chronic pain. In particular, CCL2 (C-C motif chemokine ligand 2) has been shown to enhance N-methyl-D-aspartate (NMDA)-induced currents in spinal outer lamina II (IIo) neurons. However, the exact molecular, synaptic, and cellular mechanisms by which CCL2 modulates central sensitization are still unclear. We found that spinal injection of the CCR2 antagonist RS504393 attenuated CCL2- and inflammation-induced hyperalgesia. Single-cell RT-PCR revealed CCR2 expression in excitatory vesicular glutamate transporter subtype 2-positive (VGLUT2) neurons. CCL2 increased NMDA-induced currents in CCR2/VGLUT2 neurons in lamina IIo; it also enhanced the synaptic NMDA currents evoked by dorsal root stimulation; and furthermore, it increased the total and synaptic NMDA currents in somatostatin-expressing excitatory neurons. Finally, intrathecal RS504393 reversed the long-term potentiation evoked in the spinal cord by C-fiber stimulation. Our findings suggest that CCL2 directly modulates synaptic plasticity in CCR2-expressing excitatory neurons in spinal lamina IIo, and this underlies the generation of central sensitization in pathological pain.

The effects of anthocyanin on chronic inflammatory pain induced by complete Freund's adjuvant and its mechanism / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects and mechanisms of anthocyanin from Ligustrum vicaryi on chronic inflammatory pain induced by complete Freund's adjuvant.@*METHODS@#Thirty male SD rats were randomly divided into three groups (=10):normal saline control group (NS), chronic inflammatory pain model group(Mod, injected with complete Freund's adjuvant(CFA) 100 μl to the left hind leg), anthocyanin treatment group(Ant, dosed with anthocyanins (90 m), mechanical pain threshold (MPT), and left toe volume in each group were measured before modeling and 1,3,5,7,9,11,13 days after operation. Antioxidant indexes in serum were mensurated by spectrophotometer, and the total capsaicin receptor (TRPV1) and phosphorylated capsaicin receptor (p-TRPV1) in hippocampus were detected by Western blot.@*RESULTS@#In comparison with controls, HPT and MPT were improved (<0.05),toe swelling was reduced(<0.05), the serum level of SOD was increased (<0.01), while the levels of MDA and NO were decreased (<0.05), the ratio of P-TRPV1/TRPV1 protein was depressed in Mod rat hippocampal region treated with anthocyanin.@*CONCLUSIONS@#The results show that anthocyanins has an analgesic effect on chronic inflammatory pain induced by CFA, and its mechanism may be related to the improvement of antioxidant capacity and the reduction of TRPV1 phosphorylation.

Identification of key genes and pathways involved in response to pain in goat and sheep by transcriptome sequencing

PURPOSE: This aim of this study was to investigate the key genes and pathways involved in the response to pain in goat and sheep by transcriptome sequencing. METHODS: Chronic pain was induced with the injection of the complete Freund's adjuvant (CFA) in sheep and goats. The animals were divided into four groups: CFA-treated sheep, control sheep, CFA-treated goat, and control goat groups (n = 3 in each group). The dorsal root ganglions of these animals were isolated and used for the construction of a cDNA library and transcriptome sequencing. Differentially expressed genes (DEGs) were identified in CFA-induced sheep and goats and gene ontology (GO) enrichment analysis was performed. RESULTS: In total, 1748 and 2441 DEGs were identified in CFA-treated goat and sheep, respectively. The DEGs identified in CFA-treated goats, such as C-C motif chemokine ligand 27 (CCL27), glutamate receptor 2 (GRIA2), and sodium voltage-gated channel alpha subunit 3 (SCN3A), were mainly enriched in GO functions associated with N-methyl-D-aspartate (NMDA) receptor, inflammatory response, and immune response. The DEGs identified in CFA-treated sheep, such as gamma-aminobutyric acid (GABA)-related DEGs (gamma-aminobutyric acid type A receptor gamma 3 subunit [GABRG3], GABRB2, and GABRB1), SCN9A, and transient receptor potential cation channel subfamily V member 1 (TRPV1), were mainly enriched in GO functions related to neuroactive ligand-receptor interaction, NMDA receptor, and defense response. CONCLUSIONS: Our data indicate that NMDA receptor, inflammatory response, and immune response as well as key DEGs such as CCL27, GRIA2, and SCN3A may regulate the process of pain response during chronic pain in goats. Neuroactive ligand-receptor interaction and NMDA receptor as well as GABA-related DEGs, SCN9A, and TRPV1 may modulate the process of response to pain in sheep. These DEGs may serve as drug targets for preventing chronic pain.

