Caracterização morfológica, expressão dos fatores de regulação miogênica (MRFS) e dos receptores nicotínicos (NACHRS) no músculo estriado de ratos submetidos à restrição protéica materna
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Data
2011-07-08
Autores
Cabeço, Ludmila Canuto [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A restrição protéica materna pode afetar vários parâmetros morfofuncionais da prole com conseqüências na vida adulta. Esse fenômeno, conhecido como programação fetal, pode causar mudanças na musculatura esquelética a longo prazo. Neste trabalho foram analisadas a morfologia e histoquímica dos tipos de fibras musculares, a expressão gênica e protéica dos fatores reguladores miogênicos MyoD e Miogenina, a morfologia das junções neuromusculares (JNMs) e a expressão gênica das subunidades ( , e ) que compõe os receptores nicotínicos de acetilcolina, nos músculos Soleus (SOL) e Extensor longo dos dedos (EDL) de ratos machos (30 dias e 16 semanas de idade), provenientes de mães alimentadas com dieta de baixa proteína (6%, LP, n=8) durante a gestação e alimentadas com dieta normoprotéica (17%, NP=8) após o nascimento dos filhotes. Nos períodos analisados, os músculos SOL e EDL foram submetidos à reação histoquímica mATPase para a análise da freqüência (%) e área (CSA) das fibras; a morfologia das JNMs foi analisada por microscopia eletrônica de transmissão; a expressão gênica e protéica foram determinadas pelo RT-qPCR e Western Blot, respectivamente. Nossos resultados mostraram que ao nascimento e com 30 dias de idade, o peso corporal dos filhotes do grupo LP foi estatisticamente menor comparado aos filhotes do grupo NP e com 16 semanas de idade, nenhuma diferença foi observada no peso corporal. Aos 30 dias de idade, o peso do músculo SOL foi menor no grupo LP comparado ao NP (P<0,05) e nenhuma diferença estatística foi observada no peso do músculo EDL. Com 16 semanas de idade, a razão peso muscular/peso corpóreo foi menor no músculo SOL e nenhuma diferença estatística foi observada no músculo EDL. Aumento na freqüência das fibras tipo IIB e diminuição das fibras tipo...
The maternal protein restriction can affect various morphophysiological parameters in offspring with consequences in adulthood. This phenomenon, known as fetal programming, can cause changes in skeletal muscle phenotype in long term. We investigated muscle fiber type changes, MyoD and Myogenin expression, neuromuscular junction (NMJs) morphology and , and nAChRs subunits expression in SOL and EDL muscles in offspring rats, with 30 and 16-weeks-old, from dams fed with low protein diet (6% protein, LP, n=8) and normoproteic diet (17% protein, NP, n=8). Muscles collected were submitted to myofibrillar adenosine triphosphatase (mATPase) histochemistry reaction for muscle fiber types frequency and the cross sectional areas (CSA) analysis. The neuromuscular junction (NMJs) morphology was analyzed using transmission electron microscope. The gene and protein expression were determined by RT-qPCR and Western Blot, respectively. Our results showed that at birth and with 30-days-old, the body weight of pups was statistically lower in LP compared to NP group; at 16-week-old, no significant difference were observed. At 30-days, the SOL muscle weight (g) was lower in LP compared to NP group (P<0.05) and no statistical difference was observed in the EDL muscle weight. At 16-week-old, SOL muscle weight/body weight ratio was lower in LP group compared to NP group, P<0.05. Increasing in IIB and decreased in I and IIA+IID fiber frequency in EDL muscle and no difference in fiber frequency in SOL muscle were observed in LP group, with 30-days-age. At 16-weeks-age, there were no differences in muscle fiber types frequency for both muscles. In LP group, muscle fiber I CSA decreased only in SOL muscle in all periods studied. MyoD and Myogenin expression no changes in response to maternal... (Complete abstract click electronic access below)
The maternal protein restriction can affect various morphophysiological parameters in offspring with consequences in adulthood. This phenomenon, known as fetal programming, can cause changes in skeletal muscle phenotype in long term. We investigated muscle fiber type changes, MyoD and Myogenin expression, neuromuscular junction (NMJs) morphology and , and nAChRs subunits expression in SOL and EDL muscles in offspring rats, with 30 and 16-weeks-old, from dams fed with low protein diet (6% protein, LP, n=8) and normoproteic diet (17% protein, NP, n=8). Muscles collected were submitted to myofibrillar adenosine triphosphatase (mATPase) histochemistry reaction for muscle fiber types frequency and the cross sectional areas (CSA) analysis. The neuromuscular junction (NMJs) morphology was analyzed using transmission electron microscope. The gene and protein expression were determined by RT-qPCR and Western Blot, respectively. Our results showed that at birth and with 30-days-old, the body weight of pups was statistically lower in LP compared to NP group; at 16-week-old, no significant difference were observed. At 30-days, the SOL muscle weight (g) was lower in LP compared to NP group (P<0.05) and no statistical difference was observed in the EDL muscle weight. At 16-week-old, SOL muscle weight/body weight ratio was lower in LP group compared to NP group, P<0.05. Increasing in IIB and decreased in I and IIA+IID fiber frequency in EDL muscle and no difference in fiber frequency in SOL muscle were observed in LP group, with 30-days-age. At 16-weeks-age, there were no differences in muscle fiber types frequency for both muscles. In LP group, muscle fiber I CSA decreased only in SOL muscle in all periods studied. MyoD and Myogenin expression no changes in response to maternal... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Músculo estriado esquelético, Restição protéica materna
Como citar
CABEÇO, Ludmila Canuto. Caracterização morfológica, expressão dos fatores de regulação miogênica (MRFS) e dos receptores nicotínicos (NACHRS) no músculo estriado de ratos submetidos à restrição protéica materna. 2011. 95 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.