RESUMO
The presence of CD40 on carcinoma cells is an important factor for the generation of tumor-specific responses induced by CD40 ligation. In an N-methyl-N-nitrosourea (MNU)-induced autochthonous mammary tumor model, we analyzed the immune features of primary tumor cells. Here, CD40 was frequently detected on the primary tumor cultures and selectively expressed on the malignant mammary tissue in vivo. On the other hand, every mammary tumor cell culture had a heterogeneous and reduced expression of proinflammatory TNFalpha, IL-1beta, IL-6 and CXCL1 cytokines compared to normal mammary epithelial cells. Low-efficiency transfection of CD40 ligand (CD40L) gene enhanced the expression of proinflammatory cytokines in the tumor cells and strengthened allogeneic immune reactions and costimulatory activity which may help overwhelming suppressive features of the tumor.
Assuntos
Ligante de CD40/genética , Ligante de CD40/imunologia , Carcinoma/imunologia , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/imunologia , Alquilantes/toxicidade , Animais , Animais não Endogâmicos , Carcinoma/induzido quimicamente , Carcinoma/genética , Carcinoma/patologia , Linhagem Celular Tumoral , Meios de Cultura/química , Etídio/metabolismo , Feminino , Corantes Fluorescentes/metabolismo , Proteínas de Fluorescência Verde/genética , Imuno-Histoquímica , Lipossomos , Neoplasias Mamárias Experimentais/induzido quimicamente , Neoplasias Mamárias Experimentais/patologia , Metilnitrosoureia/toxicidade , Mucina-1/imunologia , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/imunologia , Transfecção/métodosRESUMO
BACKGROUND: Decreased mesenteric blood flow and multiple organ injury due to free radicals are the consequences of septic shock. Since the blockade of endothelin receptors was reported to exert beneficial effects, we investigated the effects of tezosentan, a novel dual endothelin receptor antagonist, in two different experimental models of septic shock induced either by the injection of Escherichia coli endotoxin (ETX, 20 mg/kg, i.p.) or by cecal ligation and puncture (CLP). STUDY DESIGN: Swiss albino mice received tezosentan (10 mg/kg, i.p.) or its solvent saline (0.9% NaCl, w/v) twice at 2 and 22 h after ETX or CLP. At 24 h, the animals were anesthetized and the mesenteric blood flow was monitored for 15 min by using perivascular ultrasonic Doppler flowmeter. Then the animals were exsanguinated, and spleen, liver, and kidneys were isolated accordingly for histopathological examination. Thiobarbituric acid reacting substances and glutathione and myeloperoxides activities were also determined in the liver. RESULTS: In both ETX and CLP models, there was a decrease in mesenteric blood flow which was blocked by tezosentan. Similarly, tezosentan significantly attenuated the histopathological injury inflicted by both models. Although the glutathione levels were decreased and thiobarbituric acid reacting substances and myeloperoxidase activity were increased by ETX and CLP, tezosentan has failed to block these alterations in a consistent manner. However, a significant interaction between CLP and tezosentan with regard to myeloperoxidase activity and glutathione should be taken as partial evidence to explain the underlying mechanism of protection offered by tezosentan against liver injury. CONCLUSIONS: Therefore, we concluded that tezosentan, by working via mechanisms mostly other than the blockade of free radical induced damage, is a useful treatment option for combating the deleterious effects of septic shock such as mesenteric ischemia as well as liver, spleen, and kidney injury.
