Journal of Applied Physiology, Vol 73, Issue 2 14S-18S, Copyright © 1992 by American Physiological Society
Preosteoblast production in COSMOS 2044 rats: short-term recovery of osteogenic potential
L. P. Garetto, E. R. Morey, G. N. Durnova, A. S. Kaplansky and W. E. Roberts
Department of Orthodontics, Indiana University School of Dentistry, Indianapolis 46202.
The influence of a 13.8-day spaceflight and approximately 8.5-11 h of
recovery at 1 g on fibroblast-like osteoblast precursor cells was assessed
in the periodontal ligament of rat maxillary first molars. Preosteoblasts
(C + D cells), less differentiated progenitor cells (A + A' cells), and
nonosteogenic fibroblast-like cells (B cells) were identified by nuclear
volume analysis (i.e., A + A' = 40-79 microns 3; B = 80-119 microns 3; C +
D greater than or equal to 120 microns 3). No differences were observed
among flight (F), synchronous (SC), vivarium, and basal control groups in
the A + A' (F: 28.0 +/- 3.7 vs. SC: 27.4 +/- 2.2), B (F: 33.1 +/- 1.4 vs.
SC: 32.4 +/- 2.4), or C + D (F: 38.4 +/- 4.5 vs. SC: 39.2 +/- 1.6) cell
compartments (mean +/- SE, n = 5). Compared with previous spaceflight
experiments, the present data are consistent with a postflight response to
replenish preosteoblasts and restore periodontal ligament osteogenic
potential. These data emphasize the need to 1) unequivocally determine the
flight effect by killing the animals in-flight and 2) further assess the
postflight recovery phenomenon.
