RESUMO
6-Sulfanilamidoindazole (6SAI) is known to induce not only an acute arthritis but also serositis and arteritis which resemble those induced by some vasodilators in rats. In this study, the recovery process of ankle lesions was examined histopathologically for up to 12 weeks of recovery period in rats bearing arthritis induced by administration of 6SAI (500 mg/kg) for 2 weeks. At 2 weeks of 6SAI-treatment, exudative synovitis and exudative/edematous periarthritis with marked formation of granulation tissues and periosteal reactive bone formation were noted in the ankles, but no remarkable neutrophil infiltration was detected in those lesions. The ankle swelling induced by 6SAI diminished by 4 weeks of recovery period, and the elevated plasma fibrinogen levels were normalized by 2 weeks of recovery period. Although fibrosis and newly-formed periosteal bone were still observed after 2 weeks of recovery period, no inflammatory lesion was detected at that point. At 4 or 12 weeks of recovery periods, the ankles showed an almost normal appearance. These results indicate that 6SAI-induced arthritis is reversible in nature and does not develop into chronic phase.
Assuntos
Periartrite/patologia , Sulfanilamidas/efeitos adversos , Doença Aguda , Albuminas/análise , Animais , Articulação do Tornozelo/patologia , Fibrinogênio/análise , Hematologia , Masculino , Periartrite/induzido quimicamente , Periartrite/metabolismo , Antígeno Nuclear de Célula em Proliferação/análise , Ratos , Membrana Sinovial/química , Articulações Tarsianas/patologiaRESUMO
TNF-alpha is a pleotropic proinflammatory cytokine that has been implicated as a contributing factor in a number of disease processes, primarily through its ability to induce the expression of inflammatory and cytotoxic mediators. TNF-alpha is also involved in cell growth accompanying the healing process in multiple organ systems and influences liver repair following hepatotoxic damage or regeneration following partial hepatectomy. In this respect, TNF-alpha is a known mitogen for hepatocytes. In this paper we describe a novel role for TNF-alpha in the modulation of expression of TGF-alpha, the latter being a complete hepatocyte mitogen. TNF-alpha directly up-regulates TGF-alpha mRNA by up to 7-fold in isolated mouse hepatocytes, whereas neutralization of TNF-alpha significantly decreased liver mRNA and protein expression of TGF-alpha following chemical-induced hepatotoxicity. That TNF-alpha directly stimulated TGF-alpha was suggested by the inability of either anti-IL-6 Abs or cycloheximide to inhibit TNF-alpha-induced TGF-alpha expression in hepatocytes. However, in the presence of anti-TGF-alpha neutralizing Abs, the mitogenic activity of TNF-alpha is abrogated. Using cells transfected with the TGF-alpha promoter, and an RNA polymerase inhibitor, it was shown that TNF-alpha modulates TGF-alpha expression through both pre- and posttranscriptional events. Taken together, these data suggest that TNF-alpha participates in liver repair and regeneration, in part, by directly inducing the expression of TGF-alpha.
Assuntos
Regeneração Hepática/imunologia , Fígado/imunologia , Fígado/metabolismo , Fator de Crescimento Transformador alfa/biossíntese , Fator de Necrose Tumoral alfa/fisiologia , Animais , Tetracloreto de Carbono/toxicidade , Divisão Celular/imunologia , Linhagem Celular , Separação Celular , Células Cultivadas , Feminino , Hepatectomia , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Fígado/citologia , Fígado/efeitos dos fármacos , Regeneração Hepática/genética , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , RNA Mensageiro/biossíntese , RNA Mensageiro/efeitos dos fármacos , Transcrição Gênica , Fator de Crescimento Transformador alfa/genética , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Recent investigations have elucidated the cytokine-induced NF-kappaB activation pathway. IkappaB kinase (IKK) phosphorylates inhibitors of NF-kappaB (IkappaBs). The phosphorylation targets them for rapid degradation through a ubiquitin-proteasome pathway, allowing the nuclear translocation of NF-kappaB. We have examined the possibility that IKK can phosphorylate the p65 NF-kappaB subunit as well as IkappaB in the cytokine-induced NF-kappaB activation. In the cytoplasm of HeLa cells, the p65 subunit was rapidly phosphorylated in response to TNF-alpha in a time dependent manner similar to IkappaB phosphorylation. In vitro phosphorylation with GST-fused p65 showed that a p65 phosphorylating activity was present in the cytoplasmic fraction and the target residue was Ser-536 in the carboxyl-terminal transactivation domain. The endogenous IKK complex, overexpressed IKKs, and recombinant IKKbeta efficiently phosphorylated the same Ser residue of p65 in vitro. The major phosphorylation site in vivo was also Ser-536. Furthermore, activation of IKKs by NF-kappaB-inducing kinase induced phosphorylation of p65 in vivo. Our finding, together with previous observations, suggests dual roles for IKK complex in the regulation of NF-kappaB.IkappaB complex.
