RESUMO
Resistance physical exercise has neuroprotective and anti-inflammatory effects on many known diseases and, therefore, it has been increasingly explored. The way in which this type of exercise exerts these actions is still under investigation. In this study, we aimed to analyze the enzymes and components of the purinergic system involved in the inflammatory process triggered by the P2X7R. Rats were divided into four groups: control, exercise (EX), lipopolysaccharide (LPS), and EX + LPS. The animals in the exercise groups were subjected to a 12-week ladder-climbing resistance physical exercise and received LPS after the last session for sepsis induction. Enzymes activities (NTPDase, 5'-nucleotidase, and adenosine deaminase), purinoceptors' density (P2X7R, A1, and A2A), and the levels of inflammatory indicators (pyrin domain-containing protein 3 (NLRP3), Caspase-1, interleukin (IL)- 6, IL-1B, and tumor necrosis factor (TNF) -α) were measured in the cortex and hippocampus of the animals. The results show that exercise prevented (in the both structures) the increase of: 1) nucleoside-triphosphatase (NTPDase) and 5'-nucleotidase activities; 2) P2X7R density; 3) NLRP3 and Caspase-1; and 4) IL-6, IL-1ß, and TNF-α It is suggested that the purinergic system and the inflammatory pathway of P2X7R are of fundamental importance and influence the effects of resistance physical exercise on LPS-induced inflammation. Thus, the modulation of the P2X7R by resistance physical exercise offers new avenues for the management of inflammatory-related illnesses.
Assuntos
Lipopolissacarídeos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Ratos , Animais , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Lipopolissacarídeos/toxicidade , 5'-Nucleotidase/metabolismo , Doenças Neuroinflamatórias , Hipocampo/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Interleucina-6/metabolismo , Exercício Físico , Caspases/metabolismo , Receptores Purinérgicos P2X7/metabolismoRESUMO
Alzheimer's disease (AD) is a neurodegenerative pathology characterized by progressive impairment of memory, associated with neurochemical alterations and limited therapy. The aim of this study was to evaluate the effects of inosine on memory, neuroinflammatory cytokines, neurotrophic factors, expression of purinergic receptors, and morphological changes in the hippocampus and cerebral cortex of the rats with AD induced by streptozotocin (STZ). Male rats were divided into four groups: I, control; II, STZ; III, STZ plus inosine (50 mg/kg); and IV, STZ plus inosine (100 mg/kg). The animals received intracerebroventricular injections of STZ or buffer. Three days after the surgical procedure, animals were treated with inosine (50 mg/kg or 100 mg/kg) for 25 days. Inosine was able to prevent memory deficits and decreased the immunoreactivity of the brain A2A adenosine receptor induced by STZ. Inosine also increased the levels of brain anti-inflammatory cytokines (IL-4 and IL-10) and the expression of brain-derived neurotrophic factor and its receptor. Changes induced by STZ in the molecular layer of the hippocampus were attenuated by treatment with inosine. Inosine also protected against the reduction of immunoreactivity for synaptophysin induced by STZ in CA3 hippocampus region. However, inosine did not prevent the increase in GFAP in animals exposed to STZ. In conclusion, our findings suggest that inosine has therapeutic potential for AD through the modulation of different brain mechanisms involved in neuroprotection.
Assuntos
Doença de Alzheimer , Inosina , Receptores Purinérgicos , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Hipocampo/metabolismo , Inosina/farmacologia , Inosina/uso terapêutico , Masculino , Aprendizagem em Labirinto , Transtornos da Memória/tratamento farmacológico , Doenças Neuroinflamatórias , Ratos , Ratos Wistar , Receptores Purinérgicos/metabolismo , EstreptozocinaRESUMO
Aluminum (Al) is ubiquitously present in the environment and known to be a neurotoxin for humans. The trivalent free Al anion (Al3+) can cross the blood-brain barrier (BBB), accumulate in the brain, and elicit harmful effects to the central nervous system (CNS) cells. Thus, evidence has suggested that Al increases the risk of developing neurodegenerative diseases, particularly Alzheimer's disease (AD). Purinergic signaling has been shown to play a role in several neurological conditions as it can modulate the functioning of several cell types, such as microglial cells, the main resident immune cells of the CNS. However, Al effects on microglial cells and the role of the purinergic system remain elusive. Based on this background, this study is aimed at assessing the modulation of Al on purinergic system parameters of microglial cells. An in vitro study was performed using brain microglial cells exposed to Al chloride (AlCl3) and lipopolysaccharide (LPS) for 96 h. The uptake of Al, metabolism of nucleotides (ATP, ADP, and AMP) and nucleoside (adenosine), and the gene expression and protein density of purinoceptors were investigated. The results showed that both Al and LPS increased the breakdown of adenosine, whereas they decreased nucleotide hydrolysis. Furthermore, the findings revealed that both Al and LPS triggered an increase in gene expression and protein density of P2X7R and A2AR receptors, whereas reduced the A1R receptor expression and density. Taken together, the results showed that Al and LPS altered the setup of the purinergic system of microglial cells. Thus, this study provides new insights into the involvement of the purinergic system in the mechanisms underlying Al toxicity in microglial cells.
