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Master's Dissertation
DOI
https://doi.org/10.11606/D.42.2009.tde-01072009-125513
Document
Author
Full name
Vera Paschon
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2009
Supervisor
Committee
Kihara, Alexandre Hiroaki (President)
Salum, Cristiane Otero Reis
Torrão, Andréa da Silva
Title in Portuguese
Modulação da expressão de conexinas na retina: um estudo morfológico, bioquímico e funcional.
Keywords in Portuguese
Adaptação ao escuro
Conexinas
Desenvolvimento
Junções comunicantes
Neurodegeneração
Retina
Abstract in Portuguese
A vida é um processo dinâmico no tempo e no espaço, resultante da interação celular provida pelas junções comunicantes (JCs), canais formados por conexinas (Cxs) que permitem a passagem de moléculas de até 1kDa, e íons. O foco deste trabalho foi caracterizar a modulação de Cxs no desenvolvimento, adaptação visual e após trauma mecânico localizado na retina, através de técnicas como PCR em tempo real, western blot e imuno-histoquímica. No desenvolvimento, a Cx43 apresentou alta expressão no início (255%, P<0.01), a Cx45 teve alta expressão em todos os estágios, as Cx50 e Cx36 são pouco expressas no início (4-9%, P<0.01), mas muito expressas no final e no adulto. Na adaptação ao escuro houve regulação de 115% do RNam da Cx36 após 24h, evidenciando uma plasticidade do acoplamento frente às condições de iluminação. Na neurodegeneração, a expressão da Cx36 não variou nos diferentes tempos pós-lesão, mas a Cx43 aumentou após 7 dias. O papel do acoplamento na degeneração foi estudado utilizando bloqueadores e abridores de JCs combinados com métodos para avaliar a viabilidade celular (TUNEL, FluoroJade e LDH). Finalmente, o bloqueio das JCs diminuiu a morte celular secundária, mas a abertura gerou um efeito inicial pró-apoptótico que depois de 4h foi diluído no tecido.
Title in English
Modulation of connexin expression in retina: a study using morphological, biochemical and functional approaches.
Keywords in English
Connexins
Dark adaptation
Development
Grap junction blockers
Neurodegeneration
Retina
Abstract in English
Life is a dynamic process in time and space, resulting from an interaction provided by gap junctions (GJs), channels composed of connexins (Cxs) that permits the passage of molecules up to 1kDa and ions. The aim of this study was analyze the modulation of Cxs during development, dark adaptation and after local mechanical trauma in the retina using techniques like real time PCR, western blot and imunohistochemistry. In development, Cx43 was highly expressed in the beginning (255%, P<0.01), Cx45 was highly expressed during all development, Cx50 and Cx36 were virtually absent in the beginning (4-9%, P<0.01), but highly expressed in the end of development. In Dark-adaptation, Cx36 was up-regulated after 24h (115%, P < 0.05) suggesting a plasticity of the neuronal coupling in response to light conditions. In neurodegeneration, Cx36 expression didnt ranged in different days after lesion, but the Cx43 increased after 7 days. The coupling was studied by using GJ blockers and openers combined with methods to evaluating cellular viability (TUNEL, FluoroJade and LDH). Finally, blocking the cellular coupling reflects in a decrease of secondary death. GJ openers seems act allowing the spread of death in the beginning, but this effect be diluted after 4h in the tissue.
 
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Publishing Date
2009-09-01
 
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