Maternal protein restriction changes skeletal muscle metabolism and structural gene expression in aging rats

We intended to evaluate the phenotypic characteristics of the muscle microenvironment, involving muscle fiber and extracellular matrix, in skeletal muscle of elderly rats, at 540 days, arising from maternal protein restriction. Maternal protein restriction affects the postnatal skeletal muscle physiology with effects lasting until senility. Considering the different muscle adaptations after maternal protein restriction observed in previous studies, transcriptomic analysis has proven to be an excellent strategy to understand the impacts of fetal programming on skeletal muscle. To investigate the morphological, metabolic, and molecular characteristics of skeletal muscle in aged rats subjected to maternal protein restriction, we used aged male rats (540 days old) born from dams fed with protein restricted diet (6% protein) during gestation and lactation. Using molecular and morphological techniques, we evaluated the Soleus (SOL) and Extensor Digitorum Longus (EDL) muscles. Muscle fiber crosssectional area (CSA) was measured and gene expression of oxidative (Succinate Dehydrogenase-Sdha and Citrate Synthase-CS) and glycolytic (Lactate Dehydrogenase-Ldha) markers were evaluated by RT-qPCR. Global transcriptome analysis also was performed to identify deregulated genes, following the RT-qPCR validation. The oxidative SOL muscle displayed decrease in muscle fiber CSA and in the expression of oxidative metabolism marker, up-regulation of anabolic Igf-1, structural Chad, and Fmod gene, and down-regulated Hspb7 gene. The glycolytic EDL muscle had no changes in muscle fiber CSA and in expression of oxidative metabolism genes, while the gene expression of Chad was up-regulated and Myog gene was down-regulated. Collectively, our data show that maternal protein restriction induced changes in the expression of metabolic, anabolic, myogenic and structural genes, mainly in oxidative SOL muscle, in aged offspring rats.