CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O presente teve por objetivo avaliar a diminuiÃÃo da resposta hipernociceptiva inflamatÃria no curso do desenvolvimento da colite experimental induzida pelo Ãcido TNBS em ratos, bem como avaliar o papel da via NO/GMPc/PKG/K+ATP e a participaÃÃo de opioides endÃgenos e endocanabinoides neste evento. Para tanto, as colites foram induzidas por TNBS (20mg) diluÃdo em etanol a 50% ou etanol a 50%. O grupo controle recebeu somente salina via transanal. TrÃs ou quatorze dias apÃs a induÃÃo das colites foram avaliados os seguintes parÃmetros: edema de pata por carragenina (Cg; 500μg/pata direita) ou dextrana (Dxt; 500μg/pata direita.) por pletismometria, atividade da enzima mieloperoxidase (MPO), migraÃÃo de neutrÃfilos para cavidade pleural induzidas por Cg (500μg/pata direita) e a hipernocicepÃÃo mecÃnica induzida por PGE2 (100ng/pata) ou Cg (500μg/pata) aferido por analgesÃmetro digital (InsightÂ). Para verificar a participaÃÃo da via NO/GMPc/PKG/K+ATP na diminuiÃÃo da resposta hipernocicetiva da colite induzida por TNBS foram usados o L-Noarg (antagonista da NOSi; 100ng/pata) , O ODQ (bloqueador da guanilato ciclase soluivel; 8μg/pata), o KT5823 (antagonista da PKG; 1,5 μg/pata) e a glibenclamida (bloqueadora dos canais de K+ATP; 160μg/pata). Depois, para avaliar a participaÃÃo opiÃide e canabinÃide nesse evento, naloxona (antagonista de receptor opioide, 1,0 μg/pata) ou AM251 (antagonista de receptor canabinoide ; 1, 80 μg/pata) ou AM630 (antagonista de receptor canabinoide tipo 2; 25 μg/pata) foram injetados respectivamente. Os animais com colite induzida por TNBS apresentaram uma inibiÃÃo significativa do edema de pata tanto com o Cg (TrÃs ou quatorze dias apÃs a induÃÃo) quanto com Dxt (TrÃs dias apÃs a induÃÃo), quando comparados com os outros grupos em estudo. Em nenhum dos dias estudados, foram observadas diferenÃas na atividade da MPO na pata e nem na avaliaÃÃo da migraÃÃo de neutrÃfilos para a cavidade pleural induzidas por Cg. Ratos com colite induzida por TNBS apresentavam diminuiÃÃo na resposta hipernociceptiva induzida por Cg e PGE2. O tratamento com o ODQ, KT5823 e glibenclamida, naloxona, AM251 e AM630 reverteram esse efeito. O L-Noarg tambÃm reverteu o efeito entinociceptivo da colite induzida por TNBS, mas com a administraÃÃo da L-Arginina esse efeito foi recuperado. Apartir dos nossos resultados podemos concluir que a colite induzida por TNBS diminuiu a hipernocicepÃÃo inflamatÃria induzida tanto por carragenina quanto por PGE2 por dimimuir parÃmetros inflamatÃrios agudos como a resposta edematogÃnica a estÃmulos inflamatÃrios. AlÃm disso, esse efeito antinociceptivo parece ser independente da infiltraÃÃo de neutrÃfilos, mas dependente da ativaÃÃo da via final NO/GMPc/PKG/K+ATP e estimulada pelas aÃÃes dos opiÃides e canabinÃides endÃgenos. / The aim of this study was to investigate a possible involvement of the opioids, endocannabinoids and NO/cGMP/PKG/K+ATP pathway in the antinociception of the CrohnÂs experimental model in hypernociception induced by carragenan ou PGE2. Colitis was induced in the male Wistar rats (200-250) by intracolonic administration of 20 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS) in 50% ethanol, ethanol 50% or an equivalent volume of saline. Three or fourteen days after the colitis induction several parameters were evaluated: paw edema induced by carrageenan (Cg; 500μg/hind paw) or dextran (Dxt, 500μg/hind paw), myeloperoxidase activity (MPO), neutrophil migration to pleural cavity. Paw edema was evaluated the right hind paw and measured by plethysmometry. Neutrophil migration was induced by Cg injection in the right hind paw or in the peritoneal cavity. After 4h, rats were sacrificed and the skin of the right hind paw was harvested to measure neutrophil infiltration by MPO assay. Neutrophil migration induced by Cg was also evaluated in the pleural cavity, with the total e differential leucocytes counted. The mechanical behavioral tests were performed by measuring the force in grams (g) applied through a digital analgesymeter (InsightÂ). In this test the rats received PGE2 (100ng/paw) or carrageenan (Cg; 500μg/paw) into the plantar surface. In order to investigate the involvement of the NO/cGMP/PKG/K+ATP pathway in this event there were used L-Noarg (antagonist of iNOS; 100ng/paw), ODQ ( guanilate ciclase blocker; 8μg/paw), L-Arg (200mg/kg), KT5823 ( PKG blocker; 1.5 μg/paw) and Glibenclamide ( K+ATP channels blocker; 160μg/paw). To evaluated the involvement of the opioids and cannabinoids in this event naloxone (opioids receptor blocker; 1 μg/paw) or AM251 ( cannabinoid receptor blocker type I; 80 μg/paw) or AM630 (cannabinoid receptor blocker type II; 25 μg/paw) were inject respectively. Our results shows that, in animals with TNBS-induced colitis, there was a significant inhibition in the Cg (3rd or 14th after colitis induction) and Dxt (3rd after colitis induction)-induced paw edema. There were no differences in MPO activity and neither in the pleural neutrophil infiltration induced by Cg in rats inoculated with TNBS -induced colitis (3rd after colitis induction) when compares to normal animals. Rats with colitis induced by TNBS showed an increased nociceptive threshold when induced by CG and PGE2. Treatment with ODQ, KT5823 and glibenclamide, naloxone, AM251 and AM630 decreased the nociceptive threshold when compared with TNBS colitis. L-NOARG decrease the nociceptive threshold in rats with colitis induced by TNBS and L-arginine reversed this effect. Our results suggest that the antinociceptive effect of the experimental model of CrohnÂs disease induced by TNBS seemed to be mediated a decrease of inflammatory response independent of neutrophil migration and activation of the NO⁄cGMP/PKG pathway followed by the opening of K+ ATP channels and activation of opioid and cannabinoid system.
| Identifer | oai:union.ndltd.org:IBICT/oai:www.teses.ufc.br:4447 |
| Date | 17 June 2011 |
| Creators | Andrà Luiz dos Reis Barbosa |
| Contributors | Marcellus Henrique Loiola Ponte de Souza, Mariana Lima Vale, Ana Maria Sampaio Assereuy, Waldiceu Aparecido Verri JÃnior, Aytan Miranda Sipahi |
| Publisher | Universidade Federal do CearÃ, Programa de PÃs-GraduaÃÃo em Farmacologia, UFC, BR |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFC, instname:Universidade Federal do Ceará, instacron:UFC |
| Rights | info:eu-repo/semantics/openAccess |
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