Assuntos
Alumínio/efeitos adversos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Receptores Purinérgicos/metabolismo , Animais , Biomarcadores , Encéfalo/efeitos dos fármacos , Encéfalo/imunologia , Encéfalo/metabolismo , Linhagem Celular , Células Cultivadas , Imunofluorescência , Expressão Gênica , Humanos , Lipopolissacarídeos/imunologia , Camundongos , Microglia/imunologia , Receptores Purinérgicos/genéticaRESUMO
Diabetes mellitus (DM) and hypertension are highly prevalent worldwide health problems and frequently associated with severe clinical complications, such as diabetic cardiomyopathy, nephropathy, retinopathy, neuropathy, stroke, and cardiac arrhythmia, among others. Despite all existing research results and reasonable speculations, knowledge about the role of purinergic system in individuals with DM and hypertension remains restricted. Purinergic signaling accounts for a complex network of receptors and extracellular enzymes responsible for the recognition and degradation of extracellular nucleotides and adenosine. The main components of this system that will be presented in this review are: P1 and P2 receptors and the enzymatic cascade composed by CD39 (NTPDase; with ATP and ADP as a substrate), CD73 (5'-nucleotidase; with AMP as a substrate), and adenosine deaminase (ADA; with adenosine as a substrate). The purinergic system has recently emerged as a central player in several physiopathological conditions, particularly those linked to inflammatory responses such as diabetes and hypertension. Therefore, the present review focuses on changes in both purinergic P1 and P2 receptor expression as well as the activities of CD39, CD73, and ADA in diabetes and hypertension conditions. It can be postulated that the manipulation of the purinergic axis at different levels can prevent or exacerbate the insurgency and evolution of diabetes and hypertension working as a compensatory mechanism.
Assuntos
Diabetes Mellitus/metabolismo , Hipertensão/metabolismo , Purinas/metabolismo , Receptores Purinérgicos P1/metabolismo , Receptores Purinérgicos P2/metabolismo , 5'-Nucleotidase/metabolismo , Adenosina Desaminase/metabolismo , Animais , Antígenos CD/metabolismo , Apirase/metabolismo , Comunicação Celular , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/fisiopatologia , Diabetes Mellitus/terapia , Dieta Saudável , Exercício Físico , Humanos , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Hipertensão/terapia , Antagonistas de Receptores Purinérgicos P1/uso terapêutico , Antagonistas do Receptor Purinérgico P2/uso terapêutico , Transdução de SinaisRESUMO
Both the cholinergic pathway and oxidative stress are important mechanisms involved in the pathogenesis of hypothyroidism, a condition characterized by low levels of thyroid hormone that predispose the patient to brain dysfunction. Phenolic compounds have numerous health benefits, including antioxidant activity. This study evaluates the preventive effects of resveratrol in the cholinergic system and redox status in rats with methimazole-induced hypothyroidism. Hypothyroidism increases acetylcholinesterase (AChE) activity and density in the cerebral cortex and hippocampus and decreases the α7 and M1 receptor densities in the hippocampus. Hypothyroidism also increases cellular levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), but reduces total thiol content, and catalase and superoxide dismutase activities in the serum. In the cerebral cortex and hippocampus, hypothyroidism increases the levels of ROS and nitrites. In this study, resveratrol (50 mg/kg) treatment prevents the observed increase in AChE in the cerebral cortex, and increases the protein levels of NeuN, a marker of mature neurons. Resveratrol also prevents changes in serum ROS levels and brain structure, as well as the levels of TBARS, total thiol content, and serum catalase enzyme activity. These collective findings suggest that resveratrol has a high antioxidant capacity and can restore hypothyroidism-triggered alterations related to neurotransmission. Thus, it is a promising agent for the prevention of brain damage resulting from hypothyroidism.
