RESUMO
Heterotopic ossification (HO) is a pathological condition characterized by the deposition of mineralized tissue in ectopic locations such as the skeletal muscle. The precise cellular origin and molecular mechanisms underlying HO are still debated. In our study we focus on the differentiation of mesoangioblasts (MABs), a population of multipotent skeletal muscle precursors. High-content screening for small molecules that perturb MAB differentiation decisions identified Idoxuridine (IdU), an antiviral and radiotherapy adjuvant, as a molecule that promotes MAB osteogenic differentiation while inhibiting myogenesis. IdU-dependent osteogenesis does not rely on the canonical BMP-2/SMADs osteogenic pathway. At pro-osteogenic conditions IdU induces a mild DNA Damage Response (DDR) that activates ATM and p38 eventually promoting the phosphorylation of the osteogenesis master regulator RUNX2. By interfering with this pathway IdU-induced osteogenesis is severely impaired. Overall, our study suggests that induction of the DDR promotes osteogenesis in muscle resident MABs thereby offering a new mechanism that may be involved in the ectopic deposition of mineralized tissue in the muscle.
Assuntos
Diferenciação Celular , Dano ao DNA , Células-Tronco Multipotentes/patologia , Músculo Esquelético/patologia , Osteogênese , Animais , Proteína Morfogenética Óssea 2/metabolismo , Diferenciação Celular/efeitos dos fármacos , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Idoxuridina/farmacologia , Células-Tronco Multipotentes/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Ossificação Heterotópica , Proteínas Smad/metabolismoRESUMO
A group of 180 H. pylori culture positive dyspeptic patients (64 patients with peptic ulcer, PU) completed a 2-week treatment with omeprazole, amoxicillin and metronidazole and underwent endoscopy again 6-8 weeks after the end of therapy. One hundred and twenty-four patients (68.8%) were successfully treated. Factors increasing the rates of eradication were the presence of PU (p=0.007) and anti-CagA serum antibodies (p=0.003). Factors negatively modulating eradication were the presence of coccoid forms (p=0.0008) and metronidazole-resistant strains (p=0.001); degrees of histological gastritis had no significant effect on eradication rates. Microscopic examination of smeared biopsies for the detection of the coccoid morphoytpe of H. pylori may help avoiding therapeutic failures.
Assuntos
Amoxicilina/uso terapêutico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/patogenicidade , Metronidazol/uso terapêutico , Omeprazol/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/sangue , Proteínas de Bactérias/sangue , Biópsia , Farmacorresistência Bacteriana , Gastrite/microbiologia , Gastrite/patologia , Infecções por Helicobacter/patologia , Infecções por Helicobacter/prevenção & controle , Helicobacter pylori/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Úlcera Péptica/microbiologia , Úlcera Péptica/patologia , Resultado do TratamentoRESUMO
Clinical studies show an evident antidepressive effect of physical exercise and animal research corroborate such evidence. However, the neurobiological mechanisms underlying the antidepressive effect of exercise are not completely understood. Notwithstanding, it is known that exercise increases brain-derived neurotrophic factor (BDNF) expression in the hippocampus similarly to antidepressant drugs. BDNF is synthesized as a precursor molecule that undergoes a proteolytic cleavage to generate either a mature or a truncated isoform. Precursor and mature BDNF are assumed to elicit opposing biological effects in neuroplasticity. In the present study we investigated the effect of voluntary physical activity on precursor and mature brain-derived neurotrophic factor levels and on proBDNF cleavage related genes, p11 and tissue plasminogen activator (tPA), as well as the antidepressive and cognitive effects of voluntary physical activity. Mice had access to mobile or locked running wheels for 28 days and were submitted to forced-swim, tail suspension and water maze tests. Their hippocampi were dissected and analyzed by Western blot and real time RT-PCR. Voluntary physical activity, but not locked wheel exposure, induced a robust increase in hippocampal mature BDNF protein levels, as well as in p11 and tPA mRNA expression; and also promoted antidepressive effects and improved learning, when compared with sedentary mice. On the other hand, there were no significant differences between any groups in the expression of precursor or truncated isoforms of BDNF. Our data suggest that the antidepressive effect of the physical exercise may depend, at least in part, on changes in BDNF post-translational processing.
