Experimental Model of Zymosan-Induced Arthritis in the Rat Temporomandibular Joint: Role of Nitric Oxide and Neutrophils

Aims. To establish a new model of zymosan-induced temporomandibular joint (TMJ) arthritis in the rat and to investigate the role of nitric oxide. Methods. Inflammation was induced by an intra-articular injection of zymosan into the left TMJ. Mechanical hypernociception, cell influx, vascular permeability, myeloperoxidase activity, nitrite levels, and histological changes were measured in TMJ lavages or tissues at selected time points. These parameters were also evaluated after treatment with the nitric oxide synthase (NOS) inhibitors L-NAME or 1400 W. Results. Zymosan-induced TMJ arthritis caused a time-dependent leucocyte migration, plasma extravasation, mechanical hypernociception, and neutrophil accumulation between 4 and 24 h. TMJ immunohistochemical analyses showed increased inducible NOS expression. Treatment with L-NAME or 1400 W inhibited these parameters. Conclusion. Zymosan-induced TMJ arthritis is a reproducible model that may be used to assess both the mechanisms underlying TMJ inflammation and the potential tools for therapies. Nitric oxide may participate in the inflammatory temporomandibular dysfunction mechanisms

Efeito protetor da via hemeoxigenase 1/ BILIVERDINA/ CO em modelos de lesÃes gÃstricas em camundongos â papel da guanilato ciclase solÃvel (GCS) e da no sintase (NOS)

