RESUMO
Enhanced vascular permeability at the site of injury is a prominent feature in acute inflammatory pain models, commonly assessed through the Evans Blue test. However, this invasive test requires euthanasia, thereby precluding further investigations on the same animal. Due to these limitations, the integration of non-invasive tools such as IRT has been sought. Here, we aimed to evaluate the use of thermography in a common orofacial pain model that employs formalin as a chemical irritant to induce local orofacial inflammation. Male Hannover rats (290-300 g, N = 43) were used. In the first approach, radiometric images were taken before and after formalin administration, assessing temperature changes and extravasated Evans Blue. The second approach included capturing pre- and post-formalin test radiometric images, followed by cytokine measurements in excised vibrissae tissue. Rats were anesthetized for vibrissae tissue collection, allowing correlations between thermographic patterns, nocifensive behavior duration, and cytokine levels in this area. Our findings revealed a positive correlation between local temperature, measured via thermography, and vascular permeability in the contralateral (r2 = 0.3483) and ipsilateral (r2 = 0.4502) side, measured using spectrophotometry. The obtained data supports the notion that thermography-based temperature assessment can effectively evaluate vascular permeability in the orofacial region.
Assuntos
Formaldeído , Termografia , Ratos , Masculino , Animais , Formaldeído/efeitos adversos , Termografia/métodos , Permeabilidade Capilar , Azul Evans/efeitos adversos , Dor Facial/induzido quimicamente , CitocinasRESUMO
To evaluate whether acute photobiomodulation can elicit a hypotensive effect in spontaneously hypertensive rats (SHR). Male SHR were submitted to the implantation of a polyethylene cannula into the femoral artery. After 24 h, baseline measurements of the hemodynamic parameters: systolic, diastolic, and mean arterial pressure, and heart rate were accomplished for 1 h. Afterwards, laser application was simulated, and the hemodynamic parameters were recorded for 1 h. In the same animal, the laser was applied at six different positions of the rat's abdomen, and the hemodynamic parameters were also recorded until the end of the hypotensive effect. The irradiation parameters were red wavelength (660 nm); average optical power of 100 mW; 56 s per point (six points); spot area of 0.0586 cm2; and irradiance of 1.71 W/cm2 yielding to a fluency of 96 J/cm2 per point. For measuring plasma NO levels, blood was collected before the recording, as well as immediately after the end of the mediated hypotensive effect. Photobiomodulation therapy was able to reduce the systolic arterial pressure in 69% of the SHR submitted to the application, displaying a decrease in systolic, diastolic, and mean arterial pressure. No change in heart rate was observed. Nevertheless, there was an increase in serum nitric oxide levels in the SHR responsive to photobiomodulation. Our results suggest that acute irradiation with a red laser at 660 nm can elicit a hypotensive effect in SHR, probably by a mechanism involving the release of NO, without changing the heart rate.
Assuntos
Hipertensão/radioterapia , Terapia com Luz de Baixa Intensidade , Animais , Pressão Sanguínea/efeitos da radiação , Frequência Cardíaca/efeitos da radiação , Hemodinâmica/efeitos da radiação , Hipertensão/sangue , Hipertensão/fisiopatologia , Masculino , Óxido Nítrico/sangue , Ratos , Ratos Endogâmicos SHRRESUMO
BACKGROUND: Lipopolysaccharide (LPS)-induced systemic inflammation (SI) is associated with neuroinflammation in the brain, hypotension, tachycardia, and multiple organs dysfunctions. Considering that during SI these important cardiovascular and inflammatory changes take place, we measured the sensitivity of the cardiovascular reflexes baroreflex, chemoreflex, and Bezold-Jarisch that are key regulators of hemodynamic function. We also evaluated neuroinflammation in the nucleus tractus solitarius (NTS), the first synaptic station that integrates peripheral signals arising from the cardiovascular and inflammatory status. METHODS: We combined cardiovascular recordings, immunofluorescence, and assays of inflammatory markers in male Wistar rats that receive iv administration of LPS (1.5 or 2.5 mg kg-1) to investigate putative interactions of the neuroinflammation in the NTS and in the anteroventral preoptic region of the hypothalamus (AVPO) with the short-term regulation of blood pressure and heart rate. RESULTS: LPS induced hypotension, tachycardia, autonomic disbalance, hypothermia followed by fever, and reduction in spontaneous baroreflex gain. On the other hand, during SI, the bradycardic component of Bezold-Jarisch and chemoreflex activation was increased. These changes were associated with a higher number of activated microglia and interleukin (IL)-1ß levels in the NTS. CONCLUSIONS: The present data are consistent with the notion that during SI and neuroinflammation in the NTS, rats have a reduced baroreflex gain, combined with an enhancement of the bradycardic component of Bezold-Jarisch and chemoreflex despite the important cardiovascular impairments (hypotension and tachycardia). These changes in the cardiac component of Bezold-Jarisch and chemoreflex may be beneficial during SI and indicate that the improvement of theses reflexes responsiveness though specific nerve stimulations may be useful in the management of sepsis.
