There are different methods used in the surgical treatment of peripheral nerve injury. In this respect, end-to-end surgical reconnection of the damaged nerve ends or autologous nerve grafts are applied as soon as possible after the injury. When autologous tissue transplant is considered, there are some medical devices available generally for relatively short nerve defects. As a solution for this problem, different tissue engineered nerve conduits have been developed. In the current study, a pHEMA hydrogel membranes were designed to mimic the tubular conduits and they were loaded with 1-6% (w/w) multiwalled carbon nanotubes (mwCNTs) to obtain electrical conductivity. The most important reason for the use of CNTs in peripheral nerve injury is their electrical conductivity. Within the context of the study, the degree of swelling, contact angles, electrical conductivity and mechanical properties of the membranes were analyzed. As the amount of mwCNTs were increased, the contact angles, indicating higher hydrophobicity and the electrical conductivity increased. The tensile test of the mwCNT-pHEMA composite membranes showed that the membranes have viscoelastic structure similar to the structure of the soft tissues. The structure of the mwCNT containing pHEMA composite membranes were analyzed with different microscopical techniques such as SEM, CSLM and microCT. MwCNTs on the hydrogels were morphologically similar to the original. SEM micrographs also showed that the mwCNTs were grouped in clumps on hydrogel surfaces. No mwCNT leaching was observed because the mwCNTs were embedded in the hydrogel, therefore, no cytotoxic effect was observed. The pHEMA hydrogels were porous which is suitable for transportation of materials, electrolytes and gas needed for cell nutrition and growth. In the in vitro studies, SHSY5Y neuroblastoma cells were seeded on the membranes to determine the sustainability and effects of the membranes on the cell growth. Electrical potential of 1 and 2 V were used to stimulate the cells. Microscopical examination with SEM and CSLM, and MTT viability assay were used. The SHSY5Y neuroblastoma cells were attached and proliferated on both the composite and the hydrogel membranes. The cells on pHEMA membranes without mwCNTs, however, were not able to survive after application of electrical potential. As a conclusion, use of composite membranes in the treatment of peripheral nerve injury as a nerve conduit is appropriate. Electrical stimulation, however, did not induce the cells to align in contrast to the expected results, indicating potential and current application regime needs to be optimized to obtain the desired results.

Spinal cord injury results in complete failure of the central neurons to regenerate and is associated with cyst formation and enlargement of the trauma zone. In contrast to the spinal cord, axons in the injured peripheral nerve have the capacity to undergo some spontaneous regeneration. However, significant post-traumatic loss of nervous tissue causing long nerve gap is one of the main reasons for the poor restoration of function following microsurgical repair of injured nerves. The present thesis investigates the effects of biodegradable conduits prepared from fibrin glue and poly-beta-hydroxybutyrate (PHB) in combination with cultured Schwann cells, mesenchymal stem cells and extracellular matrix molecules on regeneration after spinal cord and peripheral nerve injury in adult rats. At 4-8 weeks after transplantation into the injured spinal cord, the PHB conduit was well integrated into the cavity but regenerating axons were found mainly outside the PHB. When suspension of BrdU-labeled Schwann cells was added to the PHB, regenerating axons filled the conduit and became associated with the implanted cells. Modification of the PHB surface with extracellular matrix molecules significantly increased Schwann cell attachment and proliferation but did not alter axonal regeneration. To improve the labeling technique of the transplanted cells, the efficacy of fluorescent cell tracers Fast Blue, PKH26, Vibrant DiO and Cell Tracker™ Green CMFDA was evaluated. All tested dyes