RESUMO
Type-1 diabetes mellitus (T1DM) is a chronic condition characterized by long-term hyperglycemia that results in several complications such as painful peripheral neuropathy, bone deterioration, and increased risk of bone fractures. Lithium, a first-line therapy for bipolar disorder, has become an attractive agent for attenuating peripheral neuropathy and menopause-induced bone loss. Therefore, our aim was to determine the effect of chronic lithium treatment on mechanical hypersensitivity and trabecular bone loss induced by T1DM in mice. T1DM was induced in male C57BL/6J mice by intraperitoneal injection of streptozotocin (STZ, 50 mg/kg/day, for 5 consecutive days). 12 weeks after T1DM-induction, mice received a daily intraperitoneal injection of vehicle, 30 or 60 mg/kg lithium (as LiCl) for 6 weeks. Throughout the treatment period, blood glucose levels and mechanical sensitivity were evaluated every 2 weeks. After lithium treatment, the femur and L5 vertebra were harvested for microcomputed tomography (microCT) analysis. T1DM mice showed significant hyperglycemia, mechanical hypersensitivity, and significant trabecular bone loss as compared with the control group. Chronic lithium treatment did not revert the hindpaw mechanical hypersensitivity nor hyperglycemia associated to T1DM induced by STZ. In contrast, microCT analysis revealed that lithium reverted, in a dose-dependent manner, the loss of trabecular bone associated to T1DM induced by STZ at both the distal femur and L5 vertebra. Lithium treatment by itself did not affect any trabecular bone parameter in non-diabetic mice.
Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Hiperglicemia , Animais , Glicemia , Osso Esponjoso/diagnóstico por imagem , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/induzido quimicamente , Diabetes Mellitus Tipo 1/tratamento farmacológico , Feminino , Hiperglicemia/induzido quimicamente , Lítio/farmacologia , Compostos de Lítio/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estreptozocina , Microtomografia por Raio-XRESUMO
By-products of Capsicum chinense Jacq., var Jaguar could be a source of bioactive compounds. Therefore, we evaluated the anti-inflammatory effect, antioxidant activity, and their relationship with the polyphenol content of extracts of habanero pepper by-products obtained from plants grown on black or red soils of Yucatán, Mexico. Moreover, the impact of the type of extraction on their activities was evaluated. The dry by-product extracts were obtained by maceration (ME), Soxhlet (SOX), and supercritical fluid extraction (SFE). Afterward, the in vivo anti-inflammatory effect (TPA-induced ear inflammation) and the in vitro antioxidant activity (ABTS) were evaluated. Finally, the polyphenolic content was quantified by Ultra-Performance Liquid Chromatography (UPLC), and its correlation with both bioactivities was analyzed. The results showed that the SFE extract of stems of plants grown on red soil yielded the highest anti-inflammatory effect (66.1 ± 3.1%), while the extracts obtained by ME and SOX had the highest antioxidant activity (2.80 ± 0.0052 mM Trolox equivalent) and polyphenol content (3280 ± 15.59 mg·100 g-1 dry basis), respectively. A negative correlation between the anti-inflammatory effect, the antioxidant activity, and the polyphenolic content was found. Overall, the present study proposed C. chinense by-products as a valuable source of compounds with anti-inflammatory effect and antioxidant activity.
Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Capsicum/química , Extratos Vegetais/química , Polifenóis/química , Anti-Inflamatórios/isolamento & purificação , Antioxidantes/isolamento & purificação , Fracionamento Químico/métodos , Cromatografia com Fluido Supercrítico , Especificidade de Órgãos , Compostos Fitoquímicos/químicaRESUMO
In this paper, we report the synthesis of a new series of α-aminophosphonates derivatives based in an efficient three-component reaction. All compounds prepared showed significant anti-inflammatory activity, being the compounds 1a, 1c, 1d, 1f, 2b and 2c the most promising ones, in terms of maximal efficacy (over 95%), potency (ED50 range between 0.7 and 10.1â¯mg/ear) and relative potency (range from 0.04 to 0.67). Compounds 1a, 1c, 1d and 1f significantly decrease the number of neutrophils (range from 46.7 to 63.0%) and monocytes (18.9-34.1%) in blood samples from the orbital sinus. Additionally, QSAR model revealed that the spherical molecular shape and the location of the HOMO on the phenyl ring improves the anti-inflammatory activity of the compounds. The values of R2, Q2, s and F statistical parameters and the QUIK, asymptotic Q2 and Overfitting rules validate the descriptive and predictive ability of the QSAR model. Altogether these results suggest that these new α-aminophosphonates are potential agents for the treatment of inflammation.