Objective: To evaluate the protective effect of the heme-oxygenase 1 (HO-1)/biliverdin/CO pathway in models of gastropathy in mice, evaluating the role of the soluble guanylate cyclase (GCs) and of the constitutive NOS in this event. Methods: Protocol 1: Mice were pre-treated with hemin (HO-1 inducer; 1,3,10 mg/Kg, i.p.), biliverdin (HO-1 product; 1,3 or 10 mg/Kg., i.p.), DMDC (CO donor; 2.5, 7.5, 12.5 or 10 Âmol/Kg, i.p.) or ZnPP IX (HO-1 antagonist; 0,3, 1 or 3 mg/kg. i.p.), one hour before, gastric damage was induced by ethanol 50% (hemin, biliverdin, DMDC) or 25% (ZnPP IX). In another group, the animals were pre-treated with ODQ (12.5 mg/kg, v.o) or L-NAME (3 mg/Kg, v.o), thirty minutes before of the treatments cited previously. After 1h, the mice were sacrificed and the stomachs removed for evaluation of the gastric lesions (Image J). Protocol 2: Mice were pre-treated with hemin (3 mg/Kg, i.p.), biliverdin (3 mg/Kg., i.p.), DMDC (12,5 Âmol/Kg) or ZnPP IX (3,0 mg/kg), one hour before of the administration of INDO 30 mg/Kg (hemin, biliverdin, DMDC) or 10 mg/Kg (ZnPP IX). In another group, the animals were pre-treated with ODQ (12.5 mg/kg, v.o) or L-NAME (3 mg/Kg, v.o), thirty minutes before of the treatments cited previously. Three hours after, the mice were sacrificed and the stomachs removed for evaluation of the gastric lesions, utilizing a digital paquimetry. In all of the experimental groups, fragments of the gastric mucous were collected for determination of the concentration of MDA, GSH or bilirubin. Another samples of tissue was removed for microscopic analyzes and HO-1 expression by immunohistochemistry. The detection of the TNF-α, IL-1β, IL-10 and MPO activity were evaluated only in the INDO gastropathy. Results: Ethanol increased the expression of HO-1 and the levels of bilirrubin in the gastric tissue. Hemin, biliverdin and DMDC reduced gastric damage, MDA levels and GSH consume in ethanol 50%- induced gastropathy. The histological parameters, edema, hemorrhage and loses of epithelial cells, were diminished in the presence of hemin, biliverdin or DMDC. ZnPP IX amplified the ethanol-induced gastric lesion, increased MDA formation and decreased the GSH concentration in gastric mucosa. The histological parameters also were amplified after the handling with ZnPP IX. Bilirubin concentration was elevated during the protection induced by hemin and biliverdin, but not DMDC. INDO increased the HO-1 expression and the bilirrubin levels in the gastric mucosa. Hemin, biliverdin or DMDC reduced the gastric lesion, the MPO activity, and the MDA levels and increased the GSH concentration in the gastropathy INDO- induced. The histological parameters, edema, hemorrhage, loss of epithelial cells and the presence of inflammatory cells, were inhibited by hemin, biliverdin or DMDC. ZnPP IX amplified the effect of the INDO increasing the gastric lesion, the MPO activity, the MDA levels and the GSH consume. The histological parameters also were amplified after the handling with ZnPP IX. Bilirubin was shown elevated during the protection induced by hemin and biliverdin, but not DMDC. Hemin, biliverdin and DMDC diminished the TNF-α and IL-1β concentrations and increased the IL-10. ODQ and L-NAME completely abolished the DMDC protective gastric effect, but not biliverdin in the gastropathy ethanol or INDO- induced. Conclusion: HO-1/biliverdin/CO pathway plays a protective effect against ethanol or INDO-induced gastric damage. In the gastropathy by ethanol, the protection is dependent of the anti-oxidant action by bilirubin and CO. However, in the model of INDO gastropathy, we observe an anti-oxidant and anti-inflammatory action. The mechanism of gastro protective action of the CO, but not of the biliverdin, is dependent of the CO/ NOS/ GMPc pathway.Objetivo: Avaliar o efeito protetor da via hemeoxigenase 1 (HO-1)/ biliverdina/ CO em modelos de gastropatia em camundongos e o papel da guanilato ciclase solÃvel (GCs) e da NOS constitutiva neste evento. MÃtodos: Protocolo 1: Camundongos foram prÃ-tratados hemina (indutor da HO-1; 1,3 ou 10mg/Kg, i.p.), biliverdina (produto da HO-1; 1,3 ou 10mg/Kg, i.p.), DMDC (doador de CO; 2,5, 7,5, 12,5 ou 25 μmol/Kg, i.p.) ou ZnPP I(inibidor da HO-1; 0,3, 1,0 ou 3,0 mg/kg. i.p.) uma hora antes da administraÃÃo por gavagem de etanol 50% (hemina, biliverdina, DMDC) ou 25% (ZnPP IX). Em outro grupo, os animais foram prÃ-tratados com ODQ (12,5 mg/kg, v.o) ou L-NAME (3 mg/Kg, v.o), trinta minutos antes dos tratamentos citados anteriormente. Depois de 1h, os camundongos foram sacrificados e os estÃmagos removidos para avaliaÃÃo das lesÃes gÃstricas (Image J). Protocolo 2: Camundongos foram prÃ-tratados hemina (3,0 mg/kg), biliverdina (3,0 mg/kg), DMDC (12,5 μmol/Kg) ou ZnPPIX (3,0 mg/Kg) uma hora antes da administraÃÃo de INDO 30 mg/Kg (hemina, biliverdina, DMDC) ou 10 mg/Kg (ZnPP IX). Em outro grupo os animais foram prÃ-tratados com ODQ (12,5 mg/kg, v.o) ou L-NAME (3 mg/Kg, v.o), trinta minutos antes dos tratamentos citados anteriormente. TrÃs horas depois, os camundongos foram sacrificados e os estÃmagos removidos para avaliaÃÃo das lesÃes gÃstrica, utilizando um paquÃmetro digital. Em todos os grupos experimentais, fragmentos da mucosa gÃstrica foram coletados para determinaÃÃo da concentraÃÃo de MDA, GSH e bilirrubina. Outra amostra de tecido foi retirada para analise microscÃpica e imunohistoquÃmica. A detecÃÃo das citocinas TNF-α, IL-1β e IL-10, bem como a atividade de MPO foram avaliados somente na gastropatia por INDO. Resultados: O etanol aumentou a expressÃo de enzima HO-1 e dos nÃveis de bilirrubina no tecido gÃstrico. Hemina, biliverdina ou DMDC reduziram a lesÃo gÃstrica, os nÃveis de MDA e o consumo de GSH induzido por etanol 50%. Os parÃmetros histolÃgicos, edema, hemorragia e perda de cÃlulas epiteliais, foram diminuÃdos na presenÃa de hemina, biliverdina ou DMDC. ZnPP IX amplificou o efeito do etanol 25%, aumentando a lesÃo gÃstrica, os nÃveis de MDA e o consumo de GSH. Os parÃmetros histolÃgicos tambÃm foram amplificados apÃs o tratamento com ZnPP IX. A concentraÃÃo de bilirrubina se mostrou elevada apenas na gastroproteÃÃo induzida por hemina e biliverdina, mas nÃo pelo DMDC. INDO aumentou a expressÃo da HO-1 e os nÃveis de bilirrubina na mucosa gÃstrica. Hemina, biliverdina ou DMDC reduziram a lesÃo gÃstrica, a atividade de MPO, os nÃveis de MDA e aumentaram a concentraÃÃo de GSH na gastropatia por INDO. Os parÃmetros histolÃgicos, edema, hemorragia, perda de cÃlulas epiteliais e a presenÃa de cÃlulas inflamatÃrias, foram inibidas pela hemina, biliverdina ou DMDC. ZnPP IX amplificou o efeito da INDO aumentando a lesÃo gÃstrica, a atividade de MPO, os nÃveis de MDA e o consumo de GSH. Os parÃmetros histolÃgicos tambÃm foram amplificados apÃs o tratamento com ZnPP IX. Bilirrubina se mostrou elevada apenas na gastroproteÃÃo induzida por hemina e biliverdina, mas nÃo pelo DMDC. Hemina, biliverdina e DMDC diminuÃram as concentraÃÃes de TNF-α e IL-1β e aumentaram a IL-10. ODQ e L-NAME reverteram o efeito protetor do DMDC, mas nÃo da biliverdina, na gastropatia induzida por etanol ou INDO. ConclusÃo: A via HO-1/biliverdina/CO participa do processo de defesa da mucosa gÃstrica contra lesÃes induzidas por etanol ou INDO. Na gastropatia por etanol, a proteÃÃo à dependente da aÃÃo antioxidante da bilirrubina e CO. Entretanto, no modelo de gastropatia por INDO, observamos uma aÃÃo antioxidante e antiinflamatÃria. Evidenciamos ainda que o mecanismo de aÃÃo gastroprotetor do CO, mas nÃo da biliverdina à dependente da via CO/GMPc/NOS

