RESUMO
A reduction of the neutrophil migration into the site of infection during cecal ligation and puncture-induced sepsis increases host mortality. Inhibition of heme oxygenase (HO) prevents this neutrophil paralysis and improves host survival in the cecal ligation and puncture model. Taking into account that almost 50% of all sepsis cases are a consequence of pneumonia, we designed the present study to determine the role of HO in an experimental model of pneumonia-induced sepsis. The objective of this study was to evaluate whether the inhibition of HO improves the outcome and pathophysiologic changes of sepsis induced by an intratracheal instillation of Klebsiella pneumoniae. The pretreatment of mice subjected to pneumonia-induced sepsis with ZnDPBG (zinc deuteroporphyrin 2,4-bis glycol), a nonspecific HO inhibitor, increased the number of neutrophils in the bronchoalveolar spaces, reduced the bacterial load at the site of infection, and prevented the upregulation of CD11b and the downregulation of CXCR2 on blood neutrophils. Moreover, the pretreatment with ZnDPBG decreased alveolar collapse, attenuating the deleterious changes in pulmonary mechanics and gas exchanges and, as a consequence, improved the survival rate of mice from 0% to â¼20%. These results show that heme oxygenase is involved in the pathophysiology of pneumonia-induced sepsis and suggest that HO inhibitors could be helpful for the management of this disease.
Assuntos
Bacteriemia/enzimologia , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Doenças do Sistema Imunitário/enzimologia , Infecções por Klebsiella/enzimologia , Transtornos Leucocíticos/enzimologia , Pneumonia Bacteriana/enzimologia , Alvéolos Pulmonares/enzimologia , Lesão Pulmonar Aguda/prevenção & controle , Animais , Bacteriemia/microbiologia , Brônquios/enzimologia , Quimiocinas/metabolismo , Creatina Quinase Forma MB/metabolismo , Citocinas/metabolismo , Deuteroporfirinas/farmacologia , Inibidores Enzimáticos/farmacologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae , Camundongos , Pneumonia Bacteriana/microbiologia , Receptores de Interleucina-8B/metabolismoRESUMO
Central heme oxigenase-carbon monoxide (HO-CO) pathway has been shown to play a pyretic role in the thermoregulatory response to restraint. However, the specific site in the central nervous system where CO may act modulating this response remains unclear. LC is rich not only in sGC but also in heme oxygenase (HO; the enzyme that catalyses the metabolism of heme to CO, along with biliverdin and free iron). Therefore, the possible role of the HO-CO-cGMP pathway in the restraint-induced-hypothermia by LC neurons was investigated. Body temperature dropped about 0.7 degrees C during restraint. ZnDPBG (a HO inhibitor; 5 nmol, intra-LC) prevented the hypothermic response during restraint. Conversely, induction of the HO pathway in the LC with heme-lysinate (7.6 nmol, intra-LC) intensified the hypothermic response to restraint, and this effect was prevented by pretreatment with ODQ (a sGC inhibitor; given intracerebroventricularly, 1.3 nmol). Taken together, these data suggest that CO in the LC produced by the HO pathway and acting via cGMP is implicated in thermal responses to restraint.
Assuntos
Monóxido de Carbono/metabolismo , GMP Cíclico/metabolismo , Heme Oxigenase (Desciclizante)/metabolismo , Hipotermia/metabolismo , Locus Cerúleo/enzimologia , Animais , Comportamento Animal , Temperatura Corporal/efeitos dos fármacos , Deuteroporfirinas/farmacologia , Inibidores Enzimáticos/farmacologia , Heme/análogos & derivados , Heme/farmacologia , Hipotermia/patologia , Lisina/análogos & derivados , Lisina/farmacologia , Masculino , Microinjeções , Ratos , Ratos Wistar , Restrição Física/métodosRESUMO
The aim of the present study was to investigate the role of the spinal cord heme oxygenase (HO)-carbon monoxide (CO)-soluble guanylate cyclase (sGC)-cGMP pathway in nociceptive response of rats to the formalin experimental nociceptive model. Animals were handled and adapted to the experimental environment for a few days before the formalin test was applied. For the formalin test 50 microl of a 1% formalin solution was injected subcutaneously in the dorsal surface of the right hind paw. Following injections, animals were observed for 1 h and flinching behavior was measured as the nociceptive response. Thirty min before the test, rats were pretreated with intrathecal injections with the HO inhibitor, zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) or heme-lysinate, which is known to induce the HO pathway. Control animals were treated with vehicles. We observed a significant increase in nociceptive response of rats treated with ZnDPBG, and a drastic reduction of flinching nociceptive behavioral response in the heme-lysinate treated animals. Furthermore, the HO pathway seems to act via cGMP, since methylene blue (a sGC inhibitor) prevented the reduction of flinching nociceptive behavioral response caused by heme-lysinate. These findings strongly indicate that the HO pathway plays a spinal antinociceptive role during the formalin test, acting via cGMP.