Assuntos
Anti-Inflamatórios/uso terapêutico , Etanolaminas/uso terapêutico , Inflamação/tratamento farmacológico , Organofosfonatos/uso terapêutico , Relação Quantitativa Estrutura-Atividade , Animais , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/química , Etanolaminas/síntese química , Etanolaminas/química , Camundongos , Estrutura Molecular , Monócitos/metabolismo , Neutrófilos/metabolismo , Organofosfonatos/síntese química , Organofosfonatos/químicaRESUMO
BACKGROUND: Protein hydrolysates from food plants, such as legumes, have emerged as a new alternative to treat hyperglycemia, an important risk factor contributing to the development of type 2 diabetes mellitus (T2DM) and its complications. The aim of this work was to assess the antihyperglycemic activity and inhibition of α-glucosidase, and intestinal glucose absorption, and acute toxicity of total hydrolysates and < 1 kDa fractions from Phaseolus lunatus L., Phaseolus vulgaris L., and Mucuna pruriens (L.) DC., obtained by hydrolysis with Alcalase®-Flavourzyme® or pepsine-pancreatin enzymatic systems. RESULTS: In vivo results showed that three of six total hydrolysates and four of six < 1 kDa fractions suppressed starch-induced postprandial hyperglycemia (ED50 range between 1.4 and 93 mg kg-1 ). In vitro, total hydrolysates and fractions, particularly from M. pruriens, inhibited carbohydrate intestinal absorption (from 19.2 to 40%), and α-glucosidase activity (IC50 from 0.86 to 75 mg mL-1 ). Finally, none of the hydrolysates and fractions tested did not show any signs of toxicity (LD50 > 5000 mg kg-1 ). CONCLUSION: These results suggest that hydrolysates and < 1 kDa fractions from P. lunatus, P. vulgaris and M. pruriens are suitable candidates to treat or prevent T2DM. © 2018 Society of Chemical Industry.
Assuntos
Glucose/metabolismo , Inibidores de Glicosídeo Hidrolases/administração & dosagem , Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Mucuna/química , Phaseolus/química , Hidrolisados de Proteína/administração & dosagem , Animais , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Humanos , Hiperglicemia/enzimologia , Hiperglicemia/metabolismo , Hipoglicemiantes/química , Hipoglicemiantes/isolamento & purificação , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Hidrolisados de Proteína/química , Hidrolisados de Proteína/isolamento & purificação , Ratos , Ratos Wistar , Ultrafiltração , alfa-Glucosidases/metabolismoRESUMO
Preclinical Research Metformin-dependent mechanisms have been implicated in the antinociceptive effect of some non-steroidal anti-inflammatory drugs (NSAIDs). In this study, the effect of local peripheral or systemic administration of metformin on the local peripheral or systemic antinociception induced by indomethacin, ketorolac and metamizole was assessed in the rat carrageenan-induced thermal hyperalgesia model. Rats were injected with carrageenan (1%, 50 µl) into the right hindpaw which reduced paw withdrawal latency, a measure of thermal hyperalgesia. Local peripheral or systemic administration of indomethacin, ketorolac or metamizole dose-dependently reduced carrageenan-induced thermal hyperalgesia. Local peripheral pre-treatment with metformin (800 µg/paw) partially inhibited the anti-hyperalgesic effect of indomethacin (200 µg/paw) and metamizole (200 µg/paw), but not that of ketorolac (200 µg/paw). In contrast, systemic pre-treatment with metformin (200 mg/kg) attenuated the antihyperalgesic effect of metamizole (10 mg/kg), but not that observed with either indomethacin (10 mg/kg) or ketorolac (10 mg/kg). These findings suggest that some but not all NSAIDs have effects mediated by metformin-dependent mechanisms. Drug Dev Res 78 : 98-104, 2017. ©2017 Wiley Periodicals, Inc.
Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Carragenina/efeitos adversos , Hiperalgesia/tratamento farmacológico , Metformina/administração & dosagem , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Dipirona/administração & dosagem , Dipirona/uso terapêutico , Relação Dose-Resposta a Droga , Interações Medicamentosas , Temperatura Alta , Hiperalgesia/induzido quimicamente , Indometacina/administração & dosagem , Indometacina/uso terapêutico , Cetorolaco/administração & dosagem , Cetorolaco/uso terapêutico , Masculino , Metformina/uso terapêutico , Ratos , Ratos Sprague-Dawley , Resultado do TratamentoRESUMO
Diabetes mellitus is a chronic degenerative disease that causes long-term complications and represents a serious public health problem. Turnera diffusa (damiana) is a shrub that grows throughout Mexico and is traditionally used for many illnesses including diabetes. Although a large number of plant metabolites are known, there are no reports indicating which of these are responsible for this activity, and this identification was the objective of the present work. Through bioassay-guided fractionation of a methanolic extract obtained from the aerial part of T. diffusa, teuhetenone A was isolated and identified as the main metabolite responsible for the plant's hypoglycemic activity. Alpha-glucosidase inhibitory activity and cytotoxicity of this metabolite were determined. Hypoglycemic and antidiabetic activities were evaluated in a murine model of diabetes in vivo, by monitoring glucose levels for six hours and comparing them with levels after administering various controls. Teuhetenone A was not cytotoxic at the tested concentrations, and did not show inhibitory activity in the glucosidase test, and the in vivo assays showed a gradual reduction in glucose levels in normoglycemic and diabetic mice. Considering these results, we suggest that teuhetenone A has potential as an antidiabetic compound, which could be further submitted to preclinical assays.