Assuntos
Anexina A2/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Condicionamento Físico Animal/fisiologia , Proteínas S100/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo , Animais , Anexina A2/genética , Western Blotting , Depressão/metabolismo , Hipocampo/metabolismo , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Processamento de Proteína Pós-Traducional , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas S100/genética , Ativador de Plasminogênio Tecidual/genéticaRESUMO
AIMS: Recent studies have emphasized the beneficial effects of the vascular endothelial growth factor (VEGF) on neurone survival and Schwann cell proliferation. VEGF is a potent angiogenic factor, and angiogenesis has long been recognized as an important and necessary step during tissue repair. Here, we investigated the effects of VEGF on sciatic nerve regeneration. METHODS: Using light and electron microscopy, we evaluated sciatic nerve regeneration after transection and VEGF gene therapy. We examined the survival of the neurones in the dorsal root ganglia and in lumbar 4 segment of spinal cord. We also evaluated the functional recovery using the sciatic functional index and gastrocnemius muscle weight. In addition, we evaluated the VEGF expression by immunohistochemistry. RESULTS: Fluorescein isothiocyanate-dextran (FITC-dextran) fluorescence of nerves and muscles revealed intense staining in the VEGF-treated group. Quantitative analysis showed that the numbers of myelinated fibres and blood vessels were significantly higher in VEGF-treated animals. VEGF also increased the survival of neurone cell bodies in dorsal root ganglia and in spinal cord. The sciatic functional index and gastrocnemius muscle weight reached significantly higher values in VEGF-treated animals. CONCLUSION: We demonstrate a positive relationship between increased vascularization and enhanced nerve regeneration, indicating that VEGF administration can support and enhance the growth of regenerating nerve fibres, probably through a combination of angiogenic, neurotrophic and neuroprotective effects.
Assuntos
Terapia Genética/métodos , Regeneração Nervosa/fisiologia , Traumatismos dos Nervos Periféricos/terapia , Recuperação de Função Fisiológica/fisiologia , Nervo Isquiático/fisiologia , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Feminino , Camundongos , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Traumatismos dos Nervos Periféricos/fisiopatologiaRESUMO
We investigated the ultrastructural organization of transplanted autologous grafts after storage in two different solutions. Male Wistar rats were divided into groups to obtain normal tibial nerves, freshly transplanted nerves, and nerves stored in Wisconsin/Belzer or Collins solution for 24 or 72 hours at 4 °C and transplanted (W1, W3, C1, C3). After storage or transplantation, the specimens were processed for ultrastructural analysis. All grafts showed alterations in collagen fiber organization in the endoneurial space compared to normal nerves. These fibers were more loosely organized among nerve fibers, a finding that was significantly more marked in group C3 compared to groups W1 and W3. Important alterations were also observed in the myelin sheath structure of grafts stored in the two media. These changes were characterized by separation of the lipid lamellae, clearly visible in larger diameter nerve fibers. These findings were more marked and frequent in the C1 and C3 groups compared to the W1 and W3 groups. Ultrastructural analysis showed better preservation of Schwann cells and other elements that support axonal regeneration for grafts stored in Wisconsin/Belzer solution. These results support ongoing studies for the formulation of storage solutions that permit the creation of nerve banks for heterologous transplantation.
