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Nutritionally‐induced neonatal muscle growth retardation can be rescued by sustained muscle IGF‐I expression
Author(s) -
Fiorotto Marta L,
Sosa Horacio A,
Davis Teresa A,
Villegas Carolina,
Estrada Irma J
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.265.6
Subject(s) - anabolism , endocrinology , medicine , weaning , hindlimb , skeletal muscle , wasting , biology , muscle mass , genetically modified mouse , transgene , chemistry , biochemistry , gene
Undernutrition prior to the attainment of maturation permanently compromises skeletal muscle mass. To determine if the loss in growth capacity can be overcome by precluding the developmental decline in local IGF expression, transgenic MLC/mIGF‐I mice with muscle‐specific IGF‐I overexpression were studied. From birth, nontransgenic (NTG) and transgenic (TG) littermates were suckled on NTG dams fed either a control 20 % (CP) or an 8% protein (LP) diet. At weaning all pups were fed the CP diet ad libitum and studied 0, 1, 3, and 17 wk later (n=7–9/age/genotype/diet). Hindlimb muscle masses at weaning were 20–25% smaller in all LP compared to CP pups (P<0.001); there was no protective effect of genotype. After 1 wk of refeeding, muscle mass of the LP TG and NTG pups were 6 and 20 % smaller, respectively than those of CP NTG pups. Over this week, food intake of TG and NTG LP pups were similar (2.98±0.08 g/d), but feed efficiency was higher in TG pups (0.39 and 0.33 g body weight/g food, respectively; pSD, 0.021; P<0.001). After 3 wk, muscle weights of LP TG pups were similar to those of CP NTG, and by 20 wk of age they were 20% heavier (P<0.001); LP NTG muscles remained 10% small than in CP NTG mice. The results indicate that the reduced muscle mass produced by undernutrition in early life is reversible provided appropriate anabolic stimuli are present during nutritional rehabilitation. (Supported by NIH AR46308 and USDA/ARS 6250‐51000‐043)