RESUMO
The present study was aimed at evaluating the in vivo effects of microplastics (MP), in terms of oxidative stress and histopathological effects, in two crustacean species: Procambarus clarkii and Leptuca pugilator. In addition, MP accumulation in the hepatopancreas (HP) of both species was also determined. Adults of both crayfish and crabs were exposed for one month to fluorescent polystyrene beads (size: 1 µm) at nominal concentrations of 1000 or 5000 particles/mL. During the exposure, animals were maintained under controlled feeding, aeration, temperature, and photoperiod conditions. At the end of the exposure, HP and hemolymph (HL) samples were harvested for analysis of oxidative damage and total antioxidant levels. Additionally, the presence of MPs in both tissues was confirmed. Significant differences with the control groups were observed in lipid peroxidation levels in HP in animals exposed to the lowest concentration in P. clarkii and to the highest concentration in L. pugilator. A marked increase in antioxidant levels was also observed in the HL at both concentrations in P. clarkii, and at the highest MPs concentration in L. pugilator. Moreover, several histopathological changes were detected in both gills and HP, including hypertrophied lamellae, lifting or collapse of gill epithelia, loss of normal shape of hepatopancreatic tubules, and epithelial atrophy in the HP tissue. We conclude that exposure to MP beads at selected concentrations results in oxidative damage, induces histopathological changes in gills and HP, and triggers an antioxidant response in two crustacean species.
Assuntos
Braquiúros , Poluentes Químicos da Água , Animais , Astacoidea , Braquiúros/metabolismo , Plásticos , Antioxidantes/metabolismo , Microplásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Estresse OxidativoRESUMO
BACKGROUND AND PURPOSE: Chemokine receptors CXCR1 and CXCR2 may mediate influx of neutrophils in models of acute and chronic inflammation. The potential benefits of oral administration of a CXCR1/2 inhibitor, DF 2162, in adjuvant-induced polyarthritis (AIA) were investigated. EXPERIMENTAL APPROACH: A model of AIA in rats was used to compare the therapeutic effects of the treatment with DF2162, anti-TNF or anti-CINC-1 antibodies on joint inflammation and local production of cytokines and chemokines. KEY RESULTS: DF2162 prevented chemotaxis of rat and human neutrophils induced by chemokines acting on CXCR1/2. DF2162 was orally bioavailable and metabolized to two major metabolites. Only metabolite 1 retained CXCR1/2 blocking activity. Treatment with DF2162 (15 mg kg(-1), twice daily) or metabolite 1, but not metabolite 2, starting on day 10 after arthritis induction diminished histological score, the increase in paw volume, neutrophil influx and local production of TNF, IL-1beta, CCL2 and CCL5. The effects of DF2162 were similar to those of anti-TNF, and more effective than those of anti-CINC-1, antibodies. DF2162 prevented disease progression even when started 13 days after arthritis induction. CONCLUSIONS AND IMPLICATIONS: DF 2162, a novel orally-active non-competitive allosteric inhibitor of CXCR1 and CXCR2, significantly ameliorates AIA in rats, an effect quantitatively and qualitatively similar to those of anti-TNF antibody treatment. These findings highlight the contribution of CXCR2 in the pathophysiology of AIA and suggest that blockade of CXCR1/2 may be a valid therapeutic target for further studies aiming at the development of new drugs for treatment of rheumatoid arthritis.