produced very efficient initial labeling of olfactory ensheathing glial cells in culture. The number of Fast Blue-labeled cells remained largely unchanged during the first 4 weeks whereas the number of cells labeled with other tracers was significantly reduced after 2 weeks. After transplantation into the spinal cord, Fast Blue-labeled glial cells survived for 8 weeks but demonstrated very limited migration from the injection sites. Additional immunostaining with glial and neuronal markers demonstrated transfer of the dye from the transplanted cells to the host tissue. In a sciatic nerve injury model, the extent of axonal regeneration through a 10mm gap bridged with tubular PHB conduit was compared with a fibrin glue conduit. At 2 weeks after injury, the fibrin conduit supported similar axonal regeneration and migration of the host Schwann cells compared with the PHB conduit augmented with a diluted fibrin matrix and GFP-labeled Schwann cells or mesenchymal stem cells. The long-term regenerative response was evaluated using retrograde neuronal labeling. The fibrin glue conduit promoted regeneration of 60% of sensory neurons and 52% of motoneurons when compared with the autologous nerve graft. The total number of myelinated axons in the distal nerve stump in the fibrin conduit group reached 86% of the nerve graft control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89%, respectively. When a fibrin conduit was used to bridge a 20mm sciatic nerve gap, the weight of gastrocnemius muscle reached only 43% of the nerve graft control. The morphology of the muscle showed more chaotic appearance and the mean area and diameter of fast type fibers were significantly worse than those of the corresponding 10mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. In summary, these results show that a PHB conduit promotes attachment, proliferation and survival of adult Schwann cells and supports marked axonal growth after transplantation into the injured spinal cord. The data suggest an advantage of the fibrin conduit for the important initial phase of peripheral nerve regeneration and demonstrate potential of the conduit to promote long-term neuronal regeneration and muscle recovery.

Clinically, injuries affecting the spinal cord or peripheral nerves can leave those affected with severe disability and, at present, there are limited options for treatment. Peripheral nerve injury with a significant gap between the proximal and distal stumps is currently treated with autologous nerve grafting but this is limited by availability of donor nerve and has associated morbidities. In contrast, injuries to the spinal cord lead to an inhibitory environment caused by the glial cells and thereby, limit potential axonal regeneration. This thesis investigates the effects of human adipose derived stem cells (ASC) on regeneration after peripheral nerve and spinal cord injury in adult rats. Human ASC expressed various neurotrophic molecules and growth factor stimulation of the cells in vitro resulted in increased secretion of BDNF, GDNF, VEGF-A and angiopoietin-1 proteins. Stimulated ASC also showed an enhanced ability to induce capillary-like tube formation in an in vitro angiogenesis assay. In contrast to Schwann cells, ASC did not induce activation of astrocytes and supported neurite outgrowth from the adult rat sensory DRG neurons in culture. In a peripheral nerve injury model, ASC were seeded into a fibrin conduit, which was used to bridge a 10 mm rat sciatic nerve gap. After 2 weeks, ASC enhanced GAP-43 and ATF-3 expression in the spinal cord, reduced c-jun expression in the DRG and increased the vascularity of the fibrin nerve conduits. The animals treated with stimulated ASC showed an enhanced axon regeneration and reduced caspase-3 expression in the DRG. After transplantation into the injured C3-C4 cervical spinal cord. ASC continued to express neurotrophic factors and laminin and stimulated extensive ingrowths of 5HT-positive raphaespinal axons into the trauma zone. In addition, ASC induced sprouting of raphaespinal terminals in C2 contralateral ventral horn and C6 ventral horn on both sides. Transplanted cells also changed the structure and the density of the astroglial scar. Although the transplanted cells had no effect on the density of capillaries around the lesion site, the reactivity of OX42-positive microglial cells was markedly reduced.