Assuntos
Colinérgicos/metabolismo , Hipotireoidismo/metabolismo , Hipotireoidismo/patologia , Neuroproteção/efeitos dos fármacos , Resveratrol/farmacologia , Transdução de Sinais , Acetilcolinesterase/metabolismo , Animais , Antígenos Nucleares/metabolismo , Modelos Animais de Doenças , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/metabolismo , Hipotireoidismo/sangue , Masculino , Proteínas do Tecido Nervoso/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Receptores Colinérgicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
The central nervous system of the intermediate host plays a central role in lifelong persistence of Toxoplasma gondii as well as the pathogenesis of congenital toxoplasmosis and reactivated infection in immunocompromised individuals. The purinergic system has been implicated in a wide range of immunological pathways for controlling intracellular responses to pathogens, including T. gondii. In the present study, we investigated the effect of resveratrol (RSV) on ectonucleotidases, adenosine deaminase (ADA), and purinergic receptors during chronic infection by T. gondii. For this study, Swiss mice were divided into control (CTL), resveratrol (RSV), infected (INF), and INF+RSV groups. The animals were orally infected with the VEG strain and treated with RSV (100 mg/kg, orally). Ectonucleotidase activities, P2X7, P2Y1, A1, and A2A purinergic receptor density, ROS, and thiobarbituric acid reactive substances levels were measured in the cerebral cortex of mice. T. gondii infection increased NTPDase and reduced ADA activities. Treatment with RSV also affected enzymes hydrolysing extracellular nucleotides and nucleosides. Finally, RSV affected P1 and P2 purinergic receptor expression during T. gondii infection. Overall, RSV-mediated beneficial changes in purinergic signalling and oxidative stress, possibly improving cerebral cortex homeostasis in T. gondii infection.
Assuntos
Córtex Cerebral/parasitologia , Inibidores Enzimáticos/farmacologia , Fármacos Neuroprotetores/farmacologia , Resveratrol/farmacologia , Toxoplasmose Animal/tratamento farmacológico , Adenosina Desaminase/metabolismo , Animais , Camundongos , Receptores Purinérgicos/metabolismo , Transdução de Sinais , Toxoplasma/imunologiaRESUMO
Sepsis is a generalized infection that involves alterations in inflammatory parameters, oxidant status, and purinergic signaling in many tissues. Physical exercise has emerged as a tool to prevent this disease because of its anti-inflammatory and antioxidant properties. Thus, in this study, we investigated the effects of physical exercise on preventing alterations in purinergic system components, oxidative stress, and inflammatory parameters in lipopolysaccharide (LPS)-induced sepsis in rats. Male Wistar rats were divided into four groups: control, exercise (EX), LPS, and EX+LPS. The resisted physical exercise was performed for 12 weeks on a ladder with 1 m height. After 72 hours of the last exercise session, the animals received 2.5 mg/kg of LPS for induction of sepsis, and after 24 hours, lungs and blood samples were collected for analysis. The results showed that the exercise protocol used was able to prevent, in septic animals: (1) the increase in body temperature; (2) the increase of lipid peroxidation and reactive species levels in the lung, (3) the increase in adenosine triphosphate levels in serum; (4) the change in the activity of the enzymes ectonucleotidases in lymphocytes, partially; (5) the change in the density of purinergic enzymes and receptors in the lung, and (6) the increase of IL-6 and IL-1ß gene expression. Our results revealed the involvement of purinergic signaling and oxidative damage in the mechanisms by which exercise prevents sepsis aggravations. Therefore, the regular practice of physical exercise is encouraged as a better way to prepare the body against sepsis complications.
Assuntos
Lipopolissacarídeos/toxicidade , Condicionamento Físico Animal/fisiologia , Sepse/induzido quimicamente , Sepse/prevenção & controle , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Sepse/metabolismo , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
SCOPE: Beneficial effects produced by polyphenolic compounds are used in the treatment of various diseases, including diabetes. Thus it is relevant to investigate the protective effect of lingonberry extract (LB) on the activities of nucleoside triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase (5'-NT), and adenosine deaminase (ADA); the density of A1, A2A, and P2×7 receptors; production of reactive species (RS); and the levels of thiobarbituric acid reactive substances (TBARS) in the cerebral cortex of streptozotocin-induced diabetic rats. METHODS AND RESULTS: Animals were divided into five groups (n = 10): control/saline; control/LB 50 mg kg-1 ; diabetic/saline; diabetic/LB 25 mg kg-1 ; and diabetic/LB 50 mg kg-1 ; and treated for 30 days. Our results demonstrate that the treatment with LB increased NTPDase activity in the diabetic/LB 50 group compared to diabetic/saline group. Western blot analysis showed that LB restored the density of purinergic receptors to the approximate values of the control/saline group. An increase in the levels of RS and TBARS was observed in the diabetic/saline group compared with the control/saline group, and treatment with LB can prevent this increase. CONCLUSION: This study showed that LB could reverse the modifications found in the diabetic state, suggesting that lingonberry may be a coadjuvant in the treatment of diabetes.