Assuntos
Antirreumáticos/farmacologia , Artrite Experimental/tratamento farmacológico , Benzenoacetamidas/farmacologia , Mesilatos/farmacologia , Receptores de Interleucina-8B/antagonistas & inibidores , Administração Oral , Animais , Anticorpos/farmacologia , Antirreumáticos/farmacocinética , Artrite Experimental/fisiopatologia , Benzenoacetamidas/farmacocinética , Disponibilidade Biológica , Quimiocina CXCL1/metabolismo , Progressão da Doença , Feminino , Humanos , Mesilatos/farmacocinética , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Interleucina-8A/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND AND PURPOSE: Atorvastatin is an inhibitor of the enzyme 3-hydroxyl-3-methylglutaryl coenzyme A reductase used to prevent coronary heart disease. We have studied the analgesic effect of atorvastatin in inflammatory models in which a sequential release of mediators (bradykinin, (BK), tumour necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and the chemokine, KC/CXCL) links the stimulus with release of directly acting hypernociceptive mediators such as prostaglandin E(2) (PGE(2)). EXPERIMENTAL APPROACH: The effects of orally administered atorvastatin on inflammatory mechanical hypernociception in mouse paws were evaluated with an electronic pressure-meter. Cytokines and PGE(2) were measured by ELISA and RIA. KEY RESULTS: Treatment with atorvastatin for 3 days dose-dependently reduced hypernociception induced by lipopolysaccharide (LPS) or that following antigen challenge in sensitized animals. Atorvastatin pre-treatment reduced hypernociception induced by bradykinin and cytokines (TNF-alpha, IL-1beta and KC), and the release of IL-1beta and PGE(2) in paw skin, induced by lipopolysaccharide. The antinociceptive effect of atorvastatin on LPS-induced hypernociception was prevented by mevalonate co-treatment without affecting serum cholesterol levels. Hypernociception induced by PGE(2) was inhibited by atorvastatin, suggesting intracellular antinociceptive mechanisms for atorvastatin. The antinociceptive effect of atorvastatin upon LPS- or PGE(2)-induced hypernociception was prevented by non-selective inhibitors of nitric oxide synthase (NOS) but not by selective inhibition of inducible NOS or in mice lacking this enzyme. CONCLUSIONS AND IMPLICATIONS: Antinociceptive effects of atorvastatin depend on inhibition of cytokines and prostanoid production and on stimulation of NO production by constitutive NOS. Our study suggests that statins may constitute a novel class of analgesic drugs.
Assuntos
Ácidos Heptanoicos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Hiperalgesia/tratamento farmacológico , Hiperalgesia/etiologia , Inflamação/complicações , Pirróis/farmacologia , Animais , Atorvastatina , Bradicinina/farmacologia , Colesterol/sangue , Citocinas/farmacologia , Dinoprostona/metabolismo , Inibidores Enzimáticos/farmacologia , Hidroximetilglutaril-CoA Redutases/fisiologia , Hiperalgesia/prevenção & controle , Interleucina-1/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Óxido Nítrico Sintase/antagonistas & inibidores , Medição da Dor/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/metabolismoRESUMO
The hypernociceptive effects of cytokines [TNF-alpha, keratinocyte-derived chemokine (KC), and IL-1beta] and their participation in carrageenan (Cg)-induced inflammatory hypernociception in mice were investigated. Nociceptor sensitization (hypernociception) was quantified with an electronic version of the von Frey filament test in WT and TNF receptor type 1 knockout mice (TNF-R1-/-). TNF-alpha-induced hypernociception was abolished in TNF-R1-/- mice, partially inhibited by pretreatment with IL-1 receptor antagonist (IL-1ra) or indomethacin and unaffected by Ab against KC (AbKC) or guanethidine. IL-1ra and indomethacin pretreatment strongly inhibited the hypernociception induced by IL-1beta, which was not altered by AbKC or guanethidine or by knocking out TNF-R1. KC-induced hypernociception was abolished by AbKC, inhibited by pretreatment with indomethacin plus guanethidine, and partially inhibited by IL-1ra, indomethacin, or guanethidine. In contrast, KC-induced hypernociception was not altered by knocking out TNF-R1. Cg-induced hypernociception was abolished by administration of indomethacin plus guanethidine, diminished in TNF-R1-/- mice, and partially inhibited in WT mice pretreated with AbKC, IL-1ra, indomethacin, or guanethidine. TNF-alpha, KC, and IL-1beta concentrations were elevated in the skin of Cg-injected paws. The TNF-alpha and KC concentrations rose concomitantly and peaked before that of IL-1beta. In mice, the cytokine cascade begins with the release of TNF-alpha (acting on TNF-R1 receptor) and KC, which stimulate the release of IL-1beta. As in rats, the final mediators of this cascade were prostaglandins released by IL-1beta and sympathetic amines released by KC. These results extend to mice the concept that the release of primary mediators responsible for hypernociception is preceded by a cascade of cytokines.