Assuntos
Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Turnera/química , Animais , Glicemia/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Hipoglicemiantes/isolamento & purificação , Concentração Inibidora 50 , Camundongos , Estrutura Molecular , Extratos Vegetais/isolamento & purificação , alfa-Glucosidases/metabolismoRESUMO
The aim of this study was to evaluate fosinopril-induced changes in hemodynamic parameters and tactile allodynia in a rat model of diabetes. Diabetes was induced by streptozotocin (STZ; 50 mg/kg, i.p.) in male Wistar rats. STZ produced hyperglycemia, weight loss, polydipsia, polyphagia, and polyuria as well as long-term arterial hypotension, bradycardia, and tactile allodynia at 10-12 weeks. Daily administration of the angiotensin converting enzyme inhibitor, fosinopril (25 mg/kg, p.o., for 11 weeks) partially reduced the loss of body weight, decreased hyperglycemia, and systolic blood pressure in diabetic rats. Likewise, systemic administration of fosinopril prevented the development and maintenance of tactile allodynia in STZ-induced diabetic rats. These data suggest that fosinopril may have a role in the pharmacotherapy of diabetic neuropathic pain.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Fosinopril/farmacologia , Hiperalgesia/prevenção & controle , Animais , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/fisiopatologia , Neuropatias Diabéticas/sangue , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Hiperalgesia/sangue , Hiperalgesia/fisiopatologia , Hiperglicemia/sangue , Hiperglicemia/induzido quimicamente , Hiperglicemia/tratamento farmacológico , Hiperglicemia/fisiopatologia , Insulina/sangue , Masculino , Ratos , Ratos Wistar , Redução de Peso/efeitos dos fármacosRESUMO
This study was performed to evaluate whether early, middle, or late treatment of zoledronate, an approved bisphosphonate that blocks bone resorption, can reduce nociceptive behaviors in a mouse arthritis model. Arthritis was produced by repeated intra-articular knee injections of complete Freund's adjuvant (CFA). A dose-response curve with zoledronate (3, 30, 100, and 300 µg/kg, i.p., day 4 to day 25, twice weekly for 3 weeks) was performed, and the most effective dose of zoledronate (100 µg/kg, i.p.) was initially administered at different times of disease progression: day 4 (early), day 15 (middle), or day 21 (late) and continued until day 25 after the first CFA injection. Flinching of the injected extremity (spontaneous nociceptive behavior), vertical rearings and horizontal activity (functional outcomes), and knee edema were assessed. Zoledronate improved both functional outcomes and reduced flinching behavior. At day 25, the effect of zoledronate on flinching behavior and vertical rearings was greater in magnitude when it was given early or middle rather than late in the treatment regimen. Chronic zoledronate did not reduce knee edema in CFA-injected mice nor functional outcomes in naïve mice by itself. These results suggest that zoledronate may have a positive effect on arthritis-induced nociception and functional disabilities.
Assuntos
Artrite Experimental/complicações , Artrite Experimental/tratamento farmacológico , Difosfonatos/administração & dosagem , Difosfonatos/uso terapêutico , Imidazóis/administração & dosagem , Imidazóis/uso terapêutico , Atividade Motora/efeitos dos fármacos , Dor Nociceptiva/complicações , Dor Nociceptiva/tratamento farmacológico , Animais , Artrite Experimental/induzido quimicamente , Conservadores da Densidade Óssea/administração & dosagem , Conservadores da Densidade Óssea/uso terapêutico , Difosfonatos/farmacologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Edema/complicações , Edema/tratamento farmacológico , Adjuvante de Freund , Imidazóis/farmacologia , Masculino , Camundongos , Medição da Dor/efeitos dos fármacos , Ácido ZoledrônicoRESUMO
ABSTRACT: Nociplastic pain, characterized by abnormal pain processing without an identifiable organic cause, affects a significant portion of the global population. Unfortunately, current pharmacological treatments for this condition often prove ineffective, prompting the need to explore new potential targets for inducing analgesic effects in patients with nociplastic pain. In this context, toll-like receptors (TLRs), known for their role in the immune response to infections, represent promising opportunities for pharmacological intervention because they play a relevant role in both the development and maintenance of pain. Although TLRs have been extensively studied in neuropathic and inflammatory pain, their specific contributions to nociplastic pain remain less clear, demanding further investigation. This review consolidates current evidence on the connection between TLRs and nociplastic pain, with a specific focus on prevalent conditions like fibromyalgia, stress-induced pain, sleep deprivation-related pain, and irritable bowel syndrome. In addition, we explore the association between nociplastic pain and psychiatric comorbidities, proposing that modulating TLRs can potentially alleviate both pain syndromes and related psychiatric disorders. Finally, we discuss the potential sex differences in TLR signaling, considering the higher prevalence of nociplastic pain among women. Altogether, this review aims to shed light on nociplastic pain, its underlying mechanisms, and its intriguing relationship with TLR signaling pathways, ultimately framing the potential therapeutic role of TLRs in addressing this challenging condition.
