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Neurotensin (NTS)-polyplex is a gene nanocarrier that has potential nanomedicine-based applications for the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. We assessed the acute inflammatory response to NTS-polyplex carrying a reporter gene in BALB/c mice. The intravenous injection of NTS-polyplex caused the specific expression of the reporter gene in gastrointestinal cells. Six hours after an intravenous injection of propidium iodide labeled-NTS-polyplex, fluorescent spots were located in the cells of the organs with a mononuclear phagocyte system, suggesting NTS-polyplex clearance. In contrast to lipopolysaccharide and carbon tetrachloride, NTS-polyplex did not increase the serum levels of tumor necrosis factor alpha, interleukin (IL)-1ß, IL-6, bilirubin, aspartate transaminase, and alanine transaminase. NTS-polyplex increased the levels of serum amyloid A and alkaline phosphatase, but these levels normalized after 24 h. Compared to carrageenan, the local injection of NTS-polyplex did not produce inflammation. Our results support the safety of NTS-polyplex. FROM THE CLINICAL EDITOR: This study focuses on the safety of neurotensin (NTS)-polyplex, a gene nanocarrier that has potential in the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. NTS polyplex demonstrates a better safety profile compared with carrageenan, lipopolysaccharide, and carbon tetrachloride in a murine model.
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Técnicas de Transferência de Genes , Terapia Genética/métodos , Nanopartículas , Doença de Parkinson/terapia , Receptores de Neurotensina , Segurança , Administração Intravenosa , Animais , Camundongos , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Receptores de Neurotensina/biossínteseRESUMO
Living Donor Liver Transplantation (LDLT) is a promising approach to treating end-stage liver diseases, however, some post-operatory complications such as pneumonia, bacteremia, urinary tract infections, and hepatic dysfunction have been reported. In murine models using partial hepatectomy (PHx), a model that emulates LDLT, it has been determined that the synthesis of hepatic cell proliferation factors that are associated with noradrenaline synthesis are produced in locus coeruleus (LC). In addition, studies have shown that PHx decreases GABA and 5-HT2A receptors, promotes loss of dendritic spines, and favors microgliosis in rat hippocampus. The GABA and serotonin-altered circuits suggest that catecholaminergic neurons such as dopamine and noradrenaline neurons, which are highly susceptible to cellular stress, can also be damaged. To understand post-transplant affections and to perform well-controlled studies it is necessary to know the potential causes that explain as a liver surgical procedure can produce brain damage. In this paper, we review several cellular processes that could induce gliosis in LC after rat PHx.
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Bromodeoxyuridine (BrdU) is used in studies related to cell proliferation and neurogenesis. The multiple intraperitoneal injections of this molecule could favor liver function profile changes. In this study, we evaluate the systemic and hepatocellular impact of BrdU in male adult Wistar rats in 30 %-partial hepatectomy (PHx) model. The rats received BrdU 50 mg/Kg by intraperitoneal injection at 0.5, 1, 2, 3, 6, 9 and 16 days after 30 %-PH. The rats were distributed into four groups as follows, control, sham, PHx/BrdU(-) and PHx/BrdU(+). On day 16, we evaluated hepatocellular nuclei and analyzed histopathological features by haematoxylin-eosin stain and apoptotic profile was qualified by caspase-3 presence. The systemic effect was evaluated by liver markers such as alanine transferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (AP), bilirubin, total proteins and serum albumin content. The statistical analysis consisted of a student t-test and one-way ANOVA. BrdU did not induce apoptosis or hepatocellular damage in male rats. Multiple administrations of BrdU in male rats did not induce significant decrease body weight, but increased serum ALT and LDH levels were found. Our results show that the BrdU does not produce hepatocellular damage.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Ratos , Masculino , Animais , Ratos Wistar , Bromodesoxiuridina/farmacologia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Fígado/patologia , Alanina Transaminase/metabolismo , Alanina Transaminase/farmacologia , Aspartato Aminotransferases/metabolismo , Aspartato Aminotransferases/farmacologiaRESUMO
Measurements of Morphometric Parameters of the Blood Cells (MPBC) are key for the diagnosis of both mental and metabolic diseases. Several manual approaches or computational methodologies are useful to provide reliable clinical diagnosis. The sample processing and data analysis is relevant, however the sample handling on the pre-analytical phase remains scarcely evaluated. The main goal of this study was to favor the preservation of blood smear using a histological resin. This strategy lead us two practical approaches, give a detailed morphometric description of white blood cells and establish reference intervals in male Wistar rats, which are scarcely reported. Blood smears from male Wistar rats (nâ¯=â¯120) and adult men were collected at room temperature. The integrity of Wright-stained cells was evaluated by an in silico image analysis from rat and human blood smear preserved with a toluene-based synthetic resin mounting medium. A single sample of human blood was used as a control of procedure. The reference intervals was established by cell counting. Based on the results of segmentation algorithm followed by an automatic thresholding analysis, the incorporation of resin favor the conservation of cell blood populations, and lead to identify morphologic features such as nucleus/cytoplasmic shape, granules presence and DNA appearance in nucleus of white blood cells. The use of a histological resin could favor a fast and efficient sample handling in silico MPBC measurements both in the species studied as in wild animals.