Assuntos
Citocinas/fisiologia , Hiperalgesia/fisiopatologia , Inflamação/fisiopatologia , Mecanorreceptores/fisiologia , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Knockout , Ratos , Receptores Tipo I de Fatores de Necrose Tumoral/deficiência , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/fisiologia , Especificidade da Espécie , Fator de Necrose Tumoral alfaRESUMO
Snakebites constitute a serious public health problem in Central and South America, where species of the lancehead pit vipers (genus Bothrops) cause the majority of accidents. Bothrops envenomations are very painful, and this effect is not neutralized by antivenom treatment. Two variants of secretory phospholipases A2 (sPLA2), corresponding to Asp49 and Lys49 PLA2s, have been isolated from Bothrops asper venom. These sPLA2s induce hyperalgesia in rats following subcutaneous injection. However, venom in natural Bothrops bites is frequently delivered intramuscularly, thereby potentially reaching peripheral nerve bundles. Thus, the present series of experiments tested whether these sPLA2s could exert pain-enhancing effects following administration around healthy sciatic nerve. Both were found to produce mechanical allodynia ipsilateral to the injection site; no thermal hyperalgesia was observed. As no prior study has examined potential spinal mechanisms underlying sPLA2 actions, a series of anatomical and pharmacological studies were performed. These demonstrated that both sPLA2s produce activation of dorsal horn astrocytes and microglia that is more prominent ipsilateral to the site of injection. As proinflammatory cytokines and nitric oxide have each been previously implicated in spinally mediated pain facilitation, the effect of pharmacological blockade of these substances was tested. The results demonstrate that mechanical allodynia induced by both sPLA2s is blocked by interleukin-1 receptor antagonist, anti-rat interleukin-6 neutralizing antibody, the anti-inflammatory cytokine interleukin-10, and a nitric oxide synthesis inhibitor (L-NAME). As a variety of immune cells also produce and release sPLA2s during inflammatory states, the data may have general implications for the understanding of inflammatory pain. © 2003 International Association for the Study of Pain.
Assuntos
Animais , Citocinas , /intoxicação , Óxido Nítrico/intoxicaçãoRESUMO
1. The effects of phosphodiesterase (PDE)4 and TNF-alpha inhibition were assessed on the local and remote injuries following intestinal ischaemia and reperfusion (I/R) injury in rats. 2. The PDE4 inhibitor rolipram dose-dependently (1 - 10 mg kg(-1)) suppressed the local (intestine) and remote (lung) increases in vascular permeability and neutrophil recruitment following mild I/R injury. SB207499 (ariflo), a structurally-distinct PDE4 inhibitor, also suppressed the injuries following mild I/R injury. 3. In a severe model of I/R injury, treatment with rolipram (10 mg kg(-1)) partially reversed the local and remote increases in vascular permeability, neutrophil recruitment, intestinal haemorrhage and intestinal LTB(4) concentrations. The anti-TNF-alpha anti-serum was more effective than rolipram at inhibiting local and remote injuries and prevented the lethality associated with severe I/R. 4. Rolipram and anti-TNF-alpha prevented the increase in the concentrations of TNF-alpha in the lung and intestine, but rolipram only partially inhibited the elevation of this cytokine in serum. Rolipram had little effect on the increases of IL-1 beta concentrations in lung and serum, whereas treatment with anti-TNF-alpha markedly increased the concentration of this cytokine. Concentrations of IL-10 rose significantly in the lung and serum and these increases were blocked by rolipram or anti-TNF-alpha. 5. The capacity of PDE4 inhibitors to block the recruitment of neutrophils into tissues, the production of LTB(4) and of the pro-inflammatory cytokines TNF-alpha, IL-1 beta and IL-6 appear to underlie their anti-inflammatory effects in our model of I/R injury. Overall, PDE4 inhibition was less effective than inhibition of TNF-alpha for protection against I/R injury.