Assuntos
Hemodinâmica/fisiologia , Inflamação/fisiopatologia , Núcleo Solitário/fisiopatologia , Animais , Hemodinâmica/efeitos dos fármacos , Inflamação/induzido quimicamente , Lipopolissacarídeos/toxicidade , Masculino , Ratos , Ratos Wistar , Núcleo Solitário/efeitos dos fármacosRESUMO
An exceptionally high mortality rate is observed in sepsis and septic shock. Systemic administration of lipopolysaccharide (LPS) has been used as an experimental model for sepsis resulting in an exacerbated immune response, brain neurochemistry adjustments, hypotension, and hypothermia followed by fever. Central serotonergic pathways not only modulate systemic inflammation (SI) but also are affected by SI, including in the anteroventral region of the hypothalamus (AVPO), which is the hierarchically most important region for body temperature (Tb) control. In this study, we sought to determine if central serotonin (5-HT) plays a role in SI induced by intravenous administration of LPS (1.5â¯mg/kg) in male Wistar rats (280-350â¯g) by assessing 5-HT levels in the AVPO, mean arterial pressure, heart rate, and Tb up to 300â¯min after LPS administration, as well as assessing plasma and spleen cytokine levels, nitric oxide (NO) plasma levels, and prostaglandin (PG) E2 levels in the AVPO at 75â¯min and 300â¯min after LPS administration. We observed reduced AVPO 5-HT levels, hypotension, tachycardia, hypothermia followed by fever, as well as observing increased plasma NO, plasma and spleen cytokines and AVPO PGE2 levels in SI. Intracerebroventricular (icv) administration of 5-HT 30â¯min before LPS administration prevented hypotension and hypothermia, which were accompanied by reduced plasma NO, as well as plasma TNF-α, IL-1ß, IL-6, and IL-10 and spleen TNF-α and IL-10 levels. We suggest that SI reduced 5-HT levels in the AVPO favor an increased pro-inflammatory status both centrally and peripherally that converge to hypotension and hypothermia. Moreover, our results are consistent with the notion that exogenous 5-HT given icv prevents hypotension and hypothermia probably activating the splenic anti-inflammatory pathway.
Assuntos
Citocinas/sangue , Hipotensão/metabolismo , Hipotermia/metabolismo , Inflamação/metabolismo , Serotonina/metabolismo , Baço/metabolismo , Animais , Dopamina/metabolismo , Hipotensão/complicações , Hipotálamo Anterior/metabolismo , Hipotermia/complicações , Inflamação/induzido quimicamente , Inflamação/complicações , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos/administração & dosagem , Masculino , Óxido Nítrico/sangue , Norepinefrina/metabolismo , Ratos Wistar , Serotonina/administração & dosagemRESUMO
Molecular hydrogen (H2) exerts anti-oxidative, anti-apoptotic, and anti-inflammatory effects. Here we tested the hypothesis that H2 modulates cardiovascular, inflammatory, and thermoregulatory changes in systemic inflammation (SI) induced by lipopolysaccharide (LPS) at different doses (0.1 or 1.5â¯mg/kg, intravenously, to induce mild or severe SI) in male Wistar rats (250-300â¯g). LPS or saline was injected immediately before the beginning of 360-minute inhalation of H2 (2% H2, 21% O2, balanced with nitrogen) or room air (21% O2, balanced with nitrogen). Deep body temperature (Tb) was measured by dataloggers pre-implanted in the peritoneal cavity. H2 caused no change in cardiovascular, inflammatory parameters, and Tb of control rats (treated with saline). During mild SI, H2 reduced plasma surges of proinflammatory cytokines (TNF-α and IL-6) while caused an increase in plasma IL-10 (anti-inflammatory cytokine) and prevented fever. During severe SI, H2 potentiated hypothermia, and prevented fever and hypotension, which coincided with reduced plasma nitric oxide (NO) production. Moreover, H2 caused a reduction in surges of proinflammatory cytokines (plasma TNF-α and IL-1ß) and prostaglandin E2 [(PGE2), in plasma and hypothalamus], and an increase in plasma IL-10. These data are consistent with the notion that H2 blunts fever in mild SI, and during severe SI potentiates hypothermia, prevents hypotension reducing plasma NO production, and exerts anti-inflammatory effects strong enough to prevent fever by altering febrigenic signaling and ultimately down-modulating hypothalamic PGE2 production.
