ASGSB 1998 Annual Meeting Abstracts

[16]
INITIAL RESULTS OF EXPERIMENTS WITH OSTEOBLASTS CULTURED UNDER HYPERGRAVITY CONDITIONS. M.A. Kacena^1,2, P. Todd³, and W.J. Landis¹. ¹Dept. of Orthopedics, Harvard Medical School and Children’s Hospital, Boston, MA, and ²Depts. of Aerospace Engineering and ³Chemical Engineering, University of Colorado and BioServe Space Technologies, Boulder, CO.

To understand further the role of gravity in bone growth or loss, 17-day-old embryonic chick calvarial osteoblasts were subjected to high gravitational forces at the Hypergravity Facility for Cell Culture (HyFaCC) at NASA/Ames Research Center, Moffett Field, CA. Osteoblasts, grown in DME, 10% FBS, 12.5 µg/ml ascorbate and 10 mM -glycerophosphate and attached to type I collagen-coated coverslips, were loaded into Fluid Processing Apparatus (FPA) units. Other osteoblasts were grown in 35 and 100 mm culture dishes. FPA units and dishes were placed in incubators (37^oC, 5% CO₂) and exposed to 3.3 G or 4.0 G on a 9 foot centrifuge arm of the HyFaCC or maintained as controls at 1.0 G. Cells under the various G conditions were collected at 0 and 3 hrs and 2, 4 and 6 days (interval sampling 1 hr every 2 days), and they were processed for Northern blot analysis, immunohistochemistry and electron microscopy. Results to date indicate: (1) By 2 days, scanning and transmission microscopy of all FPA units suggest osteoblasts have spread in centrifuged samples greater than in counterpart controls and contain more vacuoles and cellular debris; and (2) immunochemistry of all 35 mm centrifuged and control culture dish samples at all times shows f-actin, tubulin, vinculin, fibronectin and talin but no detectable differences among experimental and control paired groups. Northern blotting analysis remains. While preliminary, these data reveal changes in osteoblast size, shape and cytoplasmic structure following hypergravity exposure. Such alteration could be correlated with possible changes in cytoskeletal elements and attachment proteins as well as in expression of genes critical to bone formation, whose complete analyses are yet to be determined.

(Supported by NASA grants: NGT-51421 and NAG5-4377.)

Back to Meeting Program