Assuntos
Antagonistas dos Receptores de Endotelina , Endotoxemia/tratamento farmacológico , Piridinas/uso terapêutico , Choque Séptico/tratamento farmacológico , Circulação Esplâncnica/efeitos dos fármacos , Tetrazóis/uso terapêutico , Animais , Endotoxemia/metabolismo , Endotoxemia/patologia , Rim/patologia , Fígado/metabolismo , Fígado/patologia , Camundongos , Peroxidase/metabolismo , Choque Séptico/metabolismo , Choque Séptico/patologia , Baço/patologiaAssuntos
Abdome/patologia , Líquido Ascítico/patologia , Dilatação Patológica/veterinária , Pancreatite/veterinária , Peritonite/veterinária , Doenças dos Roedores/diagnóstico , Animais , Dilatação Patológica/diagnóstico , Dilatação Patológica/etiologia , Evolução Fatal , Feminino , Camundongos , Pâncreas/patologia , Pancreatite/complicações , Pancreatite/diagnóstico , Peritonite/diagnóstico , Peritonite/etiologiaRESUMO
The role of K(ATP) channels in the antiarrhythmic effect of Escherichia coli endotoxin-induced nitric oxide synthase (iNOS) was examined in an anesthetised rat model of myocardial ischemia and reperfusion arrhythmia by using glibenclamide (1 mg kg(-1)), nateglinide (10 mg kg(-1)) and repaglinide (0.5 mg kg(-1)). Endotoxin (1 mg kg(-1)) was administered intraperitoneally 4 h before the occlusion of the left coronary artery and glibenclamide, nateglinide or repaglinide was administered 30 min before coronary artery occlusion. We also evaluated the effects of K(ATP) channel blockers and nonselective K(+) channel blocker tetraethylammonium (TEA) on cardiac action potential configuration in the atria obtained from endotoxemic rats. The mean arterial blood pressure of rats receiving endotoxin was lower during both the occlusion and reperfusion periods. Endotoxin significantly reduced the total number of ectopic beats and the duration of ventricular tachycardia. Glibenclamide, but not nateglinide and repaglinide, prevented the hypotension and antiarrhythmic effects of endotoxin. Atria obtained from endotoxin-treated rats had prolonged action potential duration. This effect was abolished with pretreatment of iNOS inhibitors, l-canavanine and dexamethasone and perfusion of glibenclamide, but not with TEA and non-sulfonylurea drug, nateglinide. We demonstrated that glibenclamide inhibits the antiarrhythmic effect of endotoxin and this effect does not appear to involve K(ATP) channels.
Assuntos
Arritmias Cardíacas/fisiopatologia , Endotoxemia/fisiopatologia , Glibureto/farmacologia , Isquemia Miocárdica/fisiopatologia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/metabolismo , Potenciais de Ação/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Animais , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Carbamatos/farmacologia , Cicloexanos/farmacologia , Modelos Animais de Doenças , Interações Medicamentosas , Endotoxemia/induzido quimicamente , Endotoxemia/complicações , Endotoxemia/metabolismo , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Átrios do Coração/fisiopatologia , Sistema de Condução Cardíaco/efeitos dos fármacos , Sistema de Condução Cardíaco/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Isquemia Miocárdica/complicações , Isquemia Miocárdica/metabolismo , Nateglinida , Fenilalanina/análogos & derivados , Fenilalanina/farmacologia , Piperidinas/farmacologia , Canais de Potássio/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Taquicardia Ventricular/metabolismo , Taquicardia Ventricular/fisiopatologia , Tetraetilamônio , Fatores de Tempo , Fibrilação Ventricular/metabolismo , Fibrilação Ventricular/fisiopatologia , Complexos Ventriculares Prematuros/metabolismo , Complexos Ventriculares Prematuros/fisiopatologiaRESUMO
Electrical and pharmacologic stimulation of the efferent cholinergic antiinflammatory pathway suppress the systemic inflammatory response and can prevent lethal endotoxemia. Neostigmine, a cholinergic agent, has not been tested to determine if it can prevent histopathologic organ injury in endotoxemia. In the present study, the effects of neostigmine treatment on the histopathologic organ injury inflicted by Escherichia coli endotoxin in a mouse model of septic shock was investigated. Endotoxemia in mice caused weight loss and increased spleen, liver, and lung weight. When the organs were examined for histopathologic injury, endotoxemia increased interstitial inflammation in the lungs, liver injury, and organ injury in general terms; neostigmine, at a dose of 0.1 mg/kg, failed to attenuate these effects. Although the simultaneous administration of neostigmine at a dose of 0.3 mg/kg and endotoxin decreased interstitial inflammation in the lungs, vacuolar degeneration in the liver, and total liver injury, mortality was increased with this dose in the presence of endotoxemia. We conclude that neostigmine at a dose of 0.1 mg/kg was not protective against histopathologic organ injury in mice with endotoxemia, and a higher dose (0.3 mg/kg) was not tolerated probably owing to nonspecific parasympathetic action including cardiovascular effects. Further studies are required to determine the contribution of sites in the cholinergic antiinflammatory pathway.
