Spatial distribution of osteocyte lacunae in equine radii and third metacarpals

Considerations for cellular communication, microdamage detection and metabolism

John G. Skedros, Todd R. Grunander, Mark W Hamrick

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Osteocytes, which are embedded in bone matrix, are the most abundant cells in bone. Despite the ideal location of osteocytes to sense the local environment and influence bone remodeling, their functions, and the relative importance of these functions, remain controversial. In this study, we tested several hypotheses that address the possibilities that population densities of osteocyte lacunae (Ot.Lc.N/B.Ar) correlate with strain-, remodeling- or metabolism-related aspects of the local biomechanical environments of mid-third diaphyseal equine radii and third metacarpals from skeletally mature animals. Ot.Lc.N/B.Ar data, quantified in multiple cortical locations, were analyzed for possible correlations with (1) structural and material characteristics (e.g., cortical thickness, percent ash, secondary osteon population density, mean osteon crosssectional area, and predominant collagen fiber orientation), (2) strain characteristics, including prevalent/predominant strain magnitude and mode (tension, compression, shear), (3) hypothesized strain-mode-related microdamage characteristics, which might be perceived by osteocyte 'operational' networks, and (4) variations in remodeling dynamics and/or metabolism (i.e. presumably higher in endocortical regions than in other transcortical locations). Results showed relatively uniform Ot.Lc.N/B.Ar between regions with highly non-uniform strain and strain-related environments and markedly heterogeneous structural and material organization. These results suggest that population densities of these cells are poorly correlated with mechanobiological characteristics, including local variations in metabolic rate and strain magnitude/mode. Although osteocytes hypothetically evolved both as strain sensors and fatigue damage sensors able to direct the removal of damage as needed, the mechanisms that govern the distribution of these cells remain unclear. The results of this study provide little or no evidence that the number of osteocyte lacunae has a functional role in mechanotransduction pathways that are typically considered in bone adaptation.

Original languageEnglish (US)
Pages (from-to)215-236
Number of pages22
JournalCells Tissues Organs
Volume180
Issue number4
DOIs
StatePublished - Dec 15 2005

Fingerprint

Osteocytes
Metacarpal Bones
Horses
Population Density
Haversian System
Bone and Bones
Bone Matrix
Bone Remodeling
Fatigue
Collagen
Organizations

Keywords

  • Equine bone
  • Osteocyte lacunae
  • Third metacarpal

ASJC Scopus subject areas

  • Anatomy
  • Histology

Cite this

Spatial distribution of osteocyte lacunae in equine radii and third metacarpals : Considerations for cellular communication, microdamage detection and metabolism. / Skedros, John G.; Grunander, Todd R.; Hamrick, Mark W.

In: Cells Tissues Organs, Vol. 180, No. 4, 15.12.2005, p. 215-236.

Research output: Contribution to journalArticle

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