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Algoritmos , Processamento de Imagem Assistida por Computador , Animais , Humanos , Processamento de Imagem Assistida por Computador/métodos , Leucócitos , Masculino , Ratos , Ratos Wistar , Manejo de EspécimesRESUMO
PURPOSE: The main goal of this study was to determine the relationship of cleaved-caspase-3 (C3)-related apoptosis and hepatic proliferation, during the liver repopulation in a living liver donor rat model. MATERIAL/METHODS: Thirty-three animals were randomized into eleven groups and evaluated on postoperative from 3 âh until 384 âh after 30%-partial hepatectomy (30%-PHx). Liver sections (5 âµm) were processed by hematoxylin-eosin, and immunostaining for C3, accompanied by hepatic function test. C3 content and the hepatic lobule enlargement were analyzed by optical density, followed by cell counting. RESULTS: Transient variations of alanine transferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were found. Significant increase in the C3 levels, and cell nuclei number, were detected at 12 âh and 48 âh after 30%-PHx, evidencing a correlation of p â= â-0.3679. CONCLUSION: In the 30%-PHx rat model, C3-related apoptosis prevents proliferative pathological conditions during the hepatic lobule re-modeling.
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Apoptose , Caspase 3/metabolismo , Proliferação de Células , Hepatectomia/métodos , Regeneração Hepática , Fígado/patologia , Animais , Caspase 3/genética , Doadores Vivos/estatística & dados numéricos , Masculino , Ratos , Ratos WistarRESUMO
BackgroundDasapatrachurnam (DPC), a multicurative powder prepared from the leaves of 10 green leafy vegetables, was developed recently with known ethnobotanical and ethnopharmacological significance. However, its functional role in curing a disease is not yet scientifically proven. The present study aims at performing the phytochemical screening of DPC and exploring its possible activity as bacteriostatic, antineoplastic and anti-inflammatory. MethodsWe performed qualitative and Fourier transform infrared spectroscopy (FTIR) to find out the presence of active compounds and tested the bacteriostatic activity in four bacterial strains namely Bacillus subtilis, Escherichia coli, Streptococcus pyogenes and Staphylococcus aureus by agar well diffusion method. We further explored the antineoplastic activity in vitro in C6 and HEK293 cell lines by cell viability assay and the anti-inflammatory activity in the ovalbumin-induced inflammation in male Wistar rats. ResultsDPC showed 60% solubility in PBS and showed the presence of flavonoids and glycosides. FTIR results indicated the presence of alkyl, ketone and aldehyde groups. The bacteriostatic activity of DPC was higher (60%) in E.coli and lower (8%) in S.aureus, when compared to streptomycin. The anti-cancerous activity of DPC in C6 and HEK293 cancer cells was similar to their respective positive controls, curcumin and camptothecin. The anti-inflammatory activity of DPC was more evident with local administration in all the parameters studied in brain hippocampus, kidney, liver and spleen in ovalbumin-induced rats. ConclusionOur results, for the first time, suggest the potentiality of the DPC in treating bacterial diseases, cancer and also inflammation. Our results also suggest the possible therapeutic role of DPC in treating chronic kidney disease.
