ASGSB 2003 Annual Meeting Abstracts


MicroCT Analysis demonstrates OPG mitigates loss of spaceflight OSTEOPENIA IN proximal humerus of mice.  J.R. Milstead1, A.M. Miesse1, P.J. Kostenuik2, S. Morony2, V.L. Ferguson3, S.J. Simske3, D.L. Lacey2, T.A. Bateman1. 1Dept. of Bioengineering, Clemson Univ., Clemson, SC. 2Amgen Inc., Thousand Oaks, CA. 3BioServe Space Tech., Univ. of Colorado, Boulder.

   Mice treated with or without osteoprotegerin (OPG) were investigated to determine the effects of spaceflight (SF) on trabecular bone. C57BL/6J mice (n=12/group) were given an injection of OPG (20mg/kg, subcutaneously) or a placebo 24 hours prior to spending 12 days in orbit on Space Shuttle flight STS-108. Ground control (GC) mice (age and mass matched) were housed in either AEM or vivarium (VIV) caging, receiving similar treatments beginning 2 days post-launch.
   Trabecular bone of the proximal humerus was analyzed using micro computed tomography (Scanco), allowing bone structure and micro- architecture to be imaged at 15 micron resolution. SF had a significant effect on the properties of trabecular bone. SF trabecular thickness was less than both VIV and AEM controls, 8.5 (p<0.001) and 8.0% (p<0.001), respectively. SF also resulted in a 6.3% (p<0.05) decrease in trabecular number.
   OPG had a significant effect on both SF and GC groups. SF animals treated with OPG had a 39.9% (p<0.001) increase in trabecular density over SF/Placebo, while a 33.3% (p<0.001) and 64.8% (p<0.001) increase in trabecular density was observed for OPG/AEM and OPG/VIV groups over placebo groups, respectively. SF/OPG also had a 39.9% (p<0.05) increase in connective density as well as a 16.1% (p<0.001) increase in trabecular thickness over SF/Placebo groups. OPG GC group results were similar, with the AEM group exhibiting a 52.1% (p<0.05) increase in connective density, 8.2% (p<0.001) increase in trabecular thickness, and 9.9% (p<0.05) increase in trabecular number. OPG/VIV groups demonstrated a 122.6% (p<0.05) increase in connective density, 6.2% (p<0.001) increase in trabecular thickness, and a 20.0% (p<0.05) increase in trabecular number over VIV/placebo groups. This experiment demonstrates that OPG is effective at mitigating the deleterious effects of spaceflight on the mouse skeleton. (NASA/SC EPSCoR, Amgen, Inc.)


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