RESUMO
OBJECTIVE: Many forms of arthritis are accompanied by significant chronic joint pain. This study was undertaken to investigate whether there is significant sprouting of sensory and sympathetic nerve fibers in the painful arthritic knee joint and whether nerve growth factor (NGF) drives this pathologic reorganization. METHODS: A painful arthritic knee joint was produced by injection of Freund's complete adjuvant (CFA) into the knee joint of young adult mice. CFA-injected mice were then treated systemically with vehicle or anti-NGF antibody. Pain behaviors were assessed, and at 28 days following the initial CFA injection, the knee joints were processed for immunohistochemistry analysis using antibodies against calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kd (NF200; sensory nerve fibers), growth-associated protein 43 (GAP-43; sprouted nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), CD31 (endothelial cells), or CD68 (monocyte/macrophages). RESULTS: In CFA-injected mice, there was a significant increase in the density of CD68+ macrophages, CD31+ blood vessels, and CGRP+, NF200+, GAP-43+, and TH+ nerve fibers in the synovium, as well as a significant increase in joint pain-related behaviors. None of these findings were observed in sham-injected mice. Administration of anti-NGF reduced these pain-related behaviors and the ectopic sprouting of nerve fibers, but had no significant effect on the increase in density of CD31+ blood vessels or CD68+ macrophages. CONCLUSION: These findings demonstrate that ectopic sprouting of sensory and sympathetic nerve fibers occurs in the painful arthritic joint and may be involved in the generation and maintenance of arthritic pain.
Assuntos
Artrite Experimental/fisiopatologia , Fibras Nervosas/fisiologia , Plasticidade Neuronal/fisiologia , Dor/fisiopatologia , Células Receptoras Sensoriais/fisiologia , Sistema Nervoso Simpático/fisiopatologia , Fibras Adrenérgicas/metabolismo , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Artrite Experimental/metabolismo , Comportamento Animal/fisiologia , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Modelos Animais de Doenças , Proteína GAP-43/metabolismo , Articulação do Joelho/metabolismo , Articulação do Joelho/fisiopatologia , Masculino , Camundongos , Fibras Nervosas/metabolismo , Proteínas de Neurofilamentos/metabolismo , Dor/metabolismo , Medição da Dor , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Células Receptoras Sensoriais/metabolismo , Sistema Nervoso Simpático/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Chronic stress affects millions of people around the world, and it can trigger different behavioral disorders like nociceptive hypersensitivity and anxiety, among others. However, the mechanisms underlaying these chronic stress-induced behavioral disorders have not been yet elucidated. This study was designed to understand the role of high-mobility group box-1 (HMGB1) and toll-like receptor 4 (TLR4) in chronic stress-induced nociceptive hypersensitivity. Chronic restraint stress induced bilateral tactile allodynia, anxiety-like behaviors, phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK) and activation of spinal microglia. Moreover, chronic stress enhanced HMGB1 and TLR4 protein expression at the dorsal root ganglion, but not at the spinal cord. Intrathecal injection of HMGB1 or TLR4 antagonists reduced tactile allodynia and anxiety-like behaviors induced by chronic stress. Additionally, deletion of TLR4 diminished the establishment of chronic stress-induced tactile allodynia in male and female mice. Lastly, the antiallodynic effect of HMGB1 and TLR4 antagonists were similar in stressed male and female rats and mice. Our results suggest that chronic restraint stress induces nociceptive hypersensitivity, anxiety-like behaviors, and up-regulation of spinal HMGB1 and TLR4 expression. Blockade of HMGB1 and TLR4 reverses chronic restraint stress-induced nociceptive hypersensitivity and anxiety-like behaviors and restores altered HMGB1 and TLR4 expression. The antiallodynic effects of HMGB1 and TLR4 blockers in this model are sex independent. TLR4 could be a potential pharmacological target for the treatment of the nociceptive hypersensitivity associated with widespread chronic pain.