Assuntos
Hidrogênio/metabolismo , Hipotermia/metabolismo , Inflamação/metabolismo , Animais , Temperatura Corporal/fisiologia , Endotoxinas/metabolismo , Febre/metabolismo , Hipotensão/metabolismo , Hipotálamo/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Óxido Nítrico/metabolismo , Ratos , Ratos Wistar , Sepse/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
NEW FINDINGS: What is the central question of this study? In fever, the most striking response in the acute phase reaction of systemic inflammation, plasma H2 S concentration increases. However, the role of endogenous peripheral H2 S in fever is unknown. What is the main finding and its importance? Endogenous peripheral H2 S is permissive for increased brown adipose tissue thermogenesis to maintain thermal homeostasis in cold environments as well as to mount fever. This finding expands the physiological role of the gaseous modulator as a key regulator of thermal control in health (thermal homeostasis) and disease (fever in systemic inflammation). ABSTRACT: In recent years, hydrogen sulfide (H2 S) has been reported as a gaseous modulator acting in several tissues in health and disease. In animal models of systemic inflammation, the plasma H2 S concentration increases in response to endotoxin (bacterial lipopolysaccharide, LPS). The most striking response in the acute phase reaction of systemic inflammation is fever, but we found no reports of the peripheral action of H2 S on this thermoregulatory response. We aimed at investigating whether endogenous systemic H2 S modulates LPS-induced fever. A temperature datalogger capsule was inserted in the abdominal cavity of male Wistar rats (220-270 g) to record body core temperature. These animals received an i.p. injection of a systemic H2 S inhibitor (propargylglycine; 50 or 75 mg kg-1 ), immediately followed by an i.p. injection of LPS (50 or 2500 µg kg-1 ), and were exposed to different ambient temperatures (16, 22 or 27°C). At 22°C, but not at 27°C, propargylglycine at 75 mg kg-1 significantly attenuated (P < 0.0001) the fever induced by LPS (50 µg kg-1 ), indicating a modulatory (permissive) action of endogenous peripheral H2 S on brown adipose tissue (BAT) thermogenesis. Evidence on the modulatory role of peripheral H2 S in BAT thermogenesis was strengthened when we discarded (i) the possible influence of the gas on febrigenic signalling (when measuring plasma cytokines), and (ii) its interaction with the nitric oxide pathway, and mainly when (iii) we carried out physiological and pharmacological activations of BAT. Endogenous peripheral H2 S modulates (permits) BAT activity not only in fever but also during maintenance of thermal homeostasis in cold environments.
Assuntos
Tecido Adiposo Marrom/metabolismo , Regulação da Temperatura Corporal/fisiologia , Sulfeto de Hidrogênio/metabolismo , Termogênese/fisiologia , Alcinos/farmacologia , Animais , Regulação da Temperatura Corporal/efeitos dos fármacos , Glicina/análogos & derivados , Glicina/farmacologia , Sulfeto de Hidrogênio/antagonistas & inibidores , Masculino , Ratos , Ratos Wistar , Termogênese/efeitos dos fármacosRESUMO
Nitric oxide (NO) plays a role in thermogenesis but does not mediate immune-to-brain febrigenic signaling in rats. There are suggestions of a different situation in birds, but the underlying evidence is not compelling. The present study was designed to clarify this matter in 5-day-old chicks challenged with a low or high dose of bacterial LPS. The lower LPS dose (2 µg/kg im) induced fever at 3-5 h postinjection, whereas 100 µg/kg im decreased core body temperature (Tc) (at 1 h) followed by fever (at 4 or 5 h). Plasma nitrate levels increased 4 h after LPS injection, but they were not correlated with the magnitude of fever. The NO synthase inhibitor (N(G)-nitro-l-arginine methyl ester, l-NAME; 50 mg/kg im) attenuated the fever induced by either dose of LPS and enhanced the magnitude of the Tc reduction induced by the high dose in chicks at 31-32°C. These effects were associated with suppression of metabolic rate, at least in the case of the high LPS dose. Conversely, the effects of l-NAME on Tc disappeared in chicks maintained at 35-36°C, suggesting that febrigenic signaling was essentially unaffected. Accordingly, the LPS-induced rise in the brain level of PGE2 was not affected by l-NAME. Moreover, l-NAME augmented LPS-induced huddling, which is indicative of compensatory mechanisms to run fever in the face of attenuated thermogenesis. Therefore, as in rats, systemic inhibition of NO synthesis attenuates LPS-induced fever in chicks by affecting thermoeffector activity and not by interfering with immune-to-brain signaling. This may constitute a conserved effect of NO in endotherms.