Assuntos
Monóxido de Carbono/fisiologia , GMP Cíclico/fisiologia , Heme Oxigenase (Desciclizante)/fisiologia , Dor/fisiopatologia , Medula Espinal/fisiologia , Animais , Deuteroporfirinas/farmacologia , Heme/análogos & derivados , Heme/farmacologia , Lisina/análogos & derivados , Lisina/farmacologia , Masculino , Azul de Metileno/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
The aim of the present study was to investigate the role of the peripheral heme oxygenase (HO)-carbon monoxide (CO) pathway on nociceptive response of rats to the formalin experimental model of pain. Animals were handled and adapted to the experimental environment for a few days before the formalin test was applied. For the formalin test, 50 microl of a 1% formalin solution was used and injected subcutaneously in the dorsal surface of the right hind paw. Following injections, animals were observed for 1 h, and flinching behavior was measured as the nociceptive response. Twenty minutes before the test rats were pretreated with podal injections with the HO inhibitor, zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) or heme-lysinate, which is known to induce the HO pathway. Control animals were treated with vehicles. We observed a significant increase on nociceptive response of rats treated with ZnDPBG, and a drastic reduction of flinching nociceptive behavioral response in the heme-lysinate and CO treated animals. Among the three different HO products, CO seems to account for the heme-lysinate effect because the injection of the gas attenuated the flinching response whereas biliverdine and deferoxanine (an iron chelator) failed to cause any significant change. Furthermore, CO seems to act via cGMP, since methylene blue (a soluble guanylate cyclase inhibitor) prevented the reduction of the flinching nociceptive behavioral response caused by heme-lysinate. These findings strongly indicate that CO is the HO pathway product that plays an antinociceptive role during the formalin test, acting via cGMP.
Assuntos
Monóxido de Carbono/fisiologia , GMP Cíclico/fisiologia , Heme Oxigenase (Desciclizante)/fisiologia , Medição da Dor , Dor/fisiopatologia , Transdução de Sinais , Animais , Biliverdina/farmacologia , Desferroxamina/farmacologia , Deuteroporfirinas/farmacologia , Heme/análogos & derivados , Heme/farmacologia , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Quelantes de Ferro/farmacologia , Lisina/análogos & derivados , Lisina/farmacologia , Masculino , Dor/induzido quimicamente , Ratos , Ratos WistarRESUMO
The septic shock is characterized by decrease in median arterial pressure; many researchers have been related a deficiency in vasopressin release during the septic shock. Lipopolysaccharide administration is used to induce septic shock model in animals. We investigated the heme-oxygenase (HO) inhibition during the endotoxemic shock-like conditions. The LPS administration induced a significant decrease in MAP (-15.4 +/- 1.2 mmHg at second hour, -25.8 +/- 8.7 mmHg at fourth hour, and -22.3 +/- 8.6 mmHg at sixth hour) with a concomitant increase in heart rate (486.3 +/- 55.0, 531.8 +/- 53.8, and 510.0 +/- 55.3 bpm, respectively), a significant decrease in diuresis (from 1.1 +/- 0.7 to 0.4 +/- 0.3/100g body weight at fourth hour), and a transitory decrease in body temperature (from 37.0 +/- 0.5 to 35.4 +/- 0.8 degrees C at second hour). An increase in plasma arginine vasopressin (AVP) concentration (from 3.2 +/- 0.9 to 19.0 +/- 5.7 pg/mL at the first hour) occurred in these animals and was present for 2 h after LPS administration, returning close to basal levels thereafter and remaining unchanged until the end of the experiment. When LPS was combined with the i.c.v. administration of HO inhibitor, we observed a sustained increase in plasma AVP concentration, attenuation in the drop of MAP, and increase in antidiuresis induced by LPS treatment. These data suggest that central HO pathway may activate a control mechanism that attenuates AVP secretion during endotoxemia and may consequently regulate the MAP and diuretic output.