Assuntos
3',5'-AMP Cíclico Fosfodiesterases/antagonistas & inibidores , Soros Imunes/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Permeabilidade Capilar/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4 , Ácidos Cicloexanocarboxílicos/farmacologia , Citocinas/sangue , Citocinas/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Nitrilas , Ratos , Ratos Wistar , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/mortalidade , Rolipram/farmacologia , Taxa de Sobrevida , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The effect of interleukin-13 (IL-13) on hyperalgesic responses to intraplantar (i.pl.) injection of carrageenin, E. coli endotoxin (LPS), bradykinin, tumour necrosis factor a (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-8 (IL-8) and prostaglandin E(2) (PGE(2)) was investigated in a model of mechanical hyperalgesia in rats. Also, the cellular source of the IL-13 was investigated. IL-13, administered 30 min before the stimulus, inhibited responses to carrageenin, LPS, bradykinin, and TNF-alpha, but not responses to IL-1 beta, IL-8 and PGE2. IL-13, administered 2 hours before the injection of IL-1b, did not affect the response to IL-1b, whereas IL-13, administered 12 hours or 12 + 2 hours before the IL-1 beta, inhibited the hyperalgesia (- 35%, - 77%, respectively). In murine peritoneal macrophages, IL-13 administered 2 hours before stimulation with LPS, inhibited the production of IL-1 beta (- 67%) and PGE(2) (- 56%). IL-13 administered 12 hours before stimulation with LPS inhibited LPS-stimulated PGE(2) but not IL-1 beta. An anti-IL-13 serum potentiated responses to carrageenin, LPS, bradykinin and TNF-alpha (but not IL-1 beta and IL-8), as well as responses to bradykinin in rats depleted of mast cells with compound 40/80, but not in athymic rats. These data suggest that IL-13, released by lymphocytes, limits inflammatory hyperalgesia by the inhibition of the production TNF-alpha, IL-1 beta, IL-8 and PGs.
Assuntos
Citocinas/farmacologia , Hiperalgesia/fisiopatologia , Mediadores da Inflamação , Interleucina-13/fisiologia , Animais , Sangue , Bradicinina/farmacologia , Carragenina/farmacologia , Soros Imunes , Técnicas In Vitro , Interleucina-13/imunologia , Lipopolissacarídeos/farmacologia , Macrófagos Peritoneais/imunologia , Masculino , Camundongos , Ratos , Ratos Nus , Ratos WistarRESUMO
1. The effect of IL-1ra on response to intraplantar (i.pl.) injection of LPS, carrageenin, bradykinin, TNFalpha, IL-1beta, IL-8, PGE(2) and dopamine was investigated in a model of mechanical hyperalgesia in rats. 2. IL-1ra inhibited hyperalgesic response to LPS, carrageenin, bradykinin, TNFalpha, and IL-1beta, but not responses to IL-8, PGE(2) and dopamine. 3. A sheep anti-rat IL-1ra serum potentiated response to LPS, carrageenin, bradykinin, TNFalpha and IL-1beta but not IL-8. 4. Carrageenin and LPS stimulated and production of immunoreactive TNFalpha, IL-1beta and IL-1ra in the skin of injected paws. 5. The inhibition by IL-1ra of the hyperalgesic response to carrageenin was not affected by antibodies neutralizing IL-4 and IL-10. 6. In mice, IL-1ra inhibited the nociceptive response to i.p. injection of acetic acid. 7. These data suggest that IL-1ra, released at sites of inflammation, limits inflammatory hyperalgesia. This effect is independent of (IL-1ra-induced) IL-4 and IL-10 and appears to be the result of antagonism by IL-1ra of IL-1beta-stimulated eicosanoid production.