Assuntos
Núcleo Celular/metabolismo , NF-kappa B/química , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Serina , Ativação Transcricional , Sequência de Aminoácidos , Animais , Galinhas , Citoplasma/metabolismo , Células HeLa , Humanos , Quinase I-kappa B , Substâncias Macromoleculares , Camundongos , Dados de Sequência Molecular , Fosfatos/farmacologia , Fosforilação , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Fator de Necrose Tumoral alfa/farmacologia , XenopusRESUMO
Several mitogen-activated protein kinase kinase kinases play critical roles in nuclear factor-kappaB (NF-kappaB) activation. We recently reported that the overexpression of transforming growth factor-beta-activated kinase 1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, together with its activator TAK1-binding protein 1 (TAB1) stimulates NF-kappaB activation. Here we investigated the molecular mechanism of TAK1-induced NF-kappaB activation. Dominant negative mutants of IkappaB kinase (IKK) alpha and IKKbeta inhibited TAK1-induced NF-kappaB activation. TAK1 activated IKKalpha and IKKbeta in the presence of TAB1. IKKalpha and IKKbeta were coimmunoprecipitated with TAK1 in the absence of TAB1. TAB1-induced TAK1 activation promoted the dissociation of active forms of IKKalpha and IKKbeta from active TAK1, whereas the IKK mutants remained to interact with active TAK1. Furthermore, tumor necrosis factor-alpha activated endogenous TAK1, and the kinase-negative TAK1 acted as a dominant negative inhibitor against tumor necrosis factor-alpha-induced NF-kappaB activation. These results demonstrated a novel signaling pathway to NF-kappaB activation through TAK1 in which TAK1 may act as a regulatory kinase of IKKs.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , MAP Quinase Quinase Quinases , Proteínas Quinases Ativadas por Mitógeno , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Ativação Enzimática , Células HeLa , Humanos , Quinase I-kappa B , Proteínas Quinases JNK Ativadas por Mitógeno , NF-kappa B/metabolismo , Serina/metabolismoRESUMO
We investigated nephrotoxic serum (NTS)-induced glomerulonephritis in Wistar-Kyoto (WKY) rats as a model to evaluate antinephritic agents. WKY rats required only a small amount of NTS to induce crescentic glomerulonephritis and the rats progressively lost their renal function in a few weeks. In a comparative study with WKY and Sprague-Dawley (SD) rats, WKY rats showed a normal distribution pattern in the severity of proteinuria with a small variance. While SD rats needed a much higher amount of NTS to exhibit a comparable proteinuria which was not normal and had a large variance. The effects of clinically available antinephritic drugs, methylprednisolone, cyclophosphamide and cyclosporin A, were studied in both strains. In WKY rats, these drugs significantly inhibited the proteinuria, glomerular histological changes and decrease in creatinine clearance. On the other hand, such significant inhibitory effects on proteinuria were not observed with any of these drugs in SD rats. In conclusion, NTS nephritis in WKY rats may prove to be a useful model for studying antinephritic agents.