Assuntos
Animais , Masculino , Ratos , Curativos Biológicos , Nervo Tibial/anatomia & histologia , Nervos Periféricos/anatomia & histologia , Nervo Tibial , Nervo Tibial/fisiologia , Ratos Wistar , Células de SchwannRESUMO
Ciliary neurotrophic factor (CNTF) is a cytokine that plays a neuroprotective role in relation to axotomized motoneurons. We determined the effect of daily subcutaneous doses of CNTF (1.2 microg/g for 5 days; N = 13) or PBS (N = 13) on the levels of mRNA for Bcl-2 and Bax, as well as the expression and inter-association of Bcl-2 and Bax proteins, and the survival of motoneurons in the spinal cord lumbar enlargement of 2-day-old Wistar rats after sciatic nerve transection. Five days after transection, the effects were evaluated on histological and molecular levels using Nissl staining, immunoprecipitation, Western blot analysis, and reverse transcriptase-polymerase chain reaction. The motoneuron survival ratio, defined as the ratio between the number of motoneurons counted on the lesioned side vs those on the unlesioned side, was calculated. This ratio was 0.77 +/- 0.02 for CNTF-treated rats vs 0.53 +/- 0.02 for the PBS-treated controls (P < 0.001). Treatment with CNTF modified the level of mRNA, with the expression of Bax RNA decreasing 18% (with a consequent decrease in the level of Bax protein), while the expression of Bcl-2 RNA was increased 87%, although the level of Bcl-2 protein was unchanged. The amount of Bcl-2/Bax heterodimer increased 91% over that found in the PBS-treated controls. These data show, for the first time, that the neuroprotective effect of CNTF on neonatal rat axotomized motoneurons is associated with a reduction in free Bax, due to the inhibition of Bax expression, as well as increased Bcl-2/Bax heterodimerization. Thus, the neuroprotective action of the CNTF on axotomized motoneurons can be related to the inhibition of this apoptotic pathway.
Assuntos
Fator Neurotrófico Ciliar/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Nervo Isquiático/cirurgia , Medula Espinal/efeitos dos fármacos , Proteína X Associada a bcl-2/metabolismo , Animais , Animais Recém-Nascidos , Western Blotting , Imunoprecipitação , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medula Espinal/química , Medula Espinal/metabolismoRESUMO
Ciliary neurotrophic factor (CNTF) is a cytokine that plays a neuroprotective role in relation to axotomized motoneurons. We determined the effect of daily subcutaneous doses of CNTF (1.2 µg/g for 5 days; N = 13) or PBS (N = 13) on the levels of mRNA for Bcl-2 and Bax, as well as the expression and inter-association of Bcl-2 and Bax proteins, and the survival of motoneurons in the spinal cord lumbar enlargement of 2-day-old Wistar rats after sciatic nerve transection. Five days after transection, the effects were evaluated on histological and molecular levels using Nissl staining, immunoprecipitation, Western blot analysis, and reverse transcriptase-polymerase chain reaction. The motoneuron survival ratio, defined as the ratio between the number of motoneurons counted on the lesioned side vs those on the unlesioned side, was calculated. This ratio was 0.77 ± 0.02 for CNTF-treated rats vs 0.53 ± 0.02 for the PBS-treated controls (P < 0.001). Treatment with CNTF modified the level of mRNA, with the expression of Bax RNA decreasing 18 percent (with a consequent decrease in the level of Bax protein), while the expression of Bcl-2 RNA was increased 87 percent, although the level of Bcl-2 protein was unchanged. The amount of Bcl-2/Bax heterodimer increased 91 percent over that found in the PBS-treated controls. These data show, for the first time, that the neuroprotective effect of CNTF on neonatal rat axotomized motoneurons is associated with a reduction in free Bax, due to the inhibition of Bax expression, as well as increased Bcl-2/Bax heterodimerization. Thus, the neuroprotective action of the CNTF on axotomized motoneurons can be related to the inhibition of this apoptotic pathway.
Assuntos
Animais , Ratos , Fator Neurotrófico Ciliar/farmacologia , /metabolismo , Nervo Isquiático/cirurgia , Medula Espinal/efeitos dos fármacos , /metabolismo , Animais Recém-Nascidos , Western Blotting , Imunoprecipitação , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Mensageiro/metabolismo , Medula Espinal/química , Medula Espinal/metabolismoRESUMO
Motoneuron death induced by sciatic nerve transection in neonatal rats has been related to induction of the neuronal isoform of nitric oxide synthase (nNOS), a diaphorase of which one of the cofactors is nicotinamide adenine dinucleotide phosphate (NADPH). We transected the sciatic nerve of neonatal rats (P2) and examined nNOS expression by immunostaining in neurons of the sciatic pool and of other spinal levels on the 5th day after surgery. No correspondence was observed between the surviving motoneurons and nNOS positive cells. The appearance and distribution of nNOS positive neurons at all spinal levels and laminae were similar to those of adult animals. These results are at variance with previous studies which showed correlation between motoneuron loss after axotomy and number of NADPH-diaphorase positive motoneurons after sciatic transection.