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Encéfalo/fisiologia , Galinhas/fisiologia , Febre/induzido quimicamente , Lipopolissacarídeos/toxicidade , Óxido Nítrico/metabolismo , Animais , Comportamento Animal , Dinoprostona/metabolismo , NG-Nitroarginina Metil Éster/farmacologia , Nitratos/metabolismo , Nitritos/metabolismo , Transdução de Sinais/fisiologiaRESUMO
AIMS: We investigated the effects of chronic ethanol consumption on the cavernosal smooth muscle (CSM) reactivity to endothelin-1 (ET-1) and the expression of ET system components in this tissue. METHODS: Male Wistar rats were treated with heavy dose of ethanol (20% v/v) for 6 weeks. Reactivity experiments were performed in the isolated rat CSM. Plasma and CSM nitrate generation and also superoxide anion generation in rat CSM were measured by chemiluminescence. Protein and mRNA levels of pre-pro-ET-1, endothelin-converting enzyme-1 (ECE-1), ETA and ETB receptors, eNOS, nNOS and iNOS were assessed by western immunoblotting and quantitative real-time polymerase chain reaction, respectively. RESULTS: Chronic ethanol consumption increased plasma ET-1 levels and the contractile response induced by this peptide in the isolated CSM. The relaxation induced by acetylcholine, but not IRL1620, a selective ETB receptor agonist, was reduced in CSM from ethanol-treated rats. BQ123, a selective ETA receptor antagonist, produced a rightward displacement of the ET-1 concentration-response curves in CSM from control, but not ethanol-treated rats. Reduced levels of nitrate were found in the plasma and CSM from ethanol-treated rats. Ethanol consumption increased superoxide anion generation in the rat CSM. The mRNA levels of pre-pro-ET-1, ECE-1, ETA and ETB receptors, eNOS, nNOS and iNOS were not altered by ethanol consumption. Protein levels of ET-1, ETA receptor and iNOS were higher in the CSM from rats chronically treated with ethanol. CONCLUSION: The major findings of the present study are that heavy ethanol consumption increases plasma ET-1 levels and the contraction induced by the peptide in the CSM. Increased CSM reactivity to ET-1 and altered protein levels of ET-1 and ETA receptors could play a role in the pathogenesis of erectile dysfunction associated with chronic ethanol consumption.
Assuntos
Depressores do Sistema Nervoso Central/farmacologia , Endotelina-1/biossíntese , Etanol/farmacologia , Músculo Liso/metabolismo , Pênis/metabolismo , Animais , Ácido Aspártico Endopeptidases/biossíntese , Western Blotting , Peso Corporal/efeitos dos fármacos , Depressores do Sistema Nervoso Central/sangue , Endotelina-1/sangue , Enzimas Conversoras de Endotelina , Etanol/sangue , Luminescência , Masculino , Metaloendopeptidases/biossíntese , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Pênis/efeitos dos fármacos , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Receptor de Endotelina A/biossíntese , Receptor de Endotelina B/biossíntese , Superóxidos/metabolismoRESUMO
Heme oxygenase (HO)-1 has antioxidant and cytoprotective properties if properly expressed, whereas nitric oxide (NO) impairs tissue perfusion when greatly increased in the blood circulation. Here we hypothesized that the NO and HO-1 systems are altered during lipopolysaccharide (LPS) tolerance, and that glucocorticoids are crucial modulators of systemic NO production and hepatic HO-1 expression during this intriguing phenomenon of cellular reprogramming. Adrenalectomized (ADX) rats with or without administration of dexamethasone (DEX) were challenged with LPS for 3 consecutive days. The plasma levels of corticosterone and nitrate (NOx), and expression of HO-1 protein were assessed. During tolerance, corticosterone levels were elevated, NOx reduced, and HO-1 overexpressed. ADX rats challenged with LPS for 3 consecutive days exhibited a ~9-fold increase in NOx and a ~6-fold increase in HO-1, reverted by DEX. Our findings strongly support the fact that glucocorticoids downregulate systemic NO synthesis and counteract hepatic HO-1 overexpression during LPS tolerance.