Assuntos
Citocinas/farmacologia , Hiperalgesia/prevenção & controle , Inflamação/prevenção & controle , Sialoglicoproteínas/farmacologia , Ácido Acético/farmacologia , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Bradicinina/farmacologia , Carragenina/farmacologia , Citocinas/metabolismo , Dinoprostona/farmacologia , Dopamina/farmacologia , Relação Dose-Resposta a Droga , Membro Posterior , Hiperalgesia/metabolismo , Soros Imunes/farmacologia , Inflamação/metabolismo , Proteína Antagonista do Receptor de Interleucina 1 , Interleucina-1/metabolismo , Interleucina-1/farmacologia , Interleucina-10/imunologia , Interleucina-4/imunologia , Interleucina-8/farmacologia , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Medição da Dor , Ratos , Ratos Wistar , Ovinos , Sialoglicoproteínas/imunologia , Sialoglicoproteínas/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
There has been much interest in strategies which modulate tumour necrosis factor-alpha (TNF-alpha) levels and/or function in rheumatoid arthritis. The elevation of intracellular levels of cyclic AMP in leukocytes by phosphodiesterase 4 inhibitors is accompanied by significant inhibition of the production of TNF-alpha. Nevertheless, these drugs may enhance the hyperalgesia induced by a range of inflammatory mediators, including TNF-alpha. In the present study, we examined the effects of the phosphodiesterase 4 inhibitor rolipram on the local inflammatory infiltrate and hyperalgesia in a rat model of adjuvant-induced arthritis. Rolipram (3 mg/kg) was administered by oral gavage from day 10 to 14 after disease induction. Pretreatment with rolipram abrogated oedema formation and significantly inhibited hyperalgesia. Histopathological analysis revealed a marked inhibition of cellular influx as well as bone and cartilage destruction. Serum and local TNF-alpha levels were suppressed in treated animals whereas there were little changes in interleukin-1beta levels. Although cyclic AMP elevating agents may affect nociceptor threshold to increase the hyperalgesic responses acutely, they also possess significant anti-inflammatory activity, which may hinder local mediator release and/or action. The anti-inflammatory effects of rolipram predominate during this chronic arthritis model in the rat.
Assuntos
Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Artrite Experimental/fisiopatologia , Inibidores de Fosfodiesterase/farmacologia , Rolipram/farmacologia , 3',5'-AMP Cíclico Fosfodiesterases/antagonistas & inibidores , Animais , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4 , Modelos Animais de Doenças , Edema/fisiopatologia , Edema/prevenção & controle , Feminino , Membro Posterior , Inflamação/patologia , Inflamação/prevenção & controle , Interleucina-1/metabolismo , Ratos , Fatores de Tempo , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Intraperitoneal administration of zymosan and acetic acid induced a dose-dependent nociceptive writhing response in mice. Lavage of the peritoneal cavities with saline reduced the number of total resident peritoneal cells and caused a proportional decrease in the nociceptive responses induced by these stimuli. Furthermore, the specific reduction of the peritoneal mast cell population by intraperitoneal administration of compound 48/80 also reduced the nociceptive responses induced by zymosan and acetic acid. In contrast, enhancement of the peritoneal macrophage population by pretreatment of the cavities with thioglycollate caused an increase in the number of writhes induced by both stimuli. These data suggest that the nociceptive responses induced by zymosan and acetic acid are dependent upon the peritoneal resident macrophages and mast cells. These cells modulate the nociceptive response induced by zymosan and acetic acid via release of tumour necrosis factor alpha (TNF-alpha), interleukin 1beta and interleukin 8. This suggestion is supported by the following observations: (a) pretreatment of the peritoneal cavities with antisera against these cytokines reduced the nociceptive responses induced by these stimuli; (b) peritoneal cells harvested from cavities injected with zymosan or acetic acid released both interleukin 1beta and TNF-alpha; (c) although individual injection of TNF-alpha, interleukin 1beta or interleukin 8 did not induce the nociceptive effect, intraperitoneal injection of a mixture of these three recombinant cytokines caused a significant nociceptive writhing response. In conclusion, our results suggest that the nociceptive activity of zymosan and acetic acid in the writhing model is due to the release of TNF-alpha, interleukin 1beta and interleukin 8 by resident peritoneal macrophages and mast cells.