Assuntos
Glomerulonefrite/induzido quimicamente , Toxinas Biológicas/efeitos adversos , Animais , Membrana Basal/química , Membrana Basal/imunologia , Peso Corporal/efeitos dos fármacos , Ciclofosfamida/uso terapêutico , Ciclosporina/uso terapêutico , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Tratamento Farmacológico , Glomerulonefrite/tratamento farmacológico , Glomerulonefrite/patologia , Glucocorticoides/uso terapêutico , Imunossupressores/uso terapêutico , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/imunologia , Glomérulos Renais/patologia , Masculino , Prednisolona/uso terapêutico , Proteinúria/urina , Ratos , Ratos Endogâmicos WKY , Ratos Sprague-Dawley , Especificidade da Espécie , Toxinas Biológicas/sangue , Aumento de Peso/efeitos dos fármacosRESUMO
6-Sulfanilamidoindazole (6SAI) is a sulfonamide that induces acute, self-limiting arthritis in rats, and 6SAI-induced arthritis is thought to be a model for testing anti-inflammatory agents. In this study, in order to clarify the location of arthritis and relationships between arthritis and other changes in this model, we have investigated the detailed pathologic changes in rats administered orally with 6SAI (125, 250, 500 mg/kg) daily for 4 wk in a time-course experiment. Moderate to severe arthritis was observed in rats of middle- and high-dose groups. Histologically, in the affected ankle, exudative synovitis and periarthritis were observed at 1 wk, granulation tissue formation with angiogenesis and periosteal new bone formation at 2 wk, and marked fibrosis of affected area at 4 wk, respectively. In addition to these changes, in periarticular and periosteal tissues of affected ankles, subendothelial insudation of small-sized arteries and medial fibrinoid degeneration of medium-sized arteries were observed at 1 and 2 wk and intimal thickening and medial hypertrophy at 4 wk, respectively. No arterial changes were observed in the unaffected ankles. Similar arterial changes were often observed in the liver, thyroid glands, and lungs and rarely in various organs and tissues. Acute inflammation of serous tissues such as mesentery, mediastinum, and capsule of spleen or thymus were also present in 6SAI-treated groups, and it was sometimes accompanied by arteritis. In addition, in 6SAI-treated rats, follicular hyperplasia of thyroid glands and pituitary changes, which are thought to be related to depression of thyroid hormone production by 6SAI, were observed. These results show that 6SAI induces not only arthritis but also arteritis, serositis, and thyroid change, and it is necessary to take the interaction between these changes into consideration when anti-inflammatory agents are tested in this model.
Assuntos
Arterite/induzido quimicamente , Artrite/induzido quimicamente , Serosite/induzido quimicamente , Sulfanilamidas/toxicidade , Animais , Arterite/patologia , Artrite/patologia , Corantes , Masculino , Ratos , Serosite/patologia , Testes de ToxicidadeRESUMO
We investigated the effect of angiotensin-converting enzyme inhibition on spontaneous nephrosis in Dahl salt-sensitive (Dahl/S) rats. Dahl/S rats fed on a normal sodium diet spontaneously developed nephrosis and mild hypertension from a young age. In young Dahl/S rats, an angiotensin-converting enzyme inhibitor, imidapril, attenuated the development of proteinuria accompanied by a decrease in blood pressure. Methylprednisolone, a potent therapeutic agent for proteinuria, did not affect the development of nephrosis. An angiotensin AT1 receptor antagonist, losartan, but not a Ca2+ channel blocker, verapamil, inhibited the development of nephrosis while both agents decreased blood pressure to a similar extent as imidapril. In mature Dahl/S rats, imidapril suppressed not only the development of proteinuria but also the glomerular lesions. It is concluded that the development of spontaneous nephrosis in Dahl/S rats is mediated by angiotensin II.