Assuntos
Dexametasona/administração & dosagem , Endotoxemia/enzimologia , Glucocorticoides/administração & dosagem , Heme Oxigenase (Desciclizante)/metabolismo , Terapia de Reposição Hormonal , Fígado/efeitos dos fármacos , Óxido Nítrico/metabolismo , Adrenalectomia , Animais , Corticosterona/sangue , Modelos Animais de Doenças , Regulação para Baixo , Endotoxemia/sangue , Endotoxemia/induzido quimicamente , Febre/induzido quimicamente , Febre/enzimologia , Injeções Subcutâneas , Lipopolissacarídeos , Fígado/enzimologia , Masculino , Nitratos/sangue , Ratos , Ratos Wistar , Fatores de Tempo , Regulação para CimaRESUMO
Orofacial pain has significant psychological and physiological effects. Citral (3,7-dimethyl-2,6-octadienal) is the main component of Cymbopogon citratus (DC) Stapf, an herb with analgesic properties. Although citral has been considered a potent analgesic, its putative effects on orofacial pain are still unknown. OBJECTIVE: The objective of this study is to test the hypothesis that citral modulates orofacial pain using two experimental models: formalin-induced hyperalgesia in the vibrissae area and during persistent temporomandibular hypernociception using Complete Freund's Adjuvant - CFA test. METHODS: For the formalin test, citral (100 and 300 mg/kg, oral gavage) or its vehicle (Tween 80, 1 %) were given 1 h before the formalin injection subcutaneously (sc) into the vibrissae area. For the CFA model, we analyzed the prophylactic (100 mg/kg of citral by oral gavage, 1 h before CFA injection) and the chronic therapeutic (citral treatment 1-hour post-CFA injection and daily post-CFA injection) effect of citral or its vehicle in animals treated with CFA for 8 days. RESULTS: Citral caused a decrease in formalin-induced local inflammation and the time spent performing nociceptive behavior in a dose-dependent fashion. Similarly, prophylactic and therapeutic citral treatment decreased the CFA-induced persistent mechanical hypernociception in the temporomandibular area. CONCLUSION: Our data strengthen the notion that citral plays a powerful antinociceptive role by decreasing orofacial hypernociception in formalin and CFA models.
Assuntos
Dor Facial , Hiperalgesia , Ratos , Animais , Hiperalgesia/tratamento farmacológico , Dor Facial/tratamento farmacológico , Dor Facial/etiologia , Inflamação/tratamento farmacológico , Inflamação/induzido quimicamente , Analgésicos/farmacologia , FormaldeídoRESUMO
The effects on blood pressure produced byethanol consumption include both vasoconstriction and activation of the renin-angiotensin-aldosterone system (RAAS), although the detailed relationship between these processes is yet to be accomplished. Here, we sought to investigate the contribution of mineralocorticoid receptors (MR) to ethanol-induced hypertension and vascular hypercontractility. We analyzed blood pressure and vascular function of male Wistar Hannover rats treated with ethanol for five weeks. The contribution of the MR pathway to the cardiovascular effects of ethanol was evaluated with potassium canrenoate, a MR antagonist (MRA). Blockade of MR prevented ethanol-induced hypertension and hypercontractility of endothelium-intact and -denuded aortic rings. Ethanol up-regulated cyclooxygenase (COX)2 and augmented vascular levels of both reactive oxygen species (ROS) and thromboxane (TX)B2, a stable metabolite of TXA2. These responses were abrogated by MR blockade. Hyperreactivity to phenylephrine induced by ethanol consumption was reversed by tiron [a scavenger of superoxide (O2â-)], SC236 (a selective COX2 inhibitor) or SQ29548 (an antagonist of TP receptors). Treatment with the antioxidant apocynin prevented the vascular hypercontractility, as well as the increases in COX2 expression and TXA2 production induced by ethanol consumption. Our study has identified novel mechanisms through which ethanol consumption promotes its deleterious effects in the cardiovascular system. We provided evidence for a role of MR in the vascular hypercontractility and hypertension associated with ethanol consumption. The MR pathway triggers vascular hypercontractility through ROS generation, up-regulation of COX2 and overproduction of TXA2, which will ultimately induce vascular contraction.