Assuntos
Proteína HMGB1 , Hiperalgesia , Animais , Feminino , Masculino , Camundongos , Ratos , Alarminas/metabolismo , Doença Crônica , Proteína HMGB1/metabolismo , Hiperalgesia/tratamento farmacológico , Hiperalgesia/etiologia , Hiperalgesia/metabolismo , Nociceptividade , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Medula Espinal , Receptor 4 Toll-Like/metabolismoRESUMO
Because of the relative lack of understanding of the neurobiological mechanisms that drive toxic effects of cadmium in bone, the purpose of this study was to characterize a preclinical model of chronic cadmium exposure. Adult male C57BL/6 J mice were exposed to cadmium 25 mg/L (as CdCl2) in drinking water for 16 weeks. During this time, pain-related behaviors including hindpaw mechanical sensitivity and vertical rears were evaluated every four weeks. We assessed changes in bone microarchitecture at the femoral neck and L5 vertebra by microcomputed tomography and quantified the density of nerve fibers expressing PGP 9.5 (a pan-neuronal marker) and CGRP (a marker of sensory nerve fibers subfamily) at the femoral neck and glabrous skin of the hindpaw using immunohistochemistry. Cadmium exposure produced mechanical hypersensitivity in both hindpaws along with decreased rearing activity (surrogate for musculoskeletal-related pain) without affecting the horizontal activity (a measure of locomotor behavior) in comparison to the control group. Intraperitoneal acute treatment with morphine and gabapentin reversed pain-related behaviors in cadmium-exposed mice. Furthermore, exposure to cadmium resulted in significant trabecular bone deterioration at the femoral neck and L5 vertebra. We also observed a significant reduction in the density of both CGRP+ and PGP 9.5+ nerve fibers in the femoral neck, but not in the hindpaw glabrous skin, suggesting tissue-dependent neurotoxicity. This model may help in developing a mechanism-based understanding of the factors that generate and maintain musculoskeletal pain and bone loss caused by chronic cadmium exposure and in translating these findings into new therapies for treating cadmium-induced bone toxicity.
Assuntos
Cádmio , Colo do Fêmur , Animais , Cádmio/toxicidade , Colo do Fêmur/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dor , Microtomografia por Raio-XRESUMO
Background: Painful distal symmetrical polyneuropathy (DPN) is a frequent complication of type-2 diabetes mellitus (T2DM) that commonly presents as neuropathic pain and loss of skin nerve fibers. However, there are limited therapies to effectively treat DPN and many of the current animal models of T2DM-induced DPN do not appear to mirror the human disease. Thus, we validated a DPN mouse model induced by a cafeteria-style diet plus low-doses of streptozotocin (STZ). Methods: Female C57BL/6J mice were fed either standard (STD) diet or obesogenic cafeteria (CAF) diet for 32 weeks, starting at 8 weeks old. Eight weeks after starting diets, CAF or STD mice received either four low-doses of STZ or vehicle. Changes in body weight, blood glucose and insulin levels, as well as oral glucose- and insulin-tolerance tests (OGTT and ITT) were determined. The development of mechanical hypersensitivity of the hindpaws was determined using von Frey filaments. Moreover, the effect of the most common neuropathic pain drugs was evaluated on T2DM-induced mechanical allodynia. Finally, the density of PGP -9.5+ (a pan-neuronal marker) axons in the epidermis from the hindpaw glabrous skin was quantified. Results: At 22-24 weeks after STZ injections, CAF + STZ mice had significantly higher glucose and insulin levels compared to CAF + VEH, STD + STZ, and STD + VEH mice, and developed glucose tolerance and insulin resistance. Skin mechanical sensitivity was detected as early as 12 weeks post-STZ injections and it was significantly attenuated by intraperitoneal acute treatment with amitriptyline, gabapentin, tramadol, duloxetine, or carbamazepine but not by diclofenac. The density of PGP-9.5+ nerve fibers was reduced in CAF + STZ mice compared to other groups. Conclusion: This reverse translational study provides a painful DPN mouse model which may help in developing a better understanding of the factors that generate and maintain neuropathic pain and denervation of skin under T2DM and to identify mechanism-based new treatments.
RESUMO
The present work was undertaken to determine safety parameters of selected Mexican medicinal plants chosen on the basis of their frequency of medicinal use and commercial importance. The medicinal herbs included Amphipteryngium adstringens, Hintonia standleyana, Hintonia latiflora, Piper sanctum, Haemathoxylon brasiletto, Iostephane heterophylla, Valeriana procera, Arracacia tolucensis, Brickellia veronicaefolia, Scaphyglottis livida, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri, Poliomintha longiflora and Gnaphalium sp. In the acute toxicity studies in mice performed according to the Lorke procedure, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri and Poliomintha longiflora were the most toxic with LD(50) values between 1085 and 2mg/kg. The Ames test revealed that Gnaphalium sp. and Valeriana procera extracts induced mutations of S. typhimurium TA98 with or without the S9 microsomal fraction, and TA100 in the presence of the enzymatic fraction, respectively. The tincture of Valeriana procera, however, was non-mutagenic. Finally, in the Artemia salina lethality test Brickellia veronicaefolia, Arracacia tolucensis, Poliomintha longiflora and Piper sanctum caused significant mortality of the crustacean larvae with LC(50) in the range of 37-227 microg/mL.
