Preosteoblast production in COSMOS 2044 rats: short-term recovery of osteogenic potential.
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.
Garetto
L P
LP
Department of Orthodontics, Indiana University School of Dentistry, Indianapolis 46202.
Morey
E R
ER
Durnova
G N
GN
Kaplansky
A S
AS
Roberts
W E
WE
D000818:Animals; D001846:Bone Development / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D005881:Gingiva / Q000254:growth & development / Q000502:physiology; D007700:Kinetics; D008022:Ligaments / Q000254:growth & development / Q000502:physiology; D008297:Male; D010006:Osteoblasts / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013026:Space Flight; D013234:Stem Cells / Q000502:physiology