TET1-mediated epigenetic regulation of tumor necrosis factor-α in trigeminal ganglia contributes to chronic temporomandibular joint pain

Chronic temporomandibular joint (TMJ) pain profoundly affects patients' quality of life. Trigeminal tumor necrosis factor-α (TNFα) plays a pivotal role in mediating TMJ pain in mice, yet the underlying epigenetic mechanisms remain enigmatic. To unravel these epigenetic intricacies, we employed a multifaceted approach. Hydroxymethylated DNA immunoprecipitation (hMeDIP) and chromatin immunoprecipitation (ChIP) followed by qPCR were employed to investigate the demethylation of TNFα gene (Tnfa) and its regulation by ten-eleven translocation methylcytosine dioxygenase 1 (TET1) in a chronic TMJ pain mouse model. The global levels of 5-hydroxymethylcytosine (5hmc) and percentage of 5hmc at the Tnfa promoter region were measured in the trigeminal ganglia (TG) and spinal trigeminal nucleus caudalis (Sp5C) following complete Freund's adjuvant (CFA) or saline treatment. TET1 knockdown and pain behavioral testing were conducted to ascertain the role of TET1-mediated epigenetic regulation of TNFα in the pathogenesis of chronic TMJ pain. Our finding revealed an increase in 5hmc at the Tnfa promoter region in both TG and Sp5C of CFA-treated mice. TET1 was upregulated in the mouse TG, and the ChIP result showed TET1 direct binding to the Tnfa promoter, with higher efficiency in the CFA-treated group. Immunofluorescence revealed the predominant expression of TET1 in trigeminal neurons. TET1 knockdown in the TG significantly reversed CFA-induced TNFα upregulation and alleviated chronic TMJ pain. In conclusion, our study implicates TET1 as a vital epigenetic regulator contributing to chronic inflammatory TMJ pain via trigeminal TNFα signaling. Targeting TET1 holds promise for epigenetic interventions in TMJ pain management.

Excitatory neurons in the lateral parabrachial nucleus mediate the interruptive effect of inflammatory pain on a sustained attention task

BACKGROUND

Attentional deficits are among the most common pain-induced cognitive disorders. Pain disrupts attention and may excessively occupy attentional resources in pathological states, leading to daily function impairment and increased disability. However, the neural circuit mechanisms by which pain disrupts attention are incompletely understood.

METHODS

We used a three-choice serial reaction time task (3CSRTT) to construct a sustained-attention task model in male C57BL/6J mice. Formalin or complete Freund's adjuvant was injected into a paw to establish an inflammatory pain model. We measured changes in 3CSRTT performance in the two inflammatory pain models, and investigated the neural circuit mechanisms of pain-induced attentional deficits.

RESULTS

Acute inflammatory pain impaired 3CSRTT performance, while chronic inflammatory pain had no effect. Either inhibition of the ascending pain pathway by blockade of the conduction of nociceptive signals in the sciatic nerve using the local anesthetic lidocaine or chemogenetic inhibition of Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) neurons in the lateral parabrachial nucleus (LPBN) attenuated the acute inflammatory pain-induced impairment of 3CSRTT performance, while chemogenetic activation of CaMKIIα neurons in the LPBN disrupted the 3CSRTT. Furthermore, the activity of CaMKIIα neurons in the LPBN was significantly lower on Day 2 after complete Freund's adjuvant injection than on the day of injection, which correlated with the recovery of 3CSRTT performance during chronic inflammatory pain.

CONCLUSIONS

Activation of excitatory neurons in the LPBN is a mechanism by which acute inflammatory pain disrupts sustained attention. This finding has implications for the treatment of pain and its cognitive comorbidities.

BMP-induced non-canonical signaling is upregulated during autophagy-mediated regeneration in inflamed mesothelial cells

Previously, we showed that after Freund's adjuvant-induced peritonitis, rat mesothelial cells regain their epithelial phenotype through mesenchymal-epithelial transition (MET) accompanied by autophagy. Since bone morphogenetic proteins (BMPs) are well-known MET-inducers, we were interested in the potential expression of BMPs and BMP-induced pathways. Although mesothelial cells expressed lower amounts of BMP7, its level in the peritoneal cavity and mesothelial synthesis of BMP4 were significantly increased during inflammation. BMPR1A and BMPR2 were also significantly expressed. Expression of transforming growth factor beta-activated kinase (TAK1) and c-Jun NH2-terminal kinases (JNK1-JNK2) were more intense than that of phosphorylated Mothers Against Decapentaplegic homolog 1/5 (p-SMAD1/5), confirming that the non-canonical pathway of BMPs prevailed in our model. JNK signaling through B-cell lymphoma-2 (Bcl-2) can contribute to Beclin-1 activation. We demonstrated that TAK1-JNK-Bcl-2 signaling was upregulated simultaneously with the autophagy-mediated regeneration. A further goal of our study was to prove the regenerative role of autophagy after inflammation. We used a specific inhibitor, bafilomycin A1 (BafA1), and found that BafA1 treatment decreased the expression of microtubule-associated protein 1A/1B-light chain 3 (LC3B) and resulted in morphological signs of cell death in inflamed mesothelial cells indicating that if autophagy is arrested, regeneration turns into cell death and consequently, mesothelial cells die.

Cassia absus-mediated upregulation of IL-4, IL-10 and downregulation of IL-1β, IL-6, TNF- α, NF-κB, IFN-γ in CFA-induced arthritis model

Traditional use of Cassia absus as an anti-inflammatory in conjunctivitis and bronchitis is well reported. Owing to its anti-inflammatory potential, the current study appraised in vivo anti-arthritic activity of n-hexane and aqueous extracts of Cassia absus seeds (200 mg/kg) using Complete Freund's Adjuvant (CFA) rat model of arthritis. Changes in paw size (mm), joint diameter (mm), and pain response (sec) were recorded at the baseline and then after CFA induction at the interval of 4 days till the 28th day. Blood samples of anesthetized rats were collected for the estimation of hematological, oxidative, and inflammatory biomarkers. Results showed percent inhibition in paw edema (45.09% and 60.79%) with both n-hexane and aqueous extracts, respectively. Significant reduction in paw size and ankle joint diameter (P < 0.01) was seen in extracts treated rats. Erythrocyte Sedimentation rate, C-Reactive Protein, White Blood Cell levels significantly lowered, and Hemoglobin, Platelets and Red Blood Cell count significantly increased post-treatments. Superoxide Dismutase, Catalase, and Glutathione were significantly improved (P < 0.0001) in treated groups as compared to CFA induced arthritic control. Real-time polymerase chain reaction investigation showed significant downregulation (P < 0.05) of Interleukin-1β, Tumor Necrosis Factor-α, Interleukin-6, Cycloxygenase-2, Nuclear Factor-κB, Prostaglandin E Synthase 2, Interferon Gamma and upregulation of Interleukin-4, Interleukin-10 in both n-hexane and aqueous extract-treated groups. It is thereby concluded that Cassia absus can significantly attenuate CFA-induced arthritis by modulation of oxidative and inflammatory biomarkers.

Adjuvant Injections Altered the Ileal and Fecal Microbiota Differently with Changes in Immunoglobulin Isotypes and Antimycobacterial Antibody Responses

Alterations in the gut microbiota, "dysbiosis," have been reported in autoimmune diseases, including multiple sclerosis (MS), and their animal models. Although the animal models were induced by injections of autoantigens with adjuvants, including complete Freund's adjuvant (CFA) and pertussis toxin (PT), the effects of adjuvant injections on the microbiota are largely unknown. We aimed to clarify whether adjuvant injections could affect the microbiota in the ileum and feces. Using 16S rRNA sequencing, we found decreased alpha diversities of the gut microbiota in mice injected with CFA and PT, compared with naïve mice. Overall, microbial profiles visualized by principal component analysis demonstrated dysbiosis in feces, but not in the ileum, of adjuvant-injected mice, where the genera Lachnospiraceae NK4A136 group and Alistipes contributed to dysbiosis. When we compared the relative abundances of individual bacteria, we found changes in 16 bacterial genera in feces and seven genera in the ileum of adjuvant-injected mice, in which increased serum levels of antibody against mycobacteria (a component of CFA) and total IgG2c were correlated with the genus Facklamia. On the other hand, increased IgG1 and IgA concentrations were correlated with the genus Atopostipes. Therefore, adjuvant injections alone could alter the overall microbial profiles (i.e., microbiota) and individual bacterial abundances with altered antibody responses; dysbiosis in animal models could be partly due to adjuvant injections.

Cryoneurolysis with Injectable Ice Slurry Modulates Mechanical Skin Pain

Cutaneous pain is a common symptom of skin disease, and available therapies are inadequate. We developed a neural selective and injectable method of cryoneurolysis with ice slurry, which leads to a long-lasting decrease in mechanical pain. The aim of this study is to determine whether slurry injection reduces cutaneous pain without inducing the side effects associated with conventional cryoneurolysis. Using the rat sciatic nerve, we examined the effects of slurry on nerve structure and function in comparison with the effects of a Food and Drug Administration‒approved cryoneurolysis device (Iovera). Coherent anti-Stokes Raman scattering microscopy and immunofluorescence staining were used to investigate histological effects on the sciatic nerve and on downstream cutaneous nerve fibers. Complete Freund's Adjuvant model of cutaneous pain was used to study the effect of the slurry on reducing pain. Structural changes in myelin induced by slurry were comparable with those induced by Iovera, which uses much colder temperatures. Compared with that of Iovera, the decrease in mechanical pain due to slurry was less profound but lasted longer without signs of dysesthesia. Slurry did not cause a reduction of epidermal nerve fibers or a change in thermal pain sensitivity. Slurry-treated rats showed reduced cutaneous mechanical pain in response to Complete Freund's Adjuvant. Slurry injection can be used to successfully reduce cutaneous pain without causing dysesthesia.

