RESUMO
PURPOSE: To verify if the methylene blue (MB) administration prevents and/or reverses the compound 48/80 (C48/80)-induced anaphylactic shock in pigs. METHODS: Female Dalland pigs were anesthetized and had the hemodynamic parameters recorded during the necessary time to administer some drugs and observe their effect. The animals were randomly assigned to one of the five groups: 1) control; 2) MB: the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 3) C48/80: the animals received a bolus injection of C48/80 (4 mg/kg); 4) C48/80+MB: the animals received a bolus injection of C48/80 (4 mg/kg) and 10 minutes after the C48/80 administration the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 5) MB+C48/80: the animals received a bolus injection of MB (2 mg/kg) and 3 minutes later they received a bolus injection of C48/80 (4 mg/kg). RESULTS: The intravenous infusion of MB alone caused no changes in the mean arterial pressure (MAP) showing that the administered MB dose was safe in this experimental model. The C48/80 was effective in producing experimental anaphylactic shock since it was observed a decrease in both MAP and cardiac output (CO) after its administration. The MB did not prevent or reverse the C48/80-induced anaphylactic shock in this model. In fact, the MAP of the animals with anaphylactic shock treated with MB decreased even more than the MAP of the animals from the C48/80 group. On the other hand, the C48/80-induced epidermal alterations disappeared after the MB infusion. CONCLUSION: Despite our data, the clinical manifestations improvement brings some optimism and does not allow excluding the MB as a possible therapeutic option in the anaphylactic shock.
OBJETIVO: Verificar se a administração de azul de metileno (AM) previne e/ou reverte o choque anafilático induzido por composto 48/80 (C48/80) em suínos. MÉTODOS: Porcos fêmeas Dalland foram anestesiados e tiveram os parâmetros hemodinâmicos registados durante o tempo necessário para administrar algumas drogas e observar seu efeito. Os animais foram aleatoriamente destribuídos em um dos cinco grupos: 1) controle, 2) AM: os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/Kg /h por bomba de infusão de seringa); 3) C48/80: os animais receberam uma injeção em bolus de C48/80 (4mg/kg); 4) C48/80 + AM: os animais receberam uma injeção em bolus de C48/80 (4mg/kg) e 10 minutos após a administração de C48/80 os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/kg/h por bomba de infusão de seringa); 5) AM+C48/80: os animais receberam uma injeção em bolus de AM (2mg/kg) e três minutos depois, receberam uma injeção em bolus de C48/80 (4mg/kg). RESULTADOS: A infusão intravenosa de AM não causou mudanças na pressão arterial média (PAM), mostrando que a dose de AM administrada foi segura neste modelo experimental. O C48/80 foi eficaz na indução do choque anafilático experimental, uma vez que foi observada redução na PAM e débito cardíaco (DC), após a sua administração. O AM não preveniu ou reverte o choque anafilático induzido por C48/80 neste modelo. Na verdade, a PAM dos animais com choque anafilático tratados com AM diminuiu mais do que o PAM dos animais do grupo C48/80. Por outro lado, as alterações epidérmicas induzidas pelo C48/80 desapareceu após a infusão do AM. CONCLUSÃO: Apesar dos resultados a melhora clínica das manifestações anafiláticas permite considerar a possibilidade do azul de metileno como opção terapêutica no tratamento do choque anafilático.