Assuntos
Mutagênicos , Extratos Vegetais/toxicidade , Plantas Medicinais/toxicidade , Animais , Artemia , Relação Dose-Resposta a Droga , Masculino , Medicina Tradicional , México , Camundongos , Camundongos Endogâmicos ICR , Testes de MutagenicidadeRESUMO
The Na(+)/H(+) exchanger (NHE) is involved in the regulation of intracellular pH and volume by mediating the electroneutral transport of H(+) against an influx of Na(+) ions. Since NHE1 regulates pH in neurons and astrocytes and it is expressed in nociceptive nerve fibers, it is likely that NHE may modulate neuronal excitability and pain transmission. The purpose of this study was to assess the participation of peripheral and spinal NHE in the secondary allodynia/hyperalgesia induced by formalin. In addition, we determined whether formalin injection modifies the expression of NHE1 in lumbar dorsal root ganglia (DRG) and dorsal spinal cord. Subcutaneous injection of 0.5% formalin into the dorsal surface of the hind paw produced acute nociceptive behaviors (flinching and licking/lifting) followed by long-lasting bilateral secondary mechanical allodynia/hyperalgesia. Peripheral and intrathecal pre-treatment (-10min) with selective NHE inhibitors 5-(N,N-dimethyl)amiloride hydrochloride (DMA, 0.3-30µM), 5-(N-ethyl-N-isopropyl)amiloride (EIPA, 0.3-30µM) and [1-(quinolin-5-yl)-5-cyclopropyl-1H-pyrazole-4-carbonyl] guanidine dihydrochloride (zoniporide, 0.03-3µM) significantly increased 0.5% formalin-induced bilateral long-lasting secondary allodynia/hyperalgesia. Contrariwise, local peripheral or intrathecal post-treatment (day 6 postinjection) with these NHE inhibitors did not affect formalin-induced nociceptive behaviors. Formalin injection reduced NHE1 expression in ipsilateral and contralateral spinal dorsal horns from day 1 to 12. In addition, formalin diminished NHE1 protein expression in DRG at day 12. These results suggest that NHE1 plays a role in pain processing at peripheral and spinal levels in formalin-induced long-lasting nociceptive behaviors. Additionally, these results suggest that proteins involved in pH regulation could be targets for the development of new analgesic drugs.
Assuntos
Hiperalgesia/enzimologia , Medição da Dor/métodos , Nervos Periféricos/enzimologia , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Trocadores de Sódio-Hidrogênio/biossíntese , Medula Espinal/enzimologia , Amilorida/administração & dosagem , Amilorida/análogos & derivados , Animais , Feminino , Hiperalgesia/induzido quimicamente , Injeções Espinhais , Medição da Dor/efeitos dos fármacos , Nervos Periféricos/efeitos dos fármacos , Estimulação Física/efeitos adversos , Ratos , Ratos Wistar , Trocador 1 de Sódio-Hidrogênio , Trocadores de Sódio-Hidrogênio/fisiologia , Medula Espinal/efeitos dos fármacosRESUMO
This study assessed the role of the Na(+)/H(+) exchanger (NHE) in the formalin-induced nociception as well as the expression of the NHE isoform 1 (NHE1) in the rat spinal cord by using immunohistochemistry. Rats received a 50µl injection of diluted formalin (0.5%). Nociceptive behavior was quantified as the number of flinches of the injected paw. Intrathecal administration of the partially selective NHE1 inhibitors DMA, EIPA (0.3-30µM/rat) and the selective NHE1 inhibitor zoniporide (0.03-3µM/rat) significantly increased formalin-induced flinching behavior in a dose-dependent manner during both phases of the test. Immunohistochemical analysis of the rat lumbar spinal cord showed that NHE1 was mainly expressed in the lamina I of the dorsal horn of the spinal cord. Double immunofluorescence staining showed co-localization of NHE1 with the peptide-rich sensory nerve fiber markers, substance P and calcitonin gene-related peptide, but not with markers of neuronal cell bodies (NeuN), microglia (OX-42) or astroglia (GFAP). Collectively, these pharmacological and anatomical results suggest that spinal NHE1 plays a role in formalin-induced nociception acting as a protective protein extruding H(+).