The protective effect of Escherichia coli lipopolysaccharide in gastric injury in indomethacin rats - Involvement of cyclooxygenase type 2 NO synthase induced potassium channels and ATP-sensitive.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoINTRODUÃÃO: O papel do LPS na defesa da mucosa gÃstrica ainda nÃo està estabelecido. OBJETIVOS: 1-Verificar o efeito protetor do LPS na lesÃo gÃstrica (LG), na infiltraÃÃo de neutrÃfilos (IN), no aumento da adesÃo leucocitÃria, na diminuiÃÃo dos nÃveis de GSH induzidos por indometacina (INDO) em ratos; 2-Investigar o papel da COX-2, NOSi e dos canais de K sensÃveis ao ATP (KATP) na gastroproteÃÃo do LPS na gastropatia por INDO. MÃTODOS: Os ratos foram tratados com LPS da E. coli (30, 100 ou 300 g/Kg, e.v.). ApÃs 6 hs, foi administrado INDO (20mg/Kg, p.o.). Decorridas 3 hs, o sangue foi colhido para determinaÃÃo do leucograma. Posteriormente, os ratos foram sacrificados e a LG foi aferida. Fragmentos do estÃmago foram retirados para avaliaÃÃo da atividade de mieloperoxidase (MPO) e determinaÃÃo dos nÃveis de glutationa (GSH). A adesÃo e o rolling dos leucÃcitos foram avaliados por microscopia intravital. Diferentes grupos foram tratados com rofecoxib, L-NAME, aminoguanidina, dexametasona, glibenclamida, diazÃxido ou glibenclamida + diazÃxido. ApÃs 3 horas da administraÃÃo de INDO (20mg/Kg, p.o.), foram avaliadas a LG, a MPO e GSH. RESULTADOS: LPS reduziu a LG e o aumentou a MPO induzidas por INDO de forma dose-dependente, com o efeito mÃximo na dose de 300 g/Kg e no tempo de 6 hs. O prÃ-tratamento com LPS induziu uma neutrofilia na gastropatia induzida pela INDO. LPS reverteu à queda dos nÃveis de GSH no estÃmago com INDO. O tratamento com LPS diminui a adesÃo e aumentou o rolling dos leucÃcitos quando comparado com o tratado com INDO. Rofecoxib, L-NAME, aminoguanidina ou dexametasona nÃo reverteram o efeito protetor do LPS. Glibenclamida, mas nÃo diazÃxido, reverteu o efeito protetor do LPS na gastropatia induzida por INDO, aumentando de forma significativa a LG, MPO e diminuindo a GSH. A associaÃÃo de glibenclamida com diazÃxido nÃo reverteu o efeito protetor do LPS. CONCLUSÃES: LPS protege contra a LG por INDO, atravÃs da inibiÃÃo da IN por uma diminuiÃÃo da adesÃo de leucÃcitos ao endotÃlio e por um aumento dos nÃveis de GSH no estÃmago. Este evento dependente da abertura de KATP. Nossos dados tambÃm sugerem que a atividade de COX-2 e NOSi nÃo estÃo envolvidos no efeito protetor do LPS.INTRODUCTION: The role of the LPS in the defense of the gastric mucosa is still not established. AIMS: To verify the protective effect of the LPS in the gastric damage (GD), in the neutrophil infiltration (NI), in the increase of the leukocyte of adhesion, in the reduction of the induced glutathione levels for indomethacin (INDO) in rats and to investigate the role of the COX-2, NOSi and of ATP-sensitive k channels (KATP) in the protective effect of LPS administration on INDO- induced gastropathy. METHODS: The rats were treated with LPS of E. coli (30, 100 or 300 mg/Kg, e.v.). After 6 hs, INDO was administrated (20mg/Kg, p.o.). 3 hs later, the blood was harvested for determination the total and differential number of white blood cell counts. Later, the rats had been sacrificed and the GD was surveyed. Piece of the stomach had been removed for evaluation of the MPOactivity and determination of the GSH levels. The adhesion and rolling of the leukocytes had been evaluated by intravital microscopy. Different groups were treated with rofecoxib, L-NAME, aminoguanidine, dexamethasone, glibenclamide, diazoxide or glibenclamide + diazoxide. After 3 hs of the administration of INDO (20mg/Kg, p.o.), had been evaluated the GD, MPO and GSH. RESULTS: LPS reduced dose- dependently INDO- induced GD and increase in MPO, with the maximal effect at the dose of 300 g/kg and in the time of 6 hs. The LPS treatment neutrophilia induced in INDO induced gastropathy. LPS reverted to the fall of the GSH levels in the stomach with INDO. The LPS treatment decreased the adhesion and increased rolling of the leukocytes when compared with the INDO treated. Rofecoxib, L-NAME, aminoguanidine or dexamethasona had not reverted the protective effect of the LPS. Glibenclamide, but not diazoxide, reverted the protective effect of the LPS in the induced gastropathy for INDO, increasing of significant form the GD, MPO and decreasing the GSH. The diazoxide + glibenclamide association of with did not revert the protective effect of the LPS. CONCLUSIONS: LPS protects against INDO induced GD, through the inhibition of the NI for a reduction of the adhesion of leukocytes to the endothelin and for an increase of the GSH levels in the stomach. This dependent event of the KATP opening. Our data also suggest that the activity of COX-2 and NOSi are not involved in the protective effect of the LPS