Assuntos
Animais , Feminino , Anafilaxia/tratamento farmacológico , Hemodinâmica/efeitos dos fármacos , Azul de Metileno/uso terapêutico , p-Metoxi-N-metilfenetilamina/toxicidade , Anafilaxia/induzido quimicamente , Anafilaxia/prevenção & controle , Pressão Sanguínea/efeitos dos fármacos , Débito Cardíaco/efeitos dos fármacos , Modelos Animais de Doenças , Hemodinâmica/fisiologia , Distribuição Aleatória , Suínos , Fatores de Tempo , Resistência Vascular/efeitos dos fármacos , p-Metoxi-N-metilfenetilamina/antagonistas & inibidoresRESUMO
PURPOSE: To verify if the methylene blue (MB) administration prevents and/or reverses the compound 48/80 (C48/80)-induced anaphylactic shock in pigs. METHODS: Female Dalland pigs were anesthetized and had the hemodynamic parameters recorded during the necessary time to administer some drugs and observe their effect. The animals were randomly assigned to one of the five groups: 1) control; 2) MB: the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 3) C48/80: the animals received a bolus injection of C48/80 (4 mg/kg); 4) C48/80+MB: the animals received a bolus injection of C48/80 (4 mg/kg) and 10 minutes after the C48/80 administration the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 5) MB+C48/80: the animals received a bolus injection of MB (2 mg/kg) and 3 minutes later they received a bolus injection of C48/80 (4 mg/kg). RESULTS: The intravenous infusion of MB alone caused no changes in the mean arterial pressure (MAP) showing that the administered MB dose was safe in this experimental model. The C48/80 was effective in producing experimental anaphylactic shock since it was observed a decrease in both MAP and cardiac output (CO) after its administration. The MB did not prevent or reverse the C48/80-induced anaphylactic shock in this model. In fact, the MAP of the animals with anaphylactic shock treated with MB decreased even more than the MAP of the animals from the C48/80 group. On the other hand, the C48/80-induced epidermal alterations disappeared after the MB infusion. CONCLUSION: Despite our data, the clinical manifestations improvement brings some optimism and does not allow excluding the MB as a possible therapeutic option in the anaphylactic shock.
Assuntos
Anafilaxia/tratamento farmacológico , Hemodinâmica/efeitos dos fármacos , Azul de Metileno/uso terapêutico , p-Metoxi-N-metilfenetilamina/toxicidade , Anafilaxia/induzido quimicamente , Anafilaxia/prevenção & controle , Animais , Pressão Sanguínea/efeitos dos fármacos , Débito Cardíaco/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Hemodinâmica/fisiologia , Distribuição Aleatória , Suínos , Fatores de Tempo , Resistência Vascular/efeitos dos fármacos , p-Metoxi-N-metilfenetilamina/antagonistas & inibidoresRESUMO
In this study, the isolated use of methylene blue (MB) in the treatment of anaphylactic shock induced by Compound 48/80 (C48/80), a potent histamine releaser, was examined, and the study of the effects of MB on the function of the aorta artery endothelium was accomplished in vitro. MB was used in a single 3.0 mg/kg dose, and C48/80 was used in a single 4.5 mg/kg dose. The study protocol included the following experimental groups, containing six animals each: group I (control), animals in the absence of any drug action; group II (MB), MB infusion; Group III (C48/80), anaphylactic shock induced by using C48/80; group IV (C48/80 + MB), anaphylactic shock treated with MB infusion at the moment of major hypotension; and group V (MB + C48/80), prevention of anaphylactic shock with MB by means of MB infusion minutes before the 4.5 mg/kg C48/80 infusion. Nitric oxide plasma levels were measured in each of the experimental groups. After the in vivo studies were performed, an in vitro study was conducted using segments of the abdominal aortas of the rabbits to determine the effect of MB on the arterial endothelium. The results obtained in the present investigation have shown that MB intravenous infusion does not change the mean arterial pressure when compared with the control group (n = 6 in each group, P < 0.05); that C48/80 is effective in producing experimental anaphylactic shock (n = 6, P < 0.05); that the attempt to prevent anaphylactic shock with MB results in a mean prolongation of animal survival ranging from 17 to 34 min (n = 6 in each group, P < 0.05); that MB is effective in reversing anaphylactic shock in all the studied rabbits (n = 6, P < 0.05); that absolute and percentage plasma nitrate values obtained with the experimental groups do not differ (n = 6, each group, P < 0.05); and that the in vitro study of segments of abdominal aorta has shown that there has not been endothelial dysfunction in any of the groups (n = 6 in each group, P < 0.05). The good results obtained in this study open a research path that may offer data to define new paradigms for treating anaphylaxis.
