Noninvasive loading of the murine tibia: An in vivo model for the study of mechanotransduction

Sundar Srinivasan, Ted S. Gross, Steven D. Bain, Chung C. Liu, Thomas L. Clemens

Research output: Contribution to journalArticle

Abstract

Transgenic and knockout mice present a unique opportunity to study mechanotransduction pathways in vivo, but the difficulty inherent with applying externally controlled loads to the small mouse skeleton has hampered this approach. We have developed a novel device that enables the noninvasive application of controlled mechanical loads to the murine tibia. Calibration of tissue strains induced by the device indicated that the normal strain environment was repeatable across loading bouts. Two in vivo studies were performed to show the usefulness of the device. Using C57B1/6J mice, we found that dynamic but not static loading increased cortical bone area. This result is consistent with previous models of bone adaptation, and the lack of adaptation induced by static loading serves as a negative control for the device. In a preliminary study, transgenic mice selectively overexpressing insulin-like growth factor 1 (IGF-1) in osteoblasts underwent a low-magnitude loading regimen. Periosteal bone formation was elevated 5-fold in the IGF-1-overexpressing mice but was not elevated in wild-type littermates, showing the potential for synergism between mechanical loading and selected factors. Based on these data, we anticipate that the murine tibia-loading device will enhance assessment of mechanotransduction pathways in vivo and, as a result, has the potential to facilitate novel gene discovery and optimization of synergies between drug therapies and mechanical loading.

Original languageEnglish (US)
Pages (from-to)493-501
Number of pages9
JournalJournal of Bone and Mineral Research
Volume17
Issue number3
StatePublished - Jan 1 2002
Externally publishedYes

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Keywords

  • Bone formation
  • Insulin-like growth factor 1
  • Mechanical loading
  • Mechanotransduction
  • Mice

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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