Assuntos
Heme Oxigenase (Desciclizante)/metabolismo , Choque Séptico/metabolismo , Vasopressinas/deficiência , Animais , Arginina Vasopressina/sangue , Arginina Vasopressina/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Deuteroporfirinas/administração & dosagem , Deuteroporfirinas/farmacologia , Diurese/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Hipotensão/etiologia , Lipopolissacarídeos , Masculino , Ratos , Ratos Wistar , Choque Séptico/complicações , Choque Séptico/urina , Vasopressinas/metabolismoRESUMO
BACKGROUND AND PURPOSE: Heme oxygenase (HO) activity is known to down-regulate inflammatory events. Here, we address the role of HO and its metabolites, carbon monoxide (CO) and biliverdin (BVD), in leukocyte rolling, adhesion and neutrophil migration during inflammatory processes. EXPERIMENTAL APPROACH: Intravital microscopy was used to evaluate leukocyte rolling and adhesion in the mesenteric microcirculation of mice. TNFalpha and IL-1beta were determined by ELISA and HO-1 protein expression by Western blot. KEY RESULTS: Intraperitoneal challenge with carrageenan enhanced HO-1 protein expression in mesentery and bilirubin concentration in peritoneal exudates. Pretreatment of mice with a non-specific inhibitor of HO (ZnDPBG) or with a HO-1 specific inhibitor (ZnPP IX) enhanced neutrophil migration, rolling and adhesion on endothelium induced by carrageenan. In contrast, HO substrate (hemin), CO donor (DMDC) or BVD reduced these parameters. The reduction of neutrophil recruitment promoted by HO metabolites was independent of the production of chemotactic cytokines. Inhibitory effects of CO, but not of BVD, were counteracted by treatment with a soluble guanylate cyclase (sGC) inhibitor, ODQ. Furthermore, inhibition of HO prevented the inhibitory effect of a nitric oxide (NO) donor (SNAP) upon neutrophil migration, while the blockade of NO synthase (NOS) activity by aminoguanidine did not affect the CO or BVD effects. CONCLUSIONS AND IMPLICATIONS: Metabolites of HO decreased leukocyte rolling, adhesion and neutrophil migration to the inflammatory site by a mechanism partially dependent on sGC. Moreover, inhibition by NO of neutrophil migration was dependent on HO activity.
Assuntos
Biliverdina/farmacologia , Monóxido de Carbono/farmacologia , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Heme Oxigenase (Desciclizante)/metabolismo , Inflamação/enzimologia , Migração e Rolagem de Leucócitos/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Animais , Carragenina , Deuteroporfirinas/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Guanilato Ciclase/metabolismo , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Hemina/farmacologia , Inflamação/sangue , Inflamação/induzido quimicamente , Interleucina-1beta/sangue , Veias Mesentéricas , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Vídeo , Neutrófilos/enzimologia , Óxido Nítrico/metabolismo , Protoporfirinas/farmacologia , Receptores Citoplasmáticos e Nucleares/metabolismo , Guanilil Ciclase Solúvel , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Undifferentiated thyroid carcinoma (UTC) is a rapidly growing, highly invasive malignant tumor that currently lacks any effective treatment. Boron neutron capture therapy (BNCT) has been investigated recently for some types of tumors including glioblastoma multiforme and malignant melanoma. In previous studies we have shown the selective uptake of p-boronophenylalanine (BPA) by undifferentiated thyroid cancer cells in vitro and in vivo, as well as the histologic cure of 50% of the nude mice transplanted with human UTC cells when treated with BPA and an appropriate neutron beam. The present studies were performed to further optimize this treatment through the investigation of a boronated porphyrin, both alone and in combination with BPA. In vitro studies with cells in culture showed that BOPP (tetrakis-carborane carboxylate ester of 2,4-bis-(alpha,beta-dihydroxyethyl)-deutero-porphyrin IX) is localized intracellularly, with a highest concentration in the 11500g (mitochondrial-enriched pellet) fraction. When BOPP was administered alone to NIH nude mice transplanted with UTC human cells, no significant tumor uptake or selectivity in our in vivo model was observed. In contrast, when BOPP was injected 5-7 days before BPA and the animals were sacrificed 60 min after administration of BPA, a significant increase in boron uptake by the tumor was found (38-45 ppm with both compounds vs 20 ppm with BPA alone). On day 5 the tissue boron selectivity ratios were tumor/blood approximately 3.8 and tumor/distal skin approximately 1.8. Other important ratios were tumor/thyroid approximately 6.6 and tumor/lung approximately 2.9. These results open the possibility of improving the efficacy of BNCT for the treatment of this so far "orphan" tumor.