Assuntos
Animais Recém-Nascidos/metabolismo , Neurônios Motores/enzimologia , Óxido Nítrico Sintase/metabolismo , Degeneração Retrógrada/enzimologia , Medula Espinal/enzimologia , Animais , Animais Recém-Nascidos/anatomia & histologia , Axotomia , Contagem de Células , Imuno-Histoquímica , Neurônios Motores/patologia , NADPH Desidrogenase/metabolismo , Óxido Nítrico/metabolismo , Estresse Oxidativo/fisiologia , Isoformas de Proteínas/metabolismo , Ratos , Ratos Wistar , Degeneração Retrógrada/patologia , Nervo Isquiático/enzimologia , Nervo Isquiático/fisiopatologia , Nervo Isquiático/cirurgia , Medula Espinal/crescimento & desenvolvimento , Medula Espinal/patologiaRESUMO
Lysine has long been recognized as an essential amino acid for humans and the lack or low supply of this compound in the diet may lead to mental and physical handicaps. Since lysine is severely restricted in cereals, the most important staple food in the world, the understanding of its biological roles must be a major concern. Here we show that lysine is an important precursor for de novo synthesis of glutamate, the most significant excitatory neurotransmitter in the mammalian central nervous system. We also show that the synthesis of glutamate from lysine, which is carried out by the saccharopine pathway, is likely to take place in neurons.
Assuntos
Encéfalo/metabolismo , Ácido Glutâmico/metabolismo , Lisina/metabolismo , Neurônios/metabolismo , Animais , Encéfalo/citologia , Encéfalo/enzimologia , Cerebelo/citologia , Cerebelo/enzimologia , Cerebelo/metabolismo , Córtex Cerebral/citologia , Córtex Cerebral/enzimologia , Córtex Cerebral/metabolismo , Perfilação da Expressão Gênica , Hibridização In Situ , Camundongos , Neurônios/enzimologia , RNA Mensageiro/análise , RNA Mensageiro/genética , Sacaropina Desidrogenases/genética , Sacaropina Desidrogenases/metabolismoRESUMO
Peripheral axonal regeneration was investigated in adult male mice of the C57BL/6J (C), BALB/cJ (B) and A/J (A) strains and in their F1 descendants using a predegenerated nerve transplantation model. Four types of transplants were performed: 1) isotransplants between animals of the C, B and A strains; 2) donors of the C strain and recipients of the C x B and C x A breeding; 3) donors of the B strain and recipients of the C x B breeding, and 4) donors of the A strain and recipients of the C x A breeding. Donors had the left sciatic nerve transected and two weeks later a segment of the distal stump was transplanted into the recipient. Four weeks after transplantation the regenerated nerves were used to determine the total number of regenerated myelinated fibers (TMF), diameter of myelinated fibers (FD) and myelin thickness (MT). The highest TMF values were obtained in the groups where C57BL/6J mice were the donors (C to F1 (C x B) = 4658 +/- 304; C to F1 (C x A) = 3899 +/- 198). Also, A/J grafts led to a significantly higher TMF (A to F1 (C x A) = 3933 +/- 565). Additionally, isotransplant experiments showed that when the nerve is previously degenerated, C57BL/6J mice display the largest number of myelinated fibers (C to C = 3136 +/- 287; B to B = 2759 +/- 170, and A to A = 2835 +/- 239). We also observed that when C57BL/6J was the graft donor, FD was the highest and MT did not differ significantly when compared with the other groups. These morphometric results reinforce the idea that Schwann cells and the nerve environment of C57BL/6J provide enough support to the regenerative process. In this respect, the present results support the hypothesis that the non-neuronal cells, mainly Schwann cells, present in the sciatic nerve of C57BL/6J mice are not the main limiting factor responsible for low axonal regeneration.