Assuntos
Formaldeído/toxicidade , Dor/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Medula Espinal/metabolismo , Amilorida/análogos & derivados , Amilorida/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Relação Dose-Resposta a Droga , Feminino , Guanidinas/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Dor/induzido quimicamente , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Limiar da Dor/fisiologia , Pirazóis/farmacologia , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Medula Espinal/efeitos dos fármacosRESUMO
Early, preemptive blockade of nerve growth factor (NGF)/tropomyosin receptor kinase A (TrkA) attenuates tumor-induced nerve sprouting and bone cancer pain. A critical unanswered question is whether late blockade of NGF/TrkA can attenuate cancer pain once NGF-induced nerve sprouting and neuroma formation has occurred. By means of a mouse model of prostate cancer-induced bone pain, anti-NGF was either administered preemptively at day 14 after tumor injection when nerve sprouting had yet to occur, or late at day 35, when extensive nerve sprouting had occurred. Animals were humanely killed at day 70 when, in vehicle-treated animals, significant nerve sprouting and neuroma formation was present in the tumor-bearing bone. Although preemptive and sustained administration (days 14-70) of anti-NGF more rapidly attenuated bone cancer nociceptive behaviors than late and sustained administration (days 35-70), by day 70 after tumor injection, both preemptive and late administration of anti-NGF significantly reduced nociceptive behaviors, sensory and sympathetic nerve sprouting, and neuroma formation. In this model, as in most cancers, the individual cancer cell colonies have a limited half-life because they are constantly proliferating, metastasizing, and undergoing necrosis as the parent cancer cell colony outgrows its blood supply. Similarly, the sensory and sympathetic nerve fibers that innervate the tumor undergo sprouting at the viable/leading edge of the parent tumor, degenerate as the parent cancer cell colony becomes necrotic, and resprout in the viable, newly formed daughter cell colonies. These results suggest that preemptive or late-stage blockade of NGF/TrkA can attenuate nerve sprouting and cancer pain.
Assuntos
Anticorpos Monoclonais/farmacologia , Neoplasias da Medula Óssea/complicações , Fator de Crescimento Neural/antagonistas & inibidores , Dor/etiologia , Dor/prevenção & controle , Neoplasias da Próstata/complicações , Animais , Neoplasias da Medula Óssea/irrigação sanguínea , Neoplasias da Medula Óssea/patologia , Modelos Animais de Doenças , Cães , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias/métodos , Fator de Crescimento Neural/imunologia , Neoplasias do Sistema Nervoso/irrigação sanguínea , Neoplasias do Sistema Nervoso/complicações , Neoplasias do Sistema Nervoso/tratamento farmacológico , Neuroma/irrigação sanguínea , Neuroma/complicações , Neuroma/tratamento farmacológico , Neoplasias da Próstata/irrigação sanguínea , Neoplasias da Próstata/patologia , Transplante HeterólogoRESUMO
The role of 5-hydroxytryptamine (5-HT)(4), 5-HT(6), and 5-HT(7) receptors in formalin-induced secondary allodynia and hyperalgesia in rats was assessed. Formalin produced acute nociceptive behaviors (flinching and licking/lifting) followed by long-term secondary mechanical allodynia and hyperalgesia. Pretreatment (-10min) with cromoglycate (195-1950nmol/paw) partially inhibited acute nociceptive behaviors and completely prevented secondary allodynia and hyperalgesia on day 6 after injection. Ipsilateral peripheral pretreatment with the selective 5-HT(4) (ML-10302, 1-100nmol/paw), 5-HT(6) (EMD-386088, 0.001-0.01nmol/paw), and 5-HT(7) (LP-12, 0.01-100nmol/paw) receptor agonists significantly increased secondary allodynia and hyperalgesia in both paws. In contrast, ipsilateral peripheral pretreatment with the selective 5-HT(4) (GR-125487, 1-100nmol/paw), 5-HT(6) (SB-258585, 0.00001-0.001nmol/paw), and 5-HT(7) (SB-269970, 0.1-10nmol/paw) receptor antagonists significantly prevented formalin-induced secondary allodynia and hyperalgesia in both paws. The pronociceptive effect of ML-10302 (100nmol/paw), EMD-386088 (0.01nmol/paw), and LP-12 (100nmol/paw) were completely prevented by GR-125487 (5-HT(4) antagonist, 1nmol/paw), SB-258585 (5-HT(6) antagonist, 0.00001nmol/paw), and SB-269970 (5-HT(7), antagonist, 0.01nmol/paw), respectively. Ipsilateral peripheral posttreatment with cromoglycate or GR-125487 (1-100nmol/paw), SB-258585 (0.001-0.1nmol/paw), and SB-269970 (0.1-10nmol/paw) reversed formalin-induced secondary allodynia and hyperalgesia in both paws. Results suggest that a barrage of afferent input induced by 5-HT at peripheral 5-HT(4), 5-HT(6), and 5-HT(7) receptors participate in the development and maintenance of formalin-induced long-term secondary allodynia and hyperalgesia in the rat. 5-hydroxytryptamine (5-HT) released in peripheral tissues after formalin injection sensitized primary afferent neurons via 5-HT(4), 5-HT(6), and 5-HT(7) receptors, leading to development and maintenance of secondary allodynia and hyperalgesia.