Assuntos
Anafilaxia/complicações , Anafilaxia/tratamento farmacológico , Azul de Metileno/farmacologia , p-Metoxi-N-metilfenetilamina/toxicidade , Corticosteroides/metabolismo , Animais , Artérias/patologia , Pressão Sanguínea , Relação Dose-Resposta a Droga , Endotélio Vascular/citologia , Endotélio Vascular/patologia , Inibidores Enzimáticos/farmacologia , Epinefrina/metabolismo , Hipotensão , Masculino , Nitratos/sangue , Óxido Nítrico/sangue , Óxido Nítrico/metabolismo , Nitritos/sangue , Coelhos , Fatores de TempoRESUMO
Eosinophils are supposed to play a critical role in the pathology of several allergic diseases because after activation they can release toxic and proinflammatory agents. In this study we have investigated whether IgE-mediated rat pleurisy could be affected by an ongoing pleural eosinophilic inflammatory response. IgE-passively sensitized rats were challenged with an intrapleural (i.pl.) injection of allergen (dinitrophenylated bovine serum albumin, 1 microgram/cavity) and exudation assessed by measuring the amount of protein extravasated into the pleural cavity within 4 h. We have confirmed that lipopolysaccharide (LPS) stimulation (250 ng/cavity i.pl.) was followed by a marked pleural neutrophilia, apparent at 3 h, which was followed by an eosinophil accumulation noted within 48-72 h postchallenge. We have also confirmed that a boiled sample of LPS pleural washing (LPS-PW, 200 microliters i.pl.) caused selective eosinophilia in recipient rats. Pleural exudation remained unaltered when the allergenic challenge was performed 3 h after LPS in a condition of intense pleural fluid neutrophilia. In contrast, this was significantly reduced (P < .001) when the challenge occurred 72 h after LPS or 24 h after LPS-PW in selective pleural fluid eosinophilia. In another series of experiments repeated daily i.pl. injections of platelet-activating factor (PAF; 1 microgram/cavity) resulted in a progressive increase in eosinophil number recovered from the pleural cavity. The values were 1.2 +/- 0.2, 3.0 +/- 0.2, and 5.8 +/- 0.5 x 10(6) eosinophils/cavity (mean +/- SEM) after 0, 1, and 4 injections, respectively. Allergen challenge performed after 0, 1, or 4 PAF stimulations led to pleural protein levels of 88.6 +/- 5.7, 33.7 +/- 0.7, and 19.4 +/- 2.3 mg/cavity, respectively, indicating that the allergic pleurisy is inhibited in a manner dependent on the magnitude of eosinophil accumulation. Furthermore, the impairment of PAF-induced eosinophil accumulation by cetirizine (30 mg/kg i.p.) restored the exudatory response. Exudation triggered by compound 48/80 (25 micrograms/cavity), histamine (200 micrograms/cavity), or 5-hydroxytryptamine (100 micrograms/cavity) was not affected by four previous PAF daily injections. The findings indicate that allergen-induced exudation is selectively down-regulated in the eosinophil-enriched pleural space of rats, a suppression that increased with increasing eosinophil number and disappeared after chemical impairment of the eosinophilia.