NLRP3 inflammasome signaling as an early molecular response is negatively controlled by miR-186 in CFA-induced prosopalgia mice

The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most frequently studied in the central nervous system and has been linked to neuropathic pain. In this study, a post-translational mechanism of microRNA (miR)-186 via regulating the expression of NLRP3 in the complete Freund's adjuvant (CFA)-treated mice was investigated. The injection of CFA was used to induce trigeminal neuropathic pain in mice. miRs microarray chip assay was performed in trigeminal ganglions (TGs). CFA treatment significantly increased the mRNA expression of NLRP3, interleukin (IL)-1β, and IL-18 in TGs compared to the control group. Moreover, 26 miRs were differentially expressed in TGs from trigeminal neuropathic pain mice, and the expression of miR-186 showed the lowest level of all the miRs. Further examination revealed that NLRP3 was a candidate target gene of miR-186. We delivered miR-186 mimics to CFA-treated mice. The head withdrawal thresholds of the CFA-treated mice were significantly increased by miR-186 mimics injection compared with CFA single treatment. The mRNA and protein expression of NLRP3, IL-1β, and IL-18 in TGs from trigeminal neuropathic pain mice were significantly inhibited by miR-186 mimics treatment compared to the CFA group. miR-186 was able to suppress the neuropathic pain via regulating the NLRP3 inflammasome signaling.

Anti-inflammatory, Anti-arthritic and Analgesic Effect of the Herbal Extract Made from Bacopa monnieriis, Cassia fistula and Phyllanthus polyphyllus

Anti-inflammatory, anti-arthritic and analgesic activity of each herbal extract, which is extracted from Bacopa monnieriis, Cassia fistula and Phyllanthus polyphyllus, respectively. The treatment of herbal extract exhibited anti-inflammatory effect as a dose-dependent manner, from 1.25mg/kg to 12.5mg/kg, in acute inflammatory models (carrageen and egg-albumin induced rat hind paw edema). It also elicited significant anti-inflammatory activity in chronic inflammatory models (cotton pellet granuloma and Freund's adjuvant induced polyarthritis in rat). In cotton pellet granuloma test, the extract exhibited the inhibitory effect of 23 and 57% at the dose of 6.25 and 12.5 mg/kg, respectively. In Freund's adjuvant induced model, the treatment of the extract of 1.25, 6.25 and 12.5 mg/kg showed the inhibitory effect of 23, 56 and 66% at 8 days, respectively. In the acetic acid-induced model, the extract significantly reduced abdominal writhing in mice when compared to the control group, reducing the mean number of writhing from 41 ± 2 in the control group to 17 ± 3 and 15 ± 2 at the dose of 6.25 and 12.5 mg/kg. From these experiments, the extract, which was extracted from the combination of Bacopa monnieriis, Cassia fistula and Phyllanthus polyphyllus, (w/w/w = 1/2/1) is surprisingly found a significant analgesic and anti-inflammatory activity.