Assuntos
Hiperalgesia/metabolismo , Limiar da Dor/fisiologia , Receptores de Serotonina/metabolismo , Animais , Antiasmáticos/farmacologia , Área Sob a Curva , Cromolina Sódica/farmacologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Formaldeído/efeitos adversos , Hiperalgesia/induzido quimicamente , Limiar da Dor/efeitos dos fármacos , Ratos , Ratos Wistar , Receptores Opioides , Receptores 5-HT4 de Serotonina/metabolismo , Serotoninérgicos/farmacologia , Fatores de Tempo , Receptor de NociceptinaRESUMO
This study assessed the role of systemic and spinal 5-HT(7) receptors on rats submitted to spinal nerve injury. In addition, the 5-HT(7) receptors level in dorsal root ganglion and spinal cord was also determined. Tactile allodynia was induced by L5/L6 spinal nerve ligation. Systemic (0.01-10mg/kg) or spinal (0.3-30 µg) administration of the selective 5-HT(7) receptor antagonist SB-269970 but not vehicle reduced in a dose-dependent manner established tactile allodynia. This effect was maintained for about 6h. SB-269970 was more potent and effective by the spinal administration route than through systemic injection. Spinal nerve ligation reduced expression of 5-HT(7) receptors in the ipsilateral but not contralateral dorsal root ganglia. Moreover, 5-HT(7) receptor levels were lower in the ipsilateral dorsal spinal cord of neuropathic rats compared to naïve and sham rats. No changes in the receptor levels were observed in the contralateral dorsal spinal cord and in both regions of the ventral spinal cord. Data suggest that spinal 5-HT(7) receptors play a pronociceptive role in neuropathic rats. Results also indicate that spinal nerve injury leads to a reduced 5-HT(7) receptors level in pain processing-related areas which may result from its nociceptive role in this model. Data suggest that selective 5-HT(7) receptor antagonists may function as analgesics in nerve injury pain states.
Assuntos
Analgésicos , Hiperalgesia/tratamento farmacológico , Receptores de Serotonina/efeitos dos fármacos , Antagonistas da Serotonina/farmacologia , Animais , Área Sob a Curva , Western Blotting , Interpretação Estatística de Dados , Feminino , Lateralidade Funcional/efeitos dos fármacos , Lateralidade Funcional/fisiologia , Hiperalgesia/psicologia , Injeções Intraperitoneais , Injeções Espinhais , Ligadura , Neuralgia/tratamento farmacológico , Medição da Dor/efeitos dos fármacos , Fenóis/farmacologia , Estimulação Física , Células do Corno Posterior/metabolismo , Ratos , Ratos Wistar , Receptores de Serotonina/metabolismo , Nervos Espinhais , Sulfonamidas/farmacologiaRESUMO
UNLABELLED: Breast cancer metastasis to bone is frequently accompanied by pain. What remains unclear is why this pain tends to become more severe and difficult to control with disease progression. Here we test the hypothesis that with disease progression, sensory nerve fibers that innervate the breast cancer bearing bone undergo a pathological sprouting and reorganization, which in other nonmalignant pathologies has been shown to generate and maintain chronic pain. Injection of human breast cancer cells (MDA-MB-231-BO) into the femoral intramedullary space of female athymic nude mice induces sprouting of calcitonin gene-related peptide (CGRP(+)) sensory nerve fibers. Nearly all CGRP(+) nerve fibers that undergo sprouting also coexpress tropomyosin receptor kinase A (TrkA(+)) and growth-associated protein-43 (GAP43(+)). This ectopic sprouting occurs in periosteal sensory nerve fibers that are in close proximity to breast cancer cells, tumor-associated stromal cells, and remodeled cortical bone. Therapeutic treatment with an antibody that sequesters nerve growth factor (NGF), administered when the pain and bone remodeling were first observed, blocks this ectopic sprouting and attenuates cancer pain. The present data suggest that the breast cancer cells and tumor-associated stromal cells express and release NGF, which drives bone pain and the pathological reorganization of nearby CGRP(+)/TrkA(+)/GAP43(+) sensory nerve fibers. PERSPECTIVE: Therapies that block breast cancer pain by reducing the tumor-induced pathological sprouting and reorganization of sensory nerve fibers may provide insight into the evolving mechanisms that drive breast cancer pain and lead to more effective therapies for attenuating this chronic pain state.