Lipopolysaccharide from Escherichia coli prevents indomethacin-induced gastric damage in rats: role of non-protein sulfhydryl groups and leukocyte adherence

To investigate the role of non-protein sulfhydryl groups (NP-SH) and leukocyte adhesion in the protective effect of lipopolysaccharide (LPS) from Escherichia coli against indomethacin-induced gastropathy. Male Wistar rats were divided into four groups: saline, LPS, saline + indomethacin and LPS + indomethacin, with six rats in each group. Rats were pretreated with LPS (300 mu g/kg, by intravenous) or saline. After 6 h, indomethacin was administered (20 mg/kg, by gavage). Three hours after treatments, rats were killed. Macroscopic gastric damage, gastric NP-SH concentration, myeloperoxidase (MPO) activity and mesenteric leukocyte adhesion (intravital microscopy) were assessed. Statistical analysis was performed using one-way analysis of variance followed by the Newman-Keuls test. Statistical significance was set at P < 0.05. LPS reduced the gastric damage, gastric MPO activity and increased gastric NP-SH concentration in indomethacin-induced gastropathy. LPS alone increased gastric NP-SH when compared to saline. Indomethacin increased leukocyte adhesion when compared to the saline, and LPS reduced indomethacin-induced leukocyte adhesion. In addition, LPS alone did not change leukocyte adhesion, when compared to the saline. LPS protective effect against indomethacin-induced gastropathy is mediated by an increase in the NP-SH and a decrease in leukocyte-endothelial adhesion.CNPq (Brazil

Gastroprotective Effects of Sulphated Polysaccharides from the Alga Caulerpa mexicana Reducing Ethanol-Induced Gastric Damage

The development of the gastric lesion is complex and the result of the imbalance between aggressive and protective factors, involving the generation of free radicals and disturbance in nitric oxide (NO) production. Sulphated polysaccharides (SP), from marine algae, are widely used in biotechnological and pharmaceutical areas. In this study, we evaluated the effects of SP from the green marine alga Caulerpa mexicana (Cm-SP) in ethanol-induced gastric damage models in mice. Cm-SP (2, 20, or 200 mg/kg), administered p.o., significantly reduced gastric damage, and these effects were inhibited through pretreatment with indomethacin. Cm-SP (200 mg/kg) prevented the ethanol-induced decline in glutathione and restored its normal level. Moreover, it was able to normalize the elevated thiobarbituric acid reactive substance levels. However, Cm-SP did not show any significant effects on NO2/NO3 level, when compared to the ethanol group. The pretreatment with L- NAME induced gastric mucosal damage and did not inhibit the gastroprotective effect of Cm-SP (200 mg/kg). In conclusion, the gastroprotective effects of Cm-SP in mice involve prostaglandins and reduction in the oxidative stress and are independent of NO