eCM (Eur Cell Mater / e Cells & Materials) eCM Open Access Scientific Journal
 ISSN:1473-2262         NLM:100973416 (link)         DOI:10.22203/eCM

2014   Volume No 27 – pages 39-49

Title: Fatigue failure of osteocyte cellular processes: implications for the repair of bone

Author: C Dooley, D Cafferky, TC Lee, D Taylor

Address: Centre for Microscopy and Analysis, Trinity College Dublin, Dublin 2, Ireland

E-mail: dooleycl at tcd.ie

Key Words: Osteocytes; Microcracks; Cell fatigue failure; Osteocyte fatigue failure; Scissors model; Bone remodelling.

Publication date: January 25th 2014

Abstract: The physical effects of fatigue failure caused by cyclic strain are important and for most materials well understood. However, nothing is known about this mode of failure in living cells. We developed a novel method that allowed us to apply controlled levels of cyclic displacement to networks of osteocytes in bone. We showed that under cyclic loading, fatigue failure takes place in the dendritic processes of osteocytes at cyclic strain levels as low as one tenth of the strain needed for instantaneous rupture. The number of cycles to failure was inversely correlated with the strain level. Further experiments demonstrated that these failures were not artefacts of our methods of sample preparation and testing, and that fatigue failure of cell processes also occurs in vivo. This work is significant as it is the first time it has been possible to conduct fatigue testing on cellular material of any kind. Many types of cells experience repetitive loading which may cause failure or damage requiring repair. It is clinically important to determine how cyclic strain affects cells and how they respond in order to gain a deeper understanding of the physiological processes stimulated in this manner. The more we understand about the natural repair process in bone the more targeted the intervention methods may become if disruption of the repair process occurred. Our results will help to understand how the osteocyte cell network is disrupted in the vicinity of matrix damage, a crucial step in bone remodelling.


Article download: Pages 39-49 (PDF file)
DOI: 10.22203/eCM.v027a04