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Suplementos Nutricionais/análise , Compostos Fitoquímicos/farmacologia , Folhas de Planta/química , Preparações de Plantas/farmacologia , Verduras/química , Animais , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Flavonoides/análise , Glicosídeos/análise , Células HEK293 , Humanos , Masculino , Pós , Ratos , Ratos WistarRESUMO
The efficient extraction and fixation of a tissue allows in preserving the cytoarchitecture, chemical composition and tissue organization, which is key in physiological and histopathological studies. The main goal of this study was to establish a microsurgery technique to obtain ocular tissue and provide an optimized immersion fixation protocol based on the 10 % formalin-intraocular injection on Olive ridley sea turtle hatchlings (Lepidochelys olivacea). To evaluate this optimized technique, a histological comparison between traditional immersion and intraocular/immersion protocols was done. The eyeball were processed into five protocols: Frozen eyes (Group 1), frozen eyes immersed in 10 % formalin (Group 2), fresh eyes immersed in 10 % formalin (Group 3), fresh eyes intraocularly injected with 0.1 M phosphate buffer solution (PBS) and then immersed in 10 % formalin (Group 4), and fresh eyes fixed by 10 % formalin-intraocular followed by 10 % formalin-immersion (Group 5). In comparison with all groups evaluated, the intraocular/immersion fixation protocol lead the conservation of eyeball shape, cell integrity and maintenance of the organization of the retina layers of sea turtle hatchlings. If this method will be the key in studying sea turtle, we suppose that this procedure, with minimal adjustments, could be useful in animals with similar eye anatomy.
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Microcirurgia/métodos , Fixação de Tecidos/métodos , Animais , Congelamento , Técnicas In Vitro , Retina , TartarugasRESUMO
OBJECTIVES: Cassava (Manihot esculenta Crantz) contains cyanogenic glycosides (linamarin and lotaustralin) that have been associated with neurological disorders in humans and rats. In basal ganglia, the dopaminergic neurons of substantia nigra pars compacta (SNpc) show high cytotoxic susceptibility; therefore, the chronic consumption of cassava (CCC) could induce neurodegeneration in SNpc. In this study we examine the impact of CCC on the integrity of the nigrostriatal system, including apoptosis and microgliosis. MATERIALS AND METHODS: Male Wistar rats were administered cassava juice daily (3.57 g/kg and 28.56 g/kg, per os) or linamarin (0.15 mg/ml, IP), and its effects were evaluated in rota-rod and swim tests at days 7, 14, 21, 28, and 35 of administration. In SNpc, oxidative/nitrosative stress was determined by malondialdehyde/4-hydroxyalkenals (MDA-4-HAD) and nitrite contents. Tyrosine hydroxylase immunoreactivity (TH-IR) was evaluated in SNpc, neostriatum (NE), and nucleus accumbens (NA). Apoptosis and microgliosis were determined by active-caspase-3 (C3) and CD11b/c (OX42) expression in the medial region of SNpc. RESULTS: Chronic administration of cassava juice, or linamarin, increased motor impairment. The rats that received 28.56 g/kg cassava showed increased MDA-4-HAD content in SNpc and nitrite levels in NE with respect to controls. Significant loss of TH-IR in SNpc, NE, and NA was not found. The 28.56 g/kg cassava administration produced dopaminergic atrophy and microgliosis, whereas linamarin induced hypertrophy and C3-related apoptosis in SNpc. CONCLUSION: CCC induces cellular stress on dopaminergic neurons, which could contribute to motor impairment in the rat.
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Lipopolysaccharide (LPS) is a potent immunogen when administered locally and/or systemically. The peripheral immunization with LPS could contribute to the progression of neurological diseases because a strong link between neuroinflammation and dopaminergic degeneration has been found. The switch between the survival and neuronal death in substantia nigra could be related to M1 (neurotoxic) and M2 (neuroprotective) microglia phenotypes. In this review, we present the current findings about microglia roles, biomarkers, and natural or synthetic immune modulators determined in the LPS-based murine model.
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Modelos Animais de Doenças , Inflamação/imunologia , Lipopolissacarídeos/farmacologia , Microglia/imunologia , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Humanos , Inflamação/induzido quimicamente , Microglia/efeitos dos fármacosRESUMO
OBJECTIVES: Parkinson's disease (PD) is characterized by motor and cognitive dysfunctions. The progressive degeneration of dopamine-producing neurons that are present in the substantia nigra pars compacta (SNpc) has been the main focus of study and PD therapies since ages. MATERIALS AND METHODS: In this manuscript, a systematic revision of experimental and clinical evidence of PD-associated cell process was conducted. RESULTS: Classically, the damage in the dopaminergic neuronal circuits of SNpc is favored by reactive oxidative/nitrosative stress, leading to cell death. Interestingly, the therapy for PD has only focused on avoiding the symptom progression but not in finding a complete reversion of the disease. Recent evidence suggests that the renin-angiotensin system imbalance and neuroinflammation are the main keys in the progression of experimental PD. CONCLUSION: The progression of neurodegeneration in SNpc is due to the complex interaction of multiple processes. In this review, we analyzed the main contribution of four cellular processes and discussed in the perspective of novel experimental approaches.