Assuntos
Axônios/fisiologia , Regeneração Nervosa/fisiologia , Nervos Periféricos/fisiologia , Animais , Axônios/transplante , Masculino , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Degeneração Neural , Nervos Periféricos/transplante , Células de Schwann/fisiologia , Nervo Isquiático/fisiologia , Nervo Isquiático/transplante , Especificidade da Espécie , Transplante IsogênicoRESUMO
Peripheral axonal regeneration was investigated in adult male mice of the C57BL/6J (C), BALB/cJ (B) and A/J (A) strains and in their F1 descendants using a predegenerated nerve transplantation model. Four types of transplants were performed: 1) isotransplants between animals of the C, B and A strains; 2) donors of the C strain and recipients of the C x B and C x A breeding; 3) donors of the B strain and recipients of the C x B breeding, and 4) donors of the A strain and recipients of the C x A breeding. Donors had the left sciatic nerve transected and two weeks later a segment of the distal stump was transplanted into the recipient. Four weeks after transplantation the regenerated nerves were used to determine the total number of regenerated myelinated fibers (TMF), diameter of myelinated fibers (FD) and myelin thickness (MT). The highest TMF values were obtained in the groups where C57BL/6J mice were the donors (C to F1 (C x B) = 4658 + OR - 304; C to F1 (C x A) = 3899 + OR - 198). Also, A/J grafts led to a significantly higher TMF (A to F1 (C x A) = 3933 + OR - 565). Additionally, isotransplant experiments showed that when the nerve is previously degenerated, C57BL/6J mice display the largest number of myelinated fibers (C to C = 3136 + OR - 287; B to B = 2759 + OR - 170, and A to A = 2835 + OR - 239). We also observed that when C57BL/6J was the graft donor, FD was the highest and MT did not differ significantly when compared with the other groups. These morphometric results reinforce the idea that Schwann cells and the nerve environment of C57BL/6J provide enough support to the regenerative process. In this respect, the present results support the hypothesis that the non-neuronal cells, mainly Schwann cells, present in the sciatic nerve of C57BL/6J mice are not the main limiting factor responsible for low axonal regeneration
Assuntos
Animais , Masculino , Camundongos , Axônios/fisiologia , Axônios/transplante , Regeneração Nervosa/fisiologia , Nervos Periféricos/fisiologia , Nervos Periféricos/transplante , Camundongos Endogâmicos BALB C , Degeneração Neural , Células de Schwann/fisiologia , Nervo Isquiático/fisiologia , Nervo Isquiático/transplante , Transplante IsogênicoRESUMO
After ventral root avulsion, a large percentage of the wounded spinal motoneurons die within 2 weeks. Neuronal death is preceded by a series of morphological and physiological changes probably as a result of both apoptotic and necrotic mechanisms. Associated with neuronal death, inflammation develops in the wounded area, resulting in additional neuronal loss as well as the degeneration of fibers from different tracts of the ventral and lateral funiculi. In the present study we tested the neuroprotective and local anti-inflammatory effects of monosialoganglioside (GM-1) after an initial 150 mg/kg body weight dose, followed by the daily administration of 100 mg/kg body weight for 2 weeks. The results showed a statistically significant enhancement of surviving motoneurons which showed good morphological preservation. Also, GM-1 treatment reduced by less then a half, the number of degenerating fibers into the ventral and lateral funiculi. Taken together, our results indicate that the administration of GM-1 in high doses during the critical period of motoneuron death after avulsion is neuroprotective, and diminishes local inflammation.