Assuntos
Hipertensão , Receptores de Mineralocorticoides , Ratos , Animais , Masculino , Ciclo-Oxigenase 2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ratos Wistar , Regulação para Cima , Receptores de Mineralocorticoides/metabolismo , Hipertensão/induzido quimicamente , Hipertensão/metabolismo , Vasoconstrição , Etanol/efeitos adversos , Endotélio VascularRESUMO
BACKGROUND: Although plasmid DNA encoding an antigen from pathogens or tumor cells has been widely studied as vaccine, the use of plasmid vector (without insert) as therapeutic agent requires further investigation. RESULTS: Here, we showed that plasmid DNA (pcDNA3) at low doses inhibits the production of IL-6 and TNF-α by lipopolysaccharide (LPS)-stimulated macrophage cell line J774. These findings led us to evaluate whether plasmid DNA could act as an anti-inflammatory agent in a Wistar rat endotoxemia model. Rats injected simultaneously with 1.5 mg/kg of LPS and 10 or 20 µg of plasmid DNA had a remarkable attenuation of mean arterial blood pressure (MAP) drop at 2 hours after treatment when compared with rats injected with LPS only. The beneficial effect of the plasmid DNA on MAP was associated with decreased expression of IL-6 in liver and increased concentration of plasma vasopressin (AVP), a known vasoconstrictor that has been investigated in hemorrhagic shock management. No difference was observed in relation to nitric oxide (NO) production. CONCLUSION: Our results demonstrate for the first time that plasmid DNA vector at low doses presents anti-inflammatory property and constitutes a novel approach with therapeutic potential in inflammatory diseases.
Assuntos
Pressão Sanguínea , DNA/administração & dosagem , Endotoxemia/sangue , Endotoxemia/fisiopatologia , Plasmídeos/administração & dosagem , Vasopressinas/sangue , Animais , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Linhagem Celular , DNA/farmacologia , DNA/uso terapêutico , Endotoxemia/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Interleucina-6/biossíntese , Lipopolissacarídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Nitratos/sangue , Plasmídeos/farmacologia , Plasmídeos/uso terapêutico , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin-angiotensin system (RAS) activation. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10 mg/kg; p.o. gavage), a selective AT1 receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P)H oxidase-mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT1-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage.
Assuntos
Aorta/efeitos dos fármacos , Etanol/administração & dosagem , Etanol/toxicidade , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Superóxidos/metabolismo , Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Animais , Aorta/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Etanol/sangue , Regulação da Expressão Gênica/efeitos dos fármacos , Losartan/administração & dosagem , Losartan/farmacologia , Masculino , NADPH Oxidases/metabolismo , Nitratos , Estresse Oxidativo , Fosforilação/efeitos dos fármacos , Subunidades Proteicas , Transporte Proteico , Ratos , Ratos Wistar , Receptor Tipo 1 de Angiotensina/genética , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologiaRESUMO
AIMS: Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on arterial blood pressure, vascular reactivity to AM and the expression of AM system components in the rat mesenteric arterial bed (MAB). METHODS: Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Systolic, diastolic and mean arterial blood pressure were monitored in conscious rats. Vascular reactivity experiments were performed on isolated rat MAB. Matrix metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation were measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, CRLR (calcitonin receptor-like receptor) and RAMP1, 2 and 3 (receptor activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively. RESULTS: Ethanol consumption induced hypertension and decreased the relaxation induced by AM and acetylcholine in endothelium-intact rat MAB. Phenylephrine-induced contraction was increased in endothelium-intact MAB from ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 or the net MMP activity in the rat MAB. Ethanol consumption increased mRNA levels of pre-pro-AM and protein levels of AM in the rat MAB. Finally, no differences in protein levels or mRNA of CRLR and RAMP1, 2 and 3 were observed after treatment with ethanol. CONCLUSION: Our study demonstrates that ethanol consumption increases blood pressure and the expression of AM in the vasculature and reduces the relaxation induced by this peptide in the rat MAB.