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The peripheral inflammatory stimulus could induce cell damage in peripheral organs and activate microglial cells in the brain. One such stimulus was given to adult male Wistar rats by injecting different concentrations of lipopolysaccharide (LPS; 50, 300, 500 ïg/kg and 5 mg/kg i.p.). To verify the systemic effect of the LPS administration, the serum content of C-reactive protein (CRP), the variation of body weight and cellular changes in the spleen, liver and kidney were determined. Motor impairment was evaluated by rotarod and open field tests. Microglia activation and dopaminergic degeneration was confirmed by immunolabelling for CD11b/c (microglia) and tyrosine hydroxylase (TH), respectively. The cell counting was performed in substantia nigra pars compacta (SNpc), microglial activation was explored in SNpc, substantia nigra pars reticulata (SNpr), substantia nigra pars compacta dorsal (SNcd) and the ventral tegmental area (VTA). For the statistical analysis, one-way ANOVA followed by Tukey post hoc test (p ≤ 0.05) was used. On day 7 post intraperitoneal administration of LPS, cellular atrophy was detected in the liver, kidney and spleen at 5 mg/kg, without significant changes in CRP levels. Body weight loss and motor impairment was present only on day 1 post LPS administration. The dosage of 500 ïg/kg and 5 mg/kg of LPS caused the loss of dopaminergic neurons (40%) in SNpc and microglia migration in a dose-dependent manner in SNcd, SNpc and SNpr. LPS-induced endotoxemia favours damage to the peripheral organs and microglial migration in a dose-dependent manner in rat substantia nigra.
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Endotoxemia/patologia , Lipopolissacarídeos/toxicidade , Microglia/patologia , Substância Negra/patologia , Animais , Movimento Celular , Neurônios Dopaminérgicos/patologia , Endotoxemia/induzido quimicamente , Masculino , Ratos , Ratos WistarRESUMO
In tradition al Mexican medicine, plants from the Montanoa genus, family Asteraceae ( Montanoa tomentosa , Montanoa grandiflora , and Montanoa frutescens ) have been used to induce labor owing to their uterotonic properties like those produced by oxytocin (OXT). However, w hether infusions of these plants can activate hypothalamic OXT - producing neurons is unknown. To test this possibility, five independent groups of Wistar rats (n=4) were included: intact, vehicle, and three groups that received 50 mg/kg p.o. of M. tomentosa , M. grandiflora , and M. frutescens infusions, respectively. Ninety min after treatment, the brains were obtained and processed using double - labeled immunohistochemistry for Fos protein and oxytocin (Fos/OXT - ir). Rats that received Montanoa infusions had s ignificantly greater number of Fos/OXT - ir cells in the paraventricular (PVN) and supraoptic (SON) nuclei, with respect to intact and vehicle groups. These findings demonstrate that Montanoa infusions activated OXT neurons, an effect that may be related to the reported pharmacological properties.