Role of mast cells in experimental autoimmune prostatitis in rats / 中华男科学杂志

Objective@#To investigate the role of mast cells in chronic prostatitis / chronic pelvic pain syndrome (CP/CPPS).@*METHODS@#Forty-five male SD rats were equally randomized into a control, an experimental autoimmune prostatitis (EAP) model, and an intervention group. The EAP model was made in the latter two groups by subcutaneous injection of mixed suspension of complete Freund's adjuvant and prostate tissue, while the controls were treated subcutaneously with 0.9% sodium chloride. Tactile allodynia was quantified in the pelvic region of the control and EAP animals using Von-Frey filaments at 5, 10, 20, 30 and 40 days. After successful establishment of the EAP model, the rats of the intervention group were injected intraperitonieally with cromolyn sodium for 10 days, and meanwhile tactile allodynia was detected in the rats of the intervention and EAP model groups every other day. Then the prostates of the rats were harvested for HE and toluidine blue staining and measurement of the expression of mast cell tryptase by immunohistochemistry and Western blot.@*RESULTS@#Von-Frey assessment showed a more severe pelvic pain in the EAP model than in the control rats, but milder in the intervention group than in the EAP models. HE staining revealed infiltration of lymphocytes and neutrophils in the prostate and congestion surrounding the gland in the EAP model rats, but none in the controls. However, both the infiltration and congestion were significantly alleviated in the intervention group. Toluidine blue staining shown that. Compared with the control group, the total count of mast cells and the number degranulated mast cells were markedly increased in the EAP models (P <0.01) but decreased in the intervention group (P <0.05). Both immunohistochemistry and Western blot manifested that the expression of tryptase in the mast cells was remarkably upregulated in the EAP (both P <0.01) but down-regulated in the intervention group (P <0.05 and P <0.01).@*CONCLUSIONS@#Both the total count of mast cells and the number of degranulated mast cells are significantly increased in the prostate of EAP rats. Mast cells are one of the most important mediators of type Ⅲ prostatitis-induced chronic pelvic pain, which can be used as a target for the intervention and treatment of type Ⅲ prostatitis.

Effect of Shirexiao waist hot-compress on the expressions of Th17/Treg-specific factors in the mouse model of experimental autoimmune prostatitis with damp heat syndrome / 中华男科学杂志

Objective@#To investigate the effect of waist hot-compress with the Shirexiao (SRX) pad on the expressions of Th17/Treg-specific factors in the prostatic tissue of the mouse model of experimental autoimmune prostatitis (EAP) with damp heat syndrome, and explore its possible action mechanisms.@*METHODS@#Twenty healthy male mice were included as normal controls and another 100 chosen for establishing the model of EAP with damp heat syndrome by subcutaneous injection of purified prostate protein solution from the Wistar rat and Freund's complete adjuvant using the TCM method. The model mice were randomly divided into five groups: model control, matrix, and low-, medium- and high-dose SRX. After chemical removal of the hair at lumbar vertebrae 1－3, the animals of the low-, medium- and high-dose SRX groups were treated with the SRX pad heated to 45℃ and externally applied to the non-hair area, qd, bid, and tid, respectively, 10 minutes each time, those of the matrix group with the vaseline pad, and those of the normal and model control groups with the saline pad. After 4 weeks of continuous treatment, all the mice were sacrificed for determination of the protein and mRNA expressions of RORγt and Foxp3 in the prostate tissue by Western blot and quantitative real-time PCR.@*RESULTS@#The symptoms, signs and pathological changes of the EAP model mice were similar to the manifestations of chronic prostatitis. After intervention, the protein and mRNA expressions of Foxp3 were significantly down-regulated while those of RORγt markedly up-regulated in the EAP model group as compared with the normal control (P 0.05).@*CONCLUSIONS@#The Shirexiao waist hot-compress therapy plays a positive role in the treatment of autoimmune prostatitis with damp heat syndrome by reducing the expression of RORγt, inhibiting the differentiation of Th17 and thus checking the differentiation imbalance of Th17/Treg.