Assuntos
Endotoxemia/fisiopatologia , Infecções por Escherichia coli/patologia , Neostigmina/farmacologia , Parassimpatomiméticos/farmacologia , Choque Séptico/fisiopatologia , Animais , Modelos Animais de Doenças , Endotoxemia/tratamento farmacológico , Infecções por Escherichia coli/tratamento farmacológico , Rim/patologia , Fígado/patologia , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Neostigmina/administração & dosagem , Parassimpatomiméticos/administração & dosagem , Choque Séptico/tratamento farmacológico , Baço/patologiaRESUMO
BACKGROUND: Circulatory failure in multiple organ dysfunction syndromes (MODS) is characterized with systemic vasodilation, diminished blood flow to various vascular beds. The aim of this study was to investigate the effects of selective inhibition of nitric oxide on the mesenteric arterial blood flow (MABF), survival and organ injury of the liver, kidney, lung and spleen in zymosan-induced MODS. MATERIALS AND METHODS: Forty Swiss albino mice (20-40 g), 7 to 9 weeks old, were obtained. Animals were randomly divided into four groups. The first group were treated intraperitoneally (i.p) with vehicle (saline) and served as a sham group for aminoguanidine (AG) (n=10). The second group was treated with zymosan (500 mg/kg, suspended in saline solution, i.p). The mice in the third and fourth group received AG (15 mg/kg) 1 h and 6 h after zymosan or saline administration, respectively. Eighteen hours after the administration of zymosan, animals were assessed for MODS described subsequently. The signals from the flowmeter were also recorded on mesenteric arterial blood flow values. RESULTS: In zymosan-treated animals, the MABF was significantly lower than that of solvent (saline)-treated controls (ml min(-1), controls: 4.6 +/- 0.6; zymosan: 1.6 +/- 0.9, P <0.05). When animals were treated with AG, there were no significant differences in MABF values between AG group and solvent (saline)-treated control group. However AG prevented zymosan-induced mesenteric MABF decrease. Treatment with aminoguanidine also decreased mortality. CONCLUSION: AG is capable of inhibiting both the induction and the activity of the already iNOS; it remains a potential therapeutic agent in patients with MODS.
Assuntos
Inibidores Enzimáticos/farmacologia , Guanidinas/farmacologia , Insuficiência de Múltiplos Órgãos/tratamento farmacológico , Óxido Nítrico Sintase/antagonistas & inibidores , Circulação Esplâncnica/efeitos dos fármacos , Animais , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Camundongos , Insuficiência de Múltiplos Órgãos/induzido quimicamente , Baço/efeitos dos fármacos , Análise de Sobrevida , Zimosan/efeitos adversos , beta-Glucanas/efeitos adversosRESUMO
The role of endothelin peptides was evaluated on survival and organ injury in a model of polymicrobial sepsis, induced by caecal ligation and puncture with particular emphasis on the timing of the administration of its blocker bosentan in Swiss albino mice (20-40 g). The cardiovascular response pattern in this experimental model was characterized by an early, "hyperdynamic" phase starting at 5 h, followed by a late but "hypodynamic" phase that commence after 20 h, provided that the animals are "resuscitated" by injecting 1 ml of saline i.p. at the end of the surgery. However, if saline resuscitation is omitted, then only hypodynamic pattern is observed starting at 5 h without any hyperdynamic phase. Thus, mice were first allocated into saline-resuscitated or unresuscitated groups and endothelin receptor antagonist bosentan (30 mg kg(-1), i.p., either 5 or 20 h after caecal ligation and puncture) was then administered. The control animals received the solvent of bosentan (i.e., saline: %0.9 NaCl, w/v). The survival rates in each group (n=14) were recorded over the following 144 h. In unresuscitated mice, the overall survival at 144 h was 14.3% in controls while bosentan treatment at 5 h (78.6%, P=0.0018) or 20 h (64.3%, P=0.0183) have both significantly improved the survival. However, in saline-resuscitated mice, bosentan administered at 20 h has significantly improved the survival (71.4%, P=0.0213) while its administration at 5 h has yielded exactly the same percent of survival (i.e., 21.4%) as observed in control animals. The beneficial effects of bosentan in preventing the tissue injury due to caecal ligation and puncture were also observed histopathologically in liver, spleen and kidney. Therefore, we concluded that the blockade of endothelin receptors by using bosentan during the later (hypodynamic) stages of septic shock is a promising therapeutic manoeuvre.
