Aspectos morfofisiológicos e moleculares do músculo estriado esquelético de ratos jovens e senis submetidos à restrição proteica materna perinatal
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2019-02-22
Autores
Valente, Jessica Silvino
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Universidade Estadual Paulista (Unesp)
Resumo
A restrição nutricional durante os períodos de gestação e lactação, pode provocar adaptações fisiológicas no feto (programação fetal), estando relacionada com riscos de doenças cardiovasculares e metabólicas, além de alterações musculares nos adultos. O comprometimento muscular pode trazer consequências futuras na vida do indivíduo, dada a sua relevância na geração de força e locomoção, bem como na longevidade e qualidade de vida em idosos, fase em que ocorre aperda de massa muscular (sarcopenia). O objetivo deste trabalho foi analisar aspectos celulares e moleculares, através de técnicas morfológicas e moleculares, dos músculos Sóleo (SOL) e Extensor Longo dos Dedos (EDL) de ratos jovens e senis (21 e 540 dias) provenientes de mães alimentadas com uma dieta de baixo conteúdo protéico (6%) durante a gestação e lactação. Foram utilizados Ratos Sprague Dawley aos 21 e 540 dias, provenientes de dois grupos de genitoras submetidas a diferentes dietas (hipoproteica: 6% e padrão: 17% de proteína) durante toda a gestação e lactação. Amostras dos músculos SOL e EDL foram coletadas para as análises morfológica, imunofluoerescência e moleculares. Nossos resultados demonstraram que os animais do grupos restritos apresentaram menor peso em ambos os períodos comparado aos animais dos grupos controles. O músculo SOL apresentou diminuição da área de secção transversal (AST) das fibras musculares aos 21 e 540 dias, enquanto o músculo EDL apresentou diminuição da AST apenas aos 21 dias; nenhuma alteração na frequência dos tipos de fibras musculares foi observada nos músculos e nos períodos analisados. Aos 21 dias não foram observadas diferenças na expressão gênica dos marcadores avaliados nos músculos SOL e EDL. Aos 540 dias, no músculo SOL, houve aumento na expressão do gene IGF-1, enquanto no músculo EDL, o MRF MyoG, apresentou expressão gênica diminuída. As vias alteradas na senilidade decorrentes da restrição proteica perinatal apontadas pelas análises dos transcriptoma envolvem a proliferação e diferenciação celular durante a embriogênese, o metabolismo de lipídeo, integridade da matriz extracelular, citoesqueleto e junção neuromuscular. A restrição proteica durante a gestação e lactação interfere na manutenção do peso corporal durante a fase juvenil e na senilidade e promove hipotrofia muscular aos 21 nos músculos SOL e EDL, obsevada também aos 540 dias no músculo SOL. Os dados do transcriptoma sugerem uma adaptação (proteção) dos músculos SOL e EDL à condição de restrição proteica perinatal durante a senilidade.
Nutritional restriction during gestation and lactation can cause physiological adaptations in the fetus (fetal programming), being related to risks of cardiovascular and metabolic diseases, as well as muscular changes in adults. Muscle impairment may cause future consequences in the individual's life, given the relevance of this tissue in the generation of strength and locomotion, as well as, the longevity and quality of life in the elderly where muscle loss occurs (sarcopenia). The objective of this work is to analyze cellular and molecular aspects of SOL and EDL muscles of young and senile rats (21 days and 540 days) from mothers fed with a diet of low protein content (6%) during gestation and lactation. Sprague-Dawley rats were used at 21 and 540 days from two groups of mothers submitted to different diets (hypoproteic: 6% and standard: 17% protein) throughout gestation and lactation. Samples of SOL and EDL muscles were collected for morphological, immunofluorescence and molecular analyzes. Our results showed that the animals in the restricted groups had lower weight in both periods compared to the animals of the control groups. The SOL muscle showed a decrease in the cross-sectional area (CSA) of the muscle fibers at 21 and 540 days, whereas the EDL muscle presented a decrease of CSA only at 21 days; no change in the frequency of muscle fiber types was observed in the muscles and in the periods analyzed. At 21 days no differences were observed in the gene expression of the markers evaluated in the SOL and EDL muscles. At 540 days, in the SOL muscle, there was an increase in IGF-1 gene expression, while in the EDL muscle, the MyoG MRF showed decreased gene expression. The altered senile pathways due to perinatal protein restriction indicated by the transcriptome analysis involve cell proliferation and differentiation during embryogenesis, lipid metabolism, extracellular matrix integrity, cytoskeleton and neuromuscular junction. Protein restriction during gestation and lactation interferes with maintaining body weight during the juvenile phase and senility, promotes muscular hypotrophy at 21 in the SOL and EDL muscles, also seen at 540 days in the SOL muscle. The transcriptome data suggest an adaptation (protection) of the SOL and EDL muscles to the condition of perinatal protein restriction during senility.
Nutritional restriction during gestation and lactation can cause physiological adaptations in the fetus (fetal programming), being related to risks of cardiovascular and metabolic diseases, as well as muscular changes in adults. Muscle impairment may cause future consequences in the individual's life, given the relevance of this tissue in the generation of strength and locomotion, as well as, the longevity and quality of life in the elderly where muscle loss occurs (sarcopenia). The objective of this work is to analyze cellular and molecular aspects of SOL and EDL muscles of young and senile rats (21 days and 540 days) from mothers fed with a diet of low protein content (6%) during gestation and lactation. Sprague-Dawley rats were used at 21 and 540 days from two groups of mothers submitted to different diets (hypoproteic: 6% and standard: 17% protein) throughout gestation and lactation. Samples of SOL and EDL muscles were collected for morphological, immunofluorescence and molecular analyzes. Our results showed that the animals in the restricted groups had lower weight in both periods compared to the animals of the control groups. The SOL muscle showed a decrease in the cross-sectional area (CSA) of the muscle fibers at 21 and 540 days, whereas the EDL muscle presented a decrease of CSA only at 21 days; no change in the frequency of muscle fiber types was observed in the muscles and in the periods analyzed. At 21 days no differences were observed in the gene expression of the markers evaluated in the SOL and EDL muscles. At 540 days, in the SOL muscle, there was an increase in IGF-1 gene expression, while in the EDL muscle, the MyoG MRF showed decreased gene expression. The altered senile pathways due to perinatal protein restriction indicated by the transcriptome analysis involve cell proliferation and differentiation during embryogenesis, lipid metabolism, extracellular matrix integrity, cytoskeleton and neuromuscular junction. Protein restriction during gestation and lactation interferes with maintaining body weight during the juvenile phase and senility, promotes muscular hypotrophy at 21 in the SOL and EDL muscles, also seen at 540 days in the SOL muscle. The transcriptome data suggest an adaptation (protection) of the SOL and EDL muscles to the condition of perinatal protein restriction during senility.
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Palavras-chave
Restrição proteica, Envelhecimento, Músculo esquelético, Protein restriction, Aging, Skeletal muscle