Assuntos
Compostos de Boro/farmacocinética , Terapia por Captura de Nêutron de Boro/métodos , Fenilalanina/análogos & derivados , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/radioterapia , Animais , Boro/química , Compostos de Boro/farmacologia , Diferenciação Celular , Linhagem Celular Tumoral , Deuteroporfirinas/farmacologia , Modelos Animais de Doenças , Frutose/química , Frutose/farmacologia , Humanos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Fenilalanina/farmacocinética , Fatores de Tempo , Distribuição TecidualRESUMO
Platelet-derived growth factor (PDGF) is a multifunctional protein which is known to induce a febrile response when injected intracerebroventricularly. The gaseous neurotransmitters, nitric oxide (NO) and carbon monoxide (CO), are both known to exert thermoregulatory effects and to participate in lipopolysaccharide-induced fever. In this study, we investigated the role of NO and CO in the febrile response to PDGF-BB in rats. Intracerebroventricular (i.c.v.) injection of PDGF-BB produced a dose-dependent increase in body temperature. This increase in body temperature induced by PDGF-BB was exacerbated by N(G)-nitro-L-arginine methyl ester (L-NAME-a nonselective NO synthase inhibitor) and S-methyl-L-thiocitrulline treatment [SMTC-a neuronal NOS (nNOS) selective inhibitor], but not by aminoguanidine treatment [an inducible NOS (iNOS) selective inhibitor]. Zinc deuteroporphyrin 2,4-bis glycol treatment (ZnDPBG-a nonselective heme oxygenase (HO) blocker) did not affect PDGF-BB fever. Our data indicate that the NO but not the CO pathway participates in PDGF-BB fever. Furthermore, our data show that nNOS is the NOS isoform responsible for NO synthesis in this response.
Assuntos
Monóxido de Carbono/fisiologia , Citrulina/análogos & derivados , Febre/metabolismo , Lipopolissacarídeos , Óxido Nítrico/fisiologia , Fator de Crescimento Derivado de Plaquetas/fisiologia , Tioureia/análogos & derivados , Animais , Becaplermina , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Citrulina/farmacologia , Deuteroporfirinas/farmacologia , Inibidores Enzimáticos/farmacologia , Febre/induzido quimicamente , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Heme Oxigenase (Desciclizante)/fisiologia , Isoenzimas/antagonistas & inibidores , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico Sintase Tipo II , Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-sis , Ratos , Ratos Wistar , Tioureia/farmacologiaRESUMO
Endogenously carbon monoxide (CO) arises from the catabolism of heme to biliverdin, free iron and CO, a process catalyzed by the enzyme heme oxygenase (HO). In the present study, we tested the hypothesis that the central HO-CO pathway plays a role in hypoxia-induced hyperventilation. To this end, we used intracerebroventricular (i.c.v.) injections of the HO inhibitor zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG; 200 nmol) and of heme-lysinate (152 nmol), which is known to induce the HO pathway, and measured respiratory frequency (f), tidal volume (VT) and pulmonary ventilation (VE) by body plethysmograph in conscious rats. Hypoxia (7% inspired oxygen) evoked a typical increase in VE by either raising f and VT, ZnDPBG or its vehicle caused no change in basal VE and did not affect the increase in VE elicited by hypoxia. Conformably, i.c.v. heme-lysinate did not affect VE as well. These results do not support the hypothesis that the HO-CO pathway in the central nervous system is involved in hypoxia-induced hyperventilation.
Assuntos
Monóxido de Carbono/metabolismo , Heme Oxigenase (Desciclizante)/metabolismo , Heme/análogos & derivados , Hipóxia/metabolismo , Lisina/análogos & derivados , Animais , Deuteroporfirinas/farmacologia , Inibidores Enzimáticos/farmacologia , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Injeções Intraventriculares , Masculino , Ratos , Ratos Wistar , Respiração/efeitos dos fármacos , Volume de Ventilação Pulmonar/efeitos dos fármacos , Fatores de Tempo , Ventilação/métodosRESUMO
A reduction of body temperature (T(b)) is a phenomenon concomitant with hypoglycaemia in mammals. Haem oxygenase (HO) catalyses the metabolism of haem to biliverdin, free iron and carbon monoxide (CO). Recently, the HO pathway has been shown to play an important role in thermoregulation. The present study was designed to test the hypothesis that the HO pathway plays a role in insulin-induced hypothermia and that CO, rather than free iron or biliverdin, is the HO product involved in this response. Body temperature (T(b)) of Wistar rats was measured by biotelemetry. Infusion of insulin (0.2 U/kg per h, i.v.) caused a significant drop in T(b). Intracerebroventricular (i.c.v.) administration of zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG, a HO inhibitor, 200 nmol) combined with saline infusion had no effect on T(b) but increased insulin-induced hypothermia significantly. The i.c.v administration of neither the iron chelator deferoxamine (250 microg) nor biliverdin (152 nmol) altered the hypothermic response to insulin, whereas CO-saturated saline significantly reduced insulin-induced hypothermia. These data indicate that the HO pathway prevents excessive drops in T(b) in insulin-induced hypothermia. Because biliverdin and iron had no effect, while CO significantly reduced the hypothermic response elicited by insulin infusion, these data imply that CO is the HO product involved in the thermoregulatory effect of insulin-induced hypothermia.