Prolonged performance of a high repetition low force task induces bone adaptation in young adult rats, but loss in mature rats

We have shown that prolonged repetitive reaching and grasping tasks lead to exposure-dependent changes in bone microarchitecture and inflammatory cytokines in young adult rats. Since aging mammals show increased tissue inflammatory cytokines, we sought here to determine if aging, combined with prolo...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Experimental gerontology 2015-12, Vol.72, p.204-217
Hauptverfasser: Massicotte, Vicky S., Frara, Nagat, Harris, Michele Y., Amin, Mamta, Wade, Christine K., Popoff, Steven N., Barbe, Mary F.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:We have shown that prolonged repetitive reaching and grasping tasks lead to exposure-dependent changes in bone microarchitecture and inflammatory cytokines in young adult rats. Since aging mammals show increased tissue inflammatory cytokines, we sought here to determine if aging, combined with prolonged performance of a repetitive upper extremity task, enhances bone loss. We examined the radius, forearm flexor muscles, and serum from 16 mature (14–18months of age) and 14 young adult (2.5–6.5months of age) female rats after performance of a high repetition low force (HRLF) reaching and grasping task for 12weeks. Young adult HRLF rats showed enhanced radial bone growth (e.g., increased trabecular bone volume, osteoblast numbers, bone formation rate, and mid-diaphyseal periosteal perimeter), compared to age-matched controls. Mature HRLF rats showed several indices of radial bone loss (e.g., decreased trabecular bone volume, and increased cortical bone thinning, porosity, resorptive spaces and woven bone formation), increased osteoclast numbers and inflammatory cytokines, compared to age-matched controls and young adult HRLF rats. Mature rats weighed more yet had lower maximum reflexive grip strength, than young adult rats, although each age group was able to pull at the required reach rate (4reaches/min) and required submaximal pulling force (30force-grams) for a food reward. Serum estrogen levels and flexor digitorum muscle size were similar in each age group. Thus, mature rats had increased bone degradative changes than in young adult rats performing the same repetitive task for 12weeks, with increased inflammatory cytokine responses and osteoclast activity as possible causes. •Prolonged performance of high repetition low force task by young adult rats induced adaptive bone remodeling in distal radial metaphysis.•Prolonged performance of high repetition low force task by mature rats induced detrimental effects on radial bone morphology.•This task lead to increased bone inflammatory cytokines and osteoclasts in mature task rat bones, at levels higher than in young adult task rats.•Prolonged performance of high repetition low task by mature rats may increase radial bone fracture risk.
ISSN:0531-5565
1873-6815
DOI:10.1016/j.exger.2015.10.014