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-07-18T21:12:26Z No. of bitstreams: 1 Carla Bernardo Soldera.pdf: 1125219 bytes, checksum: a9bf43bd0d44898b4a48ec77b3f45001 (MD5) / Made available in DSpace on 2018-07-18T21:12:26Z (GMT). No. of bitstreams: 1 Carla Bernardo Soldera.pdf: 1125219 bytes, checksum: a9bf43bd0d44898b4a48ec77b3f45001 (MD5) Previous issue date: 2017-12-15 / Peripheral nerve lesions (LNP) do not clinically present a risk of death to the individual but may result in motor and sensory disturbances altering the function of the affected limb. Phototherapy using low level laser has demonstrated positive effects for the nervous and muscle repair process after different types of injury and little is known about the effects of light emitting diode (LED) therapy. Objective: To analyze the effects of LED on the nervous and muscular repair of Wistar rats after sciatic nerve crush injury. Methodology: 85 Wistar rats, weighing 200-250g, in 5 groups: Control: without any procedure; Injury: carried out only the crushing of the Left Sciatic Nerve (LSN); Injury + LEDn: LSN crushing and LED irradiation in the area corresponding to the nerve injury; Injury + LEDmm: LSN and LED crushing in Tibial Anterior muscle; Injury + LEDn + LEDmm: NSE crushing and LED irradiation in the area corresponding to nerve injury and muscle. The application of the LED in the nervous region was performed with the following parameters: wavelength of 808nm, beam area 1 cm2, average power 40Mw, power density 0.04 W/cm2, energy density 0.8 J/cm2, energy per point 0.8J , total of points 4, time per point 20sec, total time 80sec, energy per point 3.2J and in muscle region was used wavelength of 808nm, beam area 1 cm2, average power 40Mw, power density 0.04 W/ cm2, density of energy 0.4 J/ cm2, energy per point 0.4J, total of points 8, time per point 10sec, total time 80sec, energy per point 3.2J. At the end of the experimental periods, the gait analysis and the mechanical hyperalgesia test were performed. At the end of the experimental periods, gait analysis was performed using the Sciatic Function Index (IFC), as well as the analysis of mechanical hyperalgesia using the von Frey test using the pressure analgesimeter with transducer. After the euthanasia of the animals, the tibial muscles, left and right, were removed and weighed in a semi-analytical balance to determine the degree of muscular atrophy and the muscle mass ratio was calculated. Result: After the IFC, within 7 days, all groups treated with LED showed an improvement in gait compared to the lesion group. The group LEDn was the one that presented the best result compared to the control group. After 14 days, the group LEDn and LEDnm presented similar values to the control group. Regarding the muscular atrophy index, in the 7-day period, all the groups treated with LED showed a decrease of the index in relation to the Control group. In 14 days, the LED groups showed an increase in relation to the Injury group. At 21 and 28 days, the injured groups showed a decrease in relation to the Control group. Only the LEDnm group showed a decrease compared to the Injury group. Regarding mechanical hyperalgesia, the results showed that in 7 days, the LEDn group was the one that presented the best result compared to the control group. At 14 days, the LEDn and LEDm groups showed an increase in the threshold, requiring a greater pressure to promote an allergic response compared to the control group, making them more resistant to the stimuli. At 28 days, all lesioned and treated groups showed an increase in hyperalgesia in relation to the control group. Conclusion: We can conclude that LED increased gait functionality assessed by IFC after 1 and 2 weeks post LNP, especially when it was used in the nerve region associated or not to the muscle region, induced an increase in muscle mass in relation to the animals that did not receive