Assuntos
Antagonistas dos Receptores de Endotelina , Choque Séptico/prevenção & controle , Sulfonamidas/farmacologia , Animais , Anti-Hipertensivos/farmacologia , Bosentana , Ceco/lesões , Ceco/cirurgia , Modelos Animais de Doenças , Rim/efeitos dos fármacos , Rim/lesões , Rim/patologia , Ligadura/efeitos adversos , Fígado/efeitos dos fármacos , Fígado/lesões , Fígado/patologia , Camundongos , Choque Séptico/etiologia , Choque Séptico/mortalidade , Cloreto de Sódio/farmacologia , Baço/efeitos dos fármacos , Baço/lesões , Baço/patologia , Taxa de Sobrevida , Fatores de Tempo , Ferimentos e Lesões/complicaçõesRESUMO
Despite important advances in understanding its pathophysiology, therapy for septic shock remains largely symptomatic and supportive. Aiming to elevate the systemic arterial blood pressure by using vasoconstrictor manoeuvers are preferred without paying much attention to the ischaemia produced at the peripheral tissues. Since, these maneuvers proved no remarkable success in reducing the mortality up to date, we now propose a different perspective in this manuscript. Although it is not always easy to distinguish the different phases of septic shock, at least two fundamentally different phases can be distinguished, i.e. (i) hyperdynamic phase and (ii) hypodynamic phase mandating the adoption of vasodilative and vasoconstrictive interventions, consequently. Additionally, endothelium-derived vasodilator and vasoconstrictor substances such as nitric oxide and endothelin play key roles in systemic inflammatory response syndrome that lead to fatal multiple organ dysfunction. Therefore, we hypothesize that the inhibition of nitric oxide production during earlier phases of septic shock combined with the blockade of endothelin receptors at later stages appear feasible and a novel strategy for the therapy of septic shock.
Assuntos
Choque Séptico/tratamento farmacológico , Endotelinas/farmacologia , Endotélio/metabolismo , Guanidinas/farmacologia , Humanos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Choque Séptico/metabolismoRESUMO
We investigated the contribution of NO-cyclic GMP (cGMP) pathway to the antinociceptive effects of ketamine in mice by using the nitric oxide synthase inhibitor, nitro(g)- L-arginine methyl ester (L-NAME). Intraperitoneal (i.p.) (1, 5 or 10 mg/kg) or intrathecal (i.th.) (10, 30 or 60 microg/mouse) administration of ketamine produced dose-dependent antinociceptive effects in the acetic acid-induced writhing and formalin tests but not in the tail-flick nor in hot-plate tests. Pretreatment of mice with L-NAME (10 mg/kg, i.p.) which produced no antinociception on its own, significantly inhibited the antinociceptive effect of ketamine (1, 5 or 10 mg/kg, i.p.). However, L-NAME (30 microg/mouse) was given intrathecally, it neither modified the antinociceptive effect of i.th. ketamine (10, 30 or 60 microg/mouse) nor did it produce an antinociceptive effect alone. These data suggest that the activation of the NO-cGMP pathway probably at the supraspinal level, but not spinal level, contributes to the antinociceptive effects of ketamine.