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| Author(s): |
Camila Marques Freria
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas |
| Defense date: | 2009-02-26 |
| Examining board members: |
Alexandre Leite Rodrigues de Oliveira;
Ricardo de Lima Zollner;
Tania de Fatima Salvini
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| Advisor: | Leonilda Maria Barbosa dos Santos; Alexandre Leite Rodrigues de Oliveira |
| Abstract | |
Recent studies have shown that the expression of the major histocompatibility complex of class I (MHC I) directly influences the stability of nerve terminals. Also, the acute phase of the experimental autoimmune encephalomyelitis (EAE) has shown a significant impact on inputs within the spinal cord. Therefore, the present work investigated the synaptic covering of motoneurons during exacerbation and progressive remissions of the EAE. C57BL/6J mice were induced to the EAE and divided into 4 groups: normal, exacerbation (degree 3), first remission (30th day after EAE induction) e second remission (40th day). The animals were sacrificed and their lumbar spinal cords were processed for immunohistochemistry and transmission electron microscopy (TEM). The results indicate an increase of glial reaction during the exacerbation phase. In this period, the TEM analysis showed a reduction of the synaptic covering of motoneurons, corresponding to a reduction of synaptophysin immunolabeling and an increase of MHC I expression. The results observed in both remission groups indicated a return of terminals contact to the motoneuron surface. However, a possible exhaustion of the regenerative potential occurs after the 2nd remission, since the number of synapses decreases significantly. Also, the ratio between excitatory/inhibitory inputs increases, indicating the development of a possible excitotoxic process. In conclusion, the results presented herein indicate that MHC I upregulation during the course of the remittent/recurrent form of EAE correlates to the periods of synaptic plasticity induced by the infiltration of auto-reactive immune cells and that synaptic plasticity decreases after recurrent peaks of inflammation. Also, this study provided evidences that synaptic plasticity and the glial reactivity during the different phases of the MS disease, play an important role in the motor deficit and recovery that occur throughout the MS development. (AU) | |