Assuntos
Angiotensina II/fisiologia , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Glucocorticoides/farmacologia , Imidazóis/uso terapêutico , Imidazolidinas , Metilprednisolona/farmacologia , Nefrose/etiologia , Envelhecimento/metabolismo , Animais , Anti-Hipertensivos/farmacologia , Peso Corporal/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/farmacologia , Colesterol/sangue , Hipertensão/induzido quimicamente , Losartan/farmacologia , Masculino , Nefrose/patologia , Nefrose/prevenção & controle , Proteinúria/prevenção & controle , Ratos , Ratos Endogâmicos Dahl , Cloreto de Sódio na Dieta , Verapamil/farmacologiaRESUMO
IL-6 has been characterized as a pleiotropic cytokine with multiple biologic activities, but its induction and role in asbestos diseases have not been studied. Asbestos fibers were found to stimulate IL-6 expression and secretion in pulmonary type II-like epithelial A549 cells as well as in normal human bronchial epithelial cells. IL-6 induction was dependent on the intracellular redox-oxidative state, since intracellular hydroxyl scavengers and N-acetylcysteine, a precursor of glutathione, abrogated IL-6 secretion by asbestos or H2O2. IL-6 induction paralleled increased DNA binding activity to the nuclear factor-kappa B (NF-kappa B)- and NF-IL-6-recognized sites in the IL-6 promoter. The NF-kappa B and NF-IL-6 DNA binding proteins were immunochemically characterized as a heterodimer p65/p50 and a homodimer C/EBP beta, respectively. Stimulation of DNA binding activity to the NF-kappa B and NF-IL-6 binding sites of the IL-6 promoter by asbestos or H2O2 were inhibited by tetramethylthiourea, a hydroxyl radical scavenger. The role of local IL-6 production in the pathophysiologic processes of fiber-induced lung disorders was examined. Although less active than fibroblast growth factor, human rIL-6 also stimulated lung fibroblast growth, as evidenced by increased [3H]thymidine incorporation. Furthermore, elevated IL-6 levels were found in bronchoalveolar lavage fluids from patients diagnosed with lung fibrosis and work-related histories of long term asbestos exposure. Taken together, the results suggest that asbestos-induced oxidative stress is involved in the activation of NF-kappa B and NF-IL-6 transcription factors, which recognize the IL-6 promoter. The resulting increase in IL-6 expression may be involved in both inflammatory and fibrotic processes in the lung.
Assuntos
Asbesto Crocidolita/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Interleucina-6/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Espécies Reativas de Oxigênio/fisiologia , Adenocarcinoma Bronquioloalveolar , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/imunologia , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Células Epiteliais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Humanos , Interleucina-6/genética , Pulmão/metabolismo , Neoplasias Pulmonares , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Oxirredução/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/imunologia , Células Tumorais CultivadasRESUMO
After stroke-prone spontaneously hypertensive rats (SHRSP) received a salt-loaded diet to accelerate onset of stroke, the therapeutic effect of clentiazem, a benzothiazepine Ca antagonist, on neurologic and histologic disorders was examined. Treatment with clentiazem (3, 15, and 30 mg/kg) orally twice daily (b.i.d.) for 28 days after the occurrence of stroke reduced neurologic symptoms and histologic changes of brain and kidney in a dose-dependent manner. Acute treatment with clentiazem (15 mg/kg, b.i.d.) administered immediately after stroke for 1 week not only almost completely abolished neurologic symptoms during treatment, but partially improved them even after treatment. Subacute treatment with clentiazem starting 10 days after stroke and continuing for 18 days also suppressed the neurologic signs. Both acute and subacute treatment improved cerebral histology. These results suggest that clentiazem treatment in the acute and subacute phases of stroke is beneficial.