En la medicina tradicional mexicana, plantas del género Montanoa , familia Asteraceae ( Montanoa tomentosa , Montanoa grandiflora y Montanoa frutescens ), se han utilizado para inducir el parto debido a sus propiedades uterotónicas, aparentemente similares a las producidas por la hormona oxitocina (OXT). Sin embargo, se desconoce si las infusiones de estas plantas pueden activar neuronas hipotalámicas productoras de OXT. Para probar esta posibilidad, se incluyeron cinco grupos independientes (n=4): intacto, vehículo y tres grupos que recibieron 50 mg/kg p.o. de infusiones de M. tomentosa , M. grandiflora , y M. frute scens , respectivamente. Noventa minutos después del tratamiento, los cerebros fueron obtenidos y procesados por doble marcaje de inmunohistoquímica para la proteína Fos y oxitocina (Fos/OXT - ir). Las ratas que recibieron infusiones de Montanoa aumentaron si gnificativamente el número de células Fos/OXT - ir en los núcleos paraventricular (PVN) y supraóptico (SON), respecto a los grupos intacto y vehículo. Estos hallazgos demuestran que las infusiones de Montanoa activan neuronas de OXT, lo que podría estar rela cionado con sus propiedades farmacológicas
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Animais , Ratos , Ocitocina , Montanoa/química , Neurônios/efeitos dos fármacos , Imuno-Histoquímica , Extratos Vegetais/farmacologia , Ratos WistarRESUMO
The human breast adenocarcinoma cell line MDA-MB-231 has the triple-negative breast cancer (TNBC) phenotype, which is an aggressive subtype with no specific treatment. MDA-MB-231 cells express neurotensin receptor type 1 (NTSR1), which makes these cells an attractive target of therapeutic genes that are delivered by the neurotensin (NTS)-polyplex nanocarrier via the bloodstream. We addressed the relevance of this strategy for TNBC treatment using NTS-polyplex nanoparticles harboring the herpes simplex virus thymidine kinase (HSVtk) suicide gene and its complementary prodrug ganciclovir (GCV). The reporter gene encoding green fluorescent protein (GFP) was used as a control. NTS-polyplex successfully transfected both genes in cultured MDA-MB-231 cells. The transfection was demonstrated pharmacologically to be dependent on activation of NTSR1. The expression of HSVtk gene decreased cell viability by 49% (P<0.0001) and induced apoptosis in cultured MDA-MB-231 cells after complementary GCV treatment. In the MDA-MB-231 xenograft model, NTS-polyplex nanoparticles carrying either the HSVtk gene or GFP gene were injected into the tumors or via the bloodstream. Both routes of administration allowed the NTS-polyplex nanoparticles to reach and transfect tumorous cells. HSVtk expression and GCV led to apoptosis, as shown by the presence of cleaved caspase-3 and Apostain immunoreactivity, and significantly inhibited the tumor growth (55-60%) (P<0.001). At the end of the experiment, the weight of tumors transfected with the HSVtk gene was 55% less than that of control tumors (P<0.05). The intravenous transfection did not induce apoptosis in peripheral organs. Our results offer a promising gene therapy for TNBC using the NTS-polyplex nanocarrier.
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Ganciclovir/farmacologia , Genes Transgênicos Suicidas/genética , Terapia Genética/métodos , Timidina Quinase/genética , Transplante Heterólogo/métodos , Neoplasias de Mama Triplo Negativas/fisiopatologia , Neoplasias de Mama Triplo Negativas/terapia , Animais , Apoptose/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/genética , Feminino , Técnicas de Transferência de Genes , Humanos , Camundongos , Camundongos Nus , Microscopia Eletrônica de Varredura , Nanopartículas/metabolismo , Neurotensina/metabolismo , Simplexvirus/enzimologia , Timidina Quinase/metabolismoRESUMO
The 6-Hydroxydopamine (6-OHDA) rat model of Parkinson's disease is essential for a better understanding of the pathological processes underlying the human disease and for the evaluation of promising therapeutic interventions. This work evaluated whether a single striatal injection of 6-OHDA causes progressive apoptosis of dopamine (DA) neurons and activation of glycogen synthase kinase 3ß (GSK-3ß) and caspase-3 in the substantia nigra compacta (SNc). The loss of DA neurons was shown by three neuron markers; tyrosine hydroxylase (TH), NeuN, and ß-III tubulin. Apoptosis activation was determined using Apostain and immunostaining against cleaved caspase-3 and GSK-3ß pY216. We also explored the possibility that cleaved caspase-3 is produced by microglia and astrocytes. Our results showed that the 6-OHDA caused loss of nigral TH(+) cells, progressing mainly in rostrocaudal and lateromedial directions. In the neostriatum, a severe loss of TH(+) terminals occurred from day 3 after lesion. The disappearance of TH(+) cells was associated with a decrease in NeuN and ß-III tubulin immunoreactivity and an increase in Apostain, cleaved caspase-3, and GSK-3ß pY216 in the SNc. Apostain immunoreactivity was observed from days 3 to 21 postlesion. Increased levels of caspase-3 immunoreactivity in TH(+) cells were detected from days 1 to 15, and the levels then decreased to day 30 postlesion. The cleaved caspase-3 also collocated with microglia and astrocytes indicating its participation in glial activation. Our results suggest that caspase-3 and GSK-3ß pY216 activation might participate in the DA cell death and that the active caspase-3 might also participate in the neuroinflammation caused by the striatal 6-OHDA injection.
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Apoptose , Caspase 3/metabolismo , Neurônios Dopaminérgicos/enzimologia , Quinase 3 da Glicogênio Sintase/metabolismo , Doença de Parkinson Secundária/enzimologia , Substância Negra/enzimologia , Animais , Antígenos Nucleares/metabolismo , Citoesqueleto/metabolismo , Ativação Enzimática , Glicogênio Sintase Quinase 3 beta , Masculino , Proteínas do Tecido Nervoso/metabolismo , Oxidopamina , Doença de Parkinson Secundária/induzido quimicamente , Ratos , Ratos Wistar , Substância Negra/patologia , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Zinc or L-NAME administration has been shown to be protector agents, decreasing oxidative stress and cell death. However, the treatment with zinc and L-NAME by intraperitoneal injection has not been studied. The aim of our work was to study the effect of zinc and L-NAME administration on nitrosative stress and cell death. Male Wistar rats were treated with ZnCl2 (2.5 mg/kg each 24 h, for 4 days) and N-ω-nitro-L-arginine-methyl ester (L-NAME, 10 mg/kg) on the day 5 (1 hour before a common carotid-artery occlusion (CCAO)). The temporoparietal cortex and hippocampus were dissected, and zinc, nitrites, and lipoperoxidation were assayed at different times. Cell death was assayed by histopathology using hematoxylin-eosin staining and caspase-3 active by immunostaining. The subacute administration of zinc before CCAO decreases the levels of zinc, nitrites, lipoperoxidation, and cell death in the late phase of the ischemia. L-NAME administration in the rats treated with zinc showed an increase of zinc levels in the early phase and increase of zinc, nitrites, and lipoperoxidation levels, cell death by necrosis, and the apoptosis in the late phase. These results suggest that the use of these two therapeutic strategies increased the injury caused by the CCAO, unlike the alone administration of zinc.
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Artéria Carótida Primitiva/efeitos dos fármacos , Caspase 3/metabolismo , Hipóxia-Isquemia Encefálica/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , NG-Nitroarginina Metil Éster/uso terapêutico , Óxido Nítrico/metabolismo , Zinco/metabolismo , Zinco/uso terapêutico , Animais , Masculino , Estresse Oxidativo , Ratos , Ratos WistarRESUMO
The study of signal transduction in dopamine (DA)-containing neurons as well as the development of new therapeutic approaches for Parkinson's disease requires the selective expression of transgenes in such neurons. Here we describe optimization of the use of the NTS-polyplex, a gene carrier system taking advantage of neurotensin receptor internalization, to transfect mouse DA neurons in primary culture. The plasmids DsRed2 (4.7 kbp) and VGLUT2-Venus (11 kbp) were used to compare the ability of this carrier system to transfect plasmids of different sizes. We examined the impact of age of the neurons (1, 3, 5 and 8 days after seeding), of culture media used during the transfection (Neurobasal with B27 vs. conditioned medium) and of three molar ratios of plasmid DNA to carrier. While the NTS-polyplex successfully transfected both plasmids in a control N1E-115 cell line, only the pDsRed2 plasmid could be transfected in primary cultured DA neurons. We achieved 20% transfection efficiency of pDsRed2 in DA neurons, with 80% cell viability. The transfection was demonstrated pharmacologically to be dependent on activation of neurotensin receptors and to be selective for DA neurons. The presence of conditioned medium for transfection was found to be required to insure cell viability. Highest transfection efficiency was achieved in the most mature neurons. In contrast, transfection with the VGLUT2-Venus plasmid produced cell damage, most likely due to the high molar ratios required, as evidenced by a 15% cell viability of DA neurons at the three molar ratios tested (1:36, 1:39 and 1:42). We conclude that, when used at molar ratios lower than 1:33, the NTS-polyplex can selectively transfect mature cultured DA neurons with only low levels of toxicity. Our results provide evidence that the NTS-polyplex has good potential for targeted gene delivery in cultured DA neurons, an in vitro system of great use for the screening of new therapeutic approaches for Parkinson's disease.