[Effect of heat-reinforcing needling on expression of serum inflammatory factors and autophagy of knee joint synovial tissue in rheumatoid arthritis rabbits with cold syndrome]

OBJECTIVE

To observe the effect of heat-reinforcing needling on the expression of serum inflammatory factors and autophagy of knee synovial tissue in rheumatoid arthritis (RA) rabbits with cold syndrome, so as to explore its mechanism of anti-inflammatory in the treatment of RA.

METHODS

Fifty rabbits were randomly divided into normal, model, heat-reinforcing needling, inhibitor and agonist groups (n=10 rabbits in each group). The model of RA with cold syndrome was established by Freund's adjuvant and ovalbumin mixed solution injection combined with freezing and wind-cold dampness method. Heat-reinforcing needling was applied at "Zusanli" (ST36) for 30 min, once a day for 14 days. Rabbits of the inhibitor and agonist groups were given intraperitoneally injected with autophagy inhibitor 3-methyladenine (3-MA) or autophagy agonist rapamycin, once every 2 days for 7 days. The knee circumference and skin temperature of the rabbits in each group were measured. Color doppler ultrasonography was applied to examine the synovial membrane, joint effusion and blood flow signals in the knee joints of the rabbits in each group. Serum tumor necrosis factor (TNF) -α, interleukin (IL)-1β, IL-6 and C-creactive protein (CRP) were detected by ELISA. Transmission electron microscopy was applied to observe the ultrastructure and autophagosomes of synovial cells. The protein expressions of autophagy-related protein Atg5, serine/threonine protein kinase-dysregulated 51-like kinase 1 (ULK1), microtubule-associated protein light chain 3B (LC3B), and Beclin-1 were detected by Western blot. Fluorescence quantitative PCR was used to detect the mRNA expressions of NOD-like receptor 3 (NLRP3) and nuclear factor-κB (NF-κB).

RESULTS

Compared with the normal group, the circumference of the knee joint was increased (P<0.01), the skin temperature was decreased (P<0.01), the knee joint synovium was thickened and the blood flow signal was abundant, the contents of serum TNF-α, IL-1β, IL-6, and CRP were increased (P<0.01), the protein expressions of Atg5, ULK1, Beclin-1 and LC3BⅡ/LC3BⅠof synovial tissue were significantly decreased (P<0.01), the mRNA expressions of NLRP3 and NF-κB were increased (P<0.01) in the model group. In comparison with the model and inhibitor groups, the circumference of the knee joint was decreased (P<0.01), whlie the skin temperature was increased (P<0.01), the synovial membrane became thinner and the blood flow signal was wea-kened, the contents of TNF-α, IL-1β, IL-6 and CRP were decreased (P<0.01), the protein expressions of Atg5, ULK1, Beclin-1 and LC3B Ⅱ/LC3B Ⅰ were increased (P<0.01), and the mRNA expressions of NLRP3 and NF-κB were decreased (P<0.01) in the heat-reinforcing needling and agonist groups.

CONCLUSION

Heat-reinforcing needling can alleviate the inflammatory response of the knee joint synovium in RA rabbits with cold syndrome, which may be related to its function in enhancing the autophagy activity of synovial cells and inhibiting the synthesis and release of inflammatory factors TNF-α, IL-1β, IL-6 and CRP.

Jobelyn® extends the life span and improves motor function in Drosophila melanogaster exposed to lipopolysaccharide via augmentation of antioxidant status

Jobelyn® (JB), a dietary supplement, derived from polyphenol-rich leaf sheath of Sorghum bicolor, has been reported to attenuate sensorimotor deficits and oxidative stress evoked by complete Freund-adjuvant in mice. This present study evaluated its effects on the life span, motor function and changes in oxidative stress parameters as well as acetylcholinesterase activity in Drosophila melanogaster exposed to lipopolysaccharide (LPS). The flies (50 per vial), in 5 replicates were fed with LPS (250 μg/kg diet) alone or in combination with JB (0.25-1.0 mg/kg diet) daily for 7 days. The mortality rate and motor function were evaluated on day 7. The flies were afterwards processed for determination of oxidative stress parameters and acetylcholinesterase activity. The effects of JB (0.25-1.0 mg/g diet) on the longevity of Drosophila was also investigated wherein the flies were monitored daily for mortality throughout their lifespan. The flies exposed to LPS (250 μg/kg diet) had reduced life span and elevated oxidative stress when compared with control. However, JB (0.25 and 1.0 mg/kg diet) improved the motor function and also reduced the mortality rate of the flies exposed to LPS. It also restored the cellular antioxidant status and reduced acetylcholinesterase activity, accumulation of hydrogen peroxide as well as nitric oxide in Drosophila fed with LPS. JB also extended the longevity of the flies relative to control. The findings that JB improves motor function and extended the lifespan of Drosophila flies by boosting the antioxidant status and cholinergic function, suggest it might be helpful in delaying the onset of neuropsychiatric illnesses associated with the aging processes.

Complete Freund's adjuvant-induced protein dysregulation correlated with mirror image pain as assessed by quantitative proteomics of the mouse spinal cord

Inflammation or trauma occurring on one side of the body can cause pathological pain on the contralateral noninjured side in a phenomenon called mirror-image pain (MIP). Although some potential mechanisms involved in MIP have been reported, including those involving the immune system and glial cells as well as neural mechanisms, the molecular mechanisms are not well understood. In this study, we aimed to understand the molecular mechanisms in MIP using quantitative proteomics and whole-cell patch clamp recordings. Behavioral test results showed that complete Freund's adjuvant could induce MIP in the mice. The results of isobaric tags for relative and absolute quantification (iTRAQ) quantitative proteomics showed that 108 proteins were dysregulated, and these proteins may represent potential targets. Furthermore, bioinformatics analysis was applied to explore the potential molecular mechanisms during MIP after complete Freund's adjuvant (CFA) treatment. Parallel reaction monitoring (PRM) results showed that PKCδ and seven other dysregulated proteins were related to MIP after CFA treatment. Patch clamp recording results showed that CFA treatment could increase intrinsic excitability and spontaneous firing in spinal cord neurons during MIP. In summary, we found that CFA could induce MIP. The results of proteomic research on the spinal cord after CFA treatment could provide new insight into the molecular mechanisms of MIP. Moreover, the neuronal activity of spinal cord neurons was upregulated during MIP after CFA treatment. In summary, the results of the spinal cord proteomic profile provide a potential molecular mechanism for understanding MIP.

Carbamylated erythropoietin improves recognition memory by modulating microglia in a rat model of pain

Patients with chronic pain often complain about memory impairments. Experimental studies have shown neuroprotective effects of Carbamylated erythropoietin (Cepo-Fc) in the treatment of cognitive dysfunctions. However, little is currently known about its precise molecular mechanisms in a model of inflammatory pain. Therefore, this study aimed to investigate neuroprotective effects of Cepo-Fc against cognitive impairment induced by the inflammatory model of Complete Freund's Adjuvant (CFA). Carbamylated erythropoietin was administrated Intraperitoneally (i.p) on the day CFA injection, continued for a 21-days period. After conducting the behavioral tests (thermal hyperalgesia and novel object recognition test), western blot and ELISA were further preformed on days 0, 7, and 21. The results of this study indicate that Cepo-Fc can effectively reverse the CFA induced thermal hyperalgesia and recognition memory impairment. Additionally, Cepo-Fc noticeably decreased the hippocampal microglial expression, production of hippocampal IL-1β, and hippocampal apoptosis and necroptosis induced by the inflammatory pain. Therefore, our findings suggest that neuroprotective effects of Cepo-Fc in the treatment of pain related recognition memory impairment may be mediated through reducing hippocampal microglial expression as well as IL-1β production.

NLRP2 Is Overexpressed in Spinal Astrocytes at the Peak of Mechanical Pain Sensitivity during Complete Freund Adjuvant-Induced Persistent Pain

Our earlier findings revealed that interleukin-1 receptor type-1 (IL-1R1) was overexpressed in spinal neurons, and IL-1R1-deficient mice showed significant attenuation of thermal and mechanical allodynia during the course of the Complete Freund adjuvant (CFA)-induced persistent pain model. In the present study, we found that a ligand of IL-1R1, termed interleukin-1β (IL-1β), is also significantly overexpressed at the peak of mechanical pain sensitivity in the CFA-evoked pain model. Analysis of cellular distribution and modeling using IMARIS software showed that in the lumbar spinal dorsal horn, IL-1β is significantly elevated by astrocytic expression. Maturation of IL-1β to its active form is facilitated by the formation of the multiprotein complex called inflammasome; thus, we tested the expression of NOD-like receptor proteins (NLRPs) in astrocytes. At the peak of mechanical allodynia, we found expression of the NLRP2 inflammasome sensor and its significantly elevated co-localization with the GFAP astrocytic marker, while NLRP3 was moderately present and NLRP1 showed total segregation from the astrocytic profiles. Our results indicate that peripheral CFA injection induces NLRP2 inflammasome and IL-1β expression in spinal astrocytes. The release of mature IL-1β can contribute to the maintenance of persistent pain by acting on its neuronally expressed receptor, which can lead to altered neuronal excitability.

Blockade of Spinal EphA4 Reduces Chronic Inflammatory Pain in Mice

Background: Erythropoietin-producing hepatocellular (Ephs) receptor and their ligands, ephrins, orchestrate the induction of cell proliferation and migration, axonal guidance, synaptic genesis and synaptic plasticity in the central nervous system. Previous studies demonstrated that EphBs/ephrinBs participate in the pathophysiology of neuropathic pain, inflammatory pain and bone cancer pain, but the role of EphA4 in the regulation of pain in the spinal cord is unknown. Therefore, we explored the role of EphA4 receptor in regulating chronic inflammatory pain.Methods: We established a mouse model of chronic inflammatory pain through plantar injection of complete freund's adjuvant (CFA) and assessed EphA4 expression in spinal cord by western blotting. EphA4 receptor was blocked by intrathecal injection of EphA4-Fc, an EphA4 antagonist, and pain behaviors were measured by assessing thermal hyperalgesia and mechanical allodynia. Finally, immunohistochemistry was performed to analyze the changes in the expression of Fos protein in spinal cord after blocking EphA4 receptor.Results: Plantar injection of CFA produced persistent thermal hyperalgesia and mechanical allodynia, which was accompanied by significant increases in spinal EphA4 and Fos expression. Blocking spinal EphA4 receptor suppressed CFA-induced pain behaviors and reduced the expression of Fos protein in spinal cord.Conclusions: Our study demonstrated that EphA4 receptor is involved in the generation and maintenance of CFA-induced chronic inflammatory pain and that blocking the spinal EphA4 receptor could relieve persistent pain behaviors in mice.

Phytol, a Chlorophyll Component, Produces Antihyperalgesic, Anti-inflammatory, and Antiarthritic Effects: Possible NFκB Pathway Involvement and Reduced Levels of the Proinflammatory Cytokines TNF-α and IL-6

Phytol is a diterpene constituent of chlorophyll and has been shown to have several pharmacological properties, particularly in relation to the management of painful inflammatory diseases. Arthritis is one of the most common of these inflammatory diseases, mainly affecting the synovial membrane, cartilage, and bone in joints. Proinflammatory cytokines, such as TNF-α and IL-6, and the NFκB signaling pathway play a pivotal role in arthritis. However, as the mechanisms of action of phytol and its ability to reduce the levels of these cytokines are poorly understood, we decided to investigate its pharmacological effects using a mouse model of complete Freund's adjuvant (CFA)-induced arthritis. Our results showed that phytol was able to inhibit joint swelling and hyperalgesia throughout the whole treatment period. Moreover, phytol reduced myeloperoxidase (MPO) activity and proinflammatory cytokine release in synovial fluid and decreased IL-6 production as well as the COX-2 immunocontent in the spinal cord. It also downregulated the p38MAPK and NFκB signaling pathways. Therefore, our findings demonstrated that phytol can be an innovative antiarthritic agent due to its capacity to attenuate inflammatory reactions in joints and the spinal cord, mainly through the modulation of mediators that are key to the establishment of arthritic pain.

Synthetic mycobacterial molecular patterns partially complete Freund's adjuvant

Complete Freund's adjuvant (CFA) has historically been one of the most useful tools of immunologists. Essentially comprised of dead mycobacteria and mineral oil, we asked ourselves what is special about the mycobacterial part of this adjuvant, and could it be recapitulated synthetically? Here, we demonstrate the essentiality of N-glycolylated peptidoglycan plus trehalose dimycolate (both unique in mycobacteria) for the complete adjuvant effect using knockouts and chemical complementation. A combination of synthetic N-glycolyl muramyl dipeptide and minimal trehalose dimycolate motif GlcC14C18 was able to upregulate dendritic cell effectors, plus induce experimental autoimmunity qualitatively similar but quantitatively milder compared to CFA. This research outlines how to substitute CFA with a consistent, molecularly-defined adjuvant which may inform the design of immunotherapeutic agents and vaccines benefitting from cell-mediated immunity. We also anticipate using synthetic microbe-associated molecular patterns (MAMPs) to study mycobacterial immunity and immunopathogenesis.

Standard Immunization of Mice, Rats, and Hamsters

Mice, rats, or hamsters are immunized by giving biweekly injections of a purified antigen, cultured cells, or cDNA. For mice, if a pure, soluble protein antigen is being used and is abundant, a dose of 50-100 µg in adjuvant at each immunization is a sensible general recommendation; for rats and hamsters, a dose of 100-200 µg is sufficient. Lower doses can be used for antigens with higher immunogenicity. Adjuvants (Freund's, Ribi, Hunter's TiterMax, ImmunEasy, or Alum) should be mixed with the immunizing antigen for the first two immunizations only; Complete Freund's adjuvant is only used with the first immunization. Subsequent immunizations are performed in phosphate-buffered saline (PBS) or normal saline, with or without Incomplete Freund's adjuvant. The choice of adjuvant is dependent on the subclass of immunoglobulin required. Over the course of the 6-wk immunization schedule, each animal usually receives a total of six injections (three subcutaneous and three intraperitoneal). Once a good titer has developed against the antigen of interest, regular boosts and bleeds are performed to collect the maximum amount of serum. For rats and hamsters, boosts should be spaced every 2-3 wk, and serum samples of 400-500 µL should be collected 10-12 d after each boost. For mice, boosts should be spaced every 2-3 wk, and serum samples of 200-300 µL should be collected 10-12 d after each boost.

The phthalimide analogues N-3-hydroxypropylphthalimide and N-carboxymethyl-3-nitrophthalimide exhibit activity in experimental models of inflammatory and neuropathic pain

BACKGROUND

Phthalimide analogues devoid of the glutarimide moiety exhibit multiple biological activities, thus making them candidates for the treatment of patients with different diseases, including those with inflammatory and painful disorders. In the present study, the activities of five phthalimide analogues devoid of the glutarimide moiety (N-hydroxyphthalimide, N-hydroxymethylphthalimide, N-3-hydroxypropylphthalimide, N-carboxy-3-methylphthalimide, N-carboxymethyl-3-nitrophthalimide) were evaluated in experimental models of acute and chronic inflammatory and neuropathic pain.

METHODS

The phthalimide analogues were administered per os (po) in Swiss mice or Wistar rats. Nociceptive response induced by formaldehyde and mechanical allodynia induced by chronic constriction injury (CCI) of the sciatic nerve or intraplantar (ipl) injection of complete Freund's adjuvant (CFA) were used as experimental models of pain.

RESULTS

N-carboxymethyl-3-nitrophthalimide (700 mg/kg, -1 h) inhibited the second phase of the nociceptive response induced by the intraplantar injection of formaldehyde in mice. N-3-hidroxypropylphthalimide (546 mg/kg, -1 h) inhibited both phases of the nociceptive response induced by formaldehyde. Treatment of rats with N-carboxymethyl-3-nitrophthalimide (700 mg/kg) or N-3-hydroxypropylphthalimide (546 mg/kg) inhibited the mechanical allodynia induced by CCI of the sciatic nerve or ipl injection of CFA in rats. Intraperitoneal administration of the opioid antagonist naltrexone (10 mg/kg, -1.5 h) attenuated the antinociceptive activity of N-carboxymethyl-3-nitrophthalimide (700 mg/kg) in the model of nociceptive response induced by formaldehyde.

CONCLUSIONS

N-3-hydroxypropylphthalimide and N-carboxymethyl-3-nitrophthalimide, two phthalimide analogues devoid of the glutarimide moiety, exhibited activities in different experimental models of pain, including models of chronic inflammatory and neuropathic pain.

Coix lachryma-jobi extract ameliorates inflammation and oxidative stress in a complete Freund's adjuvant-induced rheumatoid arthritis model

Context: Adlay seed [Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf (Poaceae)] is a Traditional Chinese Medicine, which has been investigated to treat inflammatory diseases and rheumatism.Objective: This study evaluates the ameliorative effects of adlay seed extract (ASE) in a complete Freund's adjuvant (CFA)-induced rheumatoid arthritis (RA) rats.Materials and methods: The RA Sprague-Dawley rat model was induced and randomly divided into six groups with or without ASE treatment (50, 100 or 200 mg/kg). After 28 d administration, the symptoms, biochemical parameters and molecular mechanisms were investigated.Results: The values of paw oedema, PGE₂ and MMP-3 decreased from 1.46 ± 0.04 to 0.66 ± 0.07 cm³, from 126.2 ± 11.48 to 79.71 ± 6.8 pg/mL and from 142.7 ± 8.36 to 86.51 ± 5.95 ng/mL, respectively; the values of body weight increased from 177.25 ± 5.94 to 205 ± 6.52 g in HASE group. In addition, treatment of ASE reduced the levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, MCP-1), and increased the activities of antioxidant enzyme (GSH-Px, SOD, and CAT). Furthermore, ASE could suppress the mRNA expression of COX-2 and CHI3L1 and improve the mRNA expression of CAT and GPx-1 in ankle tissues of RA rats.Discussion and conclusions: For the first time, our results indicated ASE exerts anti-RA effects via inhibiting pro-inflammatory factors and alleviating oxidative stress. Our finding sheds light on the research and development of anti-RA functional foods from adlay seed.

Activation of trigeminal ganglion satellite glial cells in CFA-induced tooth pulp pain in rats

This study further investigated the mechanisms underlying the rat model of tooth pulp inflammatory pain elicited by complete Freund's adjuvant (CFA), in comparison to other pulpitis models. Pulps of the left maxillary first molars were accessed. In the CFA group, the pulps were exposed, and CFA application was followed by dental sealing. In the open group, the pulps were left exposed to the oral cavity. For the closed group, the pulps were exposed, and the teeth were immediately sealed. Naïve rats were used as negative controls. Several parameters were evaluated at 1, 2, 3 and 8 days. There was no statistical significant difference among the groups when body weight variation, food or water consumption were compared. Analysis of serum cytokines (IL-1β, TNF or IL-6) or differential blood cell counts did not reveal any evidence of systemic inflammation. The CFA group displayed a significant reduction in the locomotor activity (at 1 and 3 days), associated with an increased activation of satellite glial cells in the ipsilateral trigeminal ganglion (TG; for up to 8 days). Amygdala astrocyte activation was unaffected in any experimental groups. We provide novel evidence indicating that CFA-induced pulp inflammation impaired the locomotor activity, with persistent activation of ipsilateral TG satellite cells surrounding sensory neurons, without any evidence of systemic inflammation or amygdala astrogliosis.

Biological, Histological and Ultrastructural Aspects of Hodgkin's-Like Lymphomas in SJL/J Mice

Spontaneous lymphoma developed in 57 % female SJL/J mice, with a mean latent period of 58 weeks and in 33 % male SJL/J mice with a mean latent period of 72 weeks. In (CBA x SJL) F1 and F2, the incidence in females was 79 % and 67 % at a mean age of 107 and 100 weeks respectively while in males it was 53 % and 41 % at 111 and 106 weeks. In reciprocal F1 and F2 hybrids, an incidence of 62 % and 37 % was observed in females at 118 and 109 weeks of age, while in males it was 33 % and 43 % at the mean ages of 72 and 90 weeks. Gross lesions were usually restricted to mesenteric, cervical, axillary and inguinal lymph nodes, Peyer's patches and spleen. Less frequently, lungs, liver, kidney and thymus were also involved. Histological examination of nodes in the pre-neoplastic stage revealed follicular hyperplasia with prominent germinal centers, sinus hystiocytosis, precence of pyroninophilic cells within the paracortical area and medulla, medullary plasmocytosis and epithelioid sarcoid-like noduli. Nodes, spleen and other affected organs examined during overt disease showed a pleomorphic pattern characteristic of type B reticulum cell neoplasm according to Dunn and contained predominantly plasma cells, giant cells or reticulum cells. At the electron microscope, these different cell types were detected within the neoplastic tissue. In addition, cells resembling immunoblasts were frequently observed, which suggests that they might represent proliferating tumor cells capable of differentiating into plasma cells. Type C-immature and A intracisternal particles were repeatedly observed, but no type C-mature particles were seen. Attempts to transplant neoplastic tissue in syngeneic hosts were successful. Cell-free extracts from primary SJL/J lymphomas were injected in newborn RFM and CBA mice. 4 out of 9 RFM mice developed SJL/J-like lymphoma at 64–70 weeks of age, while no lymphomas were found in 8 CBA mice over 70 weeks of age. Freund adjuvant injected intraperitoneally in (CBA x SJL/J) F1 mice did not modify the incidence or the latency of the lymphomas when compared with control animals.

Cationic Liposome-Oligonucleotide Complex as an Alternative Adjuvant for Polyclonal Antibody Production in New Zealand White Rabbits (Oryctolaguscuniculus)

Because of their ideal size and temperament, rabbits are commonly used in polyclonal antibody production. Immunostimulatory adjuvants-such as Freund complete and incomplete adjuvants as well as various proprietary products-trigger a robust immune response, which increases antibody concentrations. However, these adjuvants can cause excessive soft tissue reactions, prompting concerns regarding animal wellbeing. This study assessed the safety and efficacy of cationic liposome- oligonucleotide complexes (CLDC) as an alternative adjuvant to conventional adjuvants. On days 0 and 14, 15 female New Zealand white rabbits were vaccinated subcutaneously with 15 μg ovalbumin mixed with either CLDC, Freund adjuvant (day 0, complete; day 14, incomplete), or a proprietary adjuvant (n = 5 per group). Antibody titers were measured by direct ELISA on days 0, 14, and 28. Rabbits were palpated daily for lesion development, and all lesions were measured. Rabbits in all groups developed a significant antibody response to ovalbumin over 28 d. However, the differences between groups were not statistically significant. No rabbits in the CLDC group developed skin lesions, whereas 80% of rabbits that received Freund adjuvant and 100% of those that received the proprietary product developed skin lesions. This study demonstrates that CLDC may be a valuable and effective alternative adjuvant for polyclonal antibody production in rabbits-one that avoids the palpable injection-site lesions often seen with other adjuvants.

Endosomal signaling of the receptor for calcitonin gene-related peptide mediates pain transmission

G protein-coupled receptors (GPCRs) are considered to function primarily at the plasma membrane, where they interact with extracellular ligands and couple to G proteins that transmit intracellular signals. Consequently, therapeutic drugs are designed to target GPCRs at the plasma membrane. Activated GPCRs undergo clathrin-dependent endocytosis. Whether GPCRs in endosomes control pathophysiological processes in vivo and are therapeutic targets remains uncertain. We investigated the contribution of endosomal signaling of the calcitonin receptor-like receptor (CLR) to pain transmission. Calcitonin gene-related peptide (CGRP) stimulated CLR endocytosis and activated protein kinase C (PKC) in the cytosol and extracellular signal regulated kinase (ERK) in the cytosol and nucleus. Inhibitors of clathrin and dynamin prevented CLR endocytosis and activation of cytosolic PKC and nuclear ERK, which derive from endosomal CLR. A cholestanol-conjugated antagonist, CGRP8-37, accumulated in CLR-containing endosomes and selectively inhibited CLR signaling in endosomes. CGRP caused sustained excitation of neurons in slices of rat spinal cord. Inhibitors of dynamin, ERK, and PKC suppressed persistent neuronal excitation. CGRP8-37-cholestanol, but not unconjugated CGRP8-37, prevented sustained neuronal excitation. When injected intrathecally to mice, CGRP8-37-cholestanol inhibited nociceptive responses to intraplantar injection of capsaicin, formalin, or complete Freund's adjuvant more effectively than unconjugated CGRP8-37 Our results show that CLR signals from endosomes to control pain transmission and identify CLR in endosomes as a therapeutic target for pain. Thus, GPCRs function not only at the plasma membrane but also in endosomes to control complex processes in vivo. Endosomal GPCRs are a drug target that deserve further attention.

Complete Freund's adjuvant induces experimental autoimmune myocarditis by enhancing IL-6 production during initiation of the immune response

INTRODUCTION

Complete Freund's Adjuvant (CFA) emulsified with an antigen is a widely used method to induce autoimmune disease in animal models, yet the contribution of CFA to the immune response is not well understood. We compared the effectiveness of CFA with Incomplete Freund's Adjuvant (IFA) or TiterMax Gold Adjuvant (TMax) in experimental autoimmune myocarditis (EAM) in male mice.

METHODS

EAM was induced in A/J, BALB/c, and IL6KO BALB/c male mice by injection of the myocarditogenic peptide in CFA, IFA, or TMax on days 0 and 7. EAM severity was analyzed by histology on day 21. In addition, specific flow cytometry outcomes were evaluated on day 21.

RESULTS

Only mice immunized with CFA and myocarditogenic peptide on both days 0 and 7 developed substantial myocarditis as measured by histology. We observed a significantly increased level of IL6 in the spleen 3 days after CFA immunization. In the spleen and heart on day 21, there was an expansion of myeloid cells in CFA-immunized mice, as compared to IFA or TMax-immunized animals. Recombinant IL-6 at the time of IFA immunization partially restored susceptibility of the mice to EAM. We also treated EAM-resistant IL-6 knockout mice with recombinant IL-6 around the time of the first immunization, on days -1 to 2, completely restoring disease susceptibility, showing that the requirement for IL-6 coincides with primary immunization. Examining APC populations in the lymph node draining the immunization site evidenced the contribution of IL-6 to the CFA-dependence of EAM was through controlling local dendritic cell (DC) trafficking.

CONCLUSIONS

CFA used with myocarditogenic peptide twice is required to induce EAM in both A/J and Balb/c mice. Although IFA and TiterMax induce antibody responses, only CFA preferentially induced autoantigen-specific responses. CFA expands monocytes in the heart and in the spleen. IL-6 signaling is required during short window around primary immunization to induce EAM. In addition, IL-6 deficient mice resistance to EAM could be reversed by injecting IL-6 around first immunization. IL-6 expands dendritic cell and monocytic populations and ultimately leads to a robust T-cell driven immune response in CFA immunized mice.

In vitro and in vivo evaluation of anti-arthritic, antioxidant efficacy of fucoidan from Undaria pinnatifida (Harvey) Suringar

Seaweed and their constituents have been traditionally employed for the management of various human pathologic conditions such as edema, urinary disorders and inflammatory anomalies. The current study was performed to investigate the antioxidant and anti-arthritic effects of fucoidan from Undaria pinnatifida. A noteworthy in vitro antioxidant potential at 500μg/ml in 2, 2-diphenyl-1-picrylhydrazyl scavenging assay (80% inhibition), nitrogen oxide inhibition assay (71.83%), hydroxyl scavenging assay (71.92%), iron chelating assay (73.55%) and a substantial ascorbic acid equivalent reducing power (399.35μg/mg ascorbic acid equivalent) and total antioxidant capacity (402.29μg/mg AAE) suggested fucoidan a good antioxidant agent. Down regulation of COX-2 expression in rabbit articular chondrocytes in a dose (0-100μg) and time (0-48h) dependent manner, unveiled its in vitro anti-inflammatory significance. In vivo carrageenan induced inflammatory rat model demonstrated a 68.19% inhibition of inflammation whereas an inflammation inhibition potential of 79.38% was recorded in anti-arthritic complete Freund's adjuvant-induced arthritic rat model. A substantial ameliorating effect on altered hematological and biochemical parameters in arthritic rats was also observed. Therefore, findings of the present study prospects fucoidan as a potential antioxidant that can effectively abrogate oxidative stress, edema and arthritis-mediated inflammation and mechanistic studies are recommended for observed activities.

Freund´s complete adjuvant effect on BALB/c mice: an insight into inflammation and oxidative stress after immunity challenge

Freund´s complete adjuvant (FCA) is a mean used for improving immunization efficacy in experiments and veterinary medicine. Despite high efficacy, it is not used in human vaccination due to number of adverse effects. Arthritis can be an example of a typical adverse consequence. In this work, we decided to investigate the link between oxidative stress and inflammation in animals exposed to FCA. BALB/c mice received either saline or FCA in doses 10-50 µl and were euthanized from one to three days after infection. Interleukins (IL) IL-2, IL-4 and tumor necrosis factor α (TNF-α) were determined in plasma. Ferric reducing antioxidant power (FRAP), malondialdehyde by thiobarbituric acid reactive substances assay (TBARS), reduced glutathione (GSH) and caspase-3 were measured in livers, muscles and other organs. We determined significant effect of FCA on TBARS and GSH in the livers. Beside this, TBARS were altered in muscles as well. Inflammation was confirmed by increased level of TNF-α. Taking the results into account, we infer that the harmful effect of FCA is mediated not only by inflammation but also by oxidative. This should be considered when pathological consequences of FCA are scored.

[COMPARATIVE IMMUNOGENICITY STUDIES OF ADJUVANTS FROM VARIOUS SOURCES AND WITH DIFFERENT MECHANISMS OF ACTION FOR INACTIVATED INFLUENZA VACCINES]

AIM

Direct immunogenicity comparison of adjuvants from various sources and with different mechanisms of action for inactivated influenza vaccines.

MATERIALS AND METHODS

Groups of mice were immunized intramuscularly twice with an inactivated whole-virion influenza vaccine based on A/California/07/2009 X-179A (H1N1) strain. The following adjuvants were added to the vaccine (10 in total): aluminium hydroxide, oligonucleotide CpG, complete Freund's adjuvant, poly(lactide-coglycolide) microparticles, monophosphoryl lipid A and polyoxidonium, as well as 2 adjuvants based on characterized chitosan substances with different physical/chemical properties and 2 experimental complex formulations (a multi-component adjuvant and an oil-in-water emulsion based on squalene and tocopherol). Immuogenicity was determined by HAI and MN (MDCK) sera antibodies.

RESULTS

Different adjuvants increased immunogenicity of the vaccine against the homologous strain in varying patterns. Experimental complex formulations were the most immunogenic (antibody titer increase reached 48 - 96 times compared with unadjuvanted vaccines). Chitosan based adjuvants showed high immunogenicity. Not all the adjuvants significantly increased immunogenicity, and in some cases even an immunogenicity decrease was noted with the addition of certain adjuvants.

CONCLUSION

Research and development of chitosan based adjuvants with characterization and standardization issues addressed, as well as complex adjuvants, both multi-component and emulsion based, are the most promising approaches that could lead to next generation vaccines against influenza and other human and animal infectious diseases.

Inhibition of Inactive States of Tetrodotoxin-Sensitive Sodium Channels Reduces Spontaneous Firing of C-Fiber Nociceptors and Produces Analgesia in Formalin and Complete Freund's Adjuvant Models of Pain

While genetic evidence shows that the Nav1.7 voltage-gated sodium ion channel is a key regulator of pain, it is unclear exactly how Nav1.7 governs neuronal firing and what biophysical, physiological, and distribution properties of a pharmacological Nav1.7 inhibitor are required to produce analgesia. Here we characterize a series of aminotriazine inhibitors of Nav1.7 in vitro and in rodent models of pain and test the effects of the previously reported “compound 52” aminotriazine inhibitor on the spiking properties of nociceptors in vivo. Multiple aminotriazines, including some with low terminal brain to plasma concentration ratios, showed analgesic efficacy in the formalin model of pain. Effective concentrations were consistent with the in vitro potency as measured on partially-inactivated Nav1.7 but were far below concentrations required to inhibit non-inactivated Nav1.7. Compound 52 also reversed thermal hyperalgesia in the complete Freund’s adjuvant (CFA) model of pain. To study neuronal mechanisms, electrophysiological recordings were made in vivo from single nociceptive fibers from the rat tibial nerve one day after CFA injection. Compound 52 reduced the spontaneous firing of C-fiber nociceptors from approximately 0.7 Hz to 0.2 Hz and decreased the number of action potentials evoked by suprathreshold tactile and heat stimuli. It did not, however, appreciably alter the C-fiber thresholds for response to tactile or thermal stimuli. Surprisingly, compound 52 did not affect spontaneous activity or evoked responses of Aδ-fiber nociceptors. Results suggest that inhibition of inactivated states of TTX-S channels, mostly likely Nav1.7, in the peripheral nervous system produces analgesia by regulating the spontaneous discharge of C-fiber nociceptors.

Vanillic Acid Inhibits Inflammatory Pain by Inhibiting Neutrophil Recruitment, Oxidative Stress, Cytokine Production, and NFκB Activation in Mice

Vanillic acid (1) is a flavoring agent found in edible plants and fruits. It is an oxidized form of vanillin. Phenolic compounds form a substantial part of plant foods used as antioxidants with beneficial biological activities. These compounds have received considerable attention because of their role in preventing human diseases. Especially, 1 presents antibacterial, antimicrobial, and chemopreventive effects. However, the mechanisms by which 1 exerts its anti-inflammatory effects in vivo are incompletely understood. Thus, the effect of 1 was evaluated in murine models of inflammatory pain. Treatment with 1 inhibited the overt pain-like behavior induced by acetic acid, phenyl-p-benzoquinone, the second phase of the formalin test, and complete Freund's adjuvant (CFA). Treatment with 1 also inhibited carrageenan- and CFA-induced mechanical hyperalgesia, paw edema, myeloperoxidase activity, and N-acetyl-β-D-glucosaminidase activity. The anti-inflammatory mechanisms of 1 involved the inhibition of oxidative stress, pro-inflammatory cytokine production, and NFκB activation in the carrageenan model. The present study demonstrated 1 presents analgesic and anti-inflammatory effects in a wide range of murine inflammation models, and its mechanisms of action involves antioxidant effects and NFκB-related inhibition of pro-inflammatory cytokine production.

[Activation of spinal MrgC receptors inhibits hyperalgesia in rats]

This study was aimed to investigate the mechanisms of the modulation effect of activation of spinal Mas-related gene C (MrgC) receptors on hyperalgesia induced by intraplantar (i.pl.) injection of (Tyr6)-γ2-MSH-6-12 (MSH) or complete Freund's adjuvant (CFA). Paw withdrawal latency test and immunohistochemistry were used to observe the effect of intrathecal (i.t.) administration of MSH or BAM8-22, two selective agonists of MrgC receptor, in hyperalgesia in rats. The results showed that i.t. administration of MSH inhibited acute hyperalgesic response induced by i.pl. application of MSH, while did not change thermal nociceptive threshold in naïve rats. The i.t. administration of MSH also attenuated CFA-induced inflammatory hyperalgesia. However, i.t. administration of the μ-opioid receptor (MOR) antagonist CTAP blocked the induction of delayed anti-hyperalgesia by MSH. The i.t. injection of BAM8-22 at a dose of 30 nmol evidently reduced the number of CFA-evoked nitric oxide synthase (NOS)-positive neurons and the expression of calcitonin gene-related peptide (CGRP)-immunoreactivity positive nerve fibers at L3-L5 segments of the spinal cord. These results suggest that the activation of MrgC receptor in CFA-induced inflammation reduces inflammatory hyperalgesia through inactivation of NOS neurons and down-regulation of CGRP expressions, and generates delayed but long-lasting anti-nociception through the endogenous activation of MOR via indirect mechanisms. Agonists for MrgC receptors may, therefore, represent a new class of antihyperalgesics for treating inflammatory pain because of the highly specific expression of their targets.

Molecular Diversity of Macrophages in Allergic Reaction: Comparison between the Allergenic Modes; Th1- and -Th2-Derived Immune Conditions

Activated macrophages have been classified into classical (M1) and alternative (M2) macrophages. We aimed to establish a method to yield enough number of macrophages to analyze their molecular, biological and immunological functions. We used drugs; adjuvant albumin from chicken egg whites--Imject Alum (OVA-Alum) and OVA Complete Freund Adjuvant (OVA-CFA), to induce macrophages to M2 and M1 respectively. We analyzed the phenotype of purified macrophages induced under these immune conditions, using flow cytometry (FACS) to detect cell-surface molecules and the enzyme-linked immunosorbent assay (ELISA) was used to detect cytokines. The cDNA microarray was employed to measure changes in expression level of cell surface protein between M1 and M2 macrophages. Phenotype analysis of purified macrophages, induced under these immune conditions, showed macrophages induced by OVA-Alum was almost M2 while the proportion of M1 macrophages induced by OVA-CFA was significantly higher. The results also showed higher expression level of macrophage galactose N- acetyl-galactosamine specific lectin-2 protein (MGL1/2-PE), a known M2 macrophage marker, on the surface of Alum-induced macrophages. On the basis of these preliminary data, ELISA results revealed that after macrophage stimulation with lipopolysaccharides (LPS), the level of interleukin (IL)-10 produced by Alum- induced macrophages was higher than the level of IL-10 produced by CFA-induced macrophages. In contrast, the level of tumor necrosis factor-alpha (TNF-α) produced by CFA-induced macrophages was higher than Alum-induced macrophages. The cDNA microarray confirmed previous results and suggest immunoglobulin-like type 2 receptor alpha (Pilra) as a new marker for M1, macrophage galactose N-acetylgalactosamine-specific lectin 2 (Mgl2) as M2 macrophages marker.

Long lasting activity of nociceptive muscular afferents facilitates bilateral flexion reflex pattern in the feline spinal cord

Chronic muscular limb pain requires the adoption of motor patterns distinct from the classic ipsilateral flexion, crossed extension and corresponding reciprocal inhibitions to acute exteroceptive stimulation. Using selective chemical activation of group III/IV afferents in gastrocnemius-soleus (GS) muscles we investigated bilaterally their reflex responses conditioned by (a) acute 'myositis' induced by intramuscular carrageenan; and (b) sub-acute 'myositis' induced by infusion of complete Freund's adjuvant (CFA). Reflex transmission was detected by monosynaptic testing and c-fos staining used to identify increased neuronal activity. In all control experiments with chemical stimulation of group III/IV afferents, ipsilateral responses conformed to the flexor reflex pattern. However, the expected contralateral facilitation of GS motoneurones occurred in fewer than 50% trials while only 9% of trials induced contralateral inhibition of flexor posterior-biceps-semitendinosus (PBSt) motoneurones. During carrageenan acute myositis contralateral PBSt was transiently facilitated by selective activation of group III/IV afferents. During CFA-induced myositis, contralateral only inhibition of GS motoneurones occurred instead of any facilitation, while bidirectionally a crossed facilitation of PBST dominated. These reflex changes were mirrored in an enhanced number of neurones with enhanced c-fos expression. Muscle pain, particularly if chronically persistent, requires another behavioural response pattern than acute exteroceptive pain.

Silica nanoparticles as the adjuvant for the immunisation of mice using hepatitis B core virus-like particles

Advances in nanotechnology and nanomaterials have facilitated the development of silicon dioxide, or Silica, particles as a promising immunological adjuvant for the generation of novel prophylactic and therapeutic vaccines. In the present study, we have compared the adjuvanting potential of commercially available Silica nanoparticles (initial particles size of 10–20 nm) with that of aluminium hydroxide, or Alum, as well as that of complete and incomplete Freund's adjuvants for the immunisation of BALB/c mice with virus-like particles (VLPs) formed by recombinant full-length Hepatitis B virus core (HBc) protein. The induction of B-cell and T-cell responses was studied after immunisation. Silica nanoparticles were able to adsorb maximally 40% of the added HBc, whereas the adsorption capacity of Alum exceeded 90% at the same VLPs/adjuvant ratio. Both Silica and Alum formed large complexes with HBc VLPs that sedimented rapidly after formulation, as detected by dynamic light scattering, spectrophotometry, and electron microscopy. Both Silica and Alum augmented the humoral response against HBc VLPs to the high anti-HBc level in the case of intraperitoneal immunisation, whereas in subcutaneous immunisation, the Silica-adjuvanted anti-HBc level even exceeded the level adjuvanted by Alum. The adjuvanting of HBc VLPs by Silica resulted in the same typical IgG2a/IgG1 ratios as in the case of the adjuvanting by Alum. The combination of Silica with monophosphoryl lipid A (MPL) led to the same enhancement of the HBc-specific T-cell induction as in the case of the Alum and MPL combination. These findings demonstrate that Silica is not a weaker putative adjuvant than Alum for induction of B-cell and T-cell responses against recombinant HBc VLPs. This finding may have an essential impact on the development of the set of Silica-adjuvanted vaccines based on a long list of HBc-derived virus-like particles as the biological component.

Pimaradienoic acid inhibits inflammatory pain: inhibition of NF-κB activation and cytokine production and activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway

Pimaradienoic acid (1) is a pimarane diterpene (ent-pimara-8(14),15-dien-19-oic acid) extracted at high amounts from various plants including Vigueira arenaria Baker. Compound 1 inhibited carrageenan-induced paw edema and acetic acid-induced abdominal writhing, which are its only known anti-inflammatory activities. Therefore, it is important to further investigate the analgesic effects of 1. Oral administration of 1 (1, 3, and 10 mg/kg) inhibited the acetic acid-induced writhing. This was also observed at 10 mg/kg via sc and ip routes. Both phases of the formalin- and complete Freund's adjuvant (CFA)-induced paw flinch and time spent licking the paw were inhibited by 1. Compound 1 inhibited carrageenan-, CFA-, and PGE2-induced mechanical hyperalgesia. Treatment with 1 inhibited carrageenan-induced production of TNF-α, IL-1β, IL-33, and IL-10 and nuclear factor κB activation. Pharmacological inhibitors also demonstrated that the analgesic effects of 1 depend on activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway. Compound 1 did not alter plasma levels of AST, ALT, or myeloperoxidase activity in the stomach. These results demonstrate that 1 causes analgesic effects associated with the inhibition of NF-κB activation, reduction of cytokine production, and activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway.

Decreased microRNA-125a-3p contributes to upregulation of p38 MAPK in rat trigeminal ganglions with orofacial inflammatory pain

Orofacial inflammatory pain is a difficult clinical problem, and the specific molecular mechanisms for this pain remain largely unexplained. The present study aimed to determine the differential expression of microRNAs (miRNAs) and disclose the underlying role of miR-125a-3p in orofacial inflammatory pain induced by complete Freund's adjuvant (CFA). Thirty-two differentially expressed miRNAs were first screened using a microarray chip in ipsilateral trigeminal ganglions (TGs) following CFA injection into the orofacial skin innervated by trigeminal nerve, and a portion of them, including miR-23a*, -24-2*, -26a, -92a, -125a-3p, -183 and -299 were subsequently selected and validated by qPCR. The target genes were predicted based on the miRWalk website and were further analyzed by gene ontology (GO). Further studies revealed miR-125a-3p expression was down-regulated, whereas both the expression of p38 MAPK (mitogen-activated protein kinase) alpha and CGRP (calcitonin gene-related peptide) were up-regulated in ipsilateral TGs at different time points after CFA injection compared with control. Furthermore, mechanistic study revealed that miR-125a-3p negatively regulates p38 alpha gene expression and is positively correlated with the head withdrawal threshold reflecting pain. Luciferase assay showed that binding of miR-125a-3p to the 3′UTR of p38 alpha gene suppressed the transcriptional activity, and overexpression of miR-125a-3p significantly inhibited the p38 alpha mRNA level in ND8/34 cells. Taken together, our results show that miR-125a-3p is negatively correlated with the development and maintenance of orofacial inflammatory pain via regulating p38 MAPK.

Development of an effective topical liposomal formulation for localized analgesia and anti-inflammatory actions in the Complete Freund's Adjuvant rodent model of acute inflammatory pain

BACKGROUND

Peripheral opioid receptor targeting has been well established as a novel target in clinical pain management for acute and chronic peripheral inflammatory pain. The physiochemical properties of the peripheral mu-opioid receptor agonist, loperamide HCl, limit the use of the free drug as an analgesic or anti-inflammatory agent, particularly for dermal delivery across intact skin.

OBJECTIVE

Our objective was to manufacture an effective topical formulation containing loperamide using liposomal delivery that would allow loperamide to produce analgesia and anti-inflammatory effects, by penetrating the epidermis to reach peripheral opioid receptors within the dermis of intact skin.

STUDY DESIGN

A randomized, double blind, controlled animal trial.

METHODS

Thirty-five adult male Wistar rats (200 - 250 g) were randomly divided into 5 groups: loperamide HCl-encapsulated liposomal gel, naloxone methiodide + loperamide HCl-encapsulated liposomal gel, free loperamide gel, empty liposomal gel, and 1% diclofenac gel (Voltaren®). Diclofenac gel was used as a positive control as it is clinically used as a topical analgesic and anti-inflammatory drug. Animals received an intraplantar injection of 150 μl Complete Freund's Adjuvant (CFA) into the right hindpaw and experiments were performed 5 days post-CFA injection, which corresponded to the peak inflammatory response. All manufactured formulations were applied topically on both hind paws twice daily, whereas Voltaren gel was applied 3 times a day in accordance with the manufacturer's instructions. The dose administered was 50 μl, which equated to 0.4 mg of loperamide HCl for the loperamide HCl treatment groups (low dose). Naloxone methiodide (1 mg/kg) was administered via intraplantar injection, 15 minutes prior to application of loperamide HCl-encapsulated liposomal gel to determine opioid receptor dependent activity. An investigator blinded to the treatment administered assessed time course of the antinociceptive and anti-inflammatory effects using a paw pressure analgesiometer and plethysmometer, respectively.

RESULTS

Application of loperamide HCl in a liposomal gel formulation exerted analgesic and anti-inflammatory effects exclusively in peripheral painful inflamed tissue. This formulation produced highly significant analgesic and anti-inflammatory effects over the 48-hour time course studied following topical administration in rats with CFA-induced inflammation of the paw. As expected, the diclofenac gel group showed significant antinociception over the duration of the study; however, this effect was lower in comparison to the loperamide HCl liposomal gel formulation. All other control groups showed no significant antinociceptive effects. In addition, all control groups (1% diclofenac gel, free loperamide gel, and empty liposomal gel) did not demonstrate a significant change in paw volume over 48 hours.

LIMITATIONS

In vivo studies were performed in the well-established rodent model of acute inflammatory pain. We are currently studying this approach in chronic pain models known to have clinical activation of the peripheral immune-derived opioid response.

CONCLUSIONS

The study demonstrates that topically applied loperamide encapsulated within liposomal systems has improved therapeutic efficacy over conventional formulations for the local treatment of acute peripheral inflammatory pain conditions where the skin has remained intact. Once in the inflamed peripheral tissue, loperamide provides analgesic and anti-inflammatory effects in a similar manner to peripheral endogenous opioids. This preparation optimises the retention of drug at the site where action is required.

Rapamycin inhibition of CFA-induced lymphangiogenesis in PLN is independent of mast cells

Elucidation of the events responsible for the interaction between lymphatic endothelial cells (LECs) and mast cells (MCs) may prove to be a valuable source for controlling lymphangiogenesis. In the present study, we compared immunohistochemical and RT-PCR findings of the popliteal lymph node (PLN) and footpad skin in C57BL/6J and WBB6F1 mice, the MC-deficient strain. The results indicated that MCs play certain role in complete Freund's adjuvant-induced intranodal lymphangiogenesis. VEGF-A, VEGFR-2 and TNF-α were crucial factors in lymphangiogenesis both in the PLN and skin. Moreover, the in vivo administration of the specific mTOR inhibitor, rapamycin inhibited lymphangiogenesis independent of MCs in PLN rather than in the skin. Further study on anti-lymphangiogenic effect will contribute to our understanding of LEC and MC modulation in pathological lymphangiogenesis.

The effect of whole-body, repetitive, inhomogeneous static magnetic field-exposure on the symptoms of experimental autoimmune encephalomyelitis in mice

Experimental autoimmune encephalomyelitis (EAE) is a model for human multiple sclerosis (MS) in rodents. Static magnetic field (SMF)-exposure was shown to be beneficial in specific cases of inflammatory background, where it suppresses symptoms. The null-hypothesis was that animals with induced EAE exposed to SMF would show different seriousness of symptoms, than those in the sham-exposed control group. Three replicated series of repetitive, 30 min/day whole-body exposure to SMF with 477 mT peak-to-peak magnetic induction and 48 T/m lateral induction gradient was tested on female CSJLF1 mice with a mild, mouse spinal cord homogenate emulsion-induced EAE. Conventional scores of the animal response to EAE were compared between sham- and SMF-exposed groups of animals. Following pilot test we used 18 animals per group. Primary outcome measure was the daily group average of standard EAE scores. Results show that SMF-exposure has a strong, reproducible, and significantly beneficial effect up to 51.82% (p<0.001) over sham-exposure on the symptoms of EAE in the course of the 25 days of the experiment. This study aimed to build experimental research foundation for a later therapy option by applying SMF-exposure in the clinical management of MS.

Estrogen receptor alpha is expressed in mesenteric mesothelial cells and is internalized in caveolae upon Freund's adjuvant treatment

Transformation of epithelial cells into connective tissue cells (epithelial-mesenchymal transition, EMT) is a complex mechanism involved in tumor metastasis, and in normal embryogenesis, while type II EMT is mainly associated with inflammatory events and tissue regenaration.

In this study we examined type II EMT at the ultrastructural and molecular level during the inflammatory process induced by Freund's adjuvant treatment in rat mesenteric mesothelial cells. We found that upon the inflammatory stimulus mesothelial cells lost contact with the basal lamina and with each other, and were transformed into spindle-shaped cells. These morphological changes were accompanied by release of interleukins IL-1alpha, -1beta and IL-6 and by secretion of transforming growth factor beta (TGF-β) into the peritoneal cavity. Mesothelial cells also expressed estrogen receptor alpha (ER-α) as shown by immunolabeling at the light and electron microscopical levels, as well as by quantitative RT-PCR. The mRNA level of ER-α showed an inverse correlation with the secretion of TGF-β. At the cellular and subcellular levels ER-α was colocalized with the coat protein caveolin-1 and was found in the plasma membrane of mesothelial cells, in caveolae close to multivesicular bodies (MVBs) or in the membrane of these organelles, suggesting that ER-α is internalized via caveola-mediated endocytosis during inflammation. We found asymmetric, thickened, electron dense areas on the limiting membrane of MVBs (MVB plaques) indicating that these sites may serve as platforms for collecting and organizing regulatory proteins. Our morphological observations and biochemical data can contribute to form a potential model whereby ER-α and its caveola-mediated endocytosis might play role in TGF-β induced type II EMT in vivo.

Inflammation enhances Y1 receptor signaling, neuropeptide Y-mediated inhibition of hyperalgesia, and substance P release from primary afferent neurons

Neuropeptide Y (NPY) is present in the superficial laminae of the dorsal horn and inhibits spinal nociceptive processing, but the mechanisms underlying its anti-hyperalgesic actions are unclear. We hypothesized that NPY acts at neuropeptide Y1 receptors in the dorsal horn to decrease nociception by inhibiting substance P (SP) release, and that these effects are enhanced by inflammation. To evaluate SP release, we used microdialysis and neurokinin 1 receptor (NK1R) internalization in rat. NPY decreased capsaicin-evoked SP-like immunoreactivity in the microdialysate of the dorsal horn. NPY also decreased non-noxious stimulus (paw brush)-evoked NK1R internalization (as well as mechanical hyperalgesia and mechanical and cold allodynia) after intraplantar injection of carrageenan. Similarly, in rat spinal cord slices with dorsal root attached, [Leu(31), Pro(34)]-NPY inhibited dorsal root stimulus-evoked NK1R internalization. In rat dorsal root ganglion neurons, Y1 receptors colocalized extensively with calcitonin gene-related peptide (CGRP). In dorsal horn neurons, Y1 receptors were extensively expressed and this may have masked the detection of terminal co-localization with CGRP or SP. To determine whether the pain inhibitory actions of Y1 receptors are enhanced by inflammation, we administered [Leu(31), Pro(34)]-NPY after intraplantar injection of complete Freund's adjuvant (CFA) in rat. We found that [Leu(31), Pro(34)]-NPY reduced paw clamp-induced NK1R internalization in CFA rats but not uninjured controls. To determine the contribution of increased Y1 receptor-G protein coupling, we measured [(35)S]GTPγS binding simulated by [Leu(31), Pro(34)]-NPY in mouse dorsal horn. CFA inflammation increased the affinity of Y1 receptor G-protein coupling. We conclude that Y1 receptors contribute to the anti-hyperalgesic effects of NPY by mediating the inhibition of SP release, and that Y1 receptor signaling in the dorsal horn is enhanced during inflammatory nociception.

Vitexin inhibits inflammatory pain in mice by targeting TRPV1, oxidative stress, and cytokines

The flavonoid vitexin (1) is a flavone C-glycoside (apigenin-8-C-β-D-glucopyranoside) present in several medicinal and other plants. Plant extracts containing 1 are reported to possess antinociceptive, anti-inflammatory, and antioxidant activities. However, the only evidence that 1 exhibits antinociceptive activity was demonstrated in the acetic acid-induced writhing model. Therefore, the analgesic effects and mechanisms of 1 were evaluated. In the present investigation, intraperitoneal treatment with 1 dose-dependently inhibited acetic acid-induced writhing. Furthermore, treatment with 1 also inhibited pain-like behavior induced by phenyl-p-benzoquinone, complete Freund's adjuvant (CFA), capsaicin (an agonist of transient receptor potential vanilloid 1, TRPV1), and both phases of the formalin test. It was also observed that inhibition of carrageenan-, capsaicin-, and chronic CFA-induced mechanical and thermal hyperalgesia occurred. Regarding the antinociceptive mechanisms of 1, it prevented the decrease of reduced glutathione levels, ferric-reducing ability potential, and free-radical scavenger ability, inhibited the production of hyperalgesic cytokines such as TNF-α, IL-1β, IL-6, and IL-33, and up-regulated the levels of the anti-hyperalgesic cytokine IL-10. These results demonstrate that 1 exhibits an analgesic effect in a variety of inflammatory pain models by targeting TRPV1 and oxidative stress and by modulating cytokine production.

House finches (Carpodacus mexicanus) balance investment in behavioural and immunological defences against pathogens

Infection with parasites and pathogens is costly for hosts, causing loss of nutritional resources, reproductive potential, tissue integrity and even life. In response, animals have evolved behavioural and immunological strategies to avoid infection by pathogens and infestation by parasites. Scientists generally study these strategies in isolation from each other; however, since these defences entail costs, host individuals should benefit from balancing investment in these strategies, and understanding of infectious disease dynamics would benefit from studying the relationship between them. Here, we show that Carpodacus mexicanus (house finches) avoid sick individuals. Moreover, we show that individuals investing less in behavioural defences invest more in immune defences. Such variation has important implications for the dynamics of pathogen spread through populations, and ultimately the course of epidemics. A deeper understanding of individual- and population-level disease defence strategies will improve our ability to understand, model and predict the outcomes of pathogen spread in wildlife.

Mechanisms underlying ectopic persistent tooth-pulp pain following pulpal inflammation

In order to clarify the peripheral mechanisms of ectopic persistent pain in a tooth pulp following pulpal inflammation of an adjacent tooth, masseter muscle activity, phosphorylated extracellular signal-regulated protein kinase (pERK) and TRPV1 immunohistochemistries and satellite cell activation using glial fibrillary acidic protein (GFAP) immunohistochemistry in the trigeminal ganglion (TG) were studied in the rats with molar tooth-pulp inflammation. And, Fluorogold (FG) and DiI were also used in a neuronal tracing study to analyze if some TG neurons innervate more than one tooth pulp. Complete Freund's adjuvant (CFA) or saline was applied into the upper first molar tooth pulp (M1) in pentobarbital-anesthetized rats, and capsaicin was applied into the upper second molar tooth pulp (M2) on day 3 after the CFA or saline application. Mean EMG activity elicited in the masseter muscle by capsaicin application to M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. The mean number of pERK-immunoreactive (IR) TG cells was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. Application of the satellite cell inhibitor fluorocitrate (FC) into TG caused a significant depression of capsaicin-induced masseter muscle activity and a significant reduction of satellite cell activation. The number of TRPV1-IR TG cells innervating M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats, and that was decreased following FC injection into TG. Furthermore, 6% of TG neurons innervating M1 and/or M2 innervated both M1 and M2. These findings suggest that satellite cell activation following tooth pulp inflammation and innervation of multiple tooth pulps by single TG neurons may be involved in the enhancement of the activity of TG neurons innervating adjacent non-inflamed teeth that also show enhancement of TRPV1 expression in TG neurons, resulting in the ectopic persistent tooth-pulp pain following pulpal inflammation of adjacent teeth.

Application of ED-optimality to screening experiments for analgesic compounds in an experimental model of neuropathic pain

In spite of the evidence regarding high variability in the response to evoked pain, little attention has been paid to its impact on the screening of drugs for inflammatory and neuropathic pain. In this study, we explore the feasibility of introducing optimality concepts to experimental protocols, enabling estimation of parameter and model uncertainty. Pharmacokinetic (PK) and pharmacodynamic data from different experiments in rats were pooled and modelled using nonlinear mixed effects modelling. Pain data on gabapentin and placebo-treated animals were generated in the complete Freund's adjuvant model of neuropathic pain. A logistic regression model was applied to optimise sampling times and dose levels to be used in an experimental protocol. Drug potency (EC(50)) and interindividual variability (IIV) were considered the parameters of interest. Different experimental designs were tested and validated by SSE (stochastic simulation and estimation) taking into account relevant exposure ranges. The pharmacokinetics of gabapentin was described by a two-compartment PK model with first order absorption (CL = 0.159 l h(-1), V(2) = 0.118 l, V(3) = 0.253 l, Ka = 0.26 h(-1), Q = 1.22 l h(-1)). Drug potency (EC(50)) for the anti-allodynic effects was estimated to be 1400 ng ml(-1). Protocol optimisation improved bias and precision of the EC50 by 6 and 11.9. %, respectively, whilst IIV estimates showed improvement of 31.89 and 14.91 %, respectively. Our results show that variability in behavioural models of evoked pain response leads to uncertainty in drug potency estimates, with potential impact on the ranking of compounds during screening. As illustrated for gabapentin, ED-optimality concepts enable analysis of discrete data taking into account experimental constraints.

Protective efficacy of immunoglobulins Y prepared against Cerastes cerastes snake venom in the Kingdom of Saudi Arabia

OBJECTIVES

To prepare and evaluate the protective efficacy of immunoglobulin Y (IgY) prepared against local Saudi Cerastes cerastes snake venom.

METHODS

The study was conducted between October 2009 and October 2011 at the Center of Excellence in Biotechnology Research, King Saud University, Riyadh, Kingdom of Saudi Arabia. The study designed as follow; 4 groups of 8 chickens were immunized intramuscularly with Cerastes cerastes snake venoms mixed with Freund's complete adjuvant. Three weeks later, the injections were repeated with the venoms with incomplete Freund's adjuvant. Three boosters were given with the venoms at 3 weeks intervals. The IgY was extracted by ammonium sulphate-caprylic acid method, the antibody titer were tested by enzyme linked immunosorbant assay, and the protective efficacies of the extracted immunoglobulins were performed.

RESULTS

Immunoglobulin Y preparation extracted by ammonium sulphate-caprylic acid method showed lack of low molecular weight bands. The bands representing IgY-antibodies, which have molecular weights ranged from 180-200 KD, appeared sharp and clear. Furthermore, evaluation of the prepared protective value of IgY-antibodies revealed one ml of extracted IgY-antibodies containing 15 mg/ml anti Cerastes cerastes; specific IgY could produce 100% protection against 50 LD50.

CONCLUSION

Laying hens could be used as an alternative source of polyclonal antibodies against Cerastes cerastes snake venoms due to several advantages as compared with mammals.

Kaurenoic acid from Sphagneticola trilobata Inhibits Inflammatory Pain: effect on cytokine production and activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway

Kaurenoic acid [ent-kaur-16-en-19-oic acid (1)] is a diterpene present in several plants including Sphagneticola trilobata. The only documented evidence for its antinociceptive effect is that it inhibits the writhing response induced by acetic acid in mice. Therefore, the analgesic effect of 1 in different models of pain and its mechanisms in mice were investigated further. Intraperitoneal and oral treatment with 1 dose-dependently inhibited inflammatory nociception induced by acetic acid. Oral treatment with 1 also inhibited overt nociception-like behavior induced by phenyl-p-benzoquinone, complete Freund's adjuvant (CFA), and both phases of the formalin test. Compound 1 also inhibited acute carrageenin- and PGE(2)-induced and chronic CFA-induced inflammatory mechanical hyperalgesia. Mechanistically, 1 inhibited the production of the hyperalgesic cytokines TNF-α and IL-1β. Furthermore, the analgesic effect of 1 was inhibited by l-NAME, ODQ, KT5823, and glybenclamide treatment, demonstrating that such activity also depends on activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway, respectively. These results demonstrate that 1 exhibits an analgesic effect in a consistent manner and that its mechanisms involve the inhibition of cytokine production and activation of the NO-cyclic GMP-protein kinase G-ATP-sensitive potassium channel signaling pathway.

CD4 costimulation is not required in a novel LPS-enhanced model of myasthenia gravis

The potential of lipopolysaccharide (LPS) to induce antigen-specific B cell responses to acetylcholine receptor (AChR) in myasthenia gravis (MG) was evaluated in wild type (WT) and CD4-/- C57BL/6 mice. The WT mice immunized with AChR in LPS developed an MG-like disease (LPS-EAMG) similar to that induced by immunization with AChR in complete Freund's adjuvant (CFA-EAMG). CD4-/- mice were resistant to CFA-EAMG but susceptible to LPS-EAMG. LPS abrogated EAMG resistance in CD4-/- mice by increasing high-affinity anti-AChR IgG2b in sera and enhancing immune complex deposition in muscle.

Mixed adjuvant formulations reveal a new combination that elicit antibody response comparable to Freund's adjuvants

Adjuvant formulations capable of inducing high titer and high affinity antibody responses would provide a major advance in the development of vaccines to viral infections such as HIV-1. Although oil-in-water emulsions, such as Freund's adjuvant (FCA/FIA), are known to be potent, their toxicity and reactogenicity make them unacceptable for human use. Here, we explored different adjuvants and compared their ability to elicit antibody responses to FCA/FIA. Recombinant soluble trimeric HIV-1 gp140 antigen was formulated in different adjuvants, including FCA/FIA, Carbopol-971P, Carbopol-974P and the licensed adjuvant MF59, or combinations of MF59 and Carbopol. The antigen-adjuvant formulation was administered in a prime-boost regimen into rabbits, and elicitation of antigen binding and neutralizing antibodies (nAbs) was evaluated. When used individually, only FCA/FIA elicited significantly higher titer of nAbs than the control group (gp140 in PBS (p<0.05)). Sequential prime-boost immunizations with different adjuvants did not offer improvements over the use of FCA/FIA or MF59. Remarkably however, the concurrent use of the combination of Carbopol-971P and MF59 induced potent adjuvant activity with significantly higher titer nAbs than FCA/FIA (p<0.05). This combination was not associated with any obvious local or systemic adverse effects. Antibody competition indicated that the majority of the neutralizing activities were directed to the CD4 binding site (CD4bs). Increased antibody titers to the gp41 membrane proximal external region (MPER) and gp120 V3 were detected when the more potent adjuvants were used. These data reveal that the combination of Carbopol-971P and MF59 is unusually potent for eliciting nAbs to a variety of HIV-1 nAb epitopes.

Correlation of nitric oxide levels in the cerebellum and spinal cord of experimental autoimmune encephalomyelitis rats with clinical symptoms

Experimental autoimmune encephalomyelitis (EAE) is a well-established cell-mediated autoimmune inflammatory disease of the CNS, which has been used as a model of the human demyelinating disease. EAE is characterized by infiltration of the CNS by lymphocytes and mononuclear cells, microglial and astrocytic hypertrophy, and demyelination which cumulatively contribute to clinical expression of the disease. EAE was induced in female Sprague-Dawley rats, 3 months old (300 g ± 20 g), by immunization with myelin basic protein (MBP) in combination with Complete Freund's adjuvant (CFA). The animals were divided into 7 groups: control, EAE, CFA, EAE + aminoguanidine (AG), AG, EAE + N-acetyl-L-cysteine (NAC) and NAC. The animals were sacrificed 15 days after EAE induction, and the level of nitric oxide (NO(·)) production was determined by measuring nitrite and nitrate concentrations in 10% homogenate of cerebellum and spinal cord. Obtained results showed that the level of NO(·) was significantly increased in all examined tissues of the EAE rats compared to the control and CFA groups. Also, AG and NAC treatment decreased the level of NO(·) in all tissues compared to the EAE group. The level of NO(·) is increased significantly in the spinal cord compared to the cerebellum. The clinical course of the EAE was significantly decreased in the EAE groups treated with AG and NAC during the development of the disease compared to EAE group and its correlates with the NO(·) level in cerebellum and spinal cord. The findings of our work suggest that NO(·) and its derivatives play an important role in multiple sclerosis (MS). It may be the best target for new therapies in human demyelinating disease and recommend the new therapeutic approaches based on a decreased level of NO(·) during the course of MS.

Validation of a novel rat-holding device for studying heat- and mechanical-evoked trigeminal nocifensive behavioral responses

AIMS

To test the reliability and validity of a novel rat-holding device designed to be used in conjunction with the plantar test apparatus for studying nocifensive behavioral responses in an established model of temporomandibular joint (TMJ) pathology.

METHODS

Thirty-five young adult male Sprague-Dawley rats were used. Withdrawal latencies in response to infrared 40 heat stimulation of the submandibular region in naïve animals (n = 4) and animals injected with saline or complete Freund's adjuvant (CFA) in the TMJ (n > 9) were measured over a 2-week time period. Nocifensive responses to mechanical stimulation of the cutaneous tissue directly over the TMJ with von Frey filaments were investigated in animals injected with CFA in the TMJ (n = 6). The effect on nocifensive responses to heat and mechanical stimulation of subcutaneous administration of buprenorphine (0.05 mg/kg) into the hindquarter was assessed in CFA and cotreated animals (n = 6). Statistical analysis was performed using a nonparametric Mann-Whitney U test.

RESULTS

Under basal conditions, withdrawal latencies to heat stimulation of the orofacial region remained consistently around 15 seconds over 14 days. Unilateral CFA injection in the TMJ significantly decreased heat-withdrawal latencies on days 1, 2, 7, and 14 in the ipsilateral side (P < .05), but not contralateral side, when compared with basal values. CFA also significantly decreased the nocifensive threshold to mechanical stimulation on days 1, 2, and 7 postinjection (P < .05). CFA-mediated changes in heat withdrawal and mechanical thresholds in the orofacial region were significantly suppressed by subcutaneous administration of buprenorphine into the hindquarter (P < .05).

CONCLUSION

Findings from this study provide evidence to validate the use of this holding device for studying nocifensive behaviors in the orofacial region of rats in response to heat or mechanical orofacial stimulation.

Adjuvant properties of Cytosine-phosphate-guanosine oligodeoxynucleotide in combination with various polycations in an ovalbumin-vaccine model

Oligonucleotides containing CpG motifs (cytosine-phosphate-guanosine oligodeoxynucleotide [CpG ODN]) display strong immunostimulatory effects, and polycations have been previously reported as cellular delivery system. In the present study, we investigated the adjuvant properties of combinations of a CpG ODN with various polycations (poly-arginine, poly-lysine, poly-histidine, or chitosan) in an ovalbumin vaccination model. We showed that, when combined to CpG ODN, poly-arginine and poly-histidine, but not poly-lysine or chitosan, enhanced efficiently both the IgG antibody production and the number of splenocytes secreting interferon-gamma after stimulation with a CD8+ T cell-restricted peptide. Interestingly, CpG ODN-poly-arginine, which was the most efficient, compared favorably to the complete Freund's adjuvant and aluminium salts and induced no local toxicity, making this combination a very attractive adjuvant for vaccines.