Assuntos
Anti-Hipertensivos/uso terapêutico , Encéfalo/patologia , Transtornos Cerebrovasculares/tratamento farmacológico , Diltiazem/análogos & derivados , Hipertensão/tratamento farmacológico , Rim/patologia , Administração Oral , Animais , Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Transtornos Cerebrovasculares/patologia , Diltiazem/administração & dosagem , Diltiazem/farmacologia , Diltiazem/uso terapêutico , Relação Dose-Resposta a Droga , Frequência Cardíaca/efeitos dos fármacos , Rim/efeitos dos fármacos , Sistema Nervoso/efeitos dos fármacos , Ratos , Ratos Endogâmicos SHR , Sódio na DietaRESUMO
The influence of chronic treatment with clentiazem ((+)(2S,3S)-3-acetoxy-8-chloro-5-[2-(dimethylamino)ethyl]-2,3-dihydro- 2-(4-methoxyphenyl)-1,5-benzothiazepin-4 (5H)-one maleate, TA-3090), on blood pressure, incidence of stroke, stroke-related mortality and histological changes of the brain and other organs were examined in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP that were fed an 8% NaCl-containing diet began to die of a stroke 3 weeks after salt-loading, accompanied by decreases in body weight and food intake. Most of the rats (16 out of 18) died by the 8th week of salt-loading. Chronic treatment with clentiazem (300 or 1000 ppm) delayed the occurrence of stroke and death in a dose-related manner without any hypotensive action when measured by the tail-cuff method. However, examination of circadian changes in arterial blood pressure with implanted cannula under a freely-moving condition 3 weeks after salt-loading revealed that 1000 ppm clentiazem produced significant hypotension in the dark phase but not in the light phase. Histological studies (3 weeks after salt-loading) showed that 1000 ppm Clentiazem significantly suppressed the cerebral and renal damages, and vascular hypertrophy in all organs studied. Thus, clentiazem prevents stroke and also protects renal damage and vascular hypertrophy in salt-loaded SHRSP. The hypotensive effect and organ-protective action by clentiazem may be involved in its prophylactic action against stroke.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Transtornos Cerebrovasculares/prevenção & controle , Diltiazem/análogos & derivados , Hipertensão/fisiopatologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/uso terapêutico , Córtex Cerebral/patologia , Transtornos Cerebrovasculares/patologia , Ritmo Circadiano/efeitos dos fármacos , Diltiazem/farmacologia , Diltiazem/uso terapêutico , Ingestão de Alimentos/efeitos dos fármacos , Hipertensão/induzido quimicamente , Hipertensão/patologia , Córtex Renal/patologia , Masculino , Ratos , Ratos Endogâmicos SHR , Cloreto de SódioRESUMO
The mouse strain difference in bile duct lesions was studied on male A/J, BALB/c, C57BL/6, C3H/He, DBA/2 and DDY mice 4 weeks old given intraperitoneal injections of swine serum (0.05 or 0.2 ml per mouse) twice a week for 4 weeks. The hepatic lesions were restricted to the portal tract. Biliary epithelial cells showed hypertrophy and hyperplasia, and eosinophilic and homogeneous or needle-shaped material appeared in the cytoplasm of such hypertrophied epithelial cells and in the ductular lumen. Around these damaged biliary epithelia, eosinophil leukocyte and plasma cell infiltration with proliferation of collagen fibres was commonly detected. These changes became more apparent with increasing size of bile duct. Such histopathological characteristics of hepatic lesions were essentially the same in all strains, but the severity showed a clear strain difference: the lesion was marked in the DDY, A/J and BALB/c strains, moderate in C3H/He and slight in C57BL/6 and DBA/2. A high production of anti-swine-serum antibodies associated with a marked increase in the number of mouse IgG-producing lymphocytes in the spleen was detected in the strains showing the marked hepatic lesions.
Assuntos
Doenças dos Ductos Biliares/veterinária , Ductos Biliares/patologia , Colangite/veterinária , Camundongos Endogâmicos , Doenças dos Roedores/patologia , Animais , Doenças dos Ductos Biliares/patologia , Sangue , Colangite/patologia , Imunofluorescência , Rim/patologia , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Baço/patologia , Suínos/sangueRESUMO
The neuropathogenesis of Tyzzer's organism was comparatively studied in suckling and weanling mice after intranasal inoculation. In sucklings, suppurative rhinitis was produced in 24 hr postinoculation (p.i.) and organisms were detected in olfactory as well as supporting cells of the nasal mucosa. The lesions later developed to the lamina propria and propagation of organisms was seen within basal and glandular cells. On day 3 p.i., some organisms were found along with the olfactory nerve fibers and within neurons in the olfactory bulbs. Meningoencephalitis was produced with intraneuronal growth of bacteria on day 5 p.i. or later. On day 7 p.i., the brain lesions spread multifocally to the posterior parts and bacterial antigen in the nasal mucosa disappeared. In weanlings, infection was first established in the nasal mucosa and then some necrotized lesions were produced in the olfactory bulbs though much less in severity as compared to those of sucklings. Both suckling and weanling mice had necrotizing hepatitis while hemorrhagic enteritis was seen only in some sucklings.