The Effect of Growth Restriction on Voluntary Physical Activity Engagement in Mice

Abstract

Introduction The purpose of this study was to determine the effect of growth restriction on the biological regulation of physical activity. Methods Using a cross-fostering, protein-restricted nutritive model, mice were growth-restricted during either gestation (GUN; N = 3 litters) or postnatal life (PUN; N = 3 litters). At 21 d of age, all mice pups were weaned and fed a nonrestrictive healthy diet for the remainder of the study. At 45 d of age, mice were individually housed in cages with free moving running wheels to assess physical activity engagement. At day 70, mice were euthanized, and the nucleus accumbens was analyzed for dopamine receptor 1 expression. Skeletal muscle fiber type and cross-sectional area of the soleus, extensor digitorom longus, and diaphragm were analyzed by immunohistochemistry. The soleus from the other hindleg was evaluated for calsequestrin 1 and annexin A6 expression. Results The PUN female mice (15,365 ± 8844 revolutions per day) had a reduction (P = 0.0221) in wheel revolutions per day as compared with the GUN (38,667 ± 8648 revolutions per day) and CON females (36,421.0 ± 6700 revolutions per day). The PUN female mice also expressed significantly higher dopamine receptor 1 compared (P = 0.0247) to the other groups. The PUN female soleus had a higher expression of calsequestrin 1, along with more type IIb fibers (P = 0.0398). Conclusions Growth restriction during lactation reduced physical activity in female mice by reducing the central drive to be active and displayed a more fatigable skeletal muscle phenotype.

Postnatal Growth Restriction in Mice Alters Cardiac Protein Composition and Leads to Functional Impairment in Adulthood

“…The PGR group had impairments in global cardiac function and mass (LV mass, stroke volume, cardiac output, myocardial performance index [MPI]), and diminished diastolic/systolic function (prolonged isovolumetric contraction/relaxation) in adulthood. These findings support the existing DOHaD literature, which has shown that PGR in mice impairs functional capacity of the heart, calcium flux, and exercise capacity, leading to an increased risk for CVD and mortality in adulthood [12,15,17,23,24,[28][29][30][31][32][33][34][35][36][37].…”

Physical Activity Engagement Worsens Health Outcomes and Limits Exercise Capacity in Growth-restricted Mice

“…Starting at PN7, PUN pups displayed growth stunting and were 18% smaller ( P < 0.001) than the CON and GUN mice into adulthood. These observations are consistent with the literature (6,9,11,16). At completion of the investigation (PN70) female mice were smaller than male mice within each diet group (Fig.…”

“…Echocardiography and Doppler analysis are reliable tools to diagnose fibrosis (43), but future investigations should quantify cardiac tissue fibrosis via histological methods. In addition, the present investigation did not observe differences in wheel running over 3 wk between groups, but both murine (16) and human studies (44) have shown that growth restriction reduces PA in adulthood. These studies examined PA in smaller increments (i.e., 7 d) as compared with the present investigation (21 d), indicating that frequency, intensity, and type of PA should be evaluated for health benefits.…”

The Effect of ACL Reconstruction on Involved and Contralateral Limb Vastus Lateralis Morphology and Histology: A Pilot Study

“…16 Sections were then stained for skeletal muscle histology using previously established methods. 17 Briefly, tissue sections were permeabilized with 0.5% Triton X-100/Phosphate-buffered saline, then washed and blocked with 4% Bovine serum albumin. Sections were then probed for cell membranes with Laminin (Sigma Aldrich), BA-D5 for type I fibers (Myosin heavy chain type I, Developmental Studies Hybridoma Bank), SC-71 for type IIa cells (Myosin heavy chain type IIa, Developmental Studies Hybridoma Bank), and type IIx fibers (Unstained) overnight at 4°C.…”