Organic Selenium Reaches the Central Nervous System and Downmodulates Local Inflammation: A Complementary Therapy for Multiple Sclerosis?

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). The persistent inflammation is being mainly attributed to local oxidative stress and inflammasome activation implicated in the ensuing demyelination and axonal damage. Since new control measures remain necessary, we evaluated the preventive and therapeutic potential of a beta-selenium-lactic acid derivative (LAD-ßSe), which is a source of organic selenium under development, to control experimental autoimmune encephalomyelitis (EAE) that is an animal model for MS. Two EAE murine models: C57BL/6 and SJL/J immunized with myelin oligodendrocyte glycoprotein and proteolipid protein, respectively, and a model of neurodegeneration induced by LPS in male C57BL/6 mice were used. The preventive potential of LAD-ßSe was initially tested in C57BL/6 mice, the chronic MS model, by three different protocols that were started 14 days before or 1 or 7 days after EAE induction and were extended until the acute disease phase. These three procedures were denominated preventive therapy -14 days, 1 day, and 7 days, respectively. LAD-ßSe administration significantly controlled clinical EAE development without triggering overt hepatic and renal dysfunction. In addition of a tolerogenic profile in dendritic cells from the mesenteric lymph nodes, LAD-ßSe also downregulated cell amount, activation status of macrophages and microglia, NLRP3 (NOD-like receptors) inflammasome activation and other pro-inflammatory parameters in the CNS. The high Se levels found in the CNS suggested that the product crossed the blood-brain barrier having a possible local effect. The hypothesis that LAD-ßSe was acting locally was then confirmed by using the LPS-induced neurodegeneration model that also displayed Se accumulation and downmodulation of pro-inflammatory parameters in the CNS. Remarkably, therapy with LAD-ßSe soon after the first remitting episode in SJL/J mice, also significantly downmodulated local inflammation and clinical disease severity. This study indicates that LAD-ßSe, and possibly other derivatives containing Se, are able to reach the CNS and have the potential to be used as preventive and therapeutic measures in distinct clinical forms of MS.

Lupeol inhibits LPS-induced neuroinflammation in cerebellar cultures and induces neuroprotection associated to the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.

In the central nervous system (CNS), neuroinflammation, especially that modulated by the cell response of astrocytes and microglia, is associated with damage to neurons in neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and, Multiple Sclerosis. Lupeol is a dietary triterpene that has demonstrated biological activities as antioxidant. This study investigated the anti-inflammatory and neuroprotective effects of lupeol in an in vitro model of neuroinflammation in primary cerebellar cultures. Cultures were obtained from 6-day-old Wistar rats, subjected to inflammatory damage with lipopolysaccharide (LPS, 1 µg/mL) and treated with lupeol (0.1 µM). We observed, after a 48-hour treatment, through Fluorjade-B staining and immunocytochemistry (ICQ) for ßIII-tubulin, that lupeol induced neuroprotection in cultures submitted to inflammatory damage. On the other hand, through ICQ for GFAP, it was possible to observe that lupeol modulated the astrocyte morphology for Bergmann glia-like phenotype and, especially for velate astrocyte-like phenotype, both phenotypes associated with the neuroprotective profile. Moreover, RT-qPCR analysis showed that lupeol induced the down-regulation of the mRNA expression for proinflammatory markers TNF, iNOS and NLRP3, as well as the production of nitric oxide (method of Greiss), which were up-regulated by LPS, and also induced up-regulation of the mRNA expression for arginase and IL-6 mRNA. In addition, lupeol induced up-regulation of mRNA expression for neurotrophins GDNF and NGF and also for the sonic hedgehog-Gli pathway. Together, these results lead to the conclusion that lupeol inhibits neuroinflammation in cerebellar cultures and induces neuroprotection associated with the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.

Potentiation of capsaicin-induced neurogenic inflammation by 5-HT7 receptors in the rat hind paw: Involvement of calcitonin gen-related peptide.

A decrease in the activation threshold of primary sensory neurons to transient receptor potential V1 (TRPV1) stimulation by serotonin 5-HT7 receptors has been reported but no confirmation if this might translate into facilitation of neurogenic inflammation has been provided. We analysed the modulation of capsaicin (CAP)-induced neurogenic inflammation in the rat hind paw by the selective 5-HT7 receptor agonist, LP-44, and the involvement of calcitonin gen-related peptide (CGRP) in this effect. Animals received intra-plantar injections (30 µL) of vehicle, CAP (0.05%, 0.1% and 0.2%), LP-44 (7.5 and 15 nmol) and the combination of LP-44 + CAP; then, the time course of the inflammatory responses was measured. The effect of the 5-HT7 receptor antagonist, SB-269970 (3 mg/kg, s.c.), on responses produced by LP-44 alone and combined with CAP was tested. As expected, CAP produced concentration- and time-dependent inflammatory responses in the hind paw. Interestingly, LP-44 by itself also produced inflammation in a concentration- and time-dependent manner, and magnified CAP-induced responses. Systemic pre-treatment with SB-269970 significantly blunted LP-44 (15 nmol)-induced inflammation as well as magnified inflammatory responses produced by the combination of LP-44 (7.5 and 15 nmol) + CAP (0.1%) thus confirming the involvement of 5-HT7 receptors. Finally, the non-peptide CGRP receptor antagonist, BIBN4096 (3 mg/kg, s.c.), strongly inhibited the potentiated inflammatory responses induced by LP-44 (7.5 and 15 nmol) + CAP (0.1%) thus substantiating their neurogenic nature. Thus, sensitization of CAP-sensitive primary sensory neurons by 5-HT7 receptors may result in facilitation of neurogenic inflammation involving CGRP in the rat hind paw.

Esculentoside A exerts anti-inflammatory activity in microglial cells.

Esculentoside A (EsA) is a saponin isolated from the roots of Phytolacca esculenta. This study was designed to evaluate the pharmacological effects of EsA on lipopolysaccharide (LPS)-stimulated BV2 microglia and primary microglia cells. Our results indicated that EsA pretreatment significantly decreased LPS-induced production of Nitric Oxide (NO) and Prostaglandin E2 (PGE2) and impeded LPS-mediated upregulation of pro-inflammatory mediators' expression such as nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-12 (IL-12) and tumor necrosis factor-a (TNF-α) in both BV2 microglia and primary microglia cells. Moreover, EsA markedly suppressed nuclear factor-κB p65 (NF-κB p65) translocation by blocking IκB-α phosphorylation and degradation in LPS-treated BV2 cells. EsA also decreased phosphorylation level of mitogen-activated protein kinases (MAPKs) and inhibited NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome mediated caspase-1 activation in LPS-stimulated BV2 cells. Additionally, EsA decreased ß-amyloid1-42 (Aß1-42)-induced production of TNF-α, IL-1ß and IL-6 in primary microglia. Thus, EsA might be a promising therapeutic agent for alleviating neuroinflammatory diseases.

Does dexamethasone act in neuropeptides SP and CGRP in neurogenic inflammation of the skin? An experimental study.

PURPOSE: To investigate the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) after subcutaneous injection of dexamethasone prior to skin incision in rats. METHODS: Twenty seven Wistar-EPM-1 rats were randomly divided into three groups. The sham group (SG) of rats was injected with 0.9 % saline. The second group (Dexa) was injected with 1.0 mg/kg dexamethasone, and the third group (Dexa+) was injected with 10.0 mg/kg dexamethasone. In all groups, the three subcutaneous injections were performed 30 minutes prior to the surgical skin incision and tissue collection. SP and CGRP (15 kDa pro-CGRP and 5 kDa CGRP) were quantified by Western Blotting. RESULTS: No statistically significant differences (p>0.05) were found in pro-CGRP, CGRP and SP values in all three groups. CONCLUSION: The anti-inflammatory effect of dexamethasone did not occur when the substance P and calcitonin gene-related peptide levels were altered during the neurogenic inflammation process of skin wound healing in rats.

Does dexamethasone act in neuropeptides SP and CGRP in neurogenic inflammation of the skin? An experimental study

PURPOSE: To investigate the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) after subcutaneous injection of dexamethasone prior to skin incision in rats.METHODS:Twenty seven Wistar-EPM-1 rats were randomly divided into three groups. The sham group (SG) of rats was injected with 0.9 % saline. The second group (Dexa) was injected with 1.0 mg/kg dexamethasone, and the third group (Dexa+) was injected with 10.0 mg/kg dexamethasone. In all groups, the three subcutaneous injections were performed 30 minutes prior to the surgical skin incision and tissue collection. SP and CGRP (15 kDa pro-CGRP and 5 kDa CGRP) were quantified by Western Blotting.RESULTS: No statistically significant differences (p>0.05) were found in pro-CGRP, CGRP and SP values in all three groups.CONCLUSION:The anti-inflammatory effect of dexamethasone did not occur when the substance P and calcitonin gene-related peptide levels were altered during the neurogenic inflammation process of skin wound healing in rats.

Does dexamethasone act in neuropeptides SP and CGRP in neurogenic inflammation of the skin? An experimental study

To investigate the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) after subcutaneous injection of dexamethasone prior to skin incision in rats. Twenty seven Wistar-EPM-1 rats were randomly divided into three groups. The sham group (SG) of rats was injected with 0.9 % saline. The second group (Dexa) was injected with 1.0 mg/kg dexamethasone, and the third group (Dexa+) was injected with 10.0 mg/kg dexamethasone. In all groups, the three subcutaneous injections were performed 30 minutes prior to the surgical skin incision and tissue collection. SP and CGRP (15 kDa pro-CGRP and 5 kDa CGRP) were quantified by Western Blotting. No statistically significant differences (p>0.05) were found in pro-CGRP, CGRP and SP values in all three groups. The anti-inflammatory effect of dexamethasone did not occur when the substance P and calcitonin gene-related peptide levels were altered during the neurogenic inflammation process of skin wound healing in rats.(AU)

The antinociceptive activity of harmicine on chemical-induced neurogenic and inflammatory pain models in mice.

Harmicine is a ß-carboline alkaloid isolated and identified as a major active compound present in many plant species and marine invertebrates. This alkaloid exhibits a wide spectrum of pharmacological activities, including antispasmodic, antipyretic, and anticancer properties. This report described the antinociceptive properties of harmicine by means of chemical experimental models in order to evaluate the use for pain relief. The results demonstrating the potential analgesic properties of harmicine administered intraperitoneally were shown with the writhing test, reducing writhes around 60% (1 mg/kg), and in the formalin test, where harmicine was more effective toward neurogenic (reducing reaction time around 60%, 1 mg/kg) than inflammatory (68% reduction, 10 mg/kg) pain responses. Furthermore, these effects may operate via vanilloid receptors as revealed by the capsaicin test (41% reduction, with 3 mg/kg), as well as via peripheral glutamate receptors as shown by the glutamate test (50% reduction, with 1 mg/kg). Moreover, the opioid antagonist naloxone hydrochloride did not interfere in the antinociceptive properties of harmicine in the writhing test, revealing that this effect may not have a relationship with the opioid systems. Concluding, this report highlights harmicine as a new candidate to be used as analgesic in the future. Therefore, further studies are being undertaken in order to understand the exact mechanisms involved with the antinociceptive properties of harmicine.

Chemical profile and antinociceptive efficacy of Rheedia longifolia leaf extract.

Different species of the family Clusiaceae, including Rheedia longifolia, are used in folk medicine to treat inflammatory diseases. This family is largely distributed in tropical and subtropical areas of Brazil, but their chemical and pharmacological properties have been the subject of a few studies. In previous studies, we found that the aqueous extract from R. longifolia leaves presented important anti-inflammatory and analgesic activity. We investigated the chemical profile of R. longifolia and characterized the pharmacological effect of different chemically identified fractions in pharmacological models of neurogenic and inflammatory nociception. The pharmacological tests showed that oral treatment with aqueous crude extract and fractions of methanol extract of R. longifolia leaf induced a significant antinociceptive effect using von Frey filaments. In addition, the most polar fractions presented antinociceptive activity in a neurogenic model of nociception (capsaicin model). The chromatographic analysis indicated the presence of bisflavonoids in the fractions obtained from the methanol extract. These results suggest that bisflavonoids found in methanol-extracted fractions are involved in the inhibition of inflammatory and neurogenic nociception. It is important that the R. longifolia aqueous extract treatment inhibited ulcer formation induced by indomethacin, suggesting an anti-ulcerogenic activity closely associated with its analgesic effect.

Antiparasitic, antineuroinflammatory, and cytotoxic polyketides from the marine sponge Plakortis angulospiculatus collected in Brazil.

Investigation of the bioactive crude extract from the sponge Plakortis angulospiculatus from Brazil led to the isolation of plakortenone ( 1) as a new polyketide, along with five known polyketides ( 2- 6) previously isolated from other Plakortis sponges. The known polyketides were tested in antileishmanial, antitrypanosomal, antineuroinflammatory, and cytotoxicity assays. The results show that plakortide P ( 3) is a potent antiparasitic compound, against both Leishmania chagasi and Trypanosona cruzi, and exhibited antineuroinflammatory activity. The known polyketides 2- 6 were tested for cytotoxicity against four human cancer cell lines, but displayed only moderate cytotoxic activity.

Diphenyl diselenide attenuates acute thermal hyperalgesia and persistent inflammatory and neuropathic pain behavior in mice.

Experiments were designed to address whether diphenyl diselenide (PhSe)(2) has antiallodynic and antihyperalgesic properties. The neuropathic pain was caused by a partial tying (2/3) of sciatic nerve and the inflammatory pain was induced by an intraplantar (i.pl.) injection of 20 microl of Freund's Complete Adjuvant (CFA) in mice. Seven days after sciatic nerve constriction and 24 h after CFA intraplantar (i.pl.) injection, mouse pain threshold was evaluated through tactile allodynia, using Von Frey Hair (VHF) filaments. The acute thermal hyperalgesia was induced by intrathecal (i.t.) injection of glutamate, N-methyl-d-aspartate (NMDA), bradykinin (BK) and prostaglandin E(2) (PGE(2)), and the nociceptive response was assessed using hot-plate test. (PhSe)(2) administered by oral route (p.o.) (10 mg/kg) decreased the paw withdrawal response on the ipsilateral side of the partial sciatic nerve ligation 30 min after drug administration (64+/-7%) and this effect was kept for 1 h after treatment. (PhSe)(2) (10 mg/kg, p.o.) produced a reduction in mechanical allodynia induced by CFA started 30 min after (PhSe)(2) administration (71+/-5%) and this effect was maintained for up 4 h. (PhSe)(2) (0.1-50 mg/kg, p.o.) caused a significant inhibition of glutamate-, NMDA- and BK-(PGE(2))-induced acute thermal hyperalgesia in mice. Together, the present results indicate that (PhSe)(2) produces systemic antiallodynic action when assessed in mechanical stimulus (VHF) in the hindpaw and also attenuates acute thermal hyperalgesia. Thus, this compound might be potentially interesting in the development of new clinically relevant drugs for the management of pain.

Os antiinflamatórios dexametasona, meloxicam e indometacina não inibem a inflamação nerogênica induzida pelo óleo de mostarda na atm dos ratos / Daxamethason, meloxicam and indomethacin do not inhibit the neurogenic inflammation imduced by the mustard oil in the tmj of rats

A inflamação neurogênica pode estar envolvida no desenvolvimento das desordens da articulaçao têmporo-mandibular (ATM). O óleo de mostarda (OM) tem sido muito utilizado para o estudo da inflamação neurogênica. Entretanto, na região da ATM, ainda não é totalmente conhecido o mecanismo inflamatório do OM. Investigar se, na ATM, o OM induz um processo inflamatório de caráter neurogênico e se as prostaglandinas participam dessa inflamação. Ratos machos (Wistar), anestesiados, receberam OM (0,25 por cento - grupo I; 0,5 por cento - grupo II e 2,5 por cento - grupo III) ou óleo mineral (grupo IV - controle) na ATM direta. Ratos adicionais foram tratados com win 51,708 (grupos V, VI e VII), meloxicam (grupo VIII), dexametasona(grupo IX), indometacina (grupo X), solução salina (grupos XI, XII, XIII e XIV - controles) e, na sequência, o OM (0,25 por cento) foi aplicado na ATM direita. A inflamaçaõ da ATM foi averiguada pelo extravasamento plasmático de proteínas (EP) ligadas ao corante azul de Evans. A aplicação do OM (0,25 por cento, 0,5 por cento e 2,5 por cento) na ATM induziu EP significativamente maior (p < 0,05 por cento) que o grupo controle. O win 51,708 reduziu significativamente (p < 0,05 por cento) EP induzido pelo OM a 0,25 por cento em relação ao grupo controle. Entretanto, os antiinflamatórios dexametasona, meloxican e indometacina foram ineficazes em inibir esse EP. A inflamação induzida pelo OM na ATM é decorrente de um mecanismo neurogênico e as prostaglandinas não são essenciais para o desenvolvimento do EP associado com esse modelo de inflamação