Assuntos
Gangliosídeo G(M1)/uso terapêutico , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Raízes Nervosas Espinhais/lesões , Animais , Morte Celular/efeitos dos fármacos , Gangliosídeo G(M1)/metabolismo , Injeções Subcutâneas , Laminectomia , Região Lombossacral , Masculino , Ratos , Ratos Wistar , Raízes Nervosas Espinhais/efeitos dos fármacos , Raízes Nervosas Espinhais/patologia , Raízes Nervosas Espinhais/cirurgiaRESUMO
The influence of aging on Schwann cell (SC) proliferation, migration and viability was studied in vitro. SCs were cultured in Ham F-10 medium enriched with 20% fetal calf serum (FCS), 40% FCS or collagen I gel plus 20% FCS. The migration of adult mice derived SCs was stimulated with FCS and collagen. With aging, SC migration, multiplication and viability decreased, indicating that ideal culturing conditions should be adjusted.
Assuntos
Movimento Celular/fisiologia , Células de Schwann/fisiologia , Nervo Isquiático/fisiologia , Fatores Etários , Envelhecimento/fisiologia , Animais , Proteínas Sanguíneas/farmacologia , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Colágeno/farmacologia , Meios de Cultura/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células de Schwann/citologia , Células de Schwann/efeitos dos fármacos , Nervo Isquiático/citologia , Nervo Isquiático/efeitos dos fármacosRESUMO
Lysine-oxoglutarate reductase and saccharopine dehydrogenase are enzymic activities that catalyse the first two steps of lysine degradation through the saccharopine pathway in upper eukaryotes. This paper describes the isolation and characterization of a cDNA clone encoding a bifunctional enzyme bearing domains corresponding to these two enzymic activities. We partly purified those activities from mouse liver and showed for the first time that both a bifunctional lysine-oxoglutarate reductase/saccharopine dehydrogenase and a monofunctional saccharopine dehydrogenase are likely to be present in this organ. Northern analyses indicate the existence of two mRNA species in liver and kidney. The longest molecule, 3.4 kb in size, corresponds to the isolated cDNA and encodes the bifunctional enzyme. The 2.4 kb short transcript probably codes for the monofunctional dehydrogenase. Sequence analyses show that the bifunctional enzyme is likely to be a mitochondrial protein. Furthermore, enzymic and expression analyses suggest that lysine-oxoglutarate reductase/saccharopine dehydrogenase levels increase in livers of mice under starvation. Lysine-injected mice also show an increase in lysine-oxoglutarate reductase and saccharopine dehydrogenase levels.
Assuntos
Lisina/análogos & derivados , Lisina/metabolismo , Complexos Multienzimáticos/metabolismo , Sacaropina Desidrogenases/metabolismo , Sequência de Aminoácidos , Animais , Regulação Enzimológica da Expressão Gênica , Biblioteca Gênica , Rim/enzimologia , Fígado/enzimologia , Camundongos , Dados de Sequência Molecular , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/isolamento & purificação , Sacaropina Desidrogenases/genética , Sacaropina Desidrogenases/isolamento & purificação , Homologia de Sequência de Aminoácidos , Inanição/metabolismo , Distribuição TecidualRESUMO
Transection of a peripheral nerve in neonatal rats induces an extensive death of axotomized neurons. We demonstrate here that spinal motoneurons and sensory dorsal root ganglia neurons become TUNEL-labeled after sciatic nerve transection in neonatal rats, thus indicating that apoptotic mechanisms are involved in the death process. Interestingly, there is also a profound increase of TUNEL-labeled interneurons in the deep dorsal horn. This location suggests that an intact afferent input and/or contact with target cells is essential for interneuronal survival. Death of motoneurons and sensory neurons could be a result of the injury per se and/or the deprivation of neurotrophic substances, secondary to the loss of contact with target cells.
