title: Maternal postnatal high-fat diet, rather than gestational diet, affects morphology and mTOR pathway in skeletal muscle of weaning rat.
abstract: The positive regulation of insulin pathway in skeletal muscle results in increased activity of the mammalian target of rapamycin (mTOR), a positive effector of mRNA translation rate and protein synthesis. Studies that assess the activity of this protein in response to chronic high-fat diet (HFD) are scarce and controversial, and to date, there are no studies evaluating the mTOR pathway in infants exposed to gestational and postgestational HFD. This study investigated the effect of maternal HFD on skeletal muscle morphology and on phosphorylation of proteins that comprise the intracellular mTOR signaling pathway in soleus muscle of offspring at weaning. For this purpose, 10 days prior to conception, 39 female Wistar rats were randomly assigned to either control diet (CTL) or HFD. Later, rats were distributed into four groups according to gestational and postpregnancy diet: CTL/CTL (n=10), CTL/HF (n=11), HF/HF (n=10) and HF/CTL (n=8). After 21 days of lactation, pups were killed, and blood samples and soleus and gastrocnemius skeletal muscle were collected for analysis. We observed an influence of maternal postgestational diet, rather than gestational diet, in promoting an obese phenotype, characterized by body fat accumulation, insulin resistance and high serum leptin, glucose, triglycerides and cholesterol levels (P<.05). We have also detected alterations on skeletal muscle morphology--with reduced myofiber density--and impairment on S6 kinase 1 and 4E binding protein-1 phosphorylation (P<.05). These results emphasize the importance of maternal diet during lactation on muscle morphology and on physiological adaptations of infant rats.
authors: Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, Brazil. lucascp@usp.br
authors: Lucas C
authors: LC
authors: Pantaleão
authors: Gabriela F R
authors: GF
authors: Teodoro
authors: Francisco L
authors: FL
authors: Torres-Leal
authors: Daiana
authors: D
authors: Vianna
authors: Tatyana D
authors: TD
authors: de Paula
authors: Emídio M
authors: EM
authors: de Matos-Neto
authors: Michele C C
authors: MC
authors: Trindade
authors: Marcelo M
authors: MM
authors: Rogero
authors: Carlos R
authors: CR
authors: Bueno
authors: Julio
authors: J
authors: Tirapegui
mesh_terms: D000818:Animals; D001823:Body Composition; D004041:Dietary Fats / Q000008:administration & dosage*; D005260:Female; D007333:Insulin Resistance; D008098:Litter Size; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000378:metabolism*; D011247:Pregnancy; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D014886:Weaning
chemical_list: D004041:Dietary Fats; C546845:mTOR protein, rat; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases