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Influence of increased mechanical loading by hypergravity on the microtubule cytoskeleton and prostaglandin E2 release in primary osteoblastsCells respond to a wide range of mechanical stimuli such as fluid shear and strain, although the contribution of gravity to cell structure and function is not understood. We hypothesized that bone-forming osteoblasts are sensitive to increased mechanical loading by hypergravity. A centrifuge suitable for cell culture was developed and validated, and then primary cultures of fetal rat calvarial osteoblasts at various stages of differentiation were mechanically loaded using hypergravity. We measured microtubule network morphology as well as release of the paracrine factor prostaglandin E2 (PGE2). In immature osteoblasts, a stimulus of 10x gravity (10 g) for 3 h increased PGE2 2.5-fold and decreased microtubule network height 1.12-fold without affecting cell viability. Hypergravity (3 h) caused dose-dependent (5-50 g) increases in PGE2 (5.3-fold at 50 g) and decreases (1.26-fold at 50 g) in microtubule network height. PGE2 release depended on duration but not orientation of the hypergravity load. As osteoblasts differentiated, sensitivity to hypergravity declined. We conclude that primary osteoblasts demonstrate dose- and duration-dependent sensitivity to gravitational loading, which appears to be blunted in mature osteoblasts.
Document ID
20050194247
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Searby, Nancy D.
(NASA Ames Research Center Moffett Field, CA United States)
Steele, Charles R.
Globus, Ruth K.
Date Acquired
August 23, 2013
Publication Date
July 1, 2005
Publication Information
Publication: American journal of physiology. Cell physiology
Volume: 289
Issue: 1
ISSN: 0363-6143
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other

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