Assuntos
Adrenomedulina/metabolismo , Consumo de Bebidas Alcoólicas/metabolismo , Etanol/administração & dosagem , Regulação da Expressão Gênica , Artérias Mesentéricas/metabolismo , Animais , Pressão Sanguínea , Proteína Semelhante a Receptor de Calcitonina/metabolismo , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Artérias Mesentéricas/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Wistar , Proteínas Modificadoras da Atividade de Receptores/metabolismoRESUMO
Sepsis affects 31.5 million people worldwide. It is characterized by an intense drop in blood pressure driving to cardiovascular morbidity and mortality. Modern supportive care has increased survival in patients; however, after experiencing sepsis, several complications are observed, which may be potentiated by new inflammatory events. Nevertheless, the interplay between sepsis survivors and a new immune challenge in cardiovascular regulation has not been previously defined. We hypothesized that cecal ligation and puncture (CLP) cause persistent cardiovascular dysfunctions in rats as well as changes in autonomic-induced cardiovascular responses to lipopolysaccharide (LPS). Male Wistar rats had mean arterial pressure (MAP) and heart rate (HR) recorded before and after LPS or saline administration to control or CLP survivor rats. CLP survivor rats had similar baseline MAP and HR when compared to control. LPS caused a drop in MAP accompanied by tachycardia in control, while CLP survivor rats had a noteworthy enhanced MAP and a blunted tachycardia. LPS-induced hemodynamic changes were related to an autonomic disbalance to the heart and resistance vessels that were expressed as an increased low- and high-frequency power of pulse interval in CLP survivors after saline and enhancement in the low-frequency power of systolic arterial pressure in control rats after LPS. LPS-induced plasma interferon γ, but not interleukin-10 surges, was blunted in CLP survivor rats. To further access whether or not LPS-induced autonomic disbalance in CLP survivor rats was associated with oxidative stress dysregulation, superoxide dismutase (SOD) activity and thiobarbituric acid reactive substances (TBARS) plasma levels changes were measured. LPS-induced oxidative stress was higher in CLP survivor rats. These findings indicate that key changes in hemodynamic regulation of CLP survivors rats take place in response to LPS that are associated with oxidative stress changes, i.e., reduced SOD activity and increased TBARS levels.
Assuntos
Lipopolissacarídeos , Sepse , Animais , Ceco/metabolismo , Modelos Animais de Doenças , Inflamação/etiologia , Lipopolissacarídeos/farmacologia , Masculino , Estresse Oxidativo , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismo , Sobreviventes , Substâncias Reativas com Ácido TiobarbitúricoRESUMO
Nitric oxide has been reported to modulate fever in the brain. However, the sites where NO exerts this modulation remain somewhat unclear. Locus coeruleus (LC) neurons express not only nitric oxide synthase (NOS) but also soluble guanylyl cyclase (sGC). In the present study, we evaluated in vivo and ex vivo the putative role of the LC NO-cGMP pathway in fever. To this end, deep body temperature was measured before and after pharmacological modulations of the pathway. Moreover, nitrite/nitrate (NOx) and cGMP levels in the LC were assessed. Conscious rats were microinjected within the LC with a non-selective NOS inhibitor (N(G)-monomethyl-l-arginine acetate), a NO donor (NOC12), a sGC inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) or a cGMP analogue (8-bromo-cGMP) and injected intraperitoneally with endotoxin. Inhibition of NOS or sGC before endotoxin injection significantly increased the latency to the onset of fever. During the course of fever, inhibition of NOS or sGC attenuated the febrile response, whereas microinjection of NOC12 or 8-bromo-cGMP increased the response. These findings indicate that the LC NO-cGMP pathway plays a propyretic role. Furthermore, we observed a significant increase in NOx and cGMP levels, indicating that the febrile response to endotoxin is accompanied by stimulation of the NO-cGMP pathway in the LC.
Assuntos
Febre/induzido quimicamente , Febre/fisiopatologia , Locus Cerúleo/metabolismo , Animais , GMP Cíclico/análogos & derivados , GMP Cíclico/farmacologia , Endotoxinas/farmacologia , Febre/metabolismo , Guanilato Ciclase/antagonistas & inibidores , Locus Cerúleo/efeitos dos fármacos , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/fisiologia , Compostos Nitrosos/farmacologia , Oxidiazóis/farmacologia , Quinoxalinas/farmacologia , Ratos , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Guanilil Ciclase SolúvelRESUMO
The central nervous system (CNS) is one of the first physiological systems to be affected in sepsis. During the exacerbated systemic inflammatory response at the early stage of sepsis, circulatory inflammatory mediators are able to reach the CNS leading to neuroinflammation and, consequently, long-term impairment in learning and memory formation is observed. The acute treatment with molecular hydrogen (H2) exerts important antioxidative, antiapoptotic, and anti-inflammatory effects in sepsis, but little is known about the mechanism itself and the efficacy of chronic H2 inhalation in sepsis treatment. Thus, we tested two hypotheses. We first hypothesized that chronic H2 inhalation is also an effective therapy to treat memory impairment induced by sepsis. The second hypothesis is that H2 treatment decreases sepsis-induced neuroinflammation in the hippocampus and prefrontal cortex, important areas related to short and long-term memory processing. Our results indicate that (1) chronic exposure of hydrogen gas is a simple, safe and promising therapeutic strategy to prevent memory loss in patients with sepsis and (2) acute H2 inhalation decreases neuroinflammation in memory-related areas and increases total nuclear factor E2-related factor 2 (Nrf2), a transcription factorthat regulates a vast group of antioxidant and inflammatory agents expression in these areas of septic animals.