Assuntos
Aminoidrolases/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Receptores Purinérgicos/efeitos dos fármacos , Vaccinium vitis-Idaea , 5'-Nucleotidase/metabolismo , Animais , Glicemia/análise , Córtex Cerebral/metabolismo , Diabetes Mellitus Experimental/metabolismo , Masculino , Ratos , Ratos Wistar , EstreptozocinaRESUMO
Thyroid hormones have an influence on the functioning of the central nervous system. Furthermore, the cholinergic and purinergic systems also are extensively involved in brain function. In this context, quercetin is a polyphenol with antioxidant and neuroprotective properties. This study investigated the effects of (MMI)-induced hypothyroidism on the NTPDase, 5'-nucleotidase, adenosine deaminase (ADA), and acetylcholinesterase (AChE) activities in synaptosomes of rats and whether the quercetin can prevent it. MMI at a concentration of 20 mg/100 mL was administered for 90 days in the drinking water. The animals were divided into six groups: control/water (CT/W), control/quercetin 10 mg/kg, control/quercetin 25 mg/kg, methimazole/water (MMI/W), methimazole/quercetin 10 mg/kg (MMI/Q10), and methimazole/quercetin 25 mg/kg (MMI/Q25). On the 30th day, hormonal dosing was performed to confirm hypothyroidism, and the animals were subsequently treated with 10 or 25 mg/kg quercetin for 60 days. NTPDase activity was not altered in the MMI/W group. However, treatment with quercetin decreased ATP and ADP hydrolysis in the MMI/Q10 and MMI/Q25 groups. 5'-nucleotidase activity increased in the MMI/W group, but treatments with 10 or 25 mg/kg quercetin decreased 5'-nucleotidase activity. ADA activity decreased in the CT/25 and MMI/Q25 groups. Furthermore, AChE activity was reduced in all groups with hypothyroidism. In vitro tests also demonstrated that quercetin per se decreased NTPDase, 5'-nucleotidase, and AChE activities. This study demonstrated changes in the 5'-nucleotidase and AChE activities indicating that purinergic and cholinergic neurotransmission are altered in this condition. In addition, quercetin can alter these parameters and may be a promising natural compound with important neuroprotective actions in hypothyroidism.
Assuntos
5'-Nucleotidase/metabolismo , Acetilcolinesterase/metabolismo , Hipotireoidismo/enzimologia , Nucleosídeo-Trifosfatase/metabolismo , Quercetina/uso terapêutico , Sinaptossomos/enzimologia , Animais , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Hipotireoidismo/tratamento farmacológico , Masculino , Polifenóis/farmacologia , Polifenóis/uso terapêutico , Quercetina/farmacologia , Ratos , Ratos Wistar , Sinaptossomos/efeitos dos fármacosRESUMO
Diabetes mellitus (DM) is characterised by hyperglycaemia associated with the increase of oxidative stress. Gallic acid has potent antioxidant properties. The aim of this study was to evaluate the effect of gallic acid on the biochemical, histological and oxidative stress parameters in the liver and kidney of diabetic rats. Male rats were divided in groups: control, gallic acid, diabetic and diabetic plus gallic acid. DM was induced in the animals by intraperitoneal injection of streptozotocin (65mg/kg). Gallic acid (30mg/kg) was administered orally for 21days. Our results showed an increase in reactive species levels and lipid peroxidation, and a decrease in activity of the enzymes superoxide dismutase and delta-aminolevulinic acid dehydratase in the liver and kidney of the diabetic animals (P<0.05). Gallic acid treatment showed protective effects in these parameters evaluated, and also prevented a decrease in the activity of catalase and glutathione S-transferase, and vitamin C levels in the liver of diabetic rats. In addition, gallic acid reduced the number of nuclei and increased the area of the core in hepatic tissue, and increased the glomerular area in renal tissue. These results indicate that gallic acid can protect against oxidative stress-induced damage in the diabetic state.