treatment in the period of 2 weeks post LNP and in the 2 week period post LNP provided an increase in the pain threshold compared to the control group, requiring a nociceptive stimulus of greater intensity to generate the pain stimulus indicating a better recovery. / As lesões nervosas periféricas (LNP) não apresentam clinicamente um risco de morte ao indivíduo, porém podem resultar em distúrbios motores e sensoriais alterando a funcionalidade do membro afetado. A fototerapia utilizando laser de baixa potência (LBP) tem demonstrado efeitos positivos para o processo de reparo nervoso e muscular após diferentes tipos de lesão e pouco se conhece a respeito dos efeitos da terapia com diodo emissor de luz (LED, do inglês light emitting diode). Objetivo: Analisar os efeitos do LED sobre o reparo nervoso e muscular de ratos Wistar pós lesão por esmagamento do nervo ciático. Metodologia: foram utilizados 85 ratos Wistar, pesando 200-250g, em 5 grupos: Controle: sem nenhum procedimento; Lesão: realizado apenas o esmagamento do Nervo Ciático Esquerdo (NCE); Lesão+LEDn: esmagamento do NCE e irradiação LED na área correspondente à lesão nervosa; Lesão+LEDm: esmagamento do NCE e LED no músculo Tibial Anterior; Lesão+LEDnm: esmagamento do NCE e irradiação LED na área correspondente à lesão nervosa e músculo. A aplicação do LED em região nervosa foi realizada com os seguintes parâmetros: comprimento de onda de 808nm, área do feixe 1cm2, potência média 40Mw, densidade de potência 0.04W/ cm2, densidade de energia 0.8 J/cm2, energia por ponto 0.8J, total de pontos 4, tempo por ponto 20seg, tempo total 80seg, energia por ponto 3.2J e em região muscular foi utilizado comprimento de onda de 808nm, área do feixe 1cm2, potência média 40Mw, densidade de potência 0.04W/ cm2, densidade de energia 0.4 J/cm2, energia por ponto 0.4J, total de pontos 8, tempo por ponto 10seg, tempo total 80seg, energia por ponto 3.2J. Ao término dos períodos experimentais, foi realizada a análise de marcha utilizando o Índice Funcional Ciático (IFC), bem como a análise da hiperalgesia mecânica através do teste de von Frey utilizando o analgesímetro de pressão com transdutor. Após a eutanásia dos animais os músculos Tibial Anterior direito e esquerdo foram removidos e pesados em uma balança semi-analítica para determinação do grau de atrofia muscular sendo calculada a relação de massa muscular. Resultado: Após a realização do IFC, no período de 7 dias, todos os grupos tratados com LED apresentaram uma melhora da marcha em relação ao grupo Lesão. O grupo LEDn foi o que apresentou o melhor resultado comparado ao grupo controle. Após 14 dias, o grupo LEDn e LEDnm apresentaram valores semelhantes ao grupo controle. Já em relação ao índice de atrofia muscular, no período de 7 dias, todos os grupos tratados com LED demonstraram uma diminuição do índice em relação ao grupo Controle. Em 14 dias, os grupos LED demonstraram um aumento em relação ao grupo Lesão. Em 21 e 28 dias, os grupos lesionados demonstraram uma diminuição em relação ao grupo Controle. Apenas o grupo LEDnm apresentou uma diminuição em relação ao grupo Lesão. No que diz respeito a hiperalgesia mecânica, os resultados obtidos demonstraram que em 7 dias, o grupo LEDn foi o que apresentou o melhor resultado comparado ao grupo controle. Em 14 dias, os grupos LEDn e LEDm apresentaram um aumento no limiar sendo necessário uma pressão maior para promover uma resposta álgica comparados ao grupo controle, tornando-os mais resistentes aos estímulos. Em 28 dias todos os grupos lesionados e tratados apresentaram um aumento da hiperalgesia em relação ao grupo controle. Conclusão: O LED aumentou a funcionalidade da marcha avaliada pelo IFC após 1 e 2 semanas pós LNP, especialmente quando foi usado na região nervosa associada ou não à região muscular, induziu um aumento na massa muscular em relação aos animais que não receberam tratamento no período de 2 semanas pós LNP e proporcionou um aumento no limiar álgico comparado ao grupo controle no período de 2 semanas pós LNP, sendo necessário um estímulo nociceptivo de maior intensidade para gerar o estímulo doloroso indicando uma melhor recuperação.