Assuntos
Hidrogênio/farmacologia , Transtornos da Memória/terapia , Sepse/tratamento farmacológico , Administração por Inalação , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Modelos Animais de Doenças , Hipocampo/efeitos dos fármacos , Hidrogênio/metabolismo , Inflamação/tratamento farmacológico , Mediadores da Inflamação/metabolismo , Masculino , Transtornos da Memória/metabolismo , Memória de Longo Prazo/efeitos dos fármacos , Memória de Curto Prazo/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
Physical exercise-induced inflammation may be beneficial when exercise is regular but it may be harmful when exercise is intense and performed by unaccustomed individuals/rats. Molecular hydrogen (H2) has recently emerged as a powerful anti-inflammatory, antioxidant and anti-apoptotic molecule in a number of pathological conditions, but little is known about its putative role under physiological conditions such as physical exercise. Therefore, we tested the hypothesis that H2 decreases intense acute exercise-induced inflammation in the hippocampus, since it is a brain region particularly susceptible to inflammation. Moreover, we also assessed hippocampus oxidative status. Rats ran on a sealed treadmill inhaling either the H2 (2% H2, 21% O2, balanced with N2) or the control gas (0% H2, 21% O2, balanced with N2) and hippocampal samples were collected immediately or 3â¯h after exercise. We measured hippocampal levels of cytokines [tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6 and IL-10] and oxidative markers [superoxide dismutase (SOD), thiobarbituric acid reactive species (TBARS) and nitrite/nitrate (NOx)]. Exercise increased TNF-α, IL-6 and IL-10 immediately after the session, whereas no change in IL-1ß levels was observed. Conversely, exercise did not cause any change in SOD activity, TBARS and NOx levels. H2 inhibited the exercise-induced surges in TNF-α and IL-6, and potentiated the IL-10 surge, immediately after the exercise. Moreover, no change in IL1-ß levels of rats inhaling H2 was observed. Regarding the oxidative stress markers, H2 failed to cause any change in SOD activity, TBARS and NOx levels. No significant change was observed in any of the assessed parameters 3â¯h after the exercise bout. These data are consistent with the notion that H2 acts as a powerful anti-inflammatory agent not only down-modulating pro-inflammatory cytokines (TNF-α and IL-6) but also upregulating an anti-inflammatory cytokine (IL-10) production without affecting the local oxidative stress status. These data indicate that H2 effectively decreases exercise-induced inflammation in the hippocampus, despite the fact that this region is particularly prone to inflammatory insults.
Assuntos
Anti-Inflamatórios/administração & dosagem , Hipocampo/metabolismo , Hidrogênio/administração & dosagem , Mediadores da Inflamação/metabolismo , Condicionamento Físico Animal/efeitos adversos , Comportamento Sedentário , Administração por Inalação , Animais , Hipocampo/efeitos dos fármacos , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/prevenção & controle , Mediadores da Inflamação/antagonistas & inibidores , Masculino , Condicionamento Físico Animal/tendências , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Beyond the regulation of cardiovascular function, baroreceptor afferents play polymodal roles in health and disease. Sepsis is a life-threatening condition characterized by systemic inflammation (SI) and hemodynamic dysfunction. We hypothesized that baroreceptor denervation worsens lipopolysaccharide (LPS) induced-hemodynamic collapse and SI in conscious rats. We combined: (a) hemodynamic and thermoregulatory recordings after LPS administration at a septic-like non-lethal dose (b) analysis of the cardiovascular complexity, (c) evaluation of vascular function in mesenteric resistance vessels, and (d) measurements of inflammatory cytokines (plasma and spleen). LPS-induced drop in blood pressure was higher in sino-aortic denervated (SAD) rats. LPS-induced hemodynamic collapse was associated with SAD-dependent autonomic disbalance. LPS-induced vascular dysfunction was not affected by SAD. Surprisingly, SAD blunted LPS-induced surges of plasma and spleen cytokines. These data indicate that baroreceptor afferents are key to alleviate LPS-induced hemodynamic collapse, affecting the autonomic control of cardiovascular function, without affecting resistance blood vessels. Moreover, baroreflex modulation of the LPS-induced SI and hemodynamic collapse are not dependent of each other given that baroreceptor denervation worsened hypotension and reduced SI.