Assuntos
Proteínas Sanguíneas/metabolismo , Eosinófilos/fisiologia , Exsudatos e Transudatos/citologia , Imunoglobulina E/fisiologia , Derrame Pleural/patologia , Animais , Dinitrofenóis , Eosinofilia/induzido quimicamente , Eosinofilia/patologia , Eosinofilia/fisiopatologia , Eosinófilos/imunologia , Feminino , Histamina/toxicidade , Hipersensibilidade/imunologia , Hipersensibilidade/fisiopatologia , Imunoglobulina E/imunologia , Lipopolissacarídeos/toxicidade , Masculino , Mastócitos/citologia , Fator de Ativação de Plaquetas/toxicidade , Ratos , Ratos Wistar , Serotonina/toxicidade , Soroalbumina Bovina , p-Metoxi-N-metilfenetilamina/toxicidadeRESUMO
1. The effect of purified crotapotin, a non-toxic non-enzymatic chaperon protein normally complexed to a phospholipase A2 (PLA2) in South America rattlesnake venom, was studied in the acute inflammatory response induced by carrageenin (1 mg/paw), compound 48/80 (3 micrograms/paw) and 5-hydroxytryptamine (5-HT) (3 micrograms/paw) in the rat hind-paw. The effects of crotapotin on platelet aggregation, mast cell degranulation and eicosanoid release from guinea-pig isolated lung were also investigated. 2. Subplantar co-injection of crotapotin (1 and 10 micrograms/paw) with carrageenin or injection of crotapotin (10 micrograms/paw) into the contralateral paw significantly inhibited the carrageenin-induced oedema. This inhibition was also observed when crotapotin (10-30 micrograms/paw) was administered either intraperitoneally or orally. Subplantar injection of heated crotapotin (15 min at 60 degrees C) failed to inhibit carrageenin-induced oedema. Subplantar injection of crotapotin (10 micrograms/paw) also significantly inhibited the rat paw oedema induced by compound 48/80, but it did not affect 5-HT-induced oedema. 3. In adrenalectomized animals, subplantar injection of crotapotin markedly inhibited the oedema induced by carrageenin. The inhibitory effect of crotapotin was also observed in rats depleted of histamine and 5-HT stores. 4. Crotapotin (30 micrograms/paw) had no effect on either the histamine release induced by compound 48/80 in vitro or on the platelet aggregation induced by both arachidonic acid (1 nM) and platelet activating factor (1 microM) in human platelet-rich plasma. The platelet aggregation and thromboxane B2 (TXB2) release induced by thrombin (100 mu ml-1) in washed human platelets were also not affected by crotapotin. In addition, crotapotin (10 microg/paw) did not affect the release of 6-oxo-prostaglandin Fla, and TXB2 induced by ovalbumin in sensitized guinea-pig isolated lungs.5. Our results indicate that the anti-inflammatory activity of crotapotin is not due to endogenous corticosteroid release or inhibition of cyclo-oxygenase activity. It is possible that crotapotin may interact with extracellular PLA2 generated during the inflammatory process thereby reducing its hydrolytic activity.
Assuntos
Crotoxina/uso terapêutico , Edema/tratamento farmacológico , Fosfolipases A/metabolismo , 6-Cetoprostaglandina F1 alfa/metabolismo , Administração Oral , Animais , Ácido Araquidônico/farmacologia , Carragenina/administração & dosagem , Carragenina/toxicidade , Degranulação Celular/efeitos dos fármacos , Crotoxina/administração & dosagem , Crotoxina/farmacologia , Modelos Animais de Doenças , Edema/induzido quimicamente , Cobaias , Liberação de Histamina/efeitos dos fármacos , Humanos , Injeções Intraperitoneais , Masculino , Mastócitos/efeitos dos fármacos , Mastócitos/fisiologia , Fosfolipases A2 , Fator de Ativação de Plaquetas/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Ratos , Ratos Wistar , Serotonina/administração & dosagem , Serotonina/toxicidade , Tromboxano B2/metabolismo , p-Metoxi-N-metilfenetilamina/administração & dosagem , p-Metoxi-N-metilfenetilamina/toxicidadeRESUMO
Rat mortality and contractile responses of isolated tracheas to compound 48/80 from rats made diabetic 4 days before by a single intravenous injection of alloxan and from diabetic rats that had been treated with insulin 6 h before were compared with control animals. Diabetic animals and tracheal segments from diabetic rats were significantly less responsive to compound 48/80 than control and insulin-treated diabetic animals. On the other hand, diabetic animals have a lower quantity of peritoneal mast cells than control rats, and insulin restored the normal quantity of cells in diabetic animals. These data indicate that diabetes elicits an hyposensitivity to compound 48/80, possibly related to a diabetes-induced decrease in the mast cell count.