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A parestesia é um distúrbio neurosensitivo causado por uma lesão no tecido nervoso. Ela tem uma incidência pouco freqüente após as cirurgias de terceiros molares inferiores; no entanto para o cirurgião dentista é de grande relevância. A literatura comenta sobre os tipos de lesão nervosa, causas e alternativas de tratamento não conservadores ligados à neuromicrocirurgia que são relacionados nesses casos. Nesse trabalho procurou-se estabelecer a classificação da lesão ao nervo alveolar inferior que ocorre nas exodontias de terceiros molares inferiores, entender os mecanismos fisiológicos, as causas principais que levam à ocorrência desse distúrbio e estudar as técnicas de neuromicrocirurgia, com suas indicações e contra-indicações para os tipos de lesão nervosa. / Paresthesia consists of a neurosentitive disturb resulting from nerve tissue injury. It is less likely to occur following lower third molar surgeries, despite being highly relevant for dentists. The literature comments on the types of nerve injuries, its causes and related non-conservative treatment procedures involving neuromicrosurgery in such cases. This essay is an attempt to establish the types of nerve injury classification that occur following lower third molar surgery involving the inferior alveolar nerve, understand the physiological mechanisms, the main causes that result in such disturbance, and study the neuromicrosurgery procedures, their indications and non-indications concerning types of nerve injury.

The effect of interleukin-1 beta (IL-1β) on the electrical properties of sensory neurons was assessed at comparable levels and exposure times to those found in animal models of neuropathic pain. Experiments involved whole cell current- or voltage-clamp recordings from rat dorsal root ganglion (DRG) neurons in defined medium, neuron enriched cultures. 5-6 days exposure to 100 pM IL-1β produced neuron specific effects. These included an increase in the excitability of medium diameter and small diameter isolectin B4 (IB4)-positive neurons that was comparable to that found after peripheral nerve injury. By contrast, a reduction in excitability was observed in large diameter neurons, while no effect was found in small diameter IB4-negative neurons. Further characterization of changes in medium and small IB4-positive neurons revealed that some, but not all, effects of IL-1β were mediated through its receptor, IL-1RI. Using appropriate voltage protocols and/or ion substitutions, it was found that neuron specific changes in several ionic currents, including alterations in hyperpolarization activated inward current (IH) and decreases in various K+ currents contribute to the increased excitability produced by IL-1β. Overall, these studies revealed that: 1. The effects of long-term exposure of DRG neurons to IL-1β are reflective of the enduring increase in primary afferent excitability reported after peripheral nerve injury. This expands the recognized role of IL-1β in acute inflammatory pain to neuropathic pain. 2. Hyperexcitability in medium neurons exposed to IL-1β likely includes mixed populations of neurons corresponding to nociceptive and non-nociceptive primary afferent fibres and, therefore, has relevance to hyperalgesia and allodynia, respectively. 3. The responsiveness of small IB4-positive neurons, but not IB4-negative, to prolonged IL-1β exposure is consistent with the suggestion that small IB4-negative afferents are involved in inflammatory pain, while small IB4-positive afferents are involved neuropathic pain. 4. The identification of receptor mediated effects and several contributing ionic mechanisms, may have relevance to the development of new therapeutic approaches to neuropathic pain. 5. IL-1β can contribute to increased neuronal excitability by mechanisms that are independent of IL-1RI signalling. This should be taken into account when targeting IL-1β, or more specifically IL-1RI, in the management of neuropathic pain.

In this thesis, rodent models of chronic pain were used to explore analgesic mechanisms that may potentially be engaged in spinal and peripheral compartments by systemically-administered amitriptyline, a tricyclic antidepressant. The first project (Chapter 2) identified the roles of spinal adenosine A1 and serotonin 5-HT7 receptors, as well as of peripheral adenosine A1 receptors, in the acute antinociceptive effects of amitriptyline in mice. The second project (Chapter 3) examined the potential utility of amitriptyline as a preventive analgesic against persistent post-surgical pain, and involved perioperative administration of amitriptyline after peripheral nerve injury in rats. Changes in post-injury behavioural outcomes, as well as spinal noradrenergic sprouting, were assessed. Overall, spinal serotonergic pathways linked to adenosine A1 receptors, as well as peripheral adenosine A1 receptors, appear to be important in antinociception by amitriptyline. Preventive analgesia by this drug does not appear to result from anatomical changes in spinal noradrenergic pathways.