Osteoblasts Subjected To Spaceflight And Simulated Space Shuttle Launch Conditions
acceleration; bone cells; bone-formation; Cell Biology; cells; Developmental Biology; differentiation; flight; gene-expression; growing rats; in-vitro; messenger-rna expression; microgravity; vibration; weightlessness
To understand further the effects of spaceflight on osteoblast-enriched cultures, normal chicken calvarial osteoblasts were flown aboard shuttle flight STS-77, and the total number of attached cells was determined. Spaceflight and control cultures were chemically fixed 3 h and 3 d after launch. These fixed cultures were processed for scanning electron microscopy (SEM). The SEM analysis showed that with just 3 d of exposure to spaceflight, coverslip cultures contained 300 +/- 100 cells/mm(2), whereas 1G control samples contained a confluent monolayer of cells (2400 +/- 200 cells/mm(2)). Although the cultures flown in space experienced a drastic decline in cell number in just 3 d, without further experimentation it was impossible to determine whether the decline was a result of microgravity, the harsh launch environment, or some combination of these factors. Therefore, this research attempted to address the effect of launch by subjecting osteoblasts to conditions simulating shuttle launch accelerations, noise, and vibrations. No differences, compared with controls, were seen in the number of total or viable cells after exposure to these various launch conditions. Taken together, these data indicate that the magnitude of gravitational loading (3G maximum) and vibration (7.83G rms maximum) resulting from launch does not adversely affect osteoblasts in terms of total or viable cell number immediately, but launch conditions, or the microgravity environment itself, may start a cascade of events that over several d contributes to cell loss.
Kacena M A; Todd P; Landis W J
In Vitro Cellular & Developmental Biology-Animal
2003
2003-11
Journal Article or Conference Abstract Publication
n/a
Histomorphometry of the embryonic avian growth plate by proton nuclear magnetic resonance microscopy
appearance; articular-cartilage; bone-formation; cartilage; chick; deposits; diffusion; Endocrinology & Metabolism; growth-plate; hyaline cartilage; mineral; morphology; mr-imaging characteristics; nuclear magnetic resonance microscopy; relaxation; sequences
Quantitative nuclear magnetic resonance (NMR) microscopy was used to characterize the biochemical and morphological properties of the different zones within the growth plate of an embryonic chick femur. For precalcified tissue, water proton transverse relaxation times (T-2) and magnetization transfer values (MT) were directly and inversely dependent, respectively, on tissue cellularity, defined as the intracellular area per unit area on histological sections. T-2 values extrapolated for intra- and extracellular water were 96 ms and 46 ms, respectively. The extracellular T-2 was comparable with that measured for mature cartilage. The MT values extrapolated for intra- and extracellular compartments were 0.32 and 0.85, respectively, These values were comparable with those values reported in the literature for cell pellets and for mature cartilage tissue. Thus, cellularity dominated the NMR properties of this immature cartilage tissue. Mineral deposits within calcified cartilage and periosteal bone invoked NMR relaxation processes that were dependent on the inorganic mineral phase; Additionally, collagen molecules present in mineralized zones gave rise to a significant MT effect. These results show the utility of water proton NMR microscopy for assessing both the organic and inorganic ph ases within mineralized tissues.
Potter K; Landis W J; Spencer R G S
Journal of Bone and Mineral Research
2001
2001-06
Journal Article
<a href="http://doi.org/10.1359/jbmr.2001.16.6.1092" target="_blank" rel="noreferrer noopener">10.1359/jbmr.2001.16.6.1092</a>