Assuntos
Gânglios Espinais/patologia , Neurônios/patologia , Nervo Isquiático/lesões , Medula Espinal/patologia , Animais , Animais Recém-Nascidos , Apoptose/fisiologia , Morte Celular/fisiologia , DNA Nucleotidilexotransferase , Nucleotídeos de Desoxiuracil , Interneurônios/patologia , Neurônios Motores/patologia , Neurônios Aferentes/patologia , Ratos , Ratos Sprague-DawleyRESUMO
Nerve regeneration experiments were carried out using tubular nerve guides of poly[(ethylalanato)1.4(imidazolyl)0.6phosphazene] (PEIP). By means of in vivo tests, this polymer was found to be biodegradable and transformed into harmless products. The tubular nerve guides were prepared by deposition of the dissolved polymer on a glass capillary tube, followed by evaporation of the solvent (methylene dichloride). After transectioning, rat sciatic nerve stumps were immediately sutured into the ends of 10-mm-long polymer tubes. On removal of the prosthesis, after implantation for 45 d, a tissue cable was found bridging the nerve stumps in all cases. Histological analysis revealed that the tissue cable was essentially composed of a regenerated nerve fibre bundle. A parallel series of experiments was undertaken to compare the use of silicone tubes that are not biodegradable and are most frequently used for studies of nerve regeneration with tubulization techniques. The advantages of biodegradable PEIP tubular nerve guides used for peripheral nerve repair are discussed.
Assuntos
Materiais Biocompatíveis , Regeneração Nervosa , Compostos Organofosforados , Sistema Nervoso Periférico/cirurgia , Polímeros , Próteses e Implantes , Animais , Sistema Nervoso Periférico/fisiologia , Ratos , Nervo Isquiático/cirurgia , SiliconesRESUMO
Adult male mice received sciatic nerve transection at the midthigh level and both nerve stumps were sutured into a polyethylene tube (PT) to bridge a nerve gap of 4 mm. The tubes were implanted either empty, or filled with collagen alone or in combination with gangliosides (GM1, GD1a, GD1b and GT1b). Following a survival time of 6 weeks, the PT with the regenerating nerve cables were processed for plastic embedding, and morphometric measurements were made on myelinated and unmyelinated axons. The data suggest that local application of exogenous gangliosides causes a stimulation of axonal sprouting in vivo with no effect on the rate of axonal maturation.
Assuntos
Gangliosídeos/farmacologia , Regeneração Nervosa/efeitos dos fármacos , Nervo Isquiático/cirurgia , Animais , Axônios/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Adult male mice received sciatic nerve transection at the midthigh level and both nerve stumps were sutured into a polythylene tube (PT) to bridge a nerve gap of 4 mm. The tubes were implanted either empty, or filled with collagen alone or in combination with gangliosides (GM1, GD1a, GD1b, anhd GT1b). Following a survival time of 6 weeks, the PT with the regenerating nerve cables were processed for plastic embedding, and morphometric measurements were made on myelinated and unmyelinated axons. The data suggest that local application of exogenous gangliosides causes a stimulation of axonal sprouting in vivo with no effefct on the rate of axonal maturation
Assuntos
Camundongos , Animais , Masculino , Gangliosídeos/farmacologia , Regeneração Nervosa/efeitos dos fármacos , Nervo Isquiático/cirurgia , Axônios/fisiologia , Camundongos Endogâmicos C57BLRESUMO
The sciatic nerve of adult mice was transected and the proximal and distal nerve stumps were sutured into a polyethylene tube. The tubes were implanted either umpty, or the lumen was filled with pure collagen or a mixture of collagen/nerve trowth factor (NGF). Six weeks later, cells in the L3-L5 dorsal root ganglia (DRG) were retrogradely filled with horseradish perocidase (HRP). The data demonstrate that the addition of NGF to the interior of the tubular prosthesis can significantly increase the regeneration rate of sensory neurons
Assuntos
Camundongos , Animais , Masculino , Fatores de Crescimento Neural/fisiologia , Regeneração Nervosa , Nervo Isquiático/cirurgia , Neurônios Aferentes/fisiologia , Neurônios Aferentes/análise , Próteses e ImplantesRESUMO
The sciatic nerve of adult mice was transected and the proximal and distal nerve stumps were sutured into a polyethylene tube. The tubes were implanted either empty, or the lumen was filled with pure collagen or a mixture of collagen/nerve growth factor (NGF). Six weeks later, cells in the L3-L5 dorsal root ganglia (DRG) were retrogradely filled with horseradish peroxidase (HRP). The data demonstrate that the addition of NGF to the interior of the tubular prosthesis can significantly increase the regeneration rate of sensory neurons.