Antinociceptive Effects of Prim-O-Glucosylcimifugin in Inflammatory Nociception via Reducing Spinal COX-2

We measured anti-nociceptive activity of prim-o-glucosylcimifugin (POG), a molecule from Saposhnikovia divaricate (Turcz) Schischk. Anti-nociceptive or anti-inflammatory effects of POG on a formalin-induced tonic nociceptive response and a complete Freund's adjuvant (CFA) inoculation-induced rat arthritis pain model were studied. Single subcutaneous injections of POG produced potent anti-nociception in both models that was comparable to indomethacin analgesia. Anti-nociceptive activity of POG was dose-dependent, maximally reducing pain 56.6% with an ED₅₀ of 1.6 mg. Rats given POG over time did not develop tolerance. POG also time-dependently reduced serum TNFα, IL-1β and IL-6 in arthritic rats and both POG and indomethacin reduced spinal prostaglandin E2 (PGE₂). Like indomethacin which inhibits cyclooxygenase-2 (COX-2) activity, POG dose-dependently decreased spinal COX-2 content in arthritic rats. Additionally, POG, and its metabolite cimifugin, downregulated COX-2 expression in vitro. Thus, POG produced potent anti-nociception by downregulating spinal COX-2 expression.

Analgesic Effect and Mechanism of Electroacupuncture on Rats with Chronic Inflammatory Pain / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe analgesic effect of electroacupuncture ( EA) on rats with chronic inflammatory pain and its regulatory mechanism on ispilateral dorsal root ganglion (DRG) and spinal dorsal horn (SDH) Mas-related G protein-coupled C receptor (MrgprC).</p><p><b>METHODS</b>Totally 40 healthy male SD rats were divided into 4 groups according to random number table, i.e., the normal (N) group, the model (M) group, the acupuncture (Acu) group, the EA group, 10 rats in each group. The model of chronic inflammatory pain was established by subcutaneous injecting 0. 1 mL complete Freund's adjuvant (CFA) into right hind paw. Paw withdrawal thresholds (PWTs) were measured before modeling, at day 1, 3, 5, 7, and after CFA injection, respectively. Expression levels of MrgprC in ispilateral DRG and SDH were detected by Western blot. The content of bovine adrenal medulla 22 (BAM22) in SDH was detected by immunohistochemical assay.</p><p><b>RESULTS</b>Compared with N group at each time point, PWTs significantly decreased in M group (P <0. 01). Compared with M group, PWTs significantly increased at day 5 of EA and after EA in EA group (P < 0.05, P < 0.01). Compared with Acu group at each time point, post-EA PWTs significantly increased in the EA group (P < 0.05). Compared with N group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in M group (P < 0.01). Compared with M group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in the EA group (P < 0.05).</p><p><b>CONCLUSION</b>EA had favorable analgesic effect on chronic inflammatory pain induced by CFA, and its mechanism might be possibly associated with up-regulating MrgprC expression in ispilateral DRG and BAM22 content in ispilateral SDH.</p>

The application of in vivo multi-channel recording methods in the studies of the affective pain in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To record the electrical activities of Antirior cingulate cortex (ACC) neurons by in vivo multi-channel recording methods using the model of complete freund's adjuvant (CFA) induced conditioned place avoidance (C-CPA), which has been set up in our previous studies.</p><p><b>METHODS</b>The electrode was self-made and the CPA responses were recorded by in vivo multi-channel recording method.</p><p><b>RESULTS</b>(1) The electrical activities of ACC neurons could be successfully recorded by the self-made electrode. (2) Before or after the injection of CFA, rats were respectively conditioned to the different place. The firing rates of ACC neurons in the CFA-paired place vs that in the non-CFA-paired place was (0.853 ± 1.377) imp/s vs (0.221 ± 0.971) imp/s (P < 0.05, n = 26). (3) The CPA responses in the CFA-paired place vs that in the non-CFA-paired place were (303.55 ± 61.77)s vs (140.32 ± 33.52)s(P < 0.05, n = 6).</p><p><b>CONCLUSION</b>The firing rates of rACC (rostral Anterior Cingulate Cortex